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Optimism and Self-Esteem Are Related to Sleep. Results
from a Large Community-Based Sample
Sakari Lemola &Katri Räikkönen &Veronica Gomez &
Mathias Allemand
Published online: 4 October 2012
#International Society of Behavioral Medicine 2012
Abstract
Background There is evidence that positive personality
characteristics, such as optimism and self-esteem, are
important for health. Less is known about possible deter-
minants of positive personality characteristics.
Purpose To test the relationship of optimism and self-esteem
with insomnia symptoms and sleep duration.
Method Sleep parameters, optimism, and self-esteem were
assessed by self-report in a community-based sample of
1,805 adults aged between 30 and 84 years in the USA.
Moderation of the relation between sleep and positive char-
acteristics by gender and age as well as potential confound-
ing of the association by depressive disorder was tested.
Results Individuals with insomnia symptoms scored lower
on optimism and self-esteem largely independent of age and
sex, controlling for symptoms of depression and sleep du-
ration. Short sleep duration (<6 h) was related to lower
optimism and self-esteem when compared to individuals
sleeping 7–8 h, controlling depressive symptoms. Long
sleep duration (>9 h) was also related to low optimism and
self-esteem independent of age and sex.
Conclusion Good and sufficient sleep is associated with
positive personality characteristics. This relationship is in-
dependent of the association between poor sleep and
depression.
Keywords Insomnia symptoms .Sleep duration .
Optimism .Self-esteem .Major depression
Introduction
The importance of nocturnal sleep for physical and mental
health is widely acknowledged and has been extensively
studied. Sleeping less than 7 h as well as sleeping more than
8 h is associated with a variety of physical and psycholog-
ical health problems, such as increased risk of coronary
heart disease, hypertension, and depression and anxiety dis-
orders [1–3]. In addition to short and long sleep duration,
insomnia is highly comorbid with mood and anxiety disor-
ders, and longitudinal evidence suggests that insomnia pre-
dates the onset of mental illness [4].
Compared to the large number of studies on negative
physical and mental health consequences of poor sleep,
knowledge on the relationship of sleep duration and sleep
quality with positive individual characteristics, which may
promote health and well-being, is scarce. One study showed
that individuals who slept on average 7–8 h reported more
satisfaction with life compared to others who slept less than
6 h a night [5]. Moreover, longer sleep duration prospec-
tively predicted higher self-esteem in adolescents [6], and
adequate sleep duration and short sleep onset latency related
to higher optimism in children [7]. Further, in an experi-
mental study, Haack and Mullington [8] demonstrated that
sleep deprivation resulted in a gradual reduction of self-
reported optimism and sociability in young adults, which
suggests a causal relation between sleep and positive per-
sonality characteristics.
The study of positive personality characteristics, such as
optimism and self-esteem, is important due to their well-
known links with subjective well-being and health [9]. Lon-
gitudinal studies indicate that optimism and self-esteem are
predictors of better health rather than just consequences.
S. Lemola (*):V. Gomez
Department of Psychology, University of Basel,
Missionsstrasse 62a,
4055 Basel, Switzerland
e-mail: sakari.lemola@unibas.ch
K. Räikkönen
Faculty of Behavioural Sciences, University of Helsinki,
Siltavuorenpenger 5 A, P.O. Box 9, 00014 Helsinki, Finland
M. Allemand
Department of Psychology, University of Zürich,
Binzmühlestrasse 14/24,
8050 Zürich, Switzerland
Int.J. Behav. Med. (2013) 20:567–571
DOI 10.1007/s12529-012-9272-z
Orth and colleagues [10], for instance, showed that low
levels of self-esteem are a vulnerability factor predisposing
individuals to depression, while there was no evidence for
the reverse causality. Another prospective study over a 9-
year follow-up period revealed a protective effect of dispo-
sitional optimism against all-cause and cardiovascular mor-
tality in old age controlling for the initial health status [11]. A
possible explanation for this effect is that more optimistic
individuals have more adaptive coping strategies and better
health behavior, which may decrease the risk of cardiovas-
cular morbidity.
In the present study, we therefore tested associations of
sleep parameters with optimism and self-esteem in a large
community-based sample of adults aged 30 to 84 years. In
particular, we tested relations between insomnia symptoms
and positive personality characteristics and examined
whether individuals with an average sleep duration (be-
tween 7 and 8 h/day) are more optimistic and have higher
self-esteem compared to individuals who sleep less than 7 h
or, conversely, more than 8 h/day. As it has been docu-
mented that poor sleep is comorbid with depressive symp-
toms, and optimism and self-esteem are both inversely
related with depressive symptoms, we additionally test
whether sleep and positive characteristics are related beyond
their shared overlap with depression. Furthermore, since
insomnia symptoms may be partly comorbid with short
sleep duration, we additionally tested the relation of insom-
nia symptoms and sleep duration with positive personality
characteristics controlling for the respective other sleep var-
iable. Finally, as sleep parameters undergo age-related
changes and show sex-specific disparities [12], moderation
of the relationship by participants’age and sex was
assessed.
Methods
Participants
The data for this study come from the Midlife in the US
(MIDUS) survey, which was designed to investigate fac-
tors contributing to age-related differences and changes in
physical and psychological health and social responsibil-
ity. The survey started in 1995, followed by a reassess-
ment in 2005. MIDUS is a national probability sample,
drawn with random-digit dialing procedures, which con-
sists of English-speaking, noninstitutionalized adults with
at least one telephone per household. The sample was
stratified by age and sex, with oversampling of older
people and of men. The response rate in the first wave
was 71 % with a sample size of N03,487 respondents.
Of those participants, 1,805 (52 %; 818 males and 987
females) completed a self-administered questionnaire in
the follow-up containing questions on insomnia symp-
toms, sleep duration, and positive personality character-
istics. Sample retention was selective towards higher
participation of whites, females, and married individuals
as well as individuals with better health and more
education [13]. Since no information on habitual sleep
duration was obtained in the first measurement wave,
only data from the second wave were analyzed in the
present study. Information on insomnia symptoms was
available for N01,797, and valid information on sleep
duration on weekdays and weekends was available for
N01,755. The average age was 56.9 years (SD012.6,
range 030–84 years).
Measures
Insomnia Symptoms and Sleep Duration
Insomnia symptoms were measured with three items (“Do
you have trouble falling asleep,”“Do you wake up during
the night and have difficulty going back to sleep,”and “Do
you wake up too early in the morning and be unable to get
back to sleep”) using a five-point scale ranging from never
(1)to almost always (5). These three items were summed
into a single insomnia symptoms score with a Cronbach’s
alpha of 0.81. Sleep duration was assessed by asking
participants to indicate how many hours and minutes
they generally sleep on weekdays or workdays and on
weekends or non-workdays. For the present analyses,
sleep duration on weekdays and weekends was combined
by the weighted average.
Dispositional Optimism
Dispositional optimism was measured with the Life Orienta-
tion Test-Revised (LOT-R) [14], a six-item self-report mea-
sure assessing generalized expectancies for positive and
negative outcomes. Participants were asked to rate the extent
to which they agreed with each statement on a five-point
Likert-type scale ranging from strongly agree (1)to strongly
disagree (5). The scale was coded such that higher values
indicate higher optimism. Cronbach’s alpha for the LOT-R in
the present sample was 0.79. Compared to the original version
of the LOT-R [14], the four filler items were omitted.
Dispositional Self-Esteem
Dispositional self-esteem was measured with a seven-item
version of the Self-Esteem Scale (SES) [15], a widely used
scale to assess global attitudes about the self. Participants
were asked to indicate their agreement on a seven-point
Likert-type scale ranging from strongly agree (1)to strongly
disagree (7). The scale was coded such that higher values
568 Int.J. Behav. Med. (2013) 20:567–571
indicate higher self-esteem. Cronbach’s alpha for the SES in
the present sample was 0.76.
Depression
Depression was assessed using the screening version of the
World Health Organization’s“Composite International Di-
agnostic interview,”version 1.0 [16], which was adminis-
tered by a phone call. The scale ranged from 0 (no
symptoms of depression) to 7 (highest depression); 205
participants (11.4 %) had scores of 4 or more and met
criteria for major depressive disorder according to DSM-
III-Rin the 12 months prior to the survey. In the present
study, depression scores were used as continuous variable.
Statistical Analyses
To test the relation of optimism and self-esteem with sleep,
insomnia symptoms were treated as continuous variable,
while sleep duration was dummy coded with 7–8 h serving
as reference category against which further categories of
sleeping less than 6 h, sleeping 6–7 and 8–9 h, and sleeping
more than 9 h were tested. Multiple regression analyses
using IBM SPSS 20.0 (IBM Corp., Armonk, NY, USA)
were conducted in five steps: first, only age and sex were
adjusted; second, models additionally adjusted depression
scores; third, models additionally adjusted the respective
other sleep parameter (i.e., when sleep duration was the
predictor, insomnia symptoms were adjusted and vice versa)
since insomnia symptoms and short or long sleep duration
may be comorbid conditions; fourth, models included a
sleep × participant’s sex interaction term, and finally, the
models included a sleep × participant’s age interaction term.
The moderated regression analyses were conducted as sug-
gested by Aiken and West [17].
Results
Mean Values, Sex Differences, and Correlations of Study
Variables
Table 1shows mean values and correlations of the study
variables. On average, participants reported to sleep 7.14 h.
There was a modest increase of sleep duration with age, but no
correlations between insomnia symptoms and age were found.
Gender comparisons revealed that women had more insomnia
symptoms than men [F(1/1,795) 034.6, p<0.001], while
there were no sex differences in sleep duration [F(1/1,753) 0
0.5, p00.83]. Dispositional optimism, self esteem, and de-
pression scores were correlated with age such that older par-
ticipants reported higher optimism and self-esteem and lower
depression scores. Optimism did not vary by participant’ssex
[F(1/1,791) 03.2, p00.07], but men had higher levels of self-
esteem [F(1/1,789) 023.1, p<0.001] and lower depression
scores [F(1/1,803) 041.9, p<0.001]. Optimism and self-
esteem were positively related to each other and negatively
with depression scores. Insomnia symptoms and sleep dura-
tion were negatively related.
Associations Between Sleep and Positive Personality
Characteristics
Tab l e 2shows coefficients of multiple regression analyses
testing the relationship of optimism and self-esteem with
insomnia symptoms and sleep duration. Insomnia symptoms
were related to lower levels of optimism and self-esteem. The
relations were only modestly attenuated when further control-
ling depression scores and sleep duration. Interaction terms
with age and sex were statistically not significant. Short sleep
duration (sleeping less than 6 h) was related to lower levels of
optimism. The relation remained statistically significant when
controlling depression or insomnia symptoms, although it was
considerably attenuated in size when controlling insomnia
symptoms. As the short sleep (sleeping less than 6 h) × sex
interaction term was statistically significant, the analysis was
repeated separately for men and women adjusting age. This
analysis revealed that short sleep was related to lower opti-
mism in both men (β0−0.13, t0−2.45, p00.02) and women
(β0−0.30, t0−6.50, p<0.001), but the relation was consider-
ably stronger for women. Short sleep (sleeping less than 6 h)
was also negatively related to self-esteem, adjusting partici-
pant’s age, sex, and depression, but was attenuated to insig-
nificance when adjusting insomnia symptoms. Long sleep
(sleeping more than 9 h) was also negatively related to opti-
mism and self-esteem. This relation was not moderated by
participant’s sex or age. Moreover, the relation of long sleep
with lower self-esteem held statistically significant when
adjusting depression scores or insomnia symptoms.
Discussion
Our findings are generally consistent with previous epidemi-
ological and experimental studies showing that less insomnia
symptoms and sleep duration of 7–8 h are related to higher
levels of positive personality characteristics [5–8]. Our find-
ings are further in line with evidence of better mental health
among individuals without insomnia symptoms compared to
individuals suffering from troubled sleep [4]. Generally, the
pattern of relations of sleep measures with optimism and self-
esteem was not moderated by age. With regard to participant’s
sex, we found that women—as compared to men—appear to
be more vulnerable for the negative relation of short sleep
duration with optimism. This might reflect a generally higher
vulnerability among women for negative outcomes related
Int.J. Behav. Med. (2013) 20:567–571 569
with inadequate sleep duration. For instance, women with
short sleep duration are also at higher risk for hypertension
[3], while no such increased risk was found for men. However,
more research is needed to replicate and better understand the
sex differences we found. Importantly, the relationship
between short sleep and lower optimism was independent of
possibly comorbid insomnia symptoms and held also when
controlling depression scores.
Consistent with epidemiological studies that show a rela-
tionship of long sleep duration with poor physical and mental
Table 1 Mean values and correlations of study variables
M(SD) 1 2 3 4 5
1 Age (years) 56.85 (12.62)
2 Optimism 23.05 (4.76) 0.09***
3 Self-esteem 37.49 (7.38) 0.09*** 0.60***
4 Depression 0.67 (1.80) −0.13*** −0.28*** −0.34***
5 Insomnia symptoms 7.54 (2.92) 0.01 −0.22*** −0.27*** 0.23***
6 Sleep duration (h) 7.14 (1.15) 0.05* 0.11*** 0.07** −0.09*** −0.38***
7 Sleep duration (dummy)
<6 h (n0197) –0.07 −0.22*** −0.16*** 0.15*** 0.50***
6–7h(n0399) –−0.08* −0.07* −0.08** 0.02 0.20***
8–9h(n0450) –0.13*** −0.02 −0.01 −0.02 −0.08*
>9 h (n086) –0.18*** −0.06 −0.12** 0.04 0.03
Sleep duration categories are dummy coded with the category of 7–8 h of sleep (n0623) as reference
*p<0.05; **p< 0.01; ***p< 0.001
Table 2 Associations of insomnia symptoms and sleep duration with optimism and self-esteem, standardized regression coefficients
Adj. 1
a
Adj. 2
b
Adj. 3
c
Sleep × sex Sleep × age
βtβtβtβtβt
Optimism as criterion
Insomnia symptoms −0.22 −9.49*** −0.17 −7.31*** −0.19 −7.51*** −0.02 −0.51 0.02 1.03
Sleep duration
7–8 h (reference) vs.
<6 h −0.22 −6.47*** −0.18 −5.33*** −0.10 −2.62** −0.15 −2.65** −0.03 −0.67
6–7h −0.06 −2.00* −0.06 −1.99* −0.02 −0.60 −0.10 −1.92 0.04 1.02
8–9h −0.03 −1.02 −0.03 −1.13 −0.04 −1.43 0.00 0.00 −0.03 −0.84
>9 h −0.08 −2.12* −0.06 −1.72 −0.07 −2.00* −0.04 −0.67 −0.04 −0.88
Self-esteem as criterion
Insomnia symptoms −0.26 −11.30*** −0.20 −8.77*** −0.25 −10.02*** 0.01 0.34 0.03 1.42
Sleep duration
7–8 h (reference) vs.
<6 h −0.16 −4.62*** −0.11 −3.42*** −0.02 −0.60 −0.11 −1.94 0.01 0.15
6–7h −0.08 −2.47* −0.07 −2.51* −0.02 −0.79 0.00 −0.05 0.03 0.70
8–9h −0.02 −0.68 −0.02 −0.81 −0.04 −1.28 0.02 0.39 −0.01 −0.31
>9 h −0.13 −3.47*** −0.11 −3.13** −0.12 −3.38*** −0.07 −1.12 −0.02 −0.57
The models including interaction terms (i.e., insomnia symptoms/sleep duration × sex or insomnia symptoms/sleep duration × age) additionally
adjust age and sex
a
Models adjust age and sex
b
Models adjust age, sex, and depression scores
c
Models adjust age, sex, and the respective other sleep parameter (i.e., models with sleep duration as predictor additionally adjust insomnia
symptoms and vice versa)
*p<.05; **p< .01; ***p< .001
570 Int.J. Behav. Med. (2013) 20:567–571
health [1,2], we also found evidence for lower levels of
optimism and self-esteem in individuals who slept longer than
9 h compared to their counterparts who sleep 7–8h.Ourcross-
sectional findings do not allow inferences on causality and
underlying mechanisms that link sleep and positive personality
characteristics. One possible mechanism that may associate
sleep with positive personality characteristics is that short sleep
duration and poor sleep quality lead to dysregulation of the
hypothalamic-pituitary-adrenocortical axis involving changes
in cortisol secretion [18], which, in turn, is known to be
adversely related to positive personality characteristics [19].
Equally, it is possible that positive personality characteristics
facilitate better sleep by their beneficial influence on physical
and mental well-being. Finally, also a bidirectional relationship
between sleep and personality characteristics is possible, in-
volving different causal mechanisms working at the same time.
The strength of the present study is the use of data from a
large community-based sample covering a broad age range.
However, there are also some limitations. First, as already
mentioned, our analyses were only cross-sectional and do
not inform on the direction of the relationship. Second,
sample retention of MIDUS II was selective regarding eth-
nicity, gender, marital status, higher education, and better
health, which might have affected the findings. Third, the
data are solely based on self-reported sleep duration and
insomnia symptoms. It is therefore possible that memory
distortions have influenced the report of sleep. Apart from
the self-reports of sleep duration and insomnia, also opti-
mism and self-esteem were self-reported. Thus, the relation-
ship between sleep measures, optimism, and self-esteem
might partly be due to same-method variance.
Conclusion
In sum, our findings extend previous knowledge by showing
that having less insomnia symptoms is related to higher levels
of dispositional optimism and self-esteem. Further, short sleep
duration (<6 h) was related to lower optimism and self-esteem
when compared to individuals who sleep 7–8h.
Acknowledgments This research was supported by a grant from the
MIDUS Pilot Grant Competition, National Institute on Aging, USA, to
M. Allemand. The publication is based on data from the MIDUS Study,
funded by the John D. and Catherine T. MacArthur Foundation Re-
search Network on Successful Midlife Development and the National
Institute on Aging (P01-AG020166).
Conflicts of interest None.
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