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Clinical Psychology Review
journal homepage: www.elsevier.com/locate/clinpsychrev
Doing no harm in mindfulness-based programs: Conceptual issues and
, Catherine Crane
, Edward Miller
, Willem Kuyken
University of Kentucky, USA
University of Oxford, UK
•Potential harmful outcomes of mindfulness-based programs are under-researched.
•Harm occurs in psychotherapy, pharmacotherapy, physical exercise, and meditation.
•Potential harm may be related to participant, program, and instructor factors.
•Mindfulness practice can be unpleasant and challenging without causing harm.
•Understanding of harm in mindfulness programs requires monitoring individual data.
The beneﬁts of empirically supported mindfulness-based programs (MBPs) are well documented, but the po-
tential for harm has not been comprehensively studied. The available literature, although too small for a sys-
tematic review, suggests that the question of harm in MBPs needs careful attention. We argue that greater
conceptual clarity will facilitate more systematic research and enable interpretation of existing ﬁndings. After
summarizing how mindfulness, mindfulness practices, and MBPs are deﬁned in the evidence-based context, we
examine how harm is understood and studied in related approaches to physical or psychological health and
wellbeing, including psychotherapy, pharmacotherapy, and physical exercise. We also review research on
harmful eﬀects of meditation in contemplative traditions. These bodies of literature provide helpful parallels for
understanding potential harm in MBPs and suggest three interrelated types of factors that may contribute to
harm and require further study: program-related factors, participant-related factors, and clinician- or teacher-
related factors. We discuss conceptual issues and empirical ﬁndings related to these factors and end with re-
commendations for future research and for protecting participants in MBPs from harm.
Empirically supported mindfulness-based programs (MBPs) such as
mindfulness-based stress reduction (MBSR; Kabat-Zinn, 1990) and
mindfulness-based cognitive therapy (MBCT; Segal, Williams, &
Teasdale, 2013) are widely used in healthcare, educational, and
workplace settings. Meta-analytic reviews have found MBSR, MBCT,
and closely related programs to have beneﬁcial eﬀects on a range of
outcomes (Gotink et al., 2015). These include psychological disorders,
stress, and coping with illness and pain (Khoury et al., 2013); positive
moods and compassion for self and others (Khoury, Sharma, Rush, &
Fournier, 2015); and some forms of attention and memory (Chiesa,
Calati, & Serretti, 2011). Measurable eﬀects on neural structures and
systems have been documented (Tang, Hölzel, & Posner, 2015) and
eﬀects on blood pressure and immune function have been seen in some
populations (Carlson, Speca, Faris, & Patel, 2007;Nyklíček,
Mommersteeg, Van Beugen, Ramakers, & Van Boxtel, 2013). Compar-
isons with other interventions suggest that MBPs produce better out-
comes than psychoeducation and support groups and comparable out-
comes to cognitive-behavioral therapy and maintenance antidepressant
medication (Goldberg et al., 2018;Kuyken et al., 2016).
Although the beneﬁts of MBPs are well supported, less attention has
been paid to potential harm. The study of harm in MBPs is essential for
several reasons. First, any intervention powerful enough to have sub-
stantial beneﬁts might also cause harm (Dimidjian & Hollon, 2010). In
health-related professions, prevention of harm is the primary ethical
Received 23 March 2018; Received in revised form 8 December 2018; Accepted 4 January 2019
Corresponding author at: Department of Psychology, University of Kentucky, USA.
E-mail address: firstname.lastname@example.org (R. Baer).
Clinical Psychology Review 71 (2019) 101–114
Available online 07 January 2019
0272-7358/ © 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license
duty and requires knowledge of harms that might occur and how to
mitigate them. Second, psychotherapy researchers have long re-
cognized that the study of harmful outcomes can lead to improved
treatment methods (Dimidjian & Hollon, 2011;Mohr, 1995); the same
is likely true for MBPs. Third, meditation as practiced in Buddhist tra-
ditions (e.g., Vipassana, Zen), can elicit challenging and diﬃcult ex-
periences, some of which can be serious and long lasting (Lindahl,
Fisher, Cooper, Rosen, & Britton, 2017). It is therefore essential to ask
whether similar eﬀects might arise in evidence-based MBPs. Finally,
popular media articles about “mindfulness” (often not clearly deﬁned)
sometimes suggest that it can be harmful (Foster, 2016). The scientiﬁc
literature does not yet provide suﬃcient understanding of harm in
MBPs to inform evidence-based perspectives on such articles. Thus,
both the research literature and the public interest seem to require more
systematic study of the potential for harm in MBPs.
In this paper, we discuss conceptual and empirical work from the
scientiﬁc literature on mindfulness and related topics that bears on how
to understand and investigate the harm that might arise for participants
in evidence-based MBPs. Although too small for a systematic review,
the literature suggests that the question of harm in MBPs needs careful
attention, including greater conceptual clarity to facilitate more sys-
tematic research and interpretation of extant ﬁndings. After summar-
izing how mindfulness, mindfulness practices, and MBPs are deﬁned in
the evidence-based context, we examine how harm is understood and
studied in related approaches to health and wellbeing, including psy-
chotherapy, pharmacotherapy, and physical exercise. We also review
research on harmful eﬀects of meditation in contemplative traditions.
These diverse bodies of literature provide helpful parallels for under-
standing potential harm in MBPs and suggest three types of factors that
may contribute to harm: program-related factors, participant-related
factors, and clinician- or teacher-related factors. We discuss empirical
ﬁndings and conceptual issues related to these factors and end with
recommendations for future research and for protecting participants in
MBPs from harm.
2. Deﬁning mindfulness, mindfulness practices, and MBPs in the
Evidence-based MBPs include ideas and practices adapted from
Buddhist traditions. Although discussion continues about the relation-
ship between the secular and the religious in MBPs (Brown, 2016;
Compson, 2017), most are transparent about the Buddhist roots of
mindfulness while aiming to be suitable for mainstream settings, ac-
cessible to diverse participants, and researchable within scientiﬁc dis-
ciplines related to health and wellbeing (Crane et al., 2017). To serve
these aims, central ideas and practices in MBPs are conceptualized
using contemporary scientiﬁc and discipline-speciﬁc language (Baer,
In the scientiﬁc literature, mindfulness is usually deﬁned as a form
of present-moment attention and awareness that includes two elements:
the attention itself and the qualities of the attention (sometimes de-
scribed as the what and the how of mindfulness). Examples shown in
Table 1 indicate that mindfulness is understood to be open, nonjudg-
mental, friendly, curious, accepting, compassionate, and kind. Mind-
fulness can be further conceptualized as a state in which these qualities
of awareness are present, as a dispositional or trait-like general ten-
dency to pay attention in these ways, and as a set of skills that develop
with practice (Brown, 2016;Linehan, 1993). In all three of these forms,
mindfulness has been shown to be correlated negatively with mala-
daptive psychological processes and positively with health and well-
being (Levin, Hildebrandt, Lillis, & Hayes, 2012;Khoury et al., 2013;
Quaglia et al., 2016).
2.2. Mindfulness practices
In evidence-based MBPs, mindfulness practices are exercises that
cultivate the what and how elements of mindfulness. In most practices,
participants are invited to focus their attention on present-moment
phenomena, to notice when the mind wanders and return to the in-
tended focus, and to bring an attitude of friendly curiosity and non-
judgmental acceptance to whatever is observed. In informal practices,
these skills are applied to routine activities such as eating, walking and
washing dishes. In formal practices, time is devoted solely to cultivating
these skills. Some formal practices, such as sitting meditation, have
roots in Buddhist traditions but are adapted for mainstream settings.
Other practices were developed for more speciﬁc contemporary pur-
poses. For example, in mindfulness-based childbirth and parenting
(MBCP; Veringa et al., 2016), participants hold ice cubes for 60 s (the
average length of a contraction) while attending mindfully to their
breath and the sensations in their hands. This practice is intended to
reduce the fear and stress associated with childbirth by teaching a new
way of being present with sensations of pain.
2.3. Mindfulness-based programs
MBPs integrate theories and practices from contemplative traditions
with the scientiﬁc disciplines of psychology, medicine, and education
(Crane et al., 2017). They are based on a model of human experience
that places ways of relating and responding to distress (rather than the
distress itself) at the core of many problems and disorders. Through
intensive training in formal and informal mindfulness practices and
related exercises, MBPs teach a new relationship with present-moment
experience based on approach (rather than avoidance), compassion,
and decentering. The learning process is highly experiential. Mind-
fulness practices are followed by an interactive process known as in-
quiry that helps participants learn to identify their thoughts, emotions,
and sensations, recognize habitual patterns of reacting to them, and
respond with greater awareness and ﬂexibility. Intended outcomes in-
clude attentional, emotional, and behavioral self-regulation as well as
equanimity, compassion, and wisdom.
The ﬁrst MBP to appear in the research literature was MBSR (Kabat-
Zinn, 1982), an 8-week group program for adults with stress, pain, and
health concerns. According to Kabat-Zinn (2011), one intention of
MBSR was to recontextualize mindfulness within science, medicine, and
healthcare “so that it would be maximally useful to people who could
not hear it or enter into it through the more traditional dharma gates”
(p. 288). MBSR is a skills training and psychoeducational program that
uses formal and informal mindfulness practices suitable for con-
temporary non-Buddhist settings.
In deﬁning the essential features of MBPs, Crane et al. (2017) in-
clude programs derived from or inspired by MBSR, such as MBCT,
MBCP, mindfulness-based relapse prevention (Bowen et al., 2009),
mindfulness-based eating awareness training (Kristeller, Wolever, &
Sheets, 2014), and others, but not programs such as dialectical behavior
therapy (DBT; Linehan, 2015) and acceptance and commitment therapy
(ACT; Hayes, Strosahl, & Wilson, 2012). DBT and ACT integrate
mindfulness exercises with a variety of other therapeutic strategies,
place less emphasis on formal meditation, and are generally identiﬁed
as forms of psychotherapy, whereas MBPs are often described as edu-
cational and skills training programs. For these reasons, this paper
addresses the MBSR-inspired family of MBPs but not DBT, ACT, or other
psychotherapies with mindfulness elements.
3. The study of harm in related ﬁelds
Little is known about the potential for harmful outcomes in MBPs. In
contrast, other approaches to health and wellbeing, including psy-
chotherapy, pharmacotherapy, and physical exercise, have examined
the issue in more detail. In the following sections, we summarize
R. Baer et al. Clinical Psychology Review 71 (2019) 101–114
research on harm in these ﬁelds and draw parallels that may be helpful
in understanding how the risk of harm from MBPs can be con-
ceptualized and studied. We also summarize recent work on the po-
tential for harm from meditation in contemplative traditions and con-
sider its applicability to the question of harm in MBPs.
3.1. Psychological treatment
Duggan, Parry, McMurran, Davidson, and Dennis (2014) deﬁne
harm as “a sustained deterioration that is caused directly by the psy-
chological intervention” (p. 2). Dimidjian and Hollon (2010) state that
harmful psychological treatments are damaging and injurious and cause
worse outcomes than would have occurred without treatment. The
potential for psychotherapy to cause harm has been recognized for
many years (Bergin, 1966). Large scale studies and reviews have con-
sistently concluded that between 3% and 10% of psychotherapy clients
get worse with treatment (Lambert, 2013;Mohr, 1995;Strupp, Hadley,
& Gomez-Schwartz, 1977). For example, in a sample of over 6000
psychotherapy clients in the US, Hansen, Lambert, and Forman (2002)
found that 8.2% showed reliable deterioration on a well-validated
outcome questionnaire. Crawford et al. (2016) surveyed over 75,000
recipients of psychological treatment through the National Health
Service in England and Wales and found that, of the 14,587 who re-
turned the survey, 763 (5.23%) agreed (slightly or strongly) that they
had experienced “lasting bad eﬀects from the treatment.”
Harm in psychotherapy can take many forms. The target problem
may get worse or a new problem may arise while the target problem
improves or remains unchanged (Dimidjian & Hollon, 2010). Linden
(2013) proposed deﬁnitions for several unwanted outcomes of psy-
chotherapy including adverse reactions (unwanted events caused by the
treatment), side eﬀects (unwanted events caused by an eﬀective treat-
ment), malpractice eﬀects (unwanted events caused by inappropriate
treatment), and contra-indications (serious side eﬀects rendering a
treatment inappropriate for some people). Linden and Schermuly-
Haupt (2014) further noted that unwanted events can be mild (no
consequences), moderate (distressing), severe (in need of counter-
measures), very severe (lasting negative consequences), or extremely
severe (hospitalization required or life threatening). Mild-to-moderate
events should be understood and avoided when possible but do not
appear to meet deﬁnitions of harm, whereas events higher in the scale
are clearly harmful.
When deterioration over a course of therapy is observed, its causes
may not be clear. In some cases, the deterioration might not be attri-
butable to the treatment, which may be inert or may slow but not re-
verse an ongoing worsening of symptoms. Even so, Lambert (2013)
noted that when deterioration is monitored in controlled studies, it is
often worse in treatment groups than in no-treatment controls, sug-
gesting that aspects of treatment may be responsible. Empirical work on
harm in psychotherapy has examined three types of variables that are
correlated with negative outcomes: client, therapist, and treatment
Client variables related to negative outcomes include severity of
symptoms, poor interpersonal skills (Mohr, 1995), diagnostic co-
morbidity, severe stressors (Dimidjian & Hollon, 2011), and demo-
graphic variables. Crawford et al. (2016) found that clients older than
65 years were less likely to report negative eﬀects whereas sexual and
ethnic minorities were more likely to report them. Therapist variables
include lack of skill in conducting an eﬀective therapy (Lilienfeld,
2007), lack of empathy, underestimating the severity of the client's
problems, and poor communication about the process and content of
therapy (Crawford et al., 2016;Mohr, 1995). Treatments themselves
can also be harmful. Lilienfeld (2007) identiﬁed therapies shown in
randomized trials to produce worse outcomes than comparison groups.
For example, critical incident stress debrieﬁng can worsen symptoms of
post-traumatic stress (Litz, Gray, Bryant, & Adler, 2002), perhaps by
interfering with natural processes of recovery. Boot-camp approaches to
conduct problems in adolescents may cause increases in criminal be-
haviour (Weiss, Wilson, & Whitemarsh, 2005.
Adverse drug reactions (ADRs) are deﬁned as appreciably harmful
or unpleasant reactions to medications (Aronson & Ferner, 2005) re-
sulting from error, misuse, and oﬀ-label use, as well as authorised use in
normal doses (Coleman & Pontefract, 2016). ADRs are occasionally
fatal and often uncomfortable, costly, and damaging to the patient-
prescriber relationship. Incidence of ADRs has been estimated at 5–10%
of hospitalized patients (Lazarou, Pomeranz, & Corey, 1998). The three
types of variables related to harm in psychotherapy are also recognized
in pharmacotherapy. Patient factors and drug factors are often dis-
cussed in terms of pharmacokinetics and pharmacodynamics, or “what
the body does to the drug” and “what the drug does to the body”
(Meibohm & Derendorf, 1997, p. 401). Pharmacokinetics includes how
the body absorbs, distributes, metabolizes, and excretes the drug;
pharmacodynamics, are the biochemical and physiological eﬀects of the
drug on the body. Drug eﬀects, therefore, are mediated by a complex
interaction of drug factors and patient factors, including dosage and
frequency of administration, the patient's genetic proﬁle, the presence
of other drugs in the body, and tolerance to the drug.
Clinician factors are also important. Clinicians must identify pa-
tients who are likely to be susceptible to ADRs, modify the treatment
choice accordingly, and include in the treatment plan strategies for
mitigating ADRs that arise (Coleman & Pontefract, 2016). They must
explain the risks and beneﬁts of taking or not taking the drug and al-
ternative options. For patients who choose to take the drug, failure to
take it correctly can cause harm. Bosworth et al. (2011) noted that
thousands of deaths and hospitalizations each year are attributable to
medication nonadherence. A large literature suggests that clinicians can
reduce the risk of harm from nonadherence through information, ad-
vice, and counselling that increase patients' ability and willingness to
take medication as prescribed (Schulz, 2007).
Contemporary psychological descriptions of mindfulness: what and how.
Author What How
Kabat-Zinn, 1994, 2003 Paying attention, or the awareness that arises
through paying attention
on purpose, in the present moment, and nonjudgmentally; with an aﬀectionate,
compassionate quality, a sense of openhearted, friendly presence and interest
Marlatt & Kristeller, 1999 Bringing one's complete attention to present
on a moment-to-moment basis, with an attitude of acceptance and loving-kindness
Bishop et al., 2004 Self-regulation of attention so that it is
maintained on the immediate experience
with an orientation characterized by curiosity, openness, and acceptance
Germer, Siegel, & Fulton,
Awareness of present experience with acceptance: an extension of nonjudgment that adds a measure of kindness or
Linehan, 2015 The act of focusing the mind in the present
without judgment or attachment, with openness to the ﬂuidity of each moment
R. Baer et al. Clinical Psychology Review 71 (2019) 101–114
3.3. Physical exercise
Mindfulness is sometimes compared to physical exercise, with
analogies to training the attention through mindfulness exercises “ra-
ther in the same way that we go to a gym to train muscles” (Segal et al.,
2013, p. 97). The beneﬁts and harms of physical exercise are well re-
searched. The American College of Sports Medicine (Garber et al.,
2011) notes that the beneﬁts far outweigh the risks in most adults and
include reduced mortality from many causes, prevention of chronic
medical conditions, reductions in anxiety and mood disorders, and
improved wellbeing and quality of life (Warburton, Taunton, Bredin, &
Isserow, 2016). The most common risks are musculoskeletal, including
strains, sprains, tears, inﬂammation, and fractures. More serious risks
are cardiovascular, including arrhythmias, heart attacks, and sudden
cardiac arrest. Conn, Annest, and Gilchrist (2003) reported that 2.59%
of Americans annually receive medical attention for a sports or re-
creation-related injury. The risk of a cardiovascular event linked to
aerobic exercise varies with ﬁtness level and falls between 1 in 500,000
and 1 in 2,600,000 h of exercise (Franklin & Billecke, 2012).
As in psychotherapy, risks of physical exercise are often discussed in
terms of participant, program, and instructor factors. Participant factors
include age, health status, physical activity, and ﬁtness. Program fac-
tors include intensity of the exercise, tailoring to individual partici-
pants, screening procedures, and education about risks. Instructor fac-
tors include knowledge of the physiology of exercise, competence in
screening participants, adapting programs to individuals, and en-
couraging adherence (Garber et al., 2011). These factors interact in
interesting ways to inﬂuence risk/beneﬁt ratios. For example, the dose-
response relationship between exercise and health status is not linear.
For inactive people, small increases in exercise lead to substantial
health beneﬁts (Lollgen, Bockenhoﬀ, & Knapp, 2009). In contrast, ex-
tremely active people may experience diminishing returns for health
beneﬁts as well as cardiovascular damage (Patil et al., 2012).
Warburton et al. (2016) note that people engaged in intensive training
for “ultra-endurance events” are at increased risk for cardiovascular
disease and “should be cautioned about the perils involved” (p. 216).
3.4. Meditation in contemplative traditions
Case reports of one or a few individuals describe severe symptoms
induced by meditation, including psychosis (Kuijpers, Van der Heijden,
Tuinier, & Verhoeven, 2007), negative aﬀect (French, Schmid, &
Ingalls, 1975), mania (Yorston, 2001), depersonalization and dereali-
zation (Castillo, 1990), and traumatic memories (Miller, 1993). Such
outcomes have been associated with several types of meditation
(transcendental, Zen, mindfulness) and often occurred in the context of
intensive retreats (Lustyk, Chawla, Nolan, & Marlatt, 2009). Most of
these early studies did not address the prevalence of harmful outcomes
in meditating samples or account for pre-existing psychological diﬃ-
culties. None involved evidence-based MBPs.
Larger studies reporting percentages of meditating samples with
negative experiences are summarized in Table 2.Otis (1984) found that
4.5% - 13.5% of transcendental meditation practitioners (N= 574)
reported increases in anxiety, depression, confusion, and other symp-
toms. The more experienced meditators reported more symptoms, but
also more psychological problems prior to taking up meditation. In
long-term Vipassana practitioners (N= 27), Shapiro (1992) found that
while most reported more positive than negative eﬀects, 63% reported
at least one challenging experience such as confusion, alienation, or
negative emotion. Some described these experiences as learning op-
portunities rather than problems; however, two (7%) reported severe
eﬀects (disorientation and depression) that caused them to stop medi-
tating. In an internet survey of 342 meditation practitioners (Cebolla,
Demarzo, Martins, Soler, & Garcia-Campayo, 2017), 25.4% reported
unwanted eﬀects (UEs) including negative emotions, pain, depersona-
lization, and other symptoms. Many of these symptoms were described
as transitory, although missing data were extensive. In 1.1% of the
sample, UEs caused the person to stop meditating; 5.7% sought help
from a medical professional or therapist. Positive outcomes were not
More detailed accounts are provided by Lomas, Cartwright,
Edginton, and Ridge (2015), who interviewed 30 male Buddhist med-
itators about the impact of meditation on their wellbeing. All were
regular practitioners of various types of meditation for durations ran-
ging from less than ﬁve to > 20 years. Three were receiving mental
health treatment at the time of the interview; 11 had done so in the
past. All described meditation as a valuable activity and conducive to
wellbeing. However, reports of substantial diﬃculties accounted for
about one quarter of the interview data and these reports became the
subject of the paper.
For example, most participants reported that meditation brought up
troubling thoughts and feelings that were hard to manage. Many stated
that depression, anxiety, and low self-esteem were exacerbated by
meditation. Six reported serious threats to their sense of reality; for
example, they felt unreal, disoriented, or alienated. The authors note
that “these episodes did not occur in relation to more conventional
practices like mindfulness or loving-kindness meditation” but arose
when “attempting advanced meditation practices while still being a
relative beginner” and doing so “without the guidance of an experi-
enced teacher and/or a supportive sangha” (p. 855). The most severe
diﬃculties were psychotic symptoms. One participant felt close to
psychosis when trying to resume normal life following a week of in-
tensive practice in isolation. Two others were hospitalized for psychotic
episodes; one of them, who was also suicidal, attributed this to medi-
tation. Five of the six who reported threats to their sense of reality
reported no mental health problems before starting meditation and four
attributed these experiences directly to the meditation practice. Despite
the diﬃculties, many of the participants said that they eventually
learned skills for managing them and came to see such experiences as
important to their wellbeing and psychological development. The au-
thors concluded that meditation can have substantial positive and ne-
Overall, the studies in Table 2 suggest that unpleasant and diﬃcult
experiences in meditation are common. In three of the four studies,
many participants described these experiences as temporary and useful
in developing skills and insights. Quantitative data are not always
provided, making it hard to determine the prevalence of diﬃculties that
outweigh beneﬁts. However, severe and harmful eﬀects were reported,
with 1% - 7% of participants quitting meditation, seeking professional
help, or being hospitalized.
In the most detailed qualitative study to date of meditation-related
harm, Lindahl et al. (2017) interviewed 60 Western Buddhist practi-
tioners from the Zen, Theravada, and Tibetan traditions (57% male,
mean age = 49 years, all residing in North America or Europe). Parti-
cipants were eligible only if they reported diﬃcult, challenging, dis-
tressing, or impairing experiences related to their meditation practice
that could not plausibly be attributed to pre-existing psychological or
medical conditions or other factors. Thus, this study provides no in-
formation about base rates of diﬃculties in meditating samples and is
not included in Table 2. Most participants were White and held uni-
versity degrees; 60% were meditation teachers. For 72%, meditation-
related diﬃculties began during or shortly after a retreat. For 28%, they
were associated with daily practice. None had participated in evidence-
Semi-structured interviews yielded 59 categories of meditation-re-
lated eﬀects that were clustered into seven domains: cognitive (change
in executive functioning, delusions), perceptual (hallucinations, dis-
tortions in time or space), aﬀective (positive or negative aﬀect), somatic
(pain, energy, sleep, movement-related), conative (motivation-related),
sense of self (self-other or self-world boundaries, sense of agency) and
social (social impairment, change in relationships). Most (73%) re-
ported moderate to severe impairment in at least one domain, 17%
R. Baer et al. Clinical Psychology Review 71 (2019) 101–114
reported suicidality, and 17% required inpatient hospitalization.
Median duration of impairment was 1–3 years, with a range of a few
days to > 10 years.
Analyses also yielded four types of factors potentially related to
diﬃcult meditation experiences, corresponding loosely to the three
factors identiﬁed in the previous sections (participant, program, and
clinician/instructor factors). Participant factors included psychiatric,
medical, and trauma history, motivations or goals for meditating,
worldview, and personality. Health behavior factors (which can also be
seen as participant factors) included diet, sleep, exercise, and use of
medications or recreational drugs. Practice factors included the
amount, intensity, consistency, type, and stage of practice. Relationship
factors included relationships with teachers, practice community, and
others, as well as their early life relationships. Teacher factors other
than relationship with the meditator were not discussed.
A striking ﬁnding of this study was the lack of consistency among
participants in whether speciﬁc meditation eﬀects were seen as adverse.
Many intense experiences, including aﬀect, pain, and paranoia, were
appraised in a variety of ways. The authors note that interpretive fra-
meworks in the Buddhist traditions are diverse, with diﬀerences “across
traditions, lineages, or even teachers” in whether speciﬁc meditation-
related experiences should be seen as “progress” or “pathology” (p. 25).
Diﬀerences between Buddhist and psychological or medical perspec-
tives are also evident. Experiences that seem pathological from a clin-
ical point of view (hallucinations, paranoia) might not be viewed as
harmful if understood by the practitioner and teacher as transitory
experiences that make sense within the conceptual framework of their
meditation tradition and can be managed constructively.
Participants in this study were recruited through “outlier sampling”
(p. 7) and represent the extreme adverse end of the distribution of
meditation-related eﬀects. This was intentional, as the purpose was to
study under-reported phenomena; however, it prevents conclusions
about the base rates of distressing or impairing eﬀects in the overall
population of Buddhist meditation practitioners. The extent to which
ﬁndings apply to participants in MBPs is hard to determine. Although
25% of participants who reported harm were practicing less than one
hour per day using practices similar to those in MBPs and for similar
purposes (mental health-related rather than spiritual purposes), they
may not have had the psychoeducational and structural supports typical
of MBPs (Lomas et al., 2015). We discuss these supports in more detail
in a later section.
3.5. Harm in related ﬁelds: parallels for the study of evidence-based MBPs
The literature just reviewed suggests several parallels for the study
of harm in evidence-based MBPs. First, interventions with established
beneﬁts can also cause harm. Between 3 and 10% of psychotherapy
clients get worse, 5–10% of hospitalized patients have adverse drug
reactions, a small percentage of participants in physical exercise are
injured, and an unclear percentage of meditators in contemplative
traditions experience harmful eﬀects. MBPs include meditation and are
provided in both psychotherapeutic and wellness contexts; it therefore
seems likely some participants may experience harmful outcomes.
Second, sources of potential harm in the four ﬁelds just reviewed
can be classiﬁed into three categories that may also apply to MBPs: 1)
program, treatment, or practice factors, 2) client, patient, or participant
factors, and 3) teacher, therapist, or clinician factors. Examples (not an
exhaustive list) are shown in Table 3. Although it is useful to consider
these factors separately, in many situations they probably work to-
gether. For example, some medications are hard to take correctly
(treatment factor); e.g., those that must be taken several times daily
under speciﬁc conditions. For a patient whose circumstances make this
diﬃcult or whose personality is low in conscientiousness (patient fac-
tors), help from the prescriber (clinician factor) with problem-solving
Studies reporting percentages of meditating samples (none from MBIs) describing negative or unwanted eﬀects of meditation.
1st author, year Sample Percent reporting and types of negative eﬀects Comments
Otis, 1984 574 TM practitioners 4.5% - 13.5% reported anxiety, depression, confusion,
or other symptoms
More experienced meditators reported more negative eﬀects
and more problems prior to taking up meditation
Shapiro, 1992 27 long-term Vipassana
63% reported negative emotion, confusion, alienation,
or other symptoms
7% reported severe eﬀects (disorientation, depression)
that led them to stop meditating
Many described unpleasant experiences as temporary and as
Over 80% reported positive outcomes (joy, conﬁdence,
acceptance, compassion, problem solving, resilience)
Psychiatric history not addressed
Cebolla, 2017 342 practitioners of many types of
25.4% reported unwanted events (anxiety, pain, mood
1% stopped meditating
5.7% sought professional help
Many described unwanted events as transitory
Positive eﬀects not addressed
Psychiatric history not reported
Extensive missing data
Lomas, 2015 30 male Buddhist meditators 100% described meditation as challenging (diﬃcult,
unpleasant thoughts and emotions)
25% of the interview data involved problems with
20% reported threats to sense of reality
7% hospitalized (1 suicidal)
100% described meditation as valuable and conducive to
Many described diﬃculties (even severe ones) as important to
Sources of harm in related approaches to health and wellbeing.
Discipline Program/intervention factors Participant factors Teacher/clinician factors
Psychotherapy theoretically unsound, interferes with natural
psychological processes, wrong treatment for
symptom severity, comorbidity, poor
interpersonal functioning, severe
lack of empathy, underestimating severity of
client's problems, lack of clarity about process or
content of therapy, other lack of competence
Pharmacotherapy dosage, frequency of administration,
genetic proﬁle, other drugs in body,
lack of knowledge of drug eﬀects, lack of skills for
Physical exercise not tailored for individual, too intense, lack of
screening or education about risks
age, health status, ﬁtness level, physical
lack of general competence, lack of skills for
Meditation in contemplative
amount, intensity, consistency of practice;
type or stage of practice
psychiatric, medical, or trauma history;
goals for practice, personality, health
relationship with practitioner
R. Baer et al. Clinical Psychology Review 71 (2019) 101–114
or ﬁnding a diﬀerent medication may be necessary. An example from
psychotherapy is relaxation-induced anxiety (Ferguson & Sgambati,
2008), which may be related to fear of losing control (participant
factor) and can be addressed by trying a diﬀerent form of relaxation
(program factor) or providing enhanced explanation and guidance
(therapist factor). In both of these examples, skillful reduction of the
likelihood of harm integrates participant, program, and clinician fac-
tors. The same is likely true of MBPs.
The dose-response relationship and adherence to recommendations,
which have been studied in pharmacotherapy, physical exercise, and
psychotherapy, may also be important in evidence-based MBPs.
Whether higher doses of meditation can be harmful, within the range
recommended by MBPs, is unknown. Whether lack of adherence in
MBPs can cause harm (rather than unhelpfulness) through under- or
overdosing is also unknown. Clinician or instructor factors, such as
educating participants about rationales, risks, and beneﬁts, and tai-
loring programs for individual needs, may also be important in pre-
venting harm in MBPs.
Finally, it seems clear that many approaches to health and wellbeing
can be stressful and challenging. Eﬀective medications can have un-
pleasant side eﬀects. Physical exercise can cause soreness and fatigue.
Diﬃcult experiences in meditation are sometimes seen as learning op-
portunities or indications of progress along the meditative path.
Temporary discomfort also seems to be inevitable in psychotherapy
(Duggan et al., 2014) as participants confront painful issues, learn new
skills, and apply them in problematic situations. In the next section we
consider the important distinction between lasting harm and the dis-
comfort associated with psychological change. We focus on evidence-
based psychotherapies, where discomfort has been widely discussed,
and then consider how the issues apply to MBPs.
4. Stress and discomfort in psychological change
Many evidence-based psychological treatments include diﬃcult
activities. Behavioral experiments, for example, are designed to test
unhelpful beliefs, such as, “If I participate in conversation, I'll say stupid
things and people will reject me.” Testing these beliefs by engaging in
such behavior, even in carefully planned ways, is expected to induce
anxiety (Bennett-Levy et al., 2004). In fact, behavioral experiments that
induce too little anxiety tend to be ineﬀective because they create too
little change in clients' beliefs about what they can do. An eﬀective
behavioral experiment is a “challenge to prevailing perspectives” and
likely to seem “at least somewhat threatening” (Bennett-Levy et al.,
2004; p. 43). The same applies to exposure-based therapies. A client
with obsessive-compulsive disorder may be encouraged to touch a dirty
ﬂoor and then refrain from handwashing, a person with post-traumatic
stress to recount a traumatic experience in detail. Many clients ﬁnd
these procedures challenging.
Some mental health professionals believe that exposure-based
methods cause attrition or exacerbation of symptoms and that clients
are better oﬀ continuing with the disorder than participating in the
treatment (Becker, Zayfert, & Anderson, 2004;Richard & Gloster,
2007). These concerns are inconsistent with the strong empirical evi-
dence supporting the eﬃcacy of exposure-based therapies (Olatunji,
Deacon, & Abramowitz, 2009). Deacon and Abramowitz (2005) re-
ported that people with anxiety disorders perceive exposure-based CBT
as more acceptable than medications and more likely to be eﬀective in
the long term. Foa, Zoellner, Feeny, Hembree, and Alvarez-Conrad
(2002) found that prolonged exposure for PTSD caused temporary
worsening of symptoms in a minority of participants, but that this short-
term eﬀect did not increase the risk of attrition or reduce the beneﬁts
attained by the end of treatment.
Recommendations for avoiding harm in such treatments include: (a)
remembering that many clients are “vulnerable people whose con-
ﬁdence is readily shaken” (Bennett-Levy et al., 2004, p. 33), (b) pro-
viding a clear rationale for and explanation of the activity, (c) never
coercing a client to engage in the procedure, but encouraging the client
to collaborate in designing the exercises and make their own decisions
about participating in them, (d) using tasks that objectively are no more
risky than daily life (e.g., asking a stranger for directions may feel
terrifying to a client with severe social anxiety, but is generally not
dangerous), and (e) anticipating how the activity might go awry and
how this will be interpreted and managed. Olatunji et al. (2009) note
that the potential for discomfort makes exposure-based therapies
complex to implement and that their most substantial risk may be un-
skillful delivery by therapists with inadequate training and supervision.
4.1. Stress and discomfort in MBPs
Participation in MBPs also involves discomfort. Unwanted thoughts,
emotions, and sensations inevitably arise during practices. Segal et al.
(2013) recommend discussing these diﬃculties during a pre-class in-
terview and providing a clear rationale for how the program may help
with participants' concerns. During the course, teachers often remind
participants not to push beyond limits of safety or tolerance and suggest
ways to adapt practices if diﬃculties that feel overwhelming arise.
Within these limits, however, discomfort is generally approached
(with compassion) rather than avoided. In MBCT, a handout explains
that mindful awareness in daily life means “facing what is present, even
when it is unpleasant and diﬃcult” (p. 102) and that learning to do this
gently, with the support of the teacher and the group, is “the most ef-
fective way, in the long run, to reduce unhappiness.” To cultivate ac-
ceptance skills, several MBPs include a practice in which participants
are invited to bring a problem to mind and observe the associated
thoughts and feelings with friendly curiosity. Although no studies have
examined the eﬀects of this practice separately from the rest of the
curriculum, an extensive body of research shows the maladaptive ef-
fects of avoidance and suppression of thoughts, emotions, and sensa-
tions and the beneﬁts of accepting them as they are (Cameron &
Overall, 2018;Hayes, Wilson, Giﬀord, Follette, & Strosahl, 1996;
Kashdan & Rottenberg, 2010;Levin et al., 2012). Clinical observations
suggest that learning skills for facing diﬃculties is empowering (Sears,
4.2. Weighing the risk of discomfort against the potential for beneﬁt
In their discussion of uncomfortable but eﬀective therapies, Olatunji
et al. (2009) noted that the risks of engaging in them must be balanced
against the risks of not doing so. If alternative treatments are less ef-
fective, the risk that symptoms will continue may be worse than the
temporary discomfort caused by the treatment. The balance between
acceptable discomfort and potential beneﬁt may vary with the severity
of the participant's problems. A person with a severe disorder probably
feels much distress in daily life and may ﬁnd that diﬃcult therapeutic
exercises, though uncomfortable, are within the range of discomfort
caused by their symptoms and worthwhile in light of the likely beneﬁts.
In contrast, a psychologically healthy person who takes a mindfulness
course for personal growth and unexpectedly has an intensely un-
comfortable experience may ﬁnd the discomfort disproportionate to the
expected beneﬁts. Such discomfort may not qualify as harm, by current
deﬁnitions, if it doesn't lead to sustained deterioration. If the diﬃcult
experience is disclosed, a skilled teacher may be able to help the par-
ticipant work with it in beneﬁcial ways. On the other hand, the diﬃcult
experience may be suﬃciently distressing to qualify as an adverse
event. This term is deﬁned in the next section.
5. Harm and adverse events in MBPs: Deﬁnitions and current
We suggest that the most useful deﬁnition of harm in MBPs is based
on the deﬁnitions used in psychotherapy. That is, after exposure to the
MBP (whether the participant completes it or drops out), harm has
R. Baer et al. Clinical Psychology Review 71 (2019) 101–114
occurred if the participant's symptoms or level of functioning are worse
than beforehand and this deterioration is sustained, attributable to the
program, and more severe than it would have been without the pro-
gram. As in psychological treatment, harm in MBPs can appear in a
variety of ways. We agree with Dimidjian and Hollon (2010) that harm
is worse than unhelpfulness. An unhelpful program confers no beneﬁt
and will not stop an ongoing process of deterioration, whereas a
harmful program makes matters worse than they would have been
The terms adverse events (AEs) and serious adverse events (SAEs) are
often used in healthcare research and have been adopted in some stu-
dies of MBPs. As deﬁned by the World Health Organization, an AE is an
untoward occurrence in a patient or research participant who is ad-
ministered a pharmaceutical product (Lineberry et al., 2016); an SAE is
such an event that threatens life or function (Ioannidis et al., 2004). In
behavioral health and psychotherapy trials, SAEs include events such as
suicidal behavior and psychiatric hospitalizations; AEs are less severe
changes in psychological, behavioral, or physical functioning (Peterson,
Roache, Raj, & Young-McCaughan, 2013). By deﬁnition, AEs and SAEs
are not necessarily caused by the intervention. The causes of these
events can be diﬃcult to determine. In clinical trials, AEs and SAEs are
monitored in treatment and control groups; a higher frequency in the
treatment group suggests that the treatment may be harmful.
A few trials have reported deterioration for participants in MBPs.
For example, Reynolds et al. (2017) found symptom increases in an
MBP for cancer patients. Johnson et al. (2016), in a school-based study,
reported worse post-treatment anxiety scores in the MBP than in no-
treatment for several subgroups of participants. Brooker et al. (2012), in
an uncontrolled study of work-related stress, reported mixed ﬁndings,
with deterioration on some outcome variables. These studies must be
seen in the context of meta-analyses concluding that most studies
support the beneﬁts of MBPs for these populations, including children
and adolescents (Dunning et al., 2018), cancer patients and survivors
(Piet, Würtzen, & Zachariae, 2012), and workers in various occupations
(Lomas, Medina, Ivtzan, Rupprecht, & Eiroa-Orosa, 2018).
We found four reviews addressing AEs and SAEs in MBPs; these are
summarized in Table 4.Goyal et al. (2014) reviewed 47 RCTs com-
paring a mindfulness or meditation-based program to an active control
condition. Of these, 19% (9 studies) reported on AEs; none of these
reported any harms. In a review of 12 studies of MBPs for post-trau-
matic stress, Banks, Newman, and Saleem (2015) found that two studies
did not report on AEs/SAEs, four reported that none occurred, and six
reported that some participants showed increases in symptoms that
were not clinically signiﬁcant. Collapsed across these six studies,
symptom increases occurred in 13 of 123 participants (10.6%). In two
studies, a few participants reported increased anxiety during meditation
practices but no signiﬁcant worsening of symptoms from pre- to post-
treatment. One participant reported that meditation triggered a
memory of an assault. Learning to work skilfully with such memories
was considered part of the treatment. The authors concluded that ad-
verse eﬀects in these studies were minimal.
A meta-analysis of nine RCTs of MBCT for relapse prevention in
recurrent depression (Kuyken et al., 2016) reported that four of the
trials included no data on AEs or SAEs. In the other ﬁve trials, only SAEs
were reported. Percentage of participants in whom SAEs occurred
ranged from zero (2 studies) to 5.5% (1 study) with a mean of 1.94%.
SAEs were no more common in MBCT groups than in control arms of
the trials and none were judged to be related to participation in MBCT.
These studies did not report on broader indications of harm, such as
worsening of symptoms, appearance of new symptoms, or general de-
cline in functioning or wellbeing. Finally, a systematic review of RCTs
of MBSR and MBCT (Wong, Chan, Zhang, Lee, & Tsoi, 2018) found that
195 of 231 trials (84%) did not report on AEs. When summed across the
other 36 trials, AEs occurred in 1.0% and 0.9% of participants in MBI
and control groups, respectively; these proportions were not sig-
niﬁcantly diﬀerent. The authors concluded that MBSR and MBCT
Reviews of evidence-based MBPs that include data on adverse events.
First author, year Number and type of studies in the review Percentage of studies in the review that
reported data on AEs/SAEs
Findings for AEs/SAEs Comments
Goyal, 2014 47 RCTs comparing MBPs or other
meditation-based programs to active controls
19% None reported
Banks, 2015 12 studies (various designs) of MBPs for
83% AEs in 10.6% of participants symptom increases not clinically signiﬁcant, anxietyduringmeditation practices did not
lead to pre-post deterioration, 1 trauma memory triggered seen as within purpose of
Kuyken, 2016 9 RCTs of MBCT for depressive relapse 56% SAEs in 1.94% of participants (range:
0 to 5.5%)
SAEs no more common in MBCT than in control groups; SAEs unrelated to participation
Wong, 2018 231 RCTs of MBSR or MBCT 16% AEs in 1% of MBP participants, 0.9%
of control participants
AEs no more common in MBPs than in control groups
R. Baer et al. Clinical Psychology Review 71 (2019) 101–114
appear to be relatively safe but strongly recommended more consistent
reporting of AEs and SAEs.
Qualitative studies of diﬃculties in MBPs suggest that they are
common but tend to be short-term. A meta-ethnography (Malpass et al.,
2012) reported that increases in participants' awareness of their mala-
daptive coping habits could feel temporarily overwhelming, that pre-
sent-moment awareness was occasionally frightening, and that mis-
taken expectations that mindfulness should rid the mind of all
depressive thoughts led to self-devaluation when this did not happen.
Despite these diﬃculties, the general pattern was a shift from mala-
daptive coping strategies to more adaptive forms of self-understanding.
Overall, ﬁndings show that when reported, AEs/SAEs have occurred
in 0 to 10.6% of participants in evidence-based MBPs. When compared
in MBPs and controls, AEs/SAEs occur at similar rates, suggesting that
they are unrelated to participation in the MBP. These ﬁndings must be
interpreted cautiously for several reasons. First, few studies have report
on AEs/SAEs. Second, AEs/SAEs are sometimes narrowly deﬁned, such
that general deterioration or the appearance of new symptoms might
not be included. Finally, although meta-analyses and qualitative studies
show strong evidence of improvement with MBPs, it remains unclear
whether group averages mask deterioration in some participants.
6. Potential sources of harm in MBPs
As noted earlier, sources of harm commonly discussed in other ap-
proaches to health and wellbeing include program factors, participant
factors, and teacher/clinician factors. In the following sections, we re-
view empirical ﬁndings and conceptual discussion of how these sources
may apply to MBPs.
6.1. Program factors
Here we address factors that have been studied or discussed in the
mindfulness literature: the importance of what and how elements of
mindfulness, the soundness of the programs' conceptual foundations,
the intensity of the mindfulness practices, and the adequacy of the
psychoeducational or structural support provided by the program.
6.1.1. What and how
Segal et al. (2013) state that mindfulness “cannot be reduced to
awareness or attention alone” and note that increased present-moment
awareness will not be helpful, and may even be harmful, unless
“friendliness and compassion can be brought to those elements of
present-moment experience to which we attend” (p. 137). In support of
this statement, several studies have found that the relationship between
present-moment awareness and adaptive functioning is moderated by
the quality of the awareness. Substance use, depression, rumination,
worry, and blood pressure have all been shown to be lower in partici-
pants who endorse high levels of present-moment awareness, but only if
the awareness is nonjudgmental or nonreactive (Desrosiers, Vine,
Curtiss, & Klemanski, 2014;Eisenlohr-Moul, Walsh, Charnigo, Lynam,
& Baer, 2012;Tomfohr, Pung, Mills, & Edwards, 2015). This work is
consistent with previous research showing that self-focused attention
(deﬁned as awareness of thoughts, emotions, and sensations) is adap-
tive when it is nonjudgmental and experiential but maladaptive when it
is judgmental and ruminative (Ingram, 1990;Mor & Winquist, 2002;
Watkins, 2008). These bodies of literature suggest that eﬀective
teaching of mindfulness must include both present-moment awareness
and its nonreactive, nonjudgmental qualities. Otherwise, increases in
awareness might lead to unintended increases in symptoms.
6.1.2. Conceptual foundations of the MPB
Crane et al. (2017) argued that without a sound theoretical for-
mulation of how mindfulness should help with a particular problem, an
MBP might be unhelpful. An interesting example to which this may
apply is insomnia. Ong, Ulmer, and Manber (2012) theorize that
mindfulness promotes decentering from insomnia-related thoughts and
feelings, equanimity and commitment to values, and reduced sleep-re-
lated arousal. This model was supported in randomized trial showing
improvements in self-reported sleep variables for people with insomnia
(Ong et al., 2014). On the other hand, Britton, Lindahl, Cahn, Davis,
and Goldman (2014) note that in Buddhist traditions, mindfulness is
described as a state of relaxed alertness that balances hyper- and hy-
poarousal. They summarize brain imaging studies suggesting that
“Buddhist meditation practices are associated with activation/en-
largement of the areas that underlie tonic alertness and/or prevent
sleep” (p. 69). A study of MBCT for people with partially remitted de-
pression and sleep disturbance (Britton, Haynes, Fridel, & Bootzin,
2010) found polysomnographic evidence of increased cortical arousal
post-MBCT that was correlated with amount of mindfulness practice,
although participants also reported better subjective sleep quality.
Britton et al. (2014) suggested that short-term, short-duration mind-
fulness practice may increase sleep propensity whereas longer-term,
higher-dose practice may lead to neurological changes producing
greater wakefulness. They did not discuss harm, but ﬁndings suggest
that intensive long-term practice might be unhelpful for people whose
goal is increased sleep. These ﬁndings highlight the necessity of a clear
understanding of how mindfulness meditation, as used in MBPs, should
be expected to improve sleep.
6.1.3. Intensity of the mindfulness practice
Though loosely analogous to intensity of physical exercise and do-
sage of medication, intensity of mindfulness practice is hard to deﬁne.
Participants in MBPs may have diﬀerent experiences of the intensity of
practice, perhaps related to previous meditation experience, the en-
vironment in which they practice, or other factors. The idea that in-
tensity of practice could be related to harm in MBPs comes most di-
rectly from Lindahl et al. (2017), who reported that for 72% of their
Buddhist practitioners, harmful eﬀects were associated with participa-
tion in residential retreats, which are often a week or more in duration
and involve many hours per day of meditation in a mostly silent en-
vironment removed from normal daily routines.
Most MBPs involve weekly group sessions and encourage up to an
hour per day of formal and informal home practice. Many also include a
mostly silent all-day session of about 6 h. Whether this level of intensity
can cause harmful outcomes is unclear. Lindahl et al. reported that 25%
of their participants who reported harm were practicing less than an
hour per day using practices similar to those in MBPs and for similar
purposes (mental health-related rather than spiritual purposes); ac-
cordingly, they argued that the harmful eﬀects they observed may also
occur in MBPs. While we agree that this possibility should be studied,
we also note that evidence-based MBPs include many psychoeduca-
tional and structural supports that may be less available in Buddhist
meditation settings where participants are practicing outside of mon-
itored interventions (Lomas et al., 2015). These supports may reduce
the potential for harm from challenging meditation experiences.
6.1.4. Psychoeducational and structural support for meditation practices
Many MBPs include a pre-course interview or information session
that helps participants anticipate and prepare for likely challenges. A
rationale for how mindfulness is expected to help with participants'
problems is often provided. Nearly all in-session practices are followed
by inquiry, when challenging experiences can be explored. Sessions also
include inquiry about home practice, when diﬃculties encountered at
home can be considered. Teachers are often available before and after
sessions for consultation. A range of practices, varying in duration and
focus, is introduced in a logical sequence in which learning builds from
week to week. Recordings to guide home practice are provided.
Sessions also include didactic information and non-meditative exercises
that supplement and support the meditation practices; many of these
speak directly to how to manage challenging experiences that arise in
meditation or at other times. Weekly handouts provide summaries of
R. Baer et al. Clinical Psychology Review 71 (2019) 101–114
session content and goals, rationales for the practices, descriptions of
previous participants' experiences, and worksheets for recording ob-
servations. The all-day session occurs late in the eight-week course,
allowing participants to build skills through several weeks of daily
practice and group sessions beforehand.
We identiﬁed only one example of empirical study of the eﬀects of
psychoeducational and structural supports. In a pilot trial for a study of
MBCT adapted for people at risk of suicide, Crane and Williams (2010)
found that participants who showed the greatest evidence of cognitive
vulnerabilities associated with depression and suicidality were most
likely to drop out. In the subsequent trial, the individual pre-course
interview was extended from 60 to 90 min to include more explicit,
personalised discussion of how to meet the program's likely challenges.
Use of the modiﬁed interview reduced attrition from 30% to 18%
(Williams et al., 2015), suggesting that evidence-based structural and
psychoeducational support for meditation may be helpful in high-risk
6.2. Participant factors
Table 2 suggests participant factors that could be related to the
potential for harm in MBPs. The mindfulness literature has focused
primarily on psychiatric and trauma history. Of the Buddhist medita-
tion teachers interviewed by Lindahl et al. (2017), 88% stated that a
psychiatric history is a risk factor for meditation-related challenges;
54% stated that a trauma history is important. Similarly, Lomas et al.
(2015) found that pre-existing depression and anxiety could be ex-
acerbated by Buddhist meditation. Several studies of MBPs suggest a
relationship in the opposite direction; i.e., under some circumstances,
participants with severe symptoms and traumatic backgrounds may be
more likely to beneﬁt. However, these studies have not included broad
assessments of harm. We summarize the ﬁndings here.
6.2.1. Participant vulnerabilities and response to standard MBPs
Several studies of MBCT for preventing depressive relapse have
shown stronger beneﬁts for participants with higher levels of various
vulnerabilities, including earlier onset of depression, more previous
episodes (Ma & Teasdale, 2004;Teasdale et al., 2000), unstable re-
mission (Segal et al., 2010), and childhood trauma (Kuyken et al., 2015;
Williams et al., 2014). In most of these studies, the participants with
fewer vulnerabilities showed eﬀects for MBCT that did not diﬀer from
TAU, placebo, or antidepressant medication (ADM). Several of these
studies found that participants with fewer previous episodes had non-
signiﬁcantly higher relapse rates in MBCT than in TAU. Ma & Teasdale
noted that the small sample made it unclear whether MBCT was causing
harm for the fewer-episodes subgroup (increasing the likelihood of re-
lapse) or was only unhelpful (providing no beneﬁt). An individual pa-
tient data meta-analysis (Kuyken et al., 2016) combined these and other
trials and found that in the larger sample (N> 1200) the only sig-
niﬁcant moderator of treatment eﬀect was severity of depressive
symptoms at baseline. Patients with more severe symptoms showed a
larger treatment eﬀect. No evidence of increased risk of relapse in
MBCT was seen; however, asymmetry in the funnel plot suggested the
possible existence of small unpublished studies showing this pattern.
Other MBPs have also shown better outcomes in participants with
more severe symptoms. Roos, Bowen, and Witkiewitz (2017) found that
MBRP was more eﬀective than CBT or usual care for participants with
high levels of substance use, anxiety, and depression, but similar to
these comparison groups for participants with fewer symptoms. Arch
and Ayers (2013) found that MBSR was more eﬀective than CBT for
people with comorbid anxiety and depression; CBT was more eﬀective
for those with anxiety only. These studies have not included detailed
assessments of harm.
6.2.2. MBPs adapted for speciﬁc vulnerabilities
MBPs have been adapted for psychosis, post-traumatic stress (PTS),
and suicide risk. For people with psychosis, Chadwick, Taylor, and
Abba (2005) reduced the number and duration of sessions, shortened
the meditation practices, and provided steady guidance during prac-
tices to prevent absorption in psychotic symptoms during stretches of
silence. Psychological functioning improved and no adverse eﬀects
were reported in post-treatment interviews. Since then, a meta-analytic
review of MBPs for psychosis (Khoury et al., 2013) reported a small-to-
moderate reduction in psychotic symptoms (g = 0.43) but did not
discuss harm or adverse events.
MBPs for PTS have also been studied. As noted earlier, Banks et al.
(2015) concluded that adverse eﬀects in 12 studies of MBPs for PTS
were minimal. A meta-analysis of 18 randomized trials (Hopwood &
Schutte, 2017) found a mean eﬀect size of g = 0.44 in favor of MBPs
over control conditions. For studies of MBSR, rather than unspeciﬁed
mindfulness programs, g = 0.49. There was no signiﬁcant diﬀerence
between MBSR adapted for trauma and standard MBSR. Most studies
did not mention whether AEs had been examined; a few reported that
there were none. One study reported that two participants (4.3%, one
each in the MBP and the control condition) required hospitalization for
The adaptation of MBCT for people at high risk of suicide (Williams
et al., 2014) found that MBCT was more eﬀective than control condi-
tions in preventing depressive relapse for people with a history of
childhood trauma. Fifteen SAEs were reported: ﬁve in the MBCT arm
and 10 in the control conditions (5% and 6.4% of participants, re-
spectively). Most were overnight hospital admissions for physical
health problems; 14 of the 15 events (93%) were judged to be unrelated
to participation in the study. One episode of serious suicidal ideation
was potentially attributable to the active control intervention (Williams
et al., 2014).
Overall, the literature suggests that MBPs can be signiﬁcantly
therapeutic in groups with severe symptoms, comorbid conditions, and
other vulnerabilities. Speciﬁc vulnerabilities are sometimes associated
with better outcomes. Studies that monitored AEs/SAEs in these po-
pulations have reported that they occur in 0–10% of participants, are no
more common in MBPs than control groups, and are not attributable to
the MBP when they occur (Kuyken et al., 2016). However, many studies
have not monitored harm in any way. When negative outcomes are
reported, their relationship to participation in the MBP is not always
provided. In addition, most studies report only group data, making it
impossible to know whether promising averages mask deterioration in
6.3. Teacher/clinician factors
The literature summarized in Table 2 suggests that risk of harm may
be related to characteristics of the provider, including empathy, un-
derstanding of the client's problems, communication about the nature
of the program, skillful implementation of the program, managing
diﬃculties that arise, and encouraging adherence to recommended
practice. Here we summarize recent work on assessment of similar
competencies in providers of MBPs.
6.3.1. Assessment of teacher competencies
Several methods for assessing teachers' delivery of MBPs are avail-
able. All use ratings of recorded sessions or live observation and have
shown adequate psychometric properties. The MBCT adherence scale
(MBCT-AS; Segal, Teasdale, Williams, & Gemar, 2002) is a list of es-
sential program elements; raters note the extent to which each element
is present. The mindfulness-based relapse prevention adherence and
competence scale (MBRP-AC; Chawla et al., 2010) is a similar measure
assessing the presence of required elements and the therapist's skills in
implementing them. The Mindfulness-Based Interventions – Teaching
Assessment Criteria (MBI-TAC; Crane et al., 2013) evaluates six do-
mains of competency: a) coverage, pacing, and organization of session
content, b) relational skills, c) embodiment of mindfulness, d) guiding
R. Baer et al. Clinical Psychology Review 71 (2019) 101–114
mindfulness practices, e) conveying course themes, and f) holding the
group learning environment.
Relationships between teacher competency scores and participant
outcomes have been examined in only a few studies. Using the MBRP-
AC, Chawla et al. (2010) found that therapists' adherence to required
elements of treatment was related to participants' development of
mindfulness skills. In MBCT for adults with recurrent depression,
Huijbers et al. (2017) found no signiﬁcant relationships between tea-
chers' MBI-TAC scores and any of the dependent variables. The null
ﬁndings may be related to the small sample of teachers (N= 15), re-
striction of range in competence scores, or the high level of standar-
dization of the intervention, which was provided in two clinical trials
by the same research team.
While substantial progress has been made in the assessment of
teacher competency, additional research is needed. To date, there is no
evidence that lack of competency is related to harmful outcomes.
Competency may have been assessed primarily in settings where tea-
chers are well trained, leading to restriction of range. Prevention of
harm may require skills not covered by existing measures, such as the
pre-course interview. In ostensibly nonclinical settings such as work-
places, where MBPs may be oﬀered by non-mental-health professionals,
harm might arise when teachers lack skills for screening participants for
psychological symptoms and managing mental health emergencies.
Finally, because harm can arise through ethical violations, knowledge
of professional ethics is necessary for managing issues related to in-
formed consent, conﬁdentiality, and other ethical concerns.
7. Recommendations for research
Perhaps the most basic unanswered questions are how often MBPs
cause harm, in what forms, and to whom. Answering these questions
requires detailed monitoring of potentially harmful eﬀects. Surveys of
participants about their experiences and measurement of a wide range
of participant characteristics and outcomes might help to clarify whe-
ther the target problem got worse or new problems arose, and for
whom. Attention to reasons for attrition may clarify whether dropping
out is related to harm. Examining individual-level data could clarify
whether group averages conceal the occurrence of harm in some par-
ticipants. Vagueness in existing deﬁnitions of harm (how much dete-
rioration is meaningful?) might be addressed with the reliable change
index (Jacobson & Truax, 1991), which classiﬁes participant outcomes
into three categories: reliable improvement, no reliable change, or re-
liable deterioration. At the same time, it seems important to consider
whether participants feel worse, even if their objectively measured
symptoms have not reliably decreased (Duggan et al., 2014). Qualita-
tive interviews with participants reporting harm or classiﬁed as having
deteriorated may be helpful in generating hypotheses for quantitative
More comprehensive monitoring may improve understanding of
participant, teacher, and program factors potentially related to harm.
For example, the study of moderators of outcome may clarify for whom
programs should be modiﬁed or contra-indicated. If an MBP has both
risks and beneﬁts for many participants, research could focus on for
whom the beneﬁts outweigh the risks and how to mitigate risks. Harm
that seems related to unskilful teaching may clarify essential teacher
competencies. These factors are likely to be intertwined; that is, parti-
cipant characteristics may require adaptations to programs and the
development of speciﬁc teaching skills.
Consistent reporting of harm-related information in published pa-
pers is essential to developing this body of knowledge. A revised
CONSORT checklist (Ioannidis et al., 2004) includes 10 recommenda-
tions for reporting on harm-related issues in randomized trials. These
include listing and deﬁning all adverse events that were studied, noting
whether events that occurred were anticipated or unexpected, clar-
ifying how harms-related information was collected and analyzed,
presenting risk of each adverse event for each arm of the trial, and
providing a balanced discussion of beneﬁts and harms. Despite the
longstanding availability of this checklist, such reporting is rare, for
reasons that are unclear. Peterson et al. (2013) suggested that the pri-
mary reason is that a temporary increase in symptoms or discomfort is
understood to be part of the normal therapeutic process. However, they
also argued that greater reporting of this phenomenon would increase
understanding of the overall risk and safety of therapies, especially
those known to involve signiﬁcant discomfort such as exposure-based
treatments. More consistent reporting might also help to clarify the
boundary between expected discomfort and potential harm.
Another reason for lack of reporting of harms may be overreliance
on deﬁnitions of AEs and SAEs used in medical research (Duggan et al.,
2014). Some of these events (suicide attempts, hospitalizations) may be
uncommon in trials of psychological interventions or MBPs. Monitoring
events more relevant to the program being studied would be in-
formative. Duggan et al. (2014) also note that many adverse events are
not spontaneously reported and will not come to light without sys-
tematic assessment methods such as structured interviews.
Several additional questions seem important for future research.
First, what is the dose/response relationship for mindfulness practice in
MBPs? Can high doses be harmful? To date, the literature has examined
only whether extent of self-reported home practice predicts positive
outcomes; a meta-analytic review (Parsons, Crane, Parsons, Fjorback, &
Kuyken, 2017) found a small but signiﬁcant association. This review
did not report whether any of the correlations between home practice
and outcome were negative and did not address the issue of harm.
Second, a related issue is whether the type, timing and quality of
home practice inﬂuences outcomes and whether speciﬁc ways of
practicing might cause harm. Lomas et al. (2015) found that practi-
tioners of Buddhist meditation who used advanced practices before
they were ready for them experienced diﬃcult eﬀects. Lindahl et al.
(2017) referred to “incorrect ways of practicing meditation” (p. 23) that
might cause harm; these are not clearly explained but include excessive
striving, attachments to speciﬁc states, and misunderstanding or not
following directions. For MBPs, Del Re, Fluckiger, Goldberg, and Hoyt
(2013) developed a self-report measure of practice quality and found
that symptom reduction was related to the extent to which participants
returned their attention to present-moment experiences with curiosity,
willingness, and self-compassion. However, they did not address
Third, if harm occurs, how can it be remediated? In medicine and
exercise science, more is known about treatment of overdoses, adverse
reactions, and injuries; an analogous body of knowledge is needed for
the mindfulness ﬁeld. Lindahl et al. (2017) include discussion of po-
tential remedies for challenges arising in Buddhist meditation; how-
ever, little is known about how well these apply to diﬃculties arising in
8. Recommendations for protecting participants in MBPs from
Several steps can be taken before an MBP begins. Teachers must
understand the theoretical and empirical foundations for using the MBP
with their population. Without this understanding, they will be unable
to explain to potential participants how the MBP may be relevant to
them, what diﬃculties might arise, how these can be managed, and
whether the potential beneﬁts are likely to outweigh the diﬃculties
(Kuyken, Crane, & Williams, 2012). This information should be part of a
pre-program orientation and informed consent process in which the
theoretical rationale, evidence base, and potential beneﬁts and risks are
Careful assessment of potential participants and well considered
exclusion criteria are important. Available lists of recommended ex-
clusion criteria for MBPs (Kuyken et al., 2012;Santorelli et al., 2017)
generally include substance dependence, suicidality, psychosis, PTSD,
severe depression, severe social anxiety, and recent bereavement,
R. Baer et al. Clinical Psychology Review 71 (2019) 101–114
divorce, or other personal crisis. Such conditions are likely to interfere
with ability to participate in the group or the practices, or to receive
any beneﬁt from doing so. However, because this is not true in every
case, these criteria are “subject to clinical judgement and experience of
teacher, and support available to and motivation of participant”
(Kuyken et al., p. 23). When working with the general population, as-
sessing psychiatric and trauma history as well as current functioning
and professional and personal support may facilitate sound decisions
about readiness to participate and the need for concurrent psycholo-
gical or psychiatric treatment (Dobkin, Irving, & Amar, 2012). As noted
earlier, MBPs adapted for conditions that typically appear on lists of
exclusion criteria (PTSD, suicidality, psychosis) have shown promising
results, suggesting that exclusion criteria must be viewed ﬂexibly.
Once the program begins, it is important to teach both the what and
the how elements of mindfulness and to be sure that the psychoeduca-
tional and structural supports described earlier are in place. Rationales
for the practices should be made clear and participants should feel in-
vited, rather than pressured, to engage in them. Distress and discomfort
are likely to arise as participants learn new skills and practice applying
them to the diﬃculties for which they sought help. Prevention of harm
requires understanding common types of uncomfortable experiences,
their usual range of intensity, and how to help participants respond to
them in ways that facilitate learning the desired skills. Systematic
monitoring and recording of deterioration and adverse events will in-
crease this knowledge in providers of MBPs.
Systematic monitoring may also help teachers to recognize when
unusual or unexpected distressing experiences have arisen and when
they are disproportionate to the expected beneﬁts, likely to interfere
with attaining beneﬁts, or require clinical intervention. Protocols for
responding to objective indicators of imminent harm have been used in
randomized trials for monitoring foreseeable risks; for example, referral
to a physician when a participant endorses suicidality on a ques-
tionnaire. While suicide risk is foreseeable in a depressed sample, other
potentially harmful outcomes may be harder to predict. The Oﬃce for
Human Research Protections (US Department of Health and Human
Services, 2007) notes that an event is unexpected if its nature, severity,
or frequency is inconsistent with the known or foreseeable risk asso-
ciated with the procedures involved, or if it is inconsistent with the
expected natural progression of an underlying condition. When such
events occur, prevention of harm may require adjustments in the par-
ticipant's practice, discontinuing the program, or referral to other ser-
vices. Mindfulness teachers need training in the mental health condi-
tions they are likely to encounter and how to recognize and work with
the meditation-related challenges that participants may experience. The
requirement that teachers of MBPs have their own mindfulness practice
may provide further experiential understanding of challenging mind
states that will help them work with participants' meditation-related
9. Summary and conclusions
In well-established approaches to health and wellbeing, including
psychotherapy, pharmacotherapy, and physical exercise, some partici-
pants suﬀer serious harm or get meaningfully worse. The same appears
to be true for meditation in contemplative traditions. Evidence-based
MBPs have important commonalities with these approaches. They work
with cognitions, emotions, and sensations, some of which are distres-
sing and diﬃcult; they raise issues about adherence, dosage, and dose/
response relationships; they include a variety of exercises, which can be
uncomfortable; and they place the formal practice of meditation at their
core. Because of these commonalities, it is essential to consider the
possibility that some participants in evidence-based MBPs may get
The existing literature on harm in evidence-based MBPs is sparse. A
few studies have shown worsening symptoms in MBPs; however, meta-
analyses consistently report signiﬁcant beneﬁts for many outcome
variables in a wide range of samples. Research also suggests that par-
ticipants with severe symptoms, comorbid conditions, and other vul-
nerabilities (psychosis, trauma history, suicide risk) can beneﬁt from
MBPs in standard or adapted forms, and that some may show more
beneﬁt from MBPs than participants without such vulnerabilities. The
few reviews including data on AEs and SAEs in evidence-based MBPs
report that they have occurred in zero to 10.6% of participants
(Table 4), are no more common in MBPs than comparison conditions
(Kuyken et al., 2016;Wong et al., 2018), and are not attributable to the
MBP (Kuyken et al.) or not clinically signiﬁcant (Banks et al., 2015).
However, these ﬁndings must be viewed cautiously because most
studies report only group averages that might mask meaningful dete-
rioration in some participants. Only a small minority of studies have
monitored AEs and SAEs. Those that have may have deﬁned them
narrowly or failed to ask about them in ways that elicit detailed an-
The prevalence of harm from meditation in contemplative traditions
is unclear. Nevertheless, harm clearly occurs, and the possibility that
similar harm might arise in evidence-based MBPs, despite adaptations
for contemporary mainstream contexts and the presence of structural
and psychoeducational supports described earlier, needs further study.
If such harm is occurring, it might not be detectable without systematic
monitoring of individual-level data. The ethical obligation to do no
harm requires us to enhance our monitoring methods in order to better
understand the risks for participants in MBPs, including what forms of
harm might occur, how often they occur, who is most susceptible, and
how harmful eﬀects can be prevented or remediated.
Role of funding sources
This work was partially supported by the Wellcome Trust, Grant
Reference: 104908/Z/14/Z. The Wellcome Trust had no role in plan-
ning or writing the manuscript or the decision to submit the paper for
All authors contributed to discussions about the goals and structure
of the paper. Ruth Baer wrote most of the ﬁrst draft. Catherine Crane,
Edward Miller, and Willem Kuyken wrote sections of the paper. All
authors contributed to editing and revising. All authors have approved
the ﬁnal manuscript.
Conﬂict of interest
Ruth Baer is an Associate of the Oxford Mindfulness Centre and
receives occasional payments for training workshops and presentations
related to mindfulness. She also receives royalties for several books
related to mindfulness. Catherine Crane is aﬃliated with the Oxford
Mindfulness Centre and funded by the Wellcome Trust on a strategic
award exploring the role of mindfulness training in adolescence.
However she does not receive additional remuneration for training
workshops or presentations related to mindfulness. Willem Kuyken is
the director of the Oxford Mindfulness Centre. He receives payments for
training workshops and presentations related to mindfulness and do-
nates all such payments to the Oxford Mindfulness Foundation, a
charitable trust that supports the work of the Oxford Mindfulness
Centre. Willem Kuyken was until 2015 an unpaid Director of the
Mindfulness Network Community Interest Company and gave evidence
to the UK Mindfulness All Party Parliamentary Group.
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R. Baer et al. Clinical Psychology Review 71 (2019) 101–114
Ruth Baer, PhD, is Professor of Psychology at the University of Kentucky and an
Associate of the Oxford Mindfulness Centre, Department of Psychiatry, University of
Catherine Crane, PhD, is Research Lead at the Oxford Mindfulness Centre, Department of
Psychiatry, University of Oxford.
Edward Miller, MD, is a psychiatrist and post-graduate student at the Oxford
Mindfulness Centre, Department of Psychiatry, University of Oxford.
Willem Kuyken, PhD, is Professor of Clinical Psychology and Director of the Oxford
Mindfulness Centre, Department of Psychiatry, University of Oxford.
R. Baer et al. Clinical Psychology Review 71 (2019) 101–114