Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health

Abstract

The dual-continua model of mental health suggests that mental illness and positive mental health reflect distinct continua, rather than the extreme ends of a single spectrum. The aim of this review was to scope the literature surrounding the dual-continua model of mental health, to summarise the evidence, highlight the areas of focus for individual studies and discuss the wider implications of the model. A search was conducted in PsycINFO (n = 233), PsycARTICLES (n = 25), Scopus (n = 137) and PubMed (n = 47), after which a snowballing approach was used to scope the remaining literature. The current scoping review identified 83 peer-reviewed empirical articles, including cross-sectional, longitudinal and intervention studies, which found overall support for superior explanatory power of dual-continua models of mental health over the traditional bipolar model. These studies were performed in clinical and non-clinical populations, over the entire life-course and in Western and non-Western populations. This review summarised the evidence suggesting that positive mental health and mental illness are two distinct but interrelated domains of mental health; each having shared and unique predictors, influencing each other via complex interrelationships. The results presented here have implications for policy, practice and research for mental health assessment, intervention design, and mental health care design and reform.

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© 2020 Australia and New Zealand School of Government and the authors.
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Issue 1 | (2020)
Article | DOI: 10.21307/eb-2020-001
EVIDENCE BASE
Mental Health and/or Mental Illness: A Scoping Review of
the Evidence and Implications of the Dual-Continua Model
of Mental Health
Matthew Iasiello,1,
2*
Joep van Agteren1,
3
and Eimear Muir Cochrane2
1South Australian Health and
Medical Research Institute,
Lifelong Health Theme, Wellbeing
and Resilience Centre.
2Flinders University, College of
Nursing and Health Science.
3Flinders University, College of
Education, Psychology, and
Social Work.
Author contact: matthew.iasiello@
sahmri.com
Abstract
The dual-continua model of mental health suggests that mental
illness and positive mental health reflect distinct continua, rather than
the extreme ends of a single spectrum. The aim of this review was to
scope the literature surrounding the dual-continua model of mental
health, to summarise the evidence, highlight the areas of focus for
individual studies and discuss the wider implications of the model. A
search was conducted in PsycINFO (n = 233), PsycARTICLES (n = 25),
Scopus (n = 137) and PubMed (n = 47), after which a snowballing
approach was used to scope the remaining literature. The current
scoping review identified 83 peer-reviewed empirical articles,
including cross-sectional, longitudinal and intervention studies, which
found overall support for superior explanatory power of dual-continua
models of mental health over the traditional bipolar model. These
studies were performed in clinical and non-clinical populations, over
the entire life-course and in Western and non-Western populations.
This review summarised the evidence suggesting that positive mental
health and mental illness are two distinct but interrelated domains of
mental health; each having shared and unique predictors, influencing
each other via complex interrelationships. The results presented here
have implications for policy, practice and research for mental health
assessment, intervention design, and mental health care design and
reform.
Eaton (1951) proposed that mental health ‘merges
imperceptibly and gradually like the colours of the
spectrum into mental illness’ (as cited by Herron and
Trent, 2000). This description illustrates a bipolar
relationship between mental health and mental illness;
a relationship and assumption that underpins clinical
psychology and mental health care design (Keyes,
2005). The bipolar model implies that mental health
and mental illness reflect opposite ends of the same
continuum, where an individual ‘moves’ along the
continuum, away from mental illness and towards
mental health (Trent, 1992). In this model, individuals
are either mentally ill or presumed mentally healthy
(Keyes, 2005). As the aetiology and treatment of
mental illness were researched and progressed faster
than that of mental health, the existence of mental
health became virtually synonymous with the absence
of mental illness. As such, clinical psychology and
psychiatry have primarily focused on the reduction of
mental illness symptoms or psychopathology in order
to improve mental health.
While pervasive, the model is considered an
untested assumption, and the philosophical validity
of the model has been widely criticised. For instance,
many have disparaged the arbitrary point on the
continuum where illness transitions to health, the sex
and cultural differences that influence this arbitrary
point, the impossibility of ‘gaining’ mental health
(if it is defined as the absence/loss of illness), and
the futility of improving mental health whilst being

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Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health
diagnosed with a mental illness (Herron and Trent,
2000). Criticisms and rejection of the bipolar model
in the context of mental health were documented as
early as 1958 by Marie Jahoda (Jahoda, 1958) who
argued that the absence of disorder constituted an
insufficient criterion for mental health. Jahoda outlined
six dimensions of positive mental health, which would
later be operationalised via Carol Ryff’s work on
psychological wellbeing: autonomy, environmental
mastery, personal growth, positive relations with
others, purpose in life, and self-actualisation (Ryff,
1989). In combination with Ed Diener’s (1984)
research into subjective wellbeing, Ryff’s seminal
work brought the study of positive mental health into
mainstream social science (Keyes, 2013).
Drawing on the work of humanistic psychologists
such as Rogers and Maslow, the emergence of positive
psychology in the 2000’s formalised the paradigm shift
toward the promotion of mental health as something
separate to mental illness. Mental health or positive
mental health is since defined as the experience of
positive feelings or subjective wellbeing and functioning
fully or optimally (Huppert, 2005), encompassing
individual resources such as life satisfaction (Diener,
1984), positive emotions (Fredrickson, 2001), meaning
and purpose in life (Steger et al., 2006), resilience
(Bonanno, 2004), character strengths (Peterson and
Seligman, 2004), and interpersonal relationships (Reis
and Gable, 2003). While positive psychology has
brought more attention to the importance of positive
mental health, the main body of work did not focus
on the relationship between mental illness and mental
health, and has largely been conducted in isolation
from mental illness (Payton, 2009).
Dual-continua or dual-factor models of mental
health have been proposed by various authors as
an alternative to the bipolar model, postulating that
Figure 1: Diagrammatic representation of the bipolar (a) and dual-continua (b) models of mental
health.
mental illness and positive mental health reflect
distinct continua rather than the extreme ends of a
single spectrum; see Figure 1 for a schematic on both
models (Jahoda, 1958; Keyes and Lopez, 2002; Suldo
and Shaffer, 2008; Epp, 1988; Massé et al., 1998;
Greenspoon and Saklofske, 2001). In the dual-continua
model, mental health and mental illness are considered
related but distinct constructs, and individuals can
experience high levels of positive mental health even
with the diagnosis of a mental illness (Keyes, 2005).
A useful analogy for the dual-factor model can be
found in the relationship between positive and negative
affect. Positive and negative affect were initially
assumed bipolar opposites of each other. In-depth
statistical analysis of scores on positive and negative
affect measures however resulted in the finding that
positive and negative affect are in fact independent of
each other, despite their ‘logical’ bipolarity (Bradburn,
1969; Nowlis, 1965; Feldman Barrett and Russell,
1998). Similar to the discourse on positive and negative
affect, recent and emerging research indicates that
high levels of positive mental health assets are possible
despite psychopathology and mental illness diagnosis
(Goodman et al., 2018), and positive mental health can
be built in those with a diagnosed mental illness (Fava
et al., 1998; Seligman et al., 2006). A neural precedent
of the dual-continua model has been discovered,
and evidence suggests that positive emotions are
mediated by separate neural processes to negative
emotions, and likely serve distinct evolutionary
functions (Davidson, 2000; Fredrickson, 2001).
It has been proposed that widespread and
systematic adoption of the dual-continua model
would inspire significant reform to the mental health
care system, which may better prepare systems
for the overwhelming burden of mental illness (Vigo
et al., 2016). Herron and Trent (2000) interrogated the

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EVIDENCE BASE
dual-continua model from a range of philosophical
approaches, and concluded that it had five key
implications:
1. It allows a concept (mental health or mental
illness) to be described which is independent
of other concepts, and so can be tested and
measured independently;
2. It allows an individual to be mentally healthy
and mentally ill at the same time, and thus facil-
itates the creation of groups that are impossi-
ble under bipolar models;
3. It allows an individual to disclose information
about mental health while holding confidential
information about mental illness;
4. It provides new avenues for proactive rather
than reactive system design in mental health
promotion; and
5. It is less reliant on labour-intensive downstream
interventions and therefore can be more widely
applied.
Despite these apparently significant implications to
our mental healthcare system and its patients,
the validity of the dual-continua model has been
questioned by some. For instance, Huppert (2014)
argued that while it may be possible to periodically
experience flourishing in some mental illnesses such
as schizophrenia or personality disorder, it is hard to
imagine that an individual with severe depression or
anxiety (or common mental disorder) is capable of
flourishing. In light of the implications stated by Herron
and Trent (2000), the question therefore remains
whether the dual-factor model has higher utility and
explanatory power compared to bipolar models in
general, across different mental illnesses and within
different contexts and settings.
This review was designed to scope the scientific
literature investigating the validity of the dual-continua
model of mental health. This review will summarise
the evidence of the model, determine the main focus
areas in the literature, and collate the implications of
the included studies, with the aim of informing policy,
practice and future research.
Methods
This scoping review was designed to identify peer-
reviewed scientific articles which specifically tested
mental health and mental illness as two distinct
constructs and was based on the Joanna Briggs
Institute methodology (JBI, 2015). As noted by Payton
(2009), terminology and nomenclature remains an
impasse to progress in the field of mental health
research. Mental health, mental illness, distress and
wellbeing are often used interchangeably. Similarly,
various names for dual-continua models have been
proposed, including the dual-factor model, two-
factor, two-continua, the complete state model, and
complete mental health. Due to this non-specific
and imprecise taxonomy, it was determined that a
snowballing approach was the most appropriate way
to search the literature, first beginning with the studies
that specifically mention dual-continua or dual factor
model of mental health and then using reference list
screening to effectively scope additional literature.
For ease of reading, the current review uses the term
‘dual-continua model’ to describe the models.
A search was conducted in February 2019 of
four scientific databases (Pubmed, PyscINFO,
PsycARTICLES, and Scopus). The search strategy
included all known variations of the dual-continua
model (dual-continua, dual-continuum, dual-factor,
two-continua, two-continuum, two-factor, and
complete state) AND ‘model’ AND ‘mental health’.
Inclusion criteria included: (1) title, abstract, or
keywords explicitly mention or implicitly refer to the
dual-continua model of mental health, (2) the studies
utilized an empirical study design, and (3) the study
was published in a refereed journal in the English
language. Two reviewers independently screened
titles and abstracts, to determine preliminary inclusion
status before conducting a full-text screen. Inter-rater
reliability was calculated using SPSS v25 (k = 0.88).
Data extracted included: Author, year of
publication, aim of the study, study methodology,
sample size, geographical location of participants,
sex, age, types of participants, measurement tools
used for mental illness and positive mental health,
correlations between measurements (if available), key
study results relevant to the dual-continua model,
and implications of the results.
Data analysis was conducted in a two-stage
process, first, extracted data were organised into
groups based on either methodological or thematic
similarity (for research on the validity of the model and
implications of the model respectively). The extracted
data were then interpreted and analysed narratively.
Results
Search ow
The search terms across the four databases resulted
in 477 articles; PsycINFO (n = 233), PsycARTICLES
(n = 25), Scopus (n = 137), PubMed (n = 47). After
deduplication, 395 original articles were identified.
The most common reason for exclusion during the

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Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health
title and abstract screen was no clear reference to
a dual-continua model, despite referencing both
positive mental health and mental illness. The
comprehensive description of the screening process
is displayed in the PRISMA statement, which resulted
in 83 original articles to be included in the review
(Figure 2; Moher et al., 2009). The characteristics of
all included studies can be found in Table A1.
Design of included studies
The large majority of studies used an observational
design (n = 81). Sixty-six studies used a cross-
sectional study design using data stemming from
large population-level datasets or using data that was
gathered prospectively by the researchers. Sixteen
studies used a longitudinal observational design, with
follow-up ranging between one year and ten years.
One study used a mixed-methods design, while only
two studies used an experimental intervention design.
Countries
Most studies were conducted in the United States
of America (n = 31), Netherlands (n = 12), Australia
(n = 7), United Kingdom (n = 7), Canada (n = 6), China
(n = 3), Germa ny (n = 3), S outh Korea (n = 2), Russia
(n = 2), Italy (n = 2), and Poland (n = 2). Other countries
included Spain, Argentina, South Africa, Greece,
Sweden, Singapore, Portugal, Turkey, and Serbia.
Study samples and participant
characteristics
The study samples consisted of adults (n = 55), youth
(n = 23) or both (n = 5). Overall, most studies recruited
slightly higher percentage of females (between 50%
to 70%). Sample sizes varied between 0-100 (n = 3),
101-500 (n = 21), 501-1000 (n = 12), 1000-5000
(n = 23) and 5000+ (n = 15). Studies were conducted
in populations over the life course, with mean ages
ranging from 10.5 for the youngest population to 70.3
for the oldest population.
Most study participants were recruited from the
general non-clinical population. Thirteen studies
targeted participants with a (history of) mental illness,
specifically affective disorders (n = 6), substance use
disorder (n = 1), suicide ideation (n = 2), post-traumatic
stress disorder (n = 1), eating disorders (n = 1), or a
combination of mental disorders (n = 2). One study
looked at the application of a dual-continua model in
participants with various physical illnesses.
Figure 2: PRISMA flowchart of the study selection process.
Records identified through
database searching
(n = 442)
Additional records identified
through other sources
(n = 33)
Records after duplicates removed
(n = 395)
Records screened
(n = 395)
Records excluded
(n = 283)
Full-text articles assessed
for eligibility
(n = 112)
Full-text articles excluded
Non-empirical (n = 27)
Not in English (n = 2)
Studies included in
qualitative synthesis
(n = 83)

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EVIDENCE BASE
Elementary and high school students were used in
all but two studies (89%) that focused on application
of dual-factor models in youth. In contrast, only nine
adult-focused studies (18%) used student samples.
Other populations that were specifically targeted in
the recruitment included carers (n = 3), older adults
(n = 1), the LGBTQI community (n = 2), immigrants
(n = 1), siblings of those with a chronic illness or
disability (n = 1) and medical interns (n = 1).
Measures used
Measurement of positive mental health or flourishing
was most commonly conducted using the Satisfaction
with Life Scale (n = 21) or the Mental Health Continuum –
Short Form (MHC-SF) (n = 23), administered in a range
of languages including English, Dutch, Setswana,
Polish, Korean, Spanish, Portuguese, and Italian.
Five studies combined the use of Bradburn’s Positive
Affect Balance (Bradburn, 1969), Ryff’s Psychological
Wellbeing Scales (Ryff and Keyes, 1995), and Keyes
Social Wellbeing Scales (Keyes, 1998) to determine
the level of positive mental health, which are the same
scales that the MHC-SF is based on.
Other commonly used measures included Positive
and Negative Affect Schedule for adults or children
(n = 21), Psychological Wellbeing scale (n = 12), Student’s
Life Satisfaction Scale (n = 10), Bradburn’s Affect
Balance Scale (n = 7), Social Wellbeing Scale (n = 7), the
full or brief Multidimensional student’s life satisfaction
scale (n = 5), and Positive Mental health Scale (n = 4).
Mental illness or symptoms of mental illness
was most commonly measured using validated
scales assessing affective disorders (depression
and anxiety), via the Center for Epidemiologic
Studies Depression Scale (CES-D) (n = 11), Kessler
psychological distress scale (n = 1), Patient Health
Questionnaire (PHQ) (n = 3), Depression Anxiety
Stress Scale (DASS-21) (n = 6), Generalized Anxiety
Disorder Scale (GAD) (n = 3), Beck Depression
Inventory (BDI) (n = 2). Several studies screened for
minor or non-psychiatric disorders via the GHQ
(n = 10), or general psychopathology via the Symptom
Check List-90 (SCL-90) (n = 2) and Brief Symptom
Inventory (BSI) (n = 6). Other studies relied on clinical
interview diagnosis, using the Composite International
Diagnostic Interview (WHO-CIDI) (n = 9) or structured
interviews using DSM or ICD10 criteria (n = 2). A
range of studies in the youth context, used scales
that measure behavioural or emotional problems, or
problems with coping, as their proxy to mental illness,
for instance the Behavioural Assessment System for
Children (BASC), the Youth Self Report form of the
child behaviour checklist, the Reynolds adolescent
adjustment screening inventory (RAASI), or the Self-
Report Coping Scale (SRCS).
Few studies used unvalidated measures of
positive mental health or mental illness, which limited
the interpretability of their results. For example, some
studies (n = 4) used “positive items” of measures that
are normally used to measure mental illness, such
as the General health Questionnaire (GHQ). Less
commonly used scales, including single-item scales
can be found in Table A1.
Focus areas of studies
The main focus areas of included studies have been
collated and summarised below. The specific aims
and results of each individual study are available in
Tabl e A1.
Investigation of the dual-continua
model t
Reflecting the central aim of this review, the majority
of included studies focused on whether the
relationship between positive mental health and
mental illness reflect a single bipolar continuum or a
dual-continua. This was most commonly performed
using Confirmatory Factor Analysis; a statistical
technique to test the adequacy of a theorised model
to represent the data. Three models were commonly
tested, single axis (or bipolar), two orthogonal factors
(independent and distinct factors), and two oblique
factors (independent and related factors), displayed
in Figure 3. It was consistently found that the data
best fit the two-factor oblique model, indicating that
positive mental health and mental illness represent two
separate constructs which share a degree of overlap
(Magalhaes and Calheiros, 2017; Massé et al., 1998;
Winzer et al., 2014; Kim et al., 2014; Keyes, 2005).
The analysis was usually performed in the context
of measurement tool validation, in particular validating
the MHC-SF (Lim, 2014; Lamers et al., 2011; Petrillo
et al., 2015; Lupano Perugini et al., 2017; Karas
et al., 2014; Keyes et al., 2008), with other studies
investigating the MHI (Heubeck and Neill, 2000; Veit
and Ware, 1983), or the potential appropriateness of
using the GHQ to capture positive mental health and
mental illness (Hu et al., 2007).
Validating sub-groups within
dual-continua model
A second focus area of the included studies was to
determine whether participant responses on positive
mental health and mental illness measures could

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Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health
Figure 3: The three commonly tested models in Confirmatory Factor Analysis used to test the
best model fit for the data: Single axis, which would indicate the bipolar model (a), two
orthogonal factors, independent and distinct (b), and two oblique factors, independent and
related (c). PMH = Positive mental health, MI = mental illness, MH = mental health. Circles
indicate latent constructs, and boxes indicate survey items.
lead to the identification of distinct groups within
the dual-continua model. Many studies divided their
participants into four groups: ‘Complete mental
health’ (no mental illness, high positive mental
health), ‘Vulnerable’ (low mental illness, low positive
mental health), ‘Symptomatic but content’ (high
mental illness, high mental health), and ‘Struggling’
(high mental illness, low mental health), displayed in
Figure 4. The exact descriptors of each group used
in the included studies varied, often depending on
Figure 4: Sub-groups of mental health, as postulated by dual-factor models. Keyes’ (Keyes,
2005) terminology to describe the groups is used in throughout this paper to highlight the four
mental health groups: ‘Complete Mental Health’ (no mental illness, high positive mental health),
‘Vulnerable’ (no mental illness, low positive mental health), ‘Symptomatic but content’ (mental
illness, high positive mental health), and Struggling (mental illness, low positive mental health).

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EVIDENCE BASE
the theoretical background preferred by the authors
(Keyes, 2005; Suldo and Shaffer, 2008; Greenspoon
and Saklofske, 2001). For ease of reading, we will use
Keyes’ terminology throughout the current review
and attached appendices. The apparent validity of
these sub-groups was often tested by contrasting
sub-group performance on a range of psychological,
behavioural, or physical outcomes.
Expanding on this were a small number of
longitudinal studies that focused on the stability of
group members over time, with the aim of determining
whether: (1) current levels of positive mental health
influence future scores of measures of mental illness, (2)
change in levels of positive mental health influence future
scores of measure of mental illness, and (3) whether
specific sub-groups are more transient or stable than
others (Xiong et al., 2017; Kelly et al., 2012; Lamers et al.,
2015; Wood and Joseph, 2010; Grant et al., 2013).
Differential predictors of mental
illness and positive mental health and
correlations with other key outcomes
A third area of focus of included studies was to
determine whether positive mental health and mental
illness were associated with different predictors
and variables, and whether they were associated
with positive or negative outcomes. This was often
performed for two reasons, either to establish
whether positive mental health and mental illness
are predicted by different factors (supporting the
claim that they are distinct constructs), or to assess
whether measures of mental illness or mental health
were differentially associated with other psychological
or behavioural resources or outcomes (to maximise
explanatory power of measurement tools). Examples
of specific resources or outcomes that where studied
included curiosity (Jovanovic and Brdaric, 2012),
personality (Lyons et al., 2013; Spinhoven et al., 2015;
Lamers et al., 2012), self-efficacy (Schonfeld et al.,
2016), health-risk behaviour (Venning et al., 2013),
genetics (Bartels et al., 2013), risk of cardiovascular
disease (Keyes, 2004), coping (Kinderman et al.,
2015), positive psychology constructs, and general
socio-demographic variables (Westerhof, 2013;
Weich et al., 2011; Westerhof and Keyes, 2010;
Huppert and Whittington, 2003).
Studies including youth, high school and university
students focused on determining the differential
associations between mental illness, positive
mental health, and educational, behavioural, and
developmental outcomes (Rose et al., 2017; Suldo
and Shaffer, 2008; Suldo et al., 2016; Lyons et al.,
2013; Antaramian, 2011; Magalhaes and Calheiros,
2017; Renshaw and Cohen, 2014; Eklund et al.,
2011). Examples of these outcomes included grade
point average, suspension rates, social adjustment,
self-efficacy beliefs, identity development, social
support, and school bonding.
The association with predictors and outcomes
was also studied in a range of specific and at-risk
populations such as carers (Pruchno et al., 1996;
Smith, 1996), older adults (Jiang and Lu, 2018),
chronically ill people and their siblings (Hallion et al.,
2018; Fontana et al., 1980), LBGT community (Peter,
2018; Bariola et al., 2017), migrants (du Plooy et al.,
2018), minority populations (Rose et al., 2017), and for
specific mental illness diagnoses (Baiden and Fuller-
Thomson, 2016; Seow et al., 2016; Fuller-Thomson
et al., 2016; Spinhoven et al., 2015; Van Erp Taalman
Kip and Hutschemaekers, 2018; Franken et al., 2018;
Diaz et al., 2017; Teismann et al., 2018).
Impact of interventions
A final area of focus was to determine the effect of
interventions on me asures of mental illness and posi tive
mental health, in the context of the dual-continua
model. Bohlmeijer et al. (2015) assessed the efficacy
of ACT on flourishing in depressed participants and
showed that it was possible to improve the level of
positive mental health in those with a mental illness.
Trompetter et al. (2017) investigated the differential
impact of Acceptance and Commitment Therapy
(ACT) on positive mental health and mental illness
for patients who were being treated for anxiety and
depression. This statistical approach revealed that
64% of the participants improved on either positive
mental health or anxiety symptoms post-intervention
and 72% improved in either depressive symptoms or
positive mental health.
Implications of the dual-continua model
The implications of the dual-continua model were
often explicitly discussed in the studies included in
this review. The implications extracted from each
study are available in Table A1 and were narratively
categorised into three broad themes. The first theme
of implications involves the measurement approaches
to determine mental health and mental illness status,
and whether assessment of mental health should
include measures of both positive mental health
and mental illness. The second theme related to
intervention design, delivery, and implementation.
This was discussed in the context of treatment
and prevention of mental illness, as well as the
promotion of positive mental health. The final theme

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Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health
of implications of the dual-continua model centred on
the opportunities that the model presents to mental
health care reform. This discourse included a re-
orientation from deficit- or illness-focused services
to strength-focused ones, re-conceptualising how
mental health is portrayed to reduce stigma of illness,
and the inclusion of services specifically focused
on improving positive mental health as an early
intervention or preventative approach.
Discussion
This scoping review identified a considerable body
of empirical research investigating the validity of the
dual-continua model, and the overarching notion that
positive mental health and mental illness represent
two distinct, yet related, constructs.
Evidence supporting the
dual-continua model
The evidence found by the majority of the included 83
studies supports the existence of the dual-continua
model. A large proportion of studies used CFA to
compare whether the data best fit a bipolar model or
the two variations of the dual-continua model (where
mental illness and positive mental health are either
independent of each other or share a degree of overlap;
Figure 2). Studies consistently found that the data
best fit the ‘two oblique factor’ model, indicating that
mental illness and positive mental health are distinct
but related. This finding was replicated across cultures,
sex, age, and using different measures of positive
mental health and mental illness, thereby supporting
the general validity of the dual-continua model (Franken
et al., 2018; Petrillo et al., 2015; Keyes et al., 2008).
Another common approach to test the validity
of the dual-continua model was to analyse whether
various drivers, predictors, or outcomes related
similarly to mental illness and positive mental health.
This was often done by splitting participants into
sub-groups (Figure 4). This approach was used to
indicate that the sub-groups existed, and that it was
possible for individuals to report high levels of positive
mental health despite mental illness. The existence
of these sub-groups was validated by the consistent
finding that the groups performed differently across
a broad range of psychological and behavioural
resources and outcomes. Other studies adopted
a more rigorous approach and investigated the
predictors that were associated with mental illness
and positive mental health using regression analysis.
This was best exemplified by Kinderman et al. (2015)
who showed that different individual and social
factors differentially influence positive mental health
and mental illness.
Most of this research was cross-sectional,
supported by a smaller number of longitudinal studies.
Findings consistently demonstrated that positive
mental health and mental illness differentially predict
various outcomes (Du Plooy et al., 2018; Kinderman
et al., 2015). In general, it was found that the absence
of illness was not sufficient to predict various
desirable outcomes such as academic achievement
and interpersonal relationship quality, which were
predicted by high levels of or improvements in positive
mental health (Suldo and Shaffer, 2008). The fact that
mental illness and positive mental health predict or
explain different outcomes was a strong indication
that the constructs are distinct, and the fact that there
was some overlap points to the constructs sharing
some degree of overlap.
Generalisability of the evidence
There was a great degree of variety in the
methodology of the studies included in this review,
indicating a considerable degree of confidence
in the generalisability of the support of the dual-
continua model. The studies were conducted
in twenty Western and non-Western countries,
indicating that the evidence presented is not culturally
specific. The most common method of participant
sampling was through population-level survey data,
producing nationally representative data which has
low risk of sampling bias (Banerjee and Chaudhury,
2010). Although this approach ensures appropriate
representation across sex and age, there is a possible
underrepresentation of groups that are usually
excluded from population-level surveys, for instance
the most elderly, homeless people, and mental health
inpatients. The evidence provided by studies using
population-level surveys was supported by a range
of studies that specifically recruited minority and
at-risk groups, as well as participants with various
degrees of mental illness, increasing confidence in
the generalisability of the results across societies.
Studies relied on a broad spectrum of validated
measurement tools, reducing potential bias
introduced by using a specific measurement tool
(Egloff, 1998). Mental illness was measured using
validated self-report tools designed to measure
various disorders continuously, including depression,
anxiety, and general psychopathology. Studies using
these measures were complemented by research
that relied on assessment using clinical interviews
(e.g. using CIDI or based on DSM-IV criteria), instilling
a high degree of confidence that the dual-factor

9
EVIDENCE BASE
model is not merely a statistical phenomenon of a
particular measurement design.
Similarly, positive mental health assessment
relied on assessment using a number of validated
measures, targeting different constructs ranging from
satisfaction with life and positive affect, to overall
flourishing, social wellbeing and psychological well-
being. Many articles included in this review were
validation papers of the MHC-SF, consistently finding
good internal consistency and validity. Unlike all other
continuous measures of positive mental health, the
MHC-SF is particular because it can be used to
either measure positive mental health continuously
or to categorically ‘diagnose’ flourishing similar to the
DSM-V protocol. Generally, the continuous approach
was used in confirmatory factor analysis, while the
categorical approach was used to create sub-groups
and analyse group differences. Renshaw et al.
(2016) compared the categorical and continuous
approaches, albeit using measures other than the
MHC-SF, and found that each approach resulted
in conflicting interpretations. This implies that the
method used to investigate the single- versus dual-
continua models can influence assessment results
in practice. While categorical assessment may be
criticised for a lack of discriminative power (Doll,
2008), it is closest to the current way that individual
mental illness assessment and population-based
screening work in practice, thereby supporting the
applicability of its use in practice.
Generalisability across mental illness
High levels of positive mental health assets are
attainable in individuals diagnosed with a mental illness,
demonstrated across major depressive disorder, bipolar
disorder, social anxiety, schizophrenia, and trauma-
related disorders (Goodman et al., 2018). Of the studies
included in the current review, the dual-continua model
was investigated across a range of mental illnesses and
related concepts, including participants experiencing
suicidal ideation, general psychopathology and
psychological distress, depression, anxiety, stress,
trauma, loneliness, and eating disorders. Of the studies
that focused on recruiting patients with a mental illness,
as opposed to using general populations, the large
majority supported the validity of the dual-continua
model, particularly when looking at patients with mild to
moderate mental illness.
Results for populations of patients with severe to
extremely severe mental illness are less convincing.
Van Erp Taalman Kip and Hutschemaekers (2018)
found that mental illness and positive mental health
were highly negatively correlated (r = −0.071) in severely
mentally ill populations, with positive mental health
contributing significantly less to a two-factor model
compared to the symptoms of mental illness. Other
research found high correlations between mental
illness and mental health in mentally ill, particularly
in depressed patients (Bartels et al., 2013), and
supported the researchers finding differential levels
of positive mental health depending on mental illness
diagnosis, e.g. depression versus anxiety (Seow et al.,
2016; Franken et al., 2018). The study by Van Erp
Taalman Kip and Hutschemaekers (2018) was the
sole study identified in this review that contradicted
the dual-continua model. These results imply that
in extremely severe psychopathology, particularly in
depression, positive mental health constructs may be
highly correlated with mental illness symptoms and
patients may exhibit difficulty distinguishing mental
illness symptoms from symptoms of positive mental
health. There is evidence to suggest that the precision
of positive mental health measures may change across
the range of scores, and this may also be true for the
level of psychopathology (Abbott et al., 2010).
The notion that it is possible to have a high level
of positive mental health and common mental illness
at the same time has been contested in the literature.
Huppert (2005) argued that it was difficult to imagine
a situation where an individual diagnosed with severe
depression is able to function well psychologically.
We suggest that this criticism is influenced by the
‘observational window’ and measurement approaches
considered, or in other ways we measure both
outcomes. Asking someone to judge their positive
mental health and mood symptoms in the moment, or
asking them to reflect back over their mood and positive
mental health over a longer period, will lead to different
subjective interpretations. Similarly, using measures
that consist of a large number of the same items, as
is the case for depression measures, will lead to large
overlap. For example, ratings on a meaningful life
are often asked in wellbeing questionnaires, whereas
ratings on life being meaningless are often included
in depression measures. Feldman Barrett and Russell
(1998) recommended that such ‘bipolar antonyms’ can
be misleading in analysis of independence or bipolarity,
and can be avoided by ensuring that measurement
tools include items that adequately represent the
breadth of each construct. In this context, this would
include measuring a diverse range of psychological
illness constructs, as well as a range of psychological
well-being constructs.
Massé et al. (1998) provided an example of this
approach, albeit with constructs that are no longer
considered central to either positive mental health or
mental illness. This study used CFA to test the model

10
Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health
fit of mental health as a second order structure,
underpinned by the distinct but related latent factors
of positive mental health and mental illness. As visible
in Figure 5, they included a range of constructs under
positive mental health and mental illness, some of which
relate to both positive mental health and mental illness.
Following the depression example, if only happiness
and anhedonia were used as indicative measures of
positive mental health and mental illness, then a bipolar
model would become easily apparent. However, using
a broader, multifaceted approach to positive mental
health (e.g. using the MHC-SF) and mental illness (e.g.
using the BSI), the dual-continua model would emerge
as a more appropriate fit of the data.
Overall, there is sufficient evidence to support
the validity of the dual-continua model of mental
health. Longitudinal and cross-sectional data from
around the world indicates that positive mental health
and mental illness reflect two distinct, yet related
phenomena. The validity of the dual-continua model
may however be relative to the window of time and
the definitions and assessment methods of positive
mental health and mental illness. In particular, more
work should be conducted to investigate whether
the dual-continua is appropriate in severe forms of
psychological distress or mental illness.
Implications of the dual-continua model
for policy, practice, and research
The validity of the dual-continua model has important
implication for policy, practice, and research and the
current scoping review extracted the implications
discussed by the authors of included studies. Across
the eighty-three publications, the implications were
relatively convergent and overlapping, and were
collected into three broad themes; implications for
mental health measurement and assessment, mental
health treatment and intervention design, and mental
health care system reform.
Mental health assessment
Study authors strongly advocated to assess positive
mental health and mental illness together, rather than
using only one or the other. There was a consensus,
based on their research results, that a focus on
either positive mental health or mental illness alone
would not provide a complete image of the mental
health status of an individual or population. It is well
established in positive psychology that the absence of
mental illness does guarantee optimal mental health
(Slade, 2010). The dual-continua model would equally
suggest that high levels of positive mental health do
not guarantee the absence of mental illness. Studies
found up to 36% of participants who displayed high
levels of positive mental health with symptoms of
mental illness (Venning et al., 2013).
At a population level, the inclusion of positive
mental health measures with existing indicators of
mental illness enables researchers to understand
the economic, social, and individual drivers of both
positive mental health and mental illness. It was
shown that these drivers are not necessarily the
Figure 5: Higher order theoretical relationship between mental illness (distress) and positive
mental health (wellbeing), adapted from the model presented in Massé et al. (Massé etal., 1998).
PMH = Positive mental health, MI = mental illness, MH = mental health. Circles indicate latent
constructs, and boxes indicate survey items.

11
EVIDENCE BASE
same, although there is some overlap (Kinderman
et al., 2015). This degree of insight is not available in
most population-level research, as positive mental
health measures are often not included.
At the individual level it enables professionals in
various settings to identify previously invisible sub-
groups. For example, research in schools commonly
constructed the four sub-groups (‘Complete Mental
Health’, ‘Vulnerable’, ‘Symptomatic but content’ and
Struggling’ groups) and would continue to assess
group-membership on educational, behavioural,
cognitive and emotional outcomes. Across the
studies, participants in the ‘Complete Mental Health’
group outperformed the other groups, while the
‘Vulnerable’ group scored significantly worse than
those with Complete Mental health, being consistently
associated with poor performance across the studies
(Suldo and Shaffer, 2008; Renshaw and Cohen, 2014;
Antaramian, 2015). In traditional assessment (mental
illness only), the ‘Vulnerable’ and ‘Complete mental
health’ group would have been combined as a ‘no
mental illness’ category, despite the fact that these
two groups show different performance on a range
of education, behavioural, cognitive, and emotional
outcomes.
One of the most striking examples of the
importance of capturing the sub-groups, and thereby
identifying at-risk individuals, comes from studies
that investigated the role of positive mental health as
a predictor of mental illness risk. Keyes et al. (2010)
conducted a longitudinal study of mentally healthy
participants (without a diagnosis of mental illness)
of the 1995 and 2005 waves of the Midlife in the
United States (MIDUS) National Study of Health and
Well-being. The study showed that participants who
gained or maintained high levels of positive mental
health over the 10-year period had a decreased risk
of developing a mental illness (being depression,
anxiety, and panic disorder), and that participants
whose positive mental health declined or remained
low had significantly increased risk of developing
mental illness. Similar results were observed by
Wood and Joseph (2010), who found that people
with low levels of positive mental health were several
times more likely to be depressed 10 years later.
Grant et al. (2013) and Lamers et al. (2015) supported
these findings, finding that low levels of positive
mental health predicted risk of higher depressive
symptoms within one year. There is also evidence to
suggest that high levels or increased levels of positive
mental health dramatically improve the likelihood of
recovering from a mental illness (Iasiello et al., 2019).
Positive mental health and mental illness need
to be assessed together when trying to establish a
picture of an individual’s or population mental health
status. This must be done using measurement tools
specifically designed to capture either construct in
a representative manner; as simply using positive
items of mental illness questionnaires is not a valid
measurement approach (Winzer et al., 2014).
Failing to use fit-for-use measurement tools for both
mental health and mental illness when performing
mental health assessments will lead to suboptimal
explanatory power of drivers and outcomes, and
does not allow for the identification of key at-risk
groups.
Intervention design and evaluation
A second key theme of implications relates to mental
health intervention design, with the recurring finding
that interventions that improve positive mental health
and reduce mental illness can be complementary
but different (Kinderman et al., 2015). Further, it was
found that a positive response in one continua does
not exclude, nor guarantee a positive response in
the other. Instead, interventions and mental health
promotion programs will benefit from targeting both
the reduction of illness symptoms and improvement
of positive mental health.
The efficacy of mental health interventions is
generally evaluated using average change in positive
mental health or mental illness of the entire group.
However, research using the dual-continua model
suggested that while an intervention may improve
overall positive mental health and reduce mental
illness on average, more complex interactions may
be occurring at the individual level. In particular,
Trompetter et al. (2017) re-evaluated a randomized
controlled trial of an ACT intervention that measured
dimensions of both mental illness and positive
mental health (n = 250). While this RCT revealed
average improvements in positive mental health and
reductions in mental illness at the group level, using
reliable change analysis it was found that the majority
of individuals improved in either mental illness or
positive mental health. The traditional bipolar model
would suggest that an improvement in positive
mental health and a reduction in mental illness
signify the same outcome. Instead, through the dual-
continua model, when an intervention focuses on or
can address both positive mental health and mental
illness, a failure to see an effect in either outcome
does not mean that the intervention did not have a
positive effect for the participants.
The authors commented on the utility of ACT
in relation to the dual-continua model, as it is a
commonly used treatment paradigm that can be

12
Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health
used to reduce psychopathological vulnerabilities
and build resources for improving positive mental
health. Other clinical interventions have been
designed to improve the wellbeing of individuals with
psychopathology including Wellbeing Therapy (Fava
et al., 1998) and Positive Psychotherapy (Seligman
et al., 2006), which all fall under the larger umbrella
of Positive Clinical Psychology (Wood and Tarrier,
2010). Using traditional clinical techniques such
as cognitive restructuring, scheduling of activities,
assertiveness training, and problem solving, these
interventions aim to improve positive mental health
assets such as Ryff’s domains of psychological
wellbeing (Fava et al., 1998; Duckworth et al., 2005),
while also treating mental illness. These interventions
and treatment paradigms have implicitly or explicitly
adopted the dual-continua model, by designing
program components that improve wellbeing, despite
the client’s diagnosis of mental illness.
Greater sophistication should be employed to
understand which individuals might benefit most from
interventions specifically designed to improve positive
mental health and reduce mental illness, whether
delivered simultaneously or consecutively (Schueller,
2014). An example of this sophistication comes from
Jans-Beken et al. (2017) who investigated the dual-
continua model in a longitudinal study of gratitude,
psychopathology, and subjective wellbeing. This
study found that practicing gratitude may positively
impact an individual’s future level of positive mental
health and psychopathology, but is less likely to
ameliorate symptoms of psychopathology when
they are present. This indicates that interventions to
improve traits such as gratitude should be carefully
designed to consider the trait dynamics with both
mental illness and mental health.
Adoption of the dual-continua model on
intervention design has significant potential, especially
when combined with the ability to identify at-risk
subgroups. At the individual level this can inform
better intervention design, while at the community and
society level, it may allow governments to prioritise
policies and create more targeted interventions. The
evidence to drive this change does not just need
to come from future studies; there is a substantial
literature of randomised controlled trials which have
measured both positive mental health and mental
illness. Secondary analysis of these data using the
aforementioned method proposed by Trompetter
et al. (2017) would provide much needed insight
into the efficacy of interventions through the dual-
continua model lens, and will provide greater clarity
for intervention design by identifying ‘for whom’
interventions are most effective.
Reform to the health care system
The final theme of implications of the dual-continua
model of mental health is related to mental health
care system reform, where a need to integrate
and unify traditional psychotherapy and positive
psychology was commonly advocated; a call that is
not new (Wood and Tarrier, 2010), but certainly has
not gained traction as of yet. Current approaches
are deficit-focused and preference the reduction of
mental illness symptoms, resulting in reactive health
care (Herron and Trent, 2000). Hence, the specific
inclusion of positive mental health initiatives into the
health care system to complement current services
was commonly cited as a much desired reform
to the mental health care system. In addition to
aforementioned changes in relation to measurement
and intervention, two specific treatment approaches
that could benefit from examining the evidence
provided for dual-factor models are integrated care
approaches and stepped-care approaches.
Integrated care strives to achieve optimal
outcomes for patient, provider and system (Kodner
and Spreeuwenberg, 2002); overlooking the
important role that positive mental health plays would
be detrimental to outcomes for integrated care,
regardless of whether the main presenting symptoms
are mental or physical. An important precedent for
successful implementation of positive mental health
into integrated mental health care has already been
established through interventions such as Wellbeing
Therapy and Positive Psychotherapy, and overarching
fields such as positive clinical psychology and positive
psychiatry (Jeste et al., 2015; Wood and Tarrier, 2010).
These therapies have been designed to broaden the
scope of traditional psychopathology with the central
thesis that building positive mental health assets, in
addition to treating symptoms, is effective and may
engender more meaningful recovery and reduce the
likelihood of relapse (Slade, 2009). Research found in
this review indicated that individuals who have had
severe depression or suicidal ideation can achieve
complete mental health (Baiden and Fuller-Thomson,
2016), that positive assessments of wellbeing and
strengths may transform how clients view themselves
and their satisfaction with clinical assessment
(Macaskill, 2012). Positive mental health assets such
as character strengths may provide clinicians new
resources to help individuals manage their illness
(Macaskill and Denovan, 2014). The systemic neglect
of functioning after depression is emerging in the
literature (Rottenberg et al., 2018), and positive mental
health and the dual-continua of mental health could
facilitate the shift in recovery narrative (Slade, 2010).

13
EVIDENCE BASE
In a stepped-care model of mental health care,
prevention and health promotion precede self-guided
help and low-resource intensive interventions, before
clinical intervention is required. Longitudinal research
identified in the current review indicated that positive
mental health is an important resource to reduce
the incidence of mental illness (and other physical
illness) and therefore should be a primary focus of
public policy and health promotion (Lamers et al.,
2015; Keyes et al., 2010; Wood and Joseph, 2010;
Schotanus-Dijkstra et al., 2017). This will subsequently
or conjointly lead to improvements in other crucial
areas such as health risk behaviour (Venning et al.,
2013). An important key group that needs to be
targeted, in both preventative and early intervention
efforts are those who reside in the ‘Vulnerable’ group;
this group is the most transient (Kelly et al., 2012;
Xiong et al., 2017) and across studies associated with
worse outcomes than participants with ‘Complete
Mental Health’.
Limitations
Despite identifying a broad range of publications
investigating the dual-continua model of mental
health, our ability to effectively scope the literature
was restricted by imprecise taxonomy and
nomenclature that is pervasive throughout wellbeing
and positive psychology literature (Salvador-Carulla
et al., 2014; Dodge et al., 2012). This is an avoidable
impasse, but will require consolidation, collaboration,
and standardised use of language between positive
mental health and mental illness researchers. The
non-systematic snowballing method utilised to
overcome this barrier may present a bias towards
finding papers that support the dual-continua model.
This was minimised by broad reference list screening,
which did not return a single study that contradicted
the validity of the dual-continua model. Another
potential limitation was the use of English-only studies;
however, this was likely mitigated by the inclusion of
many studies conducted in non-Western and non-
English speaking countries. Finally, assessment of
research quality was not included in this scoping
review, and poorly conducted research may have
influenced the results. The bias may be offset by
the inclusion of a wide range of study designs and
overwhelming consistency of the findings.
Conclusion
There is a sufficient body of evidence to suggest that
positive mental health and mental illness are not the
opposite ends of the same continuum, and instead
reflect two distinct yet related continua. The current
review identified eighty-three publications, which were
conducted in clinical and non-clinical populations,
over the entire life-course and in Western and non-
Western cultures. The review summarised the
evidence that positive mental health and mental illness
are two distinct but interrelated domains of mental
health; each having shared and unique predictors,
influencing each other via complex relationships.
Further research should be conducted to understand
whether the dual-continua model of mental health is
valid in the most severe cases of mental illness, and
the influence that particular measurement tools may
have on the relationship between mental illness and
mental health.
The authors of included studies strongly advocated
for the adoption of the dual-continua model in policy,
research, and practice. The main implications of the
adoption of the dual-continua model were related to
the inclusion of positive mental health measurement
into mental health assessment, utilising interventions
to improve positive mental health to promote mental
health and prevent mental illness, and the addition of
positive mental health measurement and intervention
to complement the traditional approaches to inspire
mental health care system reform.
Acknowledgments
This research was supported by the Australian and
New Zealand School of Government.
Conflict of Interest
The authors declare no conflict of interest.
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EVIDENCE BASE
Table A1. Summary of reviewed literature extraction.
Author Aims/Purpose Method Location Participants Wellbeing
tool
Mental
illness tool
Key result relevant
to current review
Key implications of
CMH
Alterman
etal. (2010)
To examine the
latent structure
of a number of
measures of
mental health and
mental ill-ness
in substance
use disorder
outpatients
Cross-sectional
study
n = 484
United
States of
America
Adult (mental
illness)
Age: 38.4 (9.4)
70% male
- Positive and
Negative Affect
Schedule
(PANAS)
- Profile of
Mood States
(POMS)
- The study found two
distinct factors for mental
illness and mental health
- Some measures
associated with positive
mental health (social
support and optimism)
showed inverse high
correlations and high factor
loadings for mental illness
- CFA support for the
existence of two obliquely
related, negatively correlated
dimensions
- Some tools related to positive
mental health also showed
high correlations with negative
mental health, which may be
influenced by the constructs
and assessments used to
measure them
Antaramian
et al. (2010)
To investigate
the utility of using
a dual-factor
approach in
youth mental
health and assess
group differences
in student
engagement,
academic
achievement,
environmental
support
Cross-sectional
study
n = 764
United
States of
America
Youth (students)
Specific age not
reported
54% female
-Students' Life
Satisfaction Scale
(SLSS)
- Positive and
Negative Affect
Scale for Children
(PANAS-C)
-Self-report
coping scale
(SRCS)
- The results support
the dual-factor model of
mental health in young
adolescents
- those with low positive
mental health and no
mental illness are similarly
at risk of developing
academic and behavioural
problems than those with
mental illness
- Monitoring of wellbeing is
recommended to help guide
systematic interventions for
those at risk of problematic
school performance, as only
students with complete mental
health show advantageous
academic and behavioural
outcomes
Antaramian
(2015)
Examine the
utility of the
dual-factor model
in understanding
the psychological
adjustment and
educational
functioning of
college students
Cross-sectional
study
n = 561
United
States of
America
Adult (students)
Age: 19.5
63% female
- Subjective
welbeing:
- Positive and
Negative Affect
Schedule
(PANAS)
- Satisfaction With
Life Scale (SWLS)
- Center for
Epidemiologic
Studies
Depression
Scale (CES-D)
- The study found four clear
groups with differing mental
illness and positive mental
health, supporting the
dual-factor model of mental
health
- The groups differed
in their educational
functioning, with
participants with
complete mental health
outperforming the other
groups on student
engagement and GPA
- Both the presence of positive
wellbeing and the absence of
psychopathological sympyoms
are important for facilitating
academic success, as positive
mental health is a contributor
to optimal college experience
and academic success,
thereby indicating that positive
mental health should be
considered in monitoring and
intervention delivery
Appendix

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Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health
Baiden
and Fuller-
Thompson
(2016)
Identify factors
associated
with complete
mental health in
individuals who
had ever seriously
considered
suicide
Cross-sectional
study
Sample 1
n = 21270
Sample 2
n = 2842
Canada Youth and
Adult (General
population)
Age not reported
Gender ratio not
reported
- Mental Health
Continuum
- Short Form
(MHC-SF)
- World Health
Organisation
- Composite
International
Diagnostic
Interview
- A dual-factor model is
useful in describing mental
health in lifetime suicide
ideations; the study found
lower complete mental
health than people who
did not show suicide
ideation
- Social support, financial
stability, older age, good
physical health and sleep
are protective modifiable
factors for complete mental
health
- Many individuals with
these positive attributes
who had previously
considered suicide made a
full recovery into complete
mental health, free of
suicidal thoughts
- There are a number of
modifiable protective factors
(social support, physical health
and sleep) that are associated
with complete mental health
in suicide ideations, and can
present a target for policy and
interventions
Bariola et al.
(2017)
To determine the
applicability of the
dual continuum
model in a sample
of lesbians and
gay men
Cross-sectional
study
n = 847
Australia Adult (general
population)
Age: 18-85
48% female
- Mental Health
Continuum
- Short Form
(MHC-SF)
- Patient Health
Questionnaire
(PHQ-9)
- Generalized
Anxiety
Disorder Scale
(GAD-7)
- There were higher rates
of generalised anxiety in
females, while no gender
differences in depression
or positive mental health
were found
- Irrespective of
displaying criteria for
mental illness, varying
levels of positive mental
health were found,
providing support for the
dual-factor model
- General perceived
health status was
higher among those
with complete mental
health, suggesting higher
adaptability than the
other groups
- The use of a dual-factor
model is appropriate for LGBT
people, and can provide extra
insight into ways to achieve
optimal health

21
EVIDENCE BASE
Bartels et al.
(2013)
The present
study examined
the association
between
subjective
well-being
(SWB) and
psychopathology,
and genetics, and
investigated the
etiology of this
association in a
large cohort of
twins
Cross-sectional
study
n = 10610
Netherlands Youth (general
population)
Age: 16.4 (1.6)
56% female
- Satisfaction with
life Scale (SWLS)
- Subjective
Happiness Scale
- Youth Self
Report (YSR)
- Substantial shared
genetic influences
on wellbeing and
psychopathology, where
genetic liability of low
subjective wellbeing
can be indicative of a
genetic liability for higher
psychopathology
- The commonality of
heritable influences
on SWB and
psychopathology may lead
to the identification of the
vulnerable at risk groups
prior to any manifestation
of psychopathology
- As there is a genetic overlap
between subjective wellbeing
and psychopathology,
screening for wellbeing can
prove to be an innovative way
to address mental illness, and
reach larger proportions of the
population, than waiting for
psychopathology to occur.
- Due to the influence of
non-shared influences, which
is complex and construct
specific, there is evidence to
suggest that mental illness and
mental health are not polar
opposites
–The genetic overlap
between wellbeing and
psychopathology justifies
the integration of prevention
and promotion in the field of
Mental Health, and indicates
that wellbeing screening can
play an important role in this
process
Bohlmeijer
et al. (2015)
To evaluate
the effect of
Acceptance and
Commitment
Therapy on
Flourishing within
the Complete
Mental Health
framework
Randomised
Controlled Trial
n = 376
Netherlands Adult (mental
illness)
Age: 18-73
70% female
- Mental Health
Continuum
- Short Form
(MHC-SF)
- Center for
Epidemiologic
Studies
Depression
Scale (CES-D)
- The use of an ACT
intervention improved
positive mental health
significantly more than the
control condition
-ACT is a treatment
modality that can be used
to promote positive mental
health in individuals with
mild to moderate depressive
symptoms
Diaz et al.
(2017)
To apply the
complete
state model of
mental health to
posttraumatic
stress disorder
(PTSD)
Cross-sectional
study
n = 69
Spain Adult (mental
illness)
Age: 42.3 (12.0)
56% female
- Satisfaction With
Life Scale (SWLS)
- Positive Affect
Scale
- Psychological
Wellbeing Scales
(PWS)
- Social Wellbeing
Scales (SWS)
- Davidson
Trauma Scale
- Structured
clinical interview
for DSM-IV-TR
Axis I (SCID-I)
- The absence of PTSD
following traumatic event
is not equivalent to
the presence of health
(although many victims
recovered from PTSD, very
few achieved complete
mental health)
- Positive affect,
self-acceptance and
positive relationships were
negatively correlated to
PTSD
- It is important that public aid
and health care for victims
of terrorist attacks are aimed
at improving victim positive
mental health, even if they no
longer meet diagnostic criteria
for PTSD, with positive affect,
self-acceptance and positive
relationships being potential
avenues for interventions

22
Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health
Dowdy et al.
(2015)
To test the
validity of ayouth
social emotional
distress survey,
and test its
appropriateness
for complete
mental health
screening
Cross-sectional
study
n = 3780
United
States of
America
Youth (students)
Age not reported,
high school
grades 9-12
52% female
- Brief
Multidimensional
Student Life
Satisfaction Scale
(BMSLSS)
- Social Emotional
Health Survey
Secondary
- Social
Emotional
Distress
Survey-
Secondary
(SEDS-S)
-Patient Health
Questionnaire
Depression
Scale
- Generalised
Anxiety
Disorder Scale
- The SED-S scale
appears to be a valid
measure ofself-reported
internalising distress
-Analysis indicated that
SED-S is related to,
but distinct from life
satisfaction and positive
psychological traits
- Constructs of
psychopathology are related
to, yet distinct from constructs
of positive mental health
du Plooy
et al. (2018)
To examine a
broad range of
factors related to
migration and their
links to flourishing
and/or distress
Cross-sectional
study
n = 1446
Australia Adult (general
population)
Age: 46.5 (17.9)
52% female
- Mental Health
Continuum
- Short Form
(MHC-SF)
- Kessler
psychological
distress scale
(K10)
- A range of factors uniquely
assocated with either
distress or flourishing,
for instance younger age
and being a student was
associated with distress,
but not flourishing.
Identifiying with the host
nation (Australia), and
being self-employed, was
associated with flourishing
but not distress
- Other factors were
associated with both,
including amount of time
spent in the host nation
and experiences od
discrimination and racism
- Factors influencing
psychological distress and
flourishing are sometimes
similar, and sometimes
different
- Informing or guiding the
implementation of policies
and interventions that
support flourishing may help
governments to reduce overall
health and social costs.
This needs to be based on
a thorough understanding
of factors associated with
flourishing, distress or both
Eklund et al.
(2011)
To explore
the utility of a
dual-factor model
of mental health in
college students
Cross-sectional
study
n = 246
United
States of
America
Adult (students)
Age: 18-25
79% female
- Brief
Multidimensional
students' life
satisfaction scale
(MBSLSS)
- Mental Health
Continuum
- Short Form
(MHC-SF)
- Behaviour
assessment
scale for
children-
second edition
(BASC-2)
- Positive traits hope, grit,
and gratitude were higher
in high wellbeing group,
regardless of level of
psychopathology
- Attention problems
were most profound for
the students showing
symptoms of mental
illness, regardless of level
of wellbeing
- Locus of control was
highest for the students
without symptoms of
mental illness, regardless
of levels of wellbeing
- Important to evaluate the
presence or absence of
psychological symptoms
and psychological wellness
to obtain a more accurate
and rounded assessment of
individual functioning and to
guide intervention design as
different groups may require
different interventions

23
EVIDENCE BASE
Fontana
etal. (1980)
To determine the
applicability of
the dual-continua
model in a
hospitalised
physically ill
population and
to test whether
positive and
negative affect are
independent with
unique correlates
Longitudinal
observational
study
n = 80
United
States of
America
Adult (physically ill)
Age: 55.7
100% male
- Bradburn's ten
items for positive
and negative
affect
- Personal
Adjustment and
Role Skills scale
(PARS)
-The study supports the
notion that psychological
impairment and
psychological health are
independent of one another
- When asking others to
rate mental illness and
positive mental health, this
construct appears less
independent, indicating
that mental health and
impairment are opposites
when conceived through
the eyes of others
- Both psychological
impairment and psychological
health should be measured,
particularly when they are
assessed from people's
self-reports
- Measurement method (e.g.
self versus other) influences
the presence of a dual-factor
model
Franken
etal. (2018)
To validate the
mental health
continuum short
form and the dual
continua model
of wellbeing in a
mental health care
setting
Cross-sectional
study
n = 472
Netherlands Adult (mentally ill)
Age: 40.0 (11.6)
59% female
- Mental Health
Continuum Short
Form (MHC-SF)
- Outcome
Questionnaire
(OQ-45)
- Correlations between
positive mental health and
psychopathology were
generally high, particularly
highest in mood disorders
- The study demonstrated
evidence to support
the validity of the dual
continua model in
clinical populations,
specifically mood
disorder, anxiety disorder,
personality disorder, and
developmental disorder
- The dual continua
model is appropriate and
applicable in mental health
care, despite relatively
high correlations between
general psychopathology and
wellbeing
Fuller-
Thomson
etal. (2016)
To investigate
factors associated
with complete
mental health
among a nationally
representative
sample of
Canadians with
a history of
depression
Cross-sectional
study
n = 20955
Canada Adult (mentally ill)
Age: 20-89
51% female
- Mental Health
Continuum
- Short Form
(MHC-SF)
- Composite
International
Diagnostic
Interview
(WHO-CIDI)
- Those who had never
experienced a depressive
episode, after controlling for
other variables, had three
times higher odds of being
in complete mental health
- Two in five people with
a history of depression
demonstrated complete
mental health
- Several modifiable factors
such as social support,
smoking, substance abuse,
pain, spirituality and physical
activity can be improved to
achieve complete mental
health
- Those with the longest
depression were equally likely
to achieve complete mental
health as those with shortest
depressive episode
- Having had depression is
associated with a lower odds
of showing complete mental
health
- It is within the grasp of many
individuals who have previously
had depression (2 in 5) to fully
flourish and achieve complete
mental health, with several
modifiable factors (smoking,
social support, pain, spirituality
and physical activity) being
identified as potential areas for
interventions

24
Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health
Furlong
et al. (2017)
To examine the
possible effects
of mischievous
response patterns
on school-based
screening results,
in the context of
the dual-factor
model of mental
health
Cross-sectional
study
n = 1857
United
States of
America
Youth (students)
51% female
- Brief
multidimensional
student's life
satisfaction scale
(BMSLSS)
- Strengths and
Difficulties
Questionnaire
(SDQ)
- 2% of the sample
responds mischievous
- most mischievous
respondents were in the
symptomatic but content
groups and the troubled
groups, not the vulnerable
groups
- The greatest number
of students in all groups,
particularly the vulnerable
and troubled groups,
respond meaningfully
- Universal screening will lead
to meaningful data for the
large majority of respondents
(98%), with particularly
high meaningful responses
noted for the vulnerable and
complete mental health group
Gilmour
(2014)
To examine the
distribution of
mental health
across the
complete mental
health subgroups
in a Canadian
community
sample
Cross-sectional
study
n = 25113
Canada Youth and
Adult (general
population)
Age: 15-75
51% female
- Mental Health
Continuum
- Short Form
(MHC-SF)
- Composite
International
Diagnostic
Interview
(WHO-CIDI)
- The study found high
rates of flourishing
(72,5%)
- Complete mental health
was only moderately
correlated with mental
disorders, mood
disorders, generalized
anxiety disorder and
substance disorder
- Older age, being
married, low
socio-economic status,
high spirituality, good
physical health were
related to complete
mental health
- While the large majority
displayed complete mental
health, the correlations
between mental illness and
mental health was only
moderate, supporting the
dual-factor models within
Canada
Grant et al.
(2013)
To assess
whether low
well-being is
a risk factor
for depressive
symptoms
Longitudinal
observational
Study
n = 1621
United
States of
America
Adult (general
population)
48% female
- Mental Health
Continuum
- Short Form
(MHC-SF)
- Patient Health
Questionnaire
(PHQ-9)
- Individuals with low
baseline wellbeing
showed significantly more
increase in depression
over time when dealing
with a stressful period
in life
- The results indicate that
assessing wellbeing status can
be a practical way to address
future risk for developing
depression
Greenspoon
and
Saklofske
(2001)
To explore the
validity and utility
of a dual-factor
approach to
mental health
and mental
illness
Cross-sectional
study
n = 407
Canada Youth (students)
Age: 10.5 (0.7)
50% female
- Multidimensional
Students’ Life
Satisfaction Scale
(MSLSS)
- Behaviour
Assessment
System for
Children
(BASC)
- Many group differences
were observed using the
dual-continua model rather
than the single illness-
health continuum
- The dual continua model
has strong application in
intervention and prevention,
especially in youth

25
EVIDENCE BASE
Hallion et al.
(2018)
To assess
complete mental
health in adult
siblings of those
with a chronic
illness or disability
Cross-sectional
study
n = 144
Australia Adult (students)
Control group:
Age: 19.0 (1.7)
51% female
Siblings group:
Age: 22.7 (8.0)
68% female
- Satisfaction with
life scale (SWLS)
- Psychological
Wellbeing Scale
(PWB)
- Social wellbeing
scale (15-item)
- Depression
Anxiety
Stress Scales
(DASS-21)
-The study found four
distinct groups in siblings
with and without illness
- The study did not find
worse outcomes for
siblings of people with
a chronic condition
compared to their peers
- The sample showed
worse findings for this
student population
compared to the general
public
- The use of CMH model
in these two populations
was supported as can be
witnessed by four distinct
groups in people with and
without siblings with illness
Headey
et al. (1993)
To determine
the dimensions
of mental health
(life satisfaction,
positive affect,
anxiety,
depression) and
assess the validity
of widely used
measures
Cross-sectional
study
n = 942
Australia Adult (general
population)
Age: 18-65
54% female
- Life as a whole
(LAW) index
- Satisfaction With
Life Scale (SWLS)
- Fordyce 0-10
Happy Scale
(1-item)
- Positive Affect
Scale (PAS)
- Negative
Affect Scale
(NAS)
- State Anxiety
Scale
- Beck
Depression
Inventory (BDI)
- General
Health
Questionnaire
(GHQ-12)
- Life satisfaction, positive
affect, anxiety, and
depression represent four
separate dimensions that
should all be measured in
general population surveys
- There are differences
in relationships between
positive and negative
constructs, depression
and life satisfaction are
strongly related (pointing
more towards a single
continuum) whereas
life satisfaction and
anxiety are less strongly
correlated (pointing to two
dimensions)
- The results might be
influenced by situational
factors (e.g. mood at the
time) as opposed to the
underlying dimensions
- Four dimensions of mental
health and mental illness (life
satisfaction, positive affect,
anxiety, depression) can be
included in population surveys,
but need to be assessed
as separate constructs, as
they influence one another
differently
Heubeck
and Neill
(2000)
To examine the
factor structure
underlying
adolescents'
responses to
the Mental
Health Inventory
in a sample of
Australian school
students
Cross-sectional
study
n = 878
Australia Youth (students)
Age: 14.7 (0.9)
49% female
- The mental
health inventory
- The mental
health inventory
- The study finds adequate
support for the existence
of a correlated two-factor
model
- A single factor model
showed poor fit
- All positively worded
items formed one factor,
and so did all the negative
ones, which may point to
the two factor structure
being a result of item
wording
- The study found evidence
of the two-factor structure of
psychological wellbeing and
psychological distress, as this
showed better fit than a single
factor model

26
Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health
Hu et al.
(2007)
To test whether
the GHQ-12
assesses both
positive and
negative mental
health, and that
these domains are
independent of
each other
Cross-sectional
study
Sample 1
n = 8978
Sample 2
n = 6451
United
Kingdom
Adult (general
population)
Sample 1:
Age: 41.7 (16.0)
53% female
Sample 2:
Age: 43.0 (16.4)
53% female
- 6 positive items
of General Health
Questionnaire
(GHQ-12)
- 6 negative
items of
General Health
Questionnaire
(GHQ-12)
- Positive mental health
and symptoms of mental
disorder were differently
associated with age (older
age = lower wellbeing),
unemployment, being
single, not having financial
strain and having good
physical health
- Fewer symptoms of
mental disorder were also
related to being male,
and neither being a single
parent nor living alone
- Measuring wellbeing in
addition to symptoms of
mental illness provides more
detail to the mental health
profile of individuals, and can
be used in population-based
research
Huppert
and
Whittington
(2003)
To compare the
characteristics
and determinants
of positive mental
health and mental
illness in a general
population sample
Longitudinal
observational
Study
n = 6317
United
Kingdom
Adult (general
population)
Age: 18-65+
Gender ratio not
reported
- Positive
General Health
Questionnaire
(POS-GHQ)
-General Health
Questionnaire
- Evidence of
independence of positive
and negative mental health,
as they show differential
response patterns over
time, response different for
men (but not for women)
- GHQ was more related
to physical health (illness
and disability), lack of
social support; factors
which don't appear to
affect wellbeing as much.
Employment on the other
hand, affected wellbeing
more, and mental illness
less
- Positive mental health and
mental illness are differently
influenced by demographic,
health, and social factors,
and need to be measured
separately to form a complete
picture of mental health status
Iasiello et al.
(2019)
To investigate
whether positive
mental health
predicts recovery
from a mental
illness over time
Longitudinal
study
n = 1723
United
States of
America
Adult (general
population)
Age not reported
Gender ratio not
reported
- Bradburn’s
scales of positive
affect
- Ryff's measures
of psychological
wellbeing
- Keyes' social
wellbeing
- Composite
International
Diagnostic
Interview Short
Form (CIDI-SF)
- Increased or maintained
high levels of positive
mental health predict
recovery from affective
disorders over a 10 year
period
- Mental health care systems
should explore offering of
services designed to improve
positive mental health in
addition to reducing mental
distress
- Positive mental health and
mental illness are separate
constructs, and both should be
included in the assessment of
patients interacting with mental
health care systems

27
EVIDENCE BASE
Jans-Beken
et al. (2017)
Investigate
prospective
associations
between gratitude
and both
dimensions of
psychopathology
and subjective
wellbeing
Longitudinal
observational
study
n = 706
Netherlands Adult (general
population)
Age: 44 (14)
69% female
- Satisfaction With
Life Scale (SWLS)
- Positive Affect
and Negative
Affect Schedule
(PANAS)
- Symptom
Check List-90
(SCL-90)
- Gratitude is only weakly
associated with lower
levels of psychopathology,
while staying moderately
associated with higher
levels of wellbeing
- Cultivating a sense of
gratitude may positively
influence wellbeing,
regardless of current levels of
psychopathology, but is less
likely to reduce symptoms
of psychopathology when
they are present, which holds
implications for gratitude
interventions
Jiang and
Lu (2018)
Examine the
prevalence and
correlates of
three mental
health categories
as described
in dual-factor
models among
older Adults in
China
Cross-sectional
study
n = 15050
China Adult (general
population)
Age: 63.0 (9.3)
53% female
- WHO Quality of
Life questionnaire
(WHO QoL)
- International
Classification
of Diseases,
10th version
(ICD-10)
- Anxiety (single
item)
- Three distinct groups
were found, which were in
line with other studies
- Correlates differed per
group, with complete
mental health outperforming
the other groups in
education, income,
employment, residence and
cognitive function
- The study finds validation of
dual-factor models within a
Chinese older adult population,
which holds implications
for interventions (e.g. more
self-realisation activities should
be promoted) as complete
mental health is associated
with a range of protective
factors for mental illness
Joseph and
McCollam
(1993)
To determine
whether one
should view
depression and
happiness as
opposite ends of a
single continuum
Cross-sectional
study
n = 56
United
Kingdom
Adult (students)
Age: 19.0
86% female
- Oxford
Happiness
Inventory
- Beck
Depression
Inventory (BDI)
- A bi-polar measure of
mental illness and positive
mental health offered
better capability to capture
the range of responses
than a unipolar measure
- Using bi-polar measures
of mental health and mental
illness can better explain
mental health within individuals
and populations
Jovanovic
and Brdaric
(2012)
To explore the
relations between
trait curiosity and
the wellbeing and
psychological
distress of
adolescents
Cross-sectional
study
n = 408
Serbia Youth (students)
Age: 16.6 (0.9)
61% female
- Multidimensional
student's life
satisfaction scale
(MSLSS)
- Inventory of
Affect based on
the Positive and
Negative Affect
Schedule-X
(SIAB-PANAS-X)
- Depression
Anxiety and
Stress Scale
(DASS-21)
- Curiosity was differentially
related to positive
wellbeing (high curiosity
was positively related to
wellbeing), and showed
no relation to depression,
anxiety, or stress
- The results indicate that
curiosity is a specific predictor
of positive wellbeing, but not of
psychological distress, giving
support to the two-continuum
model of mental health and
illness

28
Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health
Karademas
(2007)
To investigate
whether predictor
variables
differently
associate with
positive wellbeing
and mental illness
symptoms
Cross-sectional
study
n = 201
Greece Adult (general
population)
Age: 41.6 (10.2)
57% female
-Oxford happiness
inventory
- Mood
and Anxiety
Symptom
Questionnaire
– (MASQ)
- The moderate correlations
between the latent variables
of wellbeing and mental
illness support a dual-factor
model
- Optimism predicted both
wellbeing and mental illness
- Problem-solving
self-efficacy and the
positive approach coping
strategy were positively
associated with wellbeing,
while life stress was only
related to mental illness
- Mental illness and wellbeing
are predicted by different
factors, indicating the need
to select specific strategies
and techniques when trying
to improve either one, and to
further investigate the different
predictors of mental health and
mental illness
Karas et al.
(2014)
Validation of the
Polish Mental
Health Continuum
- Short Form and
verification of the
two-continua
model in a Polish
population
Cross-sectional
study
n = 2115
Poland Adult (general
population)
Age: 29.0 (10.6)
56% female
- Mental Health
Continuum-Short
Form (MHC-SF)
- Positive and
Negative Affect
Schedule
- Expanded Form
(PANAS-X)
- General
Health
Questionnaire
(GHQ-28)
- The study found that a
two-related-factor model
showed the best fit,
compared to a single and
two-factor-unrelated model
- The use of the MHC-SF in
a Polish population confirms
the two-continua model of
mental health, where mental
health and mental illness are
two related but distinguishable
factors
Kelly et al.
(2012)
Investigate
the utility of
the dual factor
model in youth
by determining
the longitudinal
stability of group
membership and
whether social
support variables
predicted
changes in group
membership
Longitudinal
observational
study
n = 730
United
States of
America
Youth (Students)
Age: 11-15
51% female
- Student’s life
satisfaction scale
- Positive and
Negative Affect
Scale for Children
(PANAS-C)
- Self-report
coping scale
(34-item)
- The study found that the
vulnerable group was the
most transient
- Those with high subjective
wellbeing were more likely to
show less psychopathology
at the follow-up
- Of students with high
psychopathology, those
with high SWB were more
likely to improve compared
to those with low SWB
- Social support positively
influenced improvement in
mental health
- Using a dual-factor approach
allows for better insight in who
improved in mental health than
measures of psychopathology
alone
Keyes
(2004)
Employ the
complete mental
health diagnosis
to investigate
its association
with coronary
artery and
cardiovascular
diseases in
community-
dwelling adults
Cross-sectional
study
n = 3032
United
States of
America
Adult (general
population)
Age: 25-74
51% female
- Bradburn’s
scales of positive
affect
- Ryff's measures
of psychological
wellbeing
- Keyes' social
wellbeing
- Composite
International
Diagnostic
Interview Short
Form (CIDI-SF)
- Complete mental health
participants have the
lowest prevalence of CVD
- Those with mental
illness and languishing
had the highest risk of
cardiovascular disease
- Older females who were
mentally healthy had lower
risks of cardiovascular
disease compared to any
of the other groups
- Complete mental health
can be useful for identifying
risk of cardiovascular disease
more accurately than either
dimension alone

29
EVIDENCE BASE
Keyes
(2005)
To test the
relationship
between
measures of
mental health and
mental illness
Cross-sectional
study
n = 3032
United
States of
America
Adult (general
population)
Age: 25-74
51% female
- Bradburn’s
scales of positive
affect
- Ryff's measures
of psychological
wellbeing
- Keyes' social
wellbeing
- Composite
International
Diagnostic
Interview Short
Form (CIDI-SF)
- The structure of mental
health is distinct from the
structure of mental illness,
with a two-factor model
showing a better fit than a
single factor model
- Complete Mental Health
was associated with low
helplessness and high goal
setting, resilience, and
intimacy
- Classifying and monitoring
a population with the added
dimension of WB useful as
anything other than complete
mental health is associated
with less healthy functioning
- Extant talk therapies may be
useful for promoting flourishing
as well as treating mental
illness (due to association of
complete mental health with
low helplessness and high
goals, resilience, and intimacy)
Keyes et al.
(2008)
To evaluate the
Mental Health
Continuum-
Short Form
in Setswana-
speaking South
Africans
Cross-sectional
study
n = 1050
South Africa Adult (general
population)
Age: 30-80+
62% female
- Mental Health
Continuum–Short
Form (MHC–SF)
- Affectometer 2
(10-item)
- Satisfaction With
Life Scale (SWLS)
- General
Health
Questionnaire
(GHQ)
- The study found a better
fit for a two-factor model
than for a one factor-model
- The study found
adequate internal
consistency for the
MHC-SF (0.74)
- Study validates the use of the
MHC-SF in a South-African
population
Keyes et al.
(2010)
To determine the
prevalence of
mental health and
mental illness,
determine its
stability over time
and test whether
changes in mental
health predict
changes in mental
illness
Longitudinal
observational
Study
n = 1723
United
States of
America
Adult (mental
illness)
Age: 25-74
Gender ratio not
reported
- Bradburn’s
scales of positive
affect
- Ryff's measures
of psychological
wellbeing
- Keyes' social
wellbeing
- Composite
International
Diagnostic
Interview Short
Form (CIDI-SF)
- Change in positive
mental health impacted
rate of mental illness,
with reductions from
flourishing to languishing
being associated with
an 8.2x risk of remaining
diagnosed with mental
illness and going from
moderate mental health
to languishing being
associated with a 4.4x risk
over a 10 year period
- Staying languishing
was associated with a
6.6x odds of remaining
diagnosed with mental
illness
- The likelihood of
remaining diagnosed with
mental illness declined by
26% per unit of change in
wellbeing
- Positive mental health
can predict the chance of
'recovery' from depression
over a 10 year period, and
can therefore be targeted in
prevention initiatives

30
Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health
Kim (2017) To investigate
group differences
in suicide
resilience using
the complete state
model of mental
health
Cross-sectional
study
n = 297
South Korea Adults (Students)
Age not reported
Gender ratio not
reported
- Mental Health
Continuum
- Short Form
(MHC-SF)
- Mental
Disorder
Inventory (MDI)
- Levels of suicide
resilience corresponded
tocomplete state model
group. In those without
a mental illness, the
'complete mental health'
group had the highest level
of suicide resilience, which
declined with wellbeing.
Similarly, in those with
a mental illness, suicide
resilience declined with
wellbeing
- The results of this study
suggest that both mental
illness and wellbeing should be
actively considered in mental
health promotion
Kim et al.
(2014)
To investigate
the relative
associations of a
strength-focused
measure and a
symptom-focused
measure on
wellbeing, and
determine gender
differences on
these associations
Cross-sectional
study
n = 118
United
States of
America
Youth (students)
Age: 15.1 (1.5)
56% female
-Social emotional
health survey
(SEHS)
- Positive and
Negative Affect
Scale for Children
(PANAS-C)
- Students’ Life
Satisfaction Scale
(SLSS)
- Behavioural
Assessment
System for
Children-2
(BASC-2)
- Behavioural
and Emotional
Screening
System (BESS)
- Prediction of subjective
wellbeing was stronger
when using both strength-
and symptom-focussed
measurements, compared
to either separately
- Using both strength-focused
and symptom-focused
screening measures could
help school practitioners better
understand the complete
mental health needs and status
of all students
Kinderman
et al. (2015)
Examine
whether anxiety,
depression and
wellbeing have
different causal
determinants and
mediators
Cross-sectional
study
n = 32827
United
Kingdom
Adult (general
population)
Age: 40.5 (14.3)
61% female
- BBC subjective
wellbeing scale
(BBC-SWB)
- Cambridge
Neuro -
psychological
Test Automated
Battery
(CANTAB)
- Goldberg
Anxiety and
Depression
scales
-Low levels of subjective
well-being were related
to social isolation and low
levels of adaptive coping
- Mental health problems
were related to negative life
events and rumination
- Both are influenced via
a complex interplay of
variables, with individual
influence of the factors
differing for wellbeing and
mental health problems
when they influenced both
-The study found support for
the hypothesis that wellbeing
and mental illness have
distinct causal pathways, with
different causal factors and
psychological mediators
- despite the existence of a
high correlation between the
two
-Interventions looking to
improve well-being and
interventions aimed at
preventing or treating
mental illness should be
complementary but different,
and should target different
causal factors and pathways

31
EVIDENCE BASE
Lamers
etal. 2011
To evaluate the
validity of the
Mental Health
Continuum-Short
form across the
life course
Cross-sectional
study
n = 1662
Netherlands Adult (general
population)
Age: 47.6 (17.7)
50% female
Mental Health
Continuum-Short
Form (MHC-SF)
- Satisfaction With
Life Scale (SWLS)
- Positive and
Negative Affect
Schedule
(PANAS)
- Happiness
(1-item)
- Brief
Symptom
Inventory (BSI)
- The study found the best
fit for the three factors
within the MHC-SF
- An overarching
two-continua model with
correlated factors showed
the best statistical fit in
confirmatory factor analysis
- Mental health and mental
illness are distinct indicators of
mental wellbeing, instead of a
single continuum
- The MHC-SF is a valid tool
for measuring mental health in
a Dutch population
Lamers
et al. (2012)
Examine whether
psychopathology
and positive
mental health
show differential
associations
with the Big Five
personality traits
Cross-sectional
study
n = 1161
Netherlands Adult (general
population)
Age: 18-88
50% female
- Mental Health
Continuum–Short
Form (MHC–SF)
- Brief symptom
inventory (BSI)
- The big five personality
traits are differentially
associated with
psychopathology and
positive mental health.
Emotional stability is
related to psychopathology
while extraversion and
agreeableness are
associated with wellbeing
- The explained
variance is greater for
psychopathology (19%)
than for wellbeing (9%)
- The study supports a
dual-factor approach and
indicates that Interventions
that look at alleviating
psychopathology may have to
focus on different underlying
factors than interventions that
aim at enhancing positive
mental health
Lamers
etal. (2015)
Investigate the
relation between
positive mental
health and mental
illness symptoms
over time
Longitudinal
study
n = 1932
Netherlands Adult (general
population)
Age: 18-65+
52% female
- Mental Health
Continuum–Short
Form (MHC–SF)
- Brief symptom
inventory (BSI)
- The study found a strong
bidirectional relationship,
with both low wellbeing
and mental illness being
a risk factor for the
development of one
another over time
- The association remains
after controlling for
baseline levels of wellbeing
and mental illness; a
finding that highlights the
existence of two factors
- Changes over time in
welbeing and mental illness
were an even stronger
predictor than absolute
levels
- This study underlines the
importance and usefulness
of monitoring positive mental
health and psychopathology
over time, for instance as part
of assessment and outcome
monitoring practices

32
Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health
Lim (2014) Examine the
psychometric
properties of the
Mental Health
Continuum-SF
in a Korean
population, and
establish the
prevalence of
mental health in
the sample
Cross-sectional
study
n = 547
South Korea Youth (Students)
Age: 16.1 (0.3)
57% female
- Mental Health
Continuum–Short
Form (MHC–SF)
- Satisfaction With
Life Scale (SWLS)
- General
Health
Questionnaire
(GHQ)
- The MHC-SF showed a
best fit when a three-factor
solution was used
- A two correlated factor
showed the best fit
between positive mental
health and mental disorder
- The current study validates
the use of the MHC-SF in
a Korean population, and
supports the dual-factor model
of mental health
Lupano
Perugini
et al. (2017)
Examine the
psychometrics of
the Mental Health
Continuum-SF in
the Argentinean
context, and to
obtain evidence of
the two-continua
model
Cross-sectional
study
n = 1300
Argentina Adult (general
population)
Age: 40.3 (13.6)
50% female
- Mental Health
Continuum–Short
Form (MHC–SF)
- Satisfaction with
Life Scale (SWLS)
- Positive and
Negative Affect
Scale (PANAS)
- Well-Being Index
(WBI)
- Center for
Epidemiologic
Studies
- Depression
Scale (CES-D)
- Symptom
Checklist-
90-Revised
(SCL-90-R)
- A three dimensional
model for subjective,
psychological and social
wellbeing showed the best
fit, regardless of gender
or age
- Scores on the MHC-SF
were positively correlated
to wellbeing indices and
negatively to mental illness
indices, supporting the
dual-factor models
- The current study validates
the use of the MHC-SF in an
Argentinian population, and
supports the dual-factor model
of mental health
Lyons et al.
(2012)
Examine the
contributions
of personality,
environmental,
and perceived
social support
variables in
classifying
adolescents using
a dual-factor
model of mental
health
Cross-sectional
study
n = 990
United
States of
America
Youth (students)
Age: 14.6 (2.1)
64% female
- Students’ Life
Satisfaction Scale
(SLSS)
- Youth
self-report
of the child
behaviour
checklist (YSR)
- The four distinct groups
as proposed by dual-factor
models emerged, with
personality and social
support factors influencing
each group differently
- Extraversion and
neuroticism were linked to
the two psychopathology
groups, but not with the
vulnerable group
- Parental social support
contributed to vulnerable
and troubled groups, while
other social support did
not differ between groups
- Acute stressful life
events predict being in the
troubled group
- Interventions aimed
at targeting student's
mental health need to take
antecedents into account
depending on the four
groups, the susceptibility to
change of these antecedents
(social support is for instance
more likely to change
than personality), and the
magnitude of the effect of
these antecedents

33
EVIDENCE BASE
Lyons et al.
(2013)
Determine the
usefulness of the
dual-factor model
in adolescents,
and its relationship
to academic
performance
and student
engagement
Longitudinal
study
n = 1809
United
States of
America
Youth (students)
Age: 12.7 (0.7)
52% female
- Students’ Life
Satisfaction Scale
(SLSS)
- Positive and
Negative Affect
Scale for Children
(PANAS-C)
- Self-Report
Coping Scale
(SRCS)
- The four distinct groups
performed differently
on GPA and student
engagement
- The participants with
low wellbeing but without
mental illness showed less
emotional engagement and
a bigger decline in GPA
than those with complete
mental health
- Professionals should consider
a student's level of positive
mental health, as it can aid in
monitoring a potential area of
risk that can affect GPA and
student engagement
Macaskill
(2012)
To measure
the relationship
between
strengths,
wellbeing
and coping
mechanisms in
individuals living
with recurrent
depression,
and assess
the usefulness
of strengths
assessment within
psychological
assessment
Mixed methods
n = 112
United
Kingdom
Adult (mental
illness)
Age: 41.3 (11.2)
24% female
- Satisfaction With
life Scale (SWLS)
- Positive and
Negative Affect
Schedule
(PANAS)
- Short
Depression-
Happiness
Scale
- Strength assessment
was considered useful and
helpful as a complement
to traditional psychological
assessment
- Integrating strengths within
psychological assessment
may transform how patients
suffering from recurrent
depression see themselves
and the satisfaction with
assessment, as well as how
they view life after depression
Macaskill
and
Donovan
(2014)
To examine
the relationship
of character
strengths with
mental illness and
wellbeing
Cross-sectional
study
n = 214
United
Kingdom
Adult (students)
Age: 19.1 (3.3)
79% female
- Satisfaction With
life Scale (SWLS)
- Positive and
Negative Affect
Schedule
(PANAS)
- General
Health
Questionnaire
(GHQ-28)
- There were no differences
between GHQ case and
non-case students found
on life satisfaction and
positive affect scores,
supporting a dual-factor
model
- There were differences
in positive and negative
affect between case
and non-case students,
indicating to the
importance of addressing
them separately in clinical
practice
- Character strengths were
generally equally important
for case and non-case
students
- Character strengths are
resources that therapists can
use to build positive mental
health in individuals with and
without mental illness

34
Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health
Magalhaes
and
Calheiros
(2017)
Explore the use
of a dual-factor
model in youth
mental care and
study group
differences as
determined by the
dual-factor model
in relation to a set
of social support
components and
resources
Cross-sectional
study
n = 369
Portugal Youth (general
population)
Age: 14.7 (1.8)
46% female
- Satisfaction With
life Scale (SWLS)
- Scales of
Psychological
wellbeing
- Reynolds
adolescent
adjustment
screening
inventory
(RAASI)
- Confirmatory factor
analysis supports a better
fit of a two-dimensional
model compared to a
one-dimensional model
- There were group
differences in social
support, with the complete
mental health group
showing better results on
social support dimensions,
and the troubled group
showing worst results
- The promotion of
protective factors (e.g.
significant and supportive
relationships) can
contribute to higher levels
of positive mental health
- This study supports the need
to implement, monitor and
evaluate interventions tailored
to the youth's needs, taking
into account their positive
mental health as well as their
psychological difficulties,
andnot one or the other
Massé et al.
(1998)
To investigate
whether
psychological
distress and
subjective
wellbeing are the
opposite poles
of the same axis
of mental health,
or independent
constructs
Cross-sectional
study
n = 398
Canada Youth and
Adult (general
population)
Age: 15-65+
52% female
- Well-Being
Manifestations
Measure Scale
(WBMMS)
- Distress
Manifestations
Measure Scale
(DMMS)
- The best model features
a structure of psychological
distress and wellbeing as
two correlated dimensions
reflecting a higher order
construct of mental health
- Assessments of mental
health in the general population
provide a better explanation
of mental health when using
measures of wellbeing and
psychological distress
Olszewski
(2012)
To use the
complete model
of mental health
to study group
differencesin
applied ways of
coping with stress
Cross-sectional
study
n = 74
Poland Adult (students)
Age: 22-44
Gender ratio not
reported
- Satisfaction with
Life Scale (SWLS)
- State-Trait
Anxiety
Inventory
- Two groups were
identified, those with high
anxiety and average life
satisfaction, and those
with above average life
satisfaction and lower than
average anxiety
- Participants in these
groups responded
differently to the COPE
scale
NA

35
EVIDENCE BASE
Payton
(2009)
To investigate
the relationship
between positive
mental health,
mental illness,
and psychological
distress
Cross-sectional
study
n = 4242
United
States of
America
Adult
Age: 25-74
Gender ratio not
reported
- Ryff's Scales
of Psychological
Wellbeing
- Disorder
composite
diagnosis of
depression,
anxiety, or
panic attack
- Distress
composite of
symptom items
to measure
mood and
malaise
- Diagnosis of mental
illness, positive mental
health, and psychological
distress are distinct, and
should not be directly
contrasted
- Conflatingdistress, disorder,
and mental health likely
obscures important underlying
variation, therefore these
variables should be measured
separately
Peter (2018) To investigate
the dual-factor
model within
a large-scale
group of gays
and lesbians, and
their heterosexual
counterparts
Cross-sectional
study
n = 25113
Canada Adult (general
population)
Age: 45.7
51% female
- Mental Health
Continuum - Short
Form (MHC-SF)
- World Health
Organisation
World Mental
Health-
Composite
International
Diagnostic
Interview
(WMH-CIDI)
criteria
- LGB individuals had less
positive mental health and
more mental illness than
heterosexual counterparts
- There were differing
proportions in each of
the four groups for LGB
compared to heterosexual
counterparts
- There were differences
between the type of mental
illness and the level of
positive mental health
experienced
- Using a dual-continua model
aids in better identification of
high-risk individuals, beyond
what is found using a single
continuum, as simply being
free of mental illness does
not guarantee optimal mental
health, and levels of positive
mental health differ depending
on the mental illness diagnosis
of the client
Petrillo 2015 Validation of the
Italian MHC-SF
and verification
of the dual-factor
model
Cross-sectional
study
n = 1438
Italy Adult (general
population)
Age: 47.1 (19.6)
52% female
- Mental Health
Continuum
- Short Form
(MHC-SF)
- Satisfaction With
life Scale (SWLS)
- Positive and
Negative Affect
Schedule
(PANAS)
- General
Health
Questionnaire
(GHQ-12)
- Center for
Epidemiologic
Studies
Depression
Scale (CED-D)
- The MHC-SF factor
structure was replicated
in this Italian sample
and showed good
psychometric properties
- The MHC-SF is validated for
use in Italian populations

36
Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health
Pruchno
et al. (1995)
Examine the
effects that
caregiving has on
the positive and
negative mental
health of multiple
caregivers, their
husbands and
the co-resident
children, and
determine whether
differential
predictors for
both exist in these
groups
Cross-sectional
study
n = 140
United
States of
America
Adult (carers)
Age: 49.4 (range
33-67)
100% female
- Positive Affect
Scale of the
Bradburn’s Affect
Balance Scale
- Center for
Epidemiologic
Studies
Depression
Scale (CES-D)
- Poorer physical health
and greater negative
appraisals were predictors
of depression, while
predictors of positive affect
were less consistent in the
population
- The study found differential
predictors for positive mental
health and negative mental
health, with predictors differing
for males and females,
highlighting the importance of
addressing different factors
when targeting positive mental
health and mental illness
Pruchno
et al. (1996)
To investigate
the relationship
between positive
and negative
wellbeing and
their differential
predictors in a
group of carers
Cross-sectional
study
n = 838
United
States of
America
Adult (carers)
Age: 65.2
100% female
-Life Satisfaction
Index A (LSIA)
-Bradburn’s Affect
Balance Scale
- Center for
Epidemiologic
Studies
Depression
Scale (CES-D)
- A two factor model
was confirmed with
different predictors being
associated with negative
and positive mental health:
positive appraisals were
uniquely predictive of
positive mental health,
while child maladaptive
behaviour was a unique
predictor of negative
mental health.
- Some predictors, e.g.
negative appraisal of
the caregiving role and
physical health, were
predictive of both positive
and negative mental health
- The study highlights the
importance of discovering
common and differential
predictors of positive and
negative mental health, and
the implications this has
for potential treatment and
prevention opportunities
Renshaw
and Cohen
(2014)
Investigate
between-group
differences
of complete
mental health
across three
key indicators of
college student
functioning
(academic
achievement,
interpersonal
connectedness,
and physical
health)
Cross-sectional
study
n = 1356
United
States of
America
Adult (students)
Age: 19.2 (2.0)
65% female
- 10-item Life
Satisfaction
subscale of the
Quality of Life
Interview, Brief
Version (QOL-BV)
- Brief
Symptom
Inventory-18
(BSI-18)
- Four distinct groups, as
postulated by the dual
factor model, could be
noted in the data set
- Life satisfaction provides
additive value in predicting
life-functioning across
interpersonal, physical
health, and academic
achievement domains
(when considered
in conjunction with
psychological distress
indicators)
- Mental health work
undertaken with college
students would benefit
from consideration of life
satisfaction as a complement
to traditional indicators of
psychological distress, as it
can aid in prediction of student
achievement

37
EVIDENCE BASE
Renshaw
et al. (2016)
Investigate the
concurrent validity
of a dual-factor
model using
two analytic
approaches,
categorical and
continuous
Cross-sectional
study
n = 951
United
States of
America
Adult (students)
Age: 20.0 (1.6)
72-75% female
- Satisfaction With
life Scale (SWLS)
- Positive and
Negative Affect
Schedule
(PANAS)
- Depression
Anxiety
Stress Scale
(DASS-21 )
- UCLA
Loneliness
Scale
- Using a categorical
approach to classifying
mental health and illness,
a dual-factor model shows
the best fit
- Using a continuous
approach to classifying
mental health and illness,
a unidimensional wellbeing
model showed a better
fit, than a bi-dimensional
model or a Uni-dimensional
distress model
- Categorical or continuous
approaches to operationalising
mental health and mental
illness can lead to different
results, and more research
into assessment methods is
required
- Categorical assessment
is currently mostly used in
practice, thereby validating
the dual-factor approach for
current mental health practice
Renshaw
(2018)
To validate the
Psychological
Wellbeing and
Distress Screener
in a Turkish
population,
and confirm
the measure's
dual-continua
structure
Cross-sectional
study
n = 399
Turkey Youth (students)
Age: 13.9 (1.6)
49% female
- Psychological
Wellbeing and
Distress Screener
(PWDS)
- Psychological
Wellbeing
and Distress
Screener
(PWDS)
- The wellbeing and
distress scales of the
PWDS best fit the
dual-continua model
- Both scales significantly
predicted positive affect,
negative affect, and
school support, yet only
the wellbeing scale was
a significant predictor of
family support and peer
support
- Measures of mental illness
and wellbeing differentially
predict variables related
to desirable educational
outcomes.
Rose et al.
(2017)
Identify mental
health groups of
African American
youth and explore
the association
between the
resulting classes
and demographic
and educational
experiences
Cross-sectional
study
n = 1170
United
States of
America
Youth (students)
Age: 15.0 (1.4)
52% female
- Life satisfaction
(Single item)
- Center for
Epidemiologic
Studies
Depression
Scale (CES-D)
- WMH-CIDI
- The study found four
distinct groups as
demonstrated by using a
dual-factor approach to
mental health
- Those demonstrating
complete mental health
had higher correlations
particularly with school
bonding, but also less
suspensions and grade
retention
- Dual factor is useful to more
comprehensively assess
mental health of school-
going youth, as can provide
a more detailed insight into
the associations of important
factors such as school bonding
(belonging) with mental health

38
Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health
Schönfeld
et al. 2016
Investigate
the potential
mediation effects
of general
self-efficacy on
positive and
negative mental
health
Cross-sectional
study
n = 10698
Germany,
China,
Russia
Adult (students)
Age: 21-26
47-69% female
- Positive mental
health scale
(PMH)
- Depression
Anxiety
Stress Scale
(DASS-21 )
- Perceived self-efficacy
mediated the effect of
stress on positive mental
health and mental illness,
but significant differences
were found such that
larger effects were seen for
positive mental health.
- These results were
replicated in all three
student samples
- Protective factors such as
self-efficacy exert different
influences on positive mental
health and negative mental
health in the context of stress-
negating processes of daily life
- Due to the changeable
nature of self-efficacy and its
significant (but different) role
in both positive and negative
mental health, it constitutes an
important target for treatment
and prevention to reduce the
effect of stress on health
Schonfeld
et al. (2017)
To compare
indicators of
complete mental
health across the
lifespan in different
countries
Cross-sectional
study
n = 6303
Germany,
Russia,
United
States of
America
Adult (general
population)
51-55% female
- Positive mental
health scale
(PMH)
- Depression
Anxiety
Stress Scale
(DASS-21 )
- Older Russians
experience more negative
mental health, while
German and American
older adults experience
more positive mental health
- Similarly, differences
in levels of depression,
anxiety and resilience were
found in the three cohorts
indicating a potential effect
of economic and social
circumstances between
nations on both indicators
- Complete mental health,
resilience, and social support
across the lifespan varies
substantially, and may be
influenced by the particular
economic and social
circumstances a nation is
exposed to
Seow et al.
(2016)
Determine levels
of positive mental
health in an
Asian outpatient
population,
establish its
correlates and
investigate
whether
higher levels of
positive mental
health would
be associated
with better life
satisfaction
and general
functioning in this
population
Cross-sectional
study
n = 218
Singapore Adults (mental
illness)
Age: 38.4 (11.7)
49% female
- Positive mental
health instrument
- Satisfaction With
life Scale (SWLS)
- Generalized
Anxiety
Disorder 7
(GAD-7)
- Patient Health
Questionnaire
(PHQ-9)
- Levels of positive mental
health in this affective
disorder outpatient
group in a non-Western
population varied
- Sociodemographic
variables influence positive
mental health: young age
and early onset of illness
was associated with lower
positive mental health
- It is important to explore
the level and determinants of
PMH among individuals with
mental illness so that clinicians
and health professionals can
formulate targeted wellbeing
interventions in the treatment
and rehabilitation of those
individuals within clinical
settings. This is particularly
relevant for younger patients
and those with early onset of
illness as these display lower
levels of positive mental health

39
EVIDENCE BASE
Shaffer-
Hudkins
et al. (2010)
To test whether
positive mental
health and mental
illness associate
differently with
various physical
health indicators
Cross-sectional
study
n = 401
United
States of
America
Youth (students)
Age: 12.96 (1.0)
60% female
- Students' Life
Satisfaction Scale
(SLSS)
- Positive and
Negative Affect
Scale for Children
(PANAS-C)
- Youth Self
Report form
of the Child
Behaviour
Checklist (YSR)
Smith
(1996)
To examine the
usefulness of a
two-factor model
in predicting
caregiving
outcomes for
older mothers
providing care
to offspring with
mental retardation
Cross-sectional
study
n = 235
United
States of
America
Adult (carers)
Age: 70.3
100% female
- Ego-integrity
subscale from the
ego adjustment
scale (10-item)
- Negative
affect scale
of the affect
balance scale
(5-item)
- Wellbeing reduced
negative mental health
via decreasing perceived
caregiver burden
- Positive caregiving appraisals
are an essential aspect of
any comprehensive theory of
caregiver wellbeing, which can
be influenced by improving
positive mental health
Spinhoven
et al. 2015
Examine whether
participants with
higher symptom
levels of a current
or past emotional
disorder report
to be less happy
than controls and
to assess whether
measurements
of extraversion
and neuroticism
predict future
happiness
independent of
measurements of
emotional disorder
or symptom
severity
Longitudinal
observational
study
n = 2142
Netherlands Adult (mental
illness)
Age: 48.2 (13.1)
66% female
- Self-rating of
Happiness scale
(1-item)
- Mood and
Anxiety Symptom
Questionnaire-
Shortened
Dutch Version
(MASQ-D30;
30-item)
- Composite
Interview
Diagnostic
Instrument
(CIDI)
- Inventory of
Depressive
symptomato-
logy self-report
(IDS-SR)
- Happiness and
emotional wellbeing were
most strongly related to
depressive disorders and
to social anxiety disorder
- Relationships to
generalised anxiety
disorder, panic disorder
and agoraphobia were
much smaller
- Personality factors,
specifically extraversion,
contribute to wellbeing,
even after controlling for
emotional disorder and
symptom severity
- Wellbeing levels differ per
affective disorder type and
personality type influences
happiness and emotional
wellbeing independently of
psychological disorder or
symptom severity, pointing
to the utility of accounting for
personality factors when trying
to address wellbeing and
happiness in people with and
without mental illness

40
Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health
Suldo and
Shaffer
(2008) and
Suldo et al.
(2011)
Examine whether
student's initial
levels of subjective
wellbeing and
psychopathology
predict school
performance one
year later
Longitudinal
observational
study
n = 341
United
States of
America
Youth (students)
Age: 13.0 (1.0)
59% female
- Students’ life
satisfaction scale
- Positive and
Negative Affect
Schedule
for Children
(PANAS-C)
- Youth
self-report
form of the
child behaviour
checklist (YSR)
- Students with low
psychopathology and
moderate to high wellbeing
had least deterioration of
academic scores, including
reading skills, attendance
rates, academic
self-perceptions and goals,
and social support from
classmates and parents
- Mean academic
performance of vulnerable
students was similar
to that of troubled
students, highlighting that
psychopathology increases
risk of underachievement
- Those with mental illness
but high wellbeing had
better physical health and
social functioning
- The absence of mental illness
is not sufficient to guarantee
optimal academic achievement
- This supports the collection
of information regarding
student's SWB in order to
provide a more complete
understanding of student's
mental health as well as
academic functioning
Suldo
(2015)
Examine the
influence of
peer behaviour
on indicators of
mental health and
psychopathology
Cross-sectional
study
n = 500
United
States of
America
Youth (students)
Age: 15.3 (1.0)
59% female
- Students’ life
satisfaction scale
- Positive and
Negative peer and
associated
- Self-report
of personality
form of the
Behaviour
Assessment
System for
Children,
Second Edition
(BASC-2)
- Positive peer relations
resulted mainly in greater
positive mental health,
being life satisfaction and
positive affect, as opposed
to psychopathology
- Negative peer behaviours
mainly influenced
psychopathology and
negative affect
- Positive and negative peer
relations and their associated
behaviours influence positive
mental health and mental
illness differently
Suldo et al.
(2016)
Determine the
proportion of
students in each
quadrant of the
dual-factor model
and examine
how mental
health, defined
in a dual-factor
model, relates
to adjustment,
social adjustment,
identity
development, and
physical health
Cross-sectional
study
n = 500
United
States of
America
Youth (students)
Age: 15.3 (1.0)
59% female
- Students’ life
satisfaction scale
- Positive and
Negative Affect
Schedule
for Children
(PANAS-C)
- Self-report
of personality
form of the
Behaviour
Assessment
System for
Children,
Second Edition
(BASC-2)
- The study found four
distinct groups as indicated
in the dual-factor model in
this student population
- The groups differ in
academic attitudes,
social adjustment, identity
development, and physical
health, with high positive
mental health being
associated with a lower
likelihood of problems in
developmental outcomes
- Complete mental health,
validated in this study, aligns
with community approach to
prevention, treatment, and
promotion of wellbeing in
youth, and can help schools
determine allocation of efforts
and resources: the most
intense services should be
reserved for troubled students,
who require both reduction
in psychopathology and
increases in SWB

41
EVIDENCE BASE
Teismann
etal. (2018)
Determine the
proportion of
participants who
demonstrate
suicide ideation
and positive
mental health, and
examine whether
the presence of
positive mental
health influences
suicide behaviour
Cross-sectional
study
n = 282
Germany Adult (Mental
illness)
Sample 1:
Age: 43.0 (12.1)
54% female
Sample 2:
Age: 37.9 (12.8)
71% female
- Positive Mental
Health Scale
(9-item)
- Depressive
Symptom
Inventory
- Suicidality
subscale
(DCI-SS)
- Suicidal
behaviours
questionnaire
- revised
(SBQ-R)
- The study could clearly
find four distinct groups
based on the dual-factor
theories
- Suicide behaviour was
different between groups,
with less suicide attempts
in suicide ideations that
have moderate to high
positive mental health
- The Complete state model
is useful for identifying risk
profiles for suicide ideations
Tomba et al.
(2014)
To assess
psychological
well-being in
out-patients with
eating disorders
and in controls
Cross-sectional
study
n = 245
Italy Youth and Adult
(mental illness)
Age: 28.3 (9.7)
96% female
- Psychological
Wellbeing Scales
- General
Health
Questionnaire
(GHQ)
- Impaired levels of
psychological wellbeing
were independent
from the presence of
psychopathology, and
differed per specific eating
disorder diagnosis
- Results support the need to
assess psychological wellbeing
in outpatients with eating
disorders, as it can share a
more detailed view on mental
health of eating disorder
patients
Trompetter
et al. (2017)
Investigate
the impact of
Acceptance and
Commitment
Therapy on
depression or
anxiety symptoms
and positive
mental health
Randomised
Controlled Trial
n = 250
Netherlands Adult (mental
illness)
Age: 45.5 (11.0)
70% female
- Mental Health
Continuum -
Short Form
- Center for
Epidemiologic
Studies
Depression
Scale (CES-D)
- Hospital
Anxiety and
Depression
Scale (HADS)
- Baseline level of and
change in positive
mental health moderately
predicted effectiveness on
depression/anxiety
- Baseline level of and
change in depression/
anxiety moderately
predicted effectiveness on
positive mental health
- Two thirds of participants
improved on either
positive mental health or
depression/anxiety, not
both
- The differential effect of ACT
on positive mental health and
mental illness, and the fact that
response differs for patients,
indicates that practitioners
benefit from monitoring and
working on and monitoring
both when treating their
patients
- Using one treatment method
may not necessarily mean that
patients can achieve complete
mental health as interventions,
for a substantial group of
participants, are only effective
on one dimension
- Systematically implementing
measurements of both
psychopathology and positive
mental health will facilitate
better informed decisions
about the continuation and
focus of patients in mental
health treatment

42
Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health
Van Erp
Taalman
Kip and
Hutsche-
maekers
(2018)
Examine whether
emotional,
psychological and
social wellbeing
are apparent
in a tripartite
structure, and test
whether wellbeing
is moderately
correlated with
mental illness
symptoms in a
mental health care
sample
Cross-sectional
study
n = 1069
Netherlands Adult (mental
illness)
Age: 47.6 (17.7)
63% female
- Mental Health
Continuum -
Short Form
- Outcome
Questionnaire
(OQ-45)
- Mental health patients
do not display a tripartite
structure for wellbeing
- A two-factor model
explained a good fit, but
the wellbeing components
only explained little
variance
- If factor independency
is a pre-requisite, a single
factor structure would be
the best fit
- Mental illness and mental
health are highly correlated
in patients with high levels of
mental illness
- Therefore CMH may be a
useful metaphor for recovery
only, or for participants who
are not mentally ill
Veit and
Ware (1983)
To describe the
development of
the Mental Health
Inventory (MHI)
and investigate
the factor
structure between
psychological
distress and
wellbeing
Cross-sectional
study
n = 5089
United
States of
America
Youth and
Adult (general
population)
Age: 13-69
54% female
- Mental health
Inventory
- Mental health
Inventory
- A large mental health
factor underlies the
mental health index,
with two underlying
factors for wellbeing and
psychological distress
- Reliance on a single
score (psychological
wellbeing or illness)
is associated with
a significant loss of
information
- Positive items clustered
together to define
psychological wellbeing
and items describing
negative states clustered
together to define
psychological distress
- A total of 5 underlying
factors influence wellbeing
(positive affect, emotional
ties) and psychological
distress (anxiety,
depression, loss of control)
- The developed tool measures
two distinct factors of mental
health, being wellbeing and
psychological distress
Vela et al.
(2016)
Examine whether
meaning in
life, hope,
mindfulness, and
grit influence
student life
satisfaction and
depression
Cross-sectional
study
n = 130
United
States of
America
Adult (students)
Age: 20.2 (3.3)
62% female
- Satisfaction With
Life Scale (SWLS)
- Center for
Epidemiologic
Studies
Depression
Scale (CES-D)
- Presence of meaning
in life, mindfulness and
hope were related to life
satisfaction
- Mindfulness and search
for meaning in life were
associated with depression
- Different individual
strengths influence life
satisfaction and depression
- Different traits associated
with positive psychology
differentially predict life
satisfaction and mental illness,
which holds implications for
intervention developers and
practitioners

43
EVIDENCE BASE
Venning
et al. (2013)
Determine the
prevalence and
distribution of
complete mental
health states in
young Australians,
and investigate
the association
of these states
to health-risk
behaviours
Cross-sectional
study
n = 3913
Australia Youth (students)
Age: 13-17
52% female
- Satisfaction With
Life Scale (SWLS)
Psychological
Wellbeing Scale
Social Wellbeing
Scale
- Depression
Anxiety
Stress Scale
(DASS-21)
- Participants who had high
wellbeing and no mental
illness (42%) engaged less
in health-risk behaviours
such as smoking or
consuming alcohol,
compared to other groups
- Measuring both mental illness
and mental health can discover
groups that previously may
have gone unnoticed; groups
who show differences in
health-risk behaviour taking
Weich et al.
(2011)
To describe
mental wellbeing
in a general
population
sample and to
test whether
indicators of
wellbeing, health
status, income
and employment
status are
independent from
mental illness
Cross-sectional
study
n = 7461
United
Kingdom
Adult (general
population)
Age: 50.5 (18.4)
58% female
- 9 single item
questions related
to wellbeing
- Clinical
Interview
Schedule
(CIS-R)
- Wellbeing and mental
illness are correlated but
independent factors
- Eudemonic and hedonic
wellbeing are distinct but
related components of
wellbeing
- The paper demonstrates
evidence of the interrelation
but independence of mental
illness and mental health in an
English population
Westerhof
and Keyes
(2010)
To study age
differences in
mental health and
mental illness,
and determine
age differences in
being completely
mental healthy
(flourishing and
no mental illness)
and mentally ill
(languishing and
mental illness)
Cross-sectional
analysis of one
time-point in
longitudinal
study
n = 1340
Netherlands Adult (general
population)
Age: 48.32 (17.7)
50% female
- Mental Health
Continuum - Short
Form (MHC-SF)
- Brief Symptom
Inventory (BSI)
- Older adults experience
similar amounts of mental
health as younger adults,
as slight differences
could be explained by
age-related differences in
life circumstances
- Younger adults do show
more mental illness, but
have no less mental health
than older adults
- This study did not find a
clear relationship between
age and level of mental health
(flourishing), but did find
differences in mental illness,
highlighting the usefulness
of the dual-factor model in
assessment of mental health
status in adults

44
Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health
Westerhof
(2013)
To analyse the
components of
complete mental
health with
sociodemo graphic
variables over time
Longitudinal
study
n = 1340
Netherlands Adult (general
population)
Age: 48.3 (17.7)
50% female
- Mental Health
Continuum - Short
Form (MHC-SF)
- Brief Symptom
Inventory (BSI)
- Sociodemographic
variables hold different
relations with different
indicators of mental illness
and mental health; relations
that are remarkably stable
across time
- The exceptions to this
stability were age and
educational level, showing
distinct time trajectories for
the different indicators of
mental health and illness
- Public mental health care is
best served by a differentiated
approach in the treatment
and prevention of mental
illness, as well as by the
promotion and protection
of mental health. Such a
differentiated approach should
be tailored to groups with
different socio-demographic
backgrounds
Wilkinson
and Walford
(1998)
To verify that,
in adolescents,
psychological
health can be
viewed as being
comprised of
two dimensions:
wellbeing and
distress
Cross-sectional
study
n = 345
Australia Youth (students)
Age: 17.1 (0.7)
79% female
- Satisfaction With
Life Scale (SWLS)
- Happiness
Thermometer
(1-item)
- Positive and
Negative Affect
Schedule
(PANAS)
- State-Trait
Anxiety
Inventory
- Center for
Epidemiologic
Studies
Depression
Scale (CES-D)
- The study found support
for the two-factor model
over a single factor
model in this adolescent
population, although the
results were less profound
when comparing results to
adults
- Anxiety and negative
mood were indicators of
psychological distress,
while happiness, life
satisfaction and positive
affect were indicators of
wellbeing
- While a two-factor model
worked in this adolescent
population, the fit was less
than what is witnessed in adult
populations, thereby indicating
that assessment may need to
take each into account
Winzer et al.
(2014)
To investigate
the existence of
the dual-continua
model in a
Swedish sample,
and explore its
associations with
demographic,
social and health
factors
Longitudinal
observational
Study
n = 23394
Sweden Adult (general
population)
Age: 16-29
56% female
- Positive Items of
the General Health
Questionnaire
(GHQ-12)
- Negative
Items of the
General Health
Questionnaire
(GHQ-12)
- An exploratory and
conformational factor
analysis found support
for a two-factor model.
Predictors for positive and
negative mental health
were "mirrored", which
points to a one-factor
model
- Measurement of two
dimensions of mental health
need to use instruments
specifically adapted for this
purpose, instead of using
measurement tools that are
designed to measure just one
construct (e.g. mental illness)
- Work needs to be done to
identify specific theoretical
predictors that are linked to
positive mental health rather
than ill-health

45
EVIDENCE BASE
Wood and
Joseph
(2010)
To test whether
people low
in wellbeing
are at risk for
having clinically
elevated levels of
depression ten
years later
Longitudinal
observational
Study
n = 5566
United
States of
America
Adult (general
population)
Age: 51-56
55% female
- Scales of
Psychological
Wellbeing
- Centre for
Epidemiologic
Studies
Depression
(CES-D)
- People with low levels of
positive wellbeing have a
7.2x higher risk of being
depressed 10 years later,
which remained 2.2x
higher when controlling for
other baseline predictors
- As low wellbeing predicts
future depression, it becomes
important to understanding
its relationship with mental
disorder, and supports
the notion that addressing
wellbeing as a means of
preventing and treating
depression is warranted
Xiong et al.
(2017)
To verify the
dual-factor model
in a Chinese
population,
investigate
differences in
self-efficacy beliefs
and academic
emotions in the
four different
dual factor
model groups,
and determine
the stability and
dynamics of
mental health
status for each
group
Longitudinal
observational
study
n = 1293
China Youth (students)
Age: 14.7 (1.9)
47% female
- Satisfaction With
Life Scale (SWLS)
- Positive and
Negative Affect
Schedule
(PANAS)
- Youth Self
Report form
of the child
behaviour
checklist
- The different
dual-factor model groups
demonstrated different
scores for self-efficacy and
academic emotions, and
different groups showed
different stability in mental
health over time. Most
notably the vulnerable
group showed high
transition rates into other
quadrants, pointing to the
importance of targeting
interventions at this group
- This measurement
approach can assist school
psychologists and others
engaged in psychological
service to children in schools
to target those most at risk to
proactively prevent problems
- Those with low subjective
wellbeing and psychology are
most transient and therefore
may require particular attention
from health providers to ensure
the likelihood of positive
change
Yoo and
Kahng
(2019)
To test the
existence of the
dual-continuum
model and to
examine the
relationship
between positive
and negative
mental health
and a range
of different
predictors of
positive youth
outcomes
Cross-sectional
study
n = 471
South Korea Youth (students)
Age: 17.9 (0.4)
50% female
- Korean Child
Wellbeing Index
- Reynold's
Suicidal
Ideation
Questionnaire
(SIQ)
- The dual-continuum
model was supported as
the data fit a two-factor
correlated model rather
than a single-factor model
- Positive mental health
and negative mental health
differentially predicted
variables related to mental
health, most notably peer
and parent relationships,
self-work, and emotion-
focused coping
- The dual continuum model
can be used to better inform
theory-based interventions.
The model provides
greater insights into which
interventions are likely to
improve well-being or reduce
mental illness