2012. Vol.3, No.12, 1067-1073
Published Online December 2012 in SciRes (http://www.SciRP.org/journal/psych) http://dx.doi.org/10.4236/psych.2012.312158
Copyright © 2012 SciRes. 1067
Effects of Positive Psychology Interventions in Depressive
Patients—A Randomized Control Study
Reinhard Pietrowsky*, Johannes Mikutta
Department of Clinical Psychology, University of Düsseldorf, Düsseldorf, Germany
Email: *R. Pietrowsky@hhu.de
Received September 26th, 2012; revised October 24th, 2012; accepted November 21st, 2012
Effects of Positive Psychology (PP) have been shown in several studies to alleviate depressive symptoms
in patients suffering from major depression or dysthymia when administered within psychotherapy. The
present study served to test for the effects of two interventions from PP (best possible self, three good
things) when practised by depressive patients for three weeks without any other concomitant psychother-
apy. Seventeen depressive patients were randomly assigned to either the PP group or the control group.
Patients in the PP group wrote down the best possible self for one week and then three good things for
another two weeks. Patients in the control group wrote down images of the future of mankind for one
week and early memories for two weeks. Prior to the intervention and again after it had finished, depres-
sive symptoms, satisfaction with life, positive and negative affect, optimism, and resilience were assessed.
While in both groups of patients well-being and resilience increased and depressive symptoms declined,
the decline of depressive symptoms and the increase of positive affect and resilience were more pro-
nounced in the PP group. The results support the notion that even a short intervention using PP alone al-
leviates depressive symptoms and increases well-being. Although the effects were of marginal signifi-
cance, this may be attributed to the relatively small sample size. Likewise, the use of an Intent-to-Treat
analysis may have affected the PP group more than the control group, indicating an underestimation of the
potency of PP in the present study.
Keywords: Positive Psychology; Depression; Randomised Control Trial; Well-Being; Resilience
Positive Psychology (PP) can be regarded as that discipline
in psychology that focuses on positive experiences, positive
emotions, positive personality traits and positive social interact-
tions. PP has the aim of extending the present focus of psycho-
therapy on negative aspects of human functioning to aspects
that lead to happiness and a successful life. Seligman and Csik-
sentmihalyi (2000: p. 5) define PP as follows: “The aim of
positive psychology is to begin to catalyze a change in the fo-
cus of psychology from preoccupation only with repairing the
worst things in life to also building positive qualities”. Thus,
the principle “fix what’s wrong” should be replaced by the
principle “build what’s strong” (Duckworth, Steen, & Seligman,
Target Factors of Positive Psychology
Main variables on which PP focuses are happiness, subjec-
tive well-being, and positive affect. These variables overlap to
some extent and each is also a component of the others. Hap-
piness can be regarded as the main goal of positive psychology
and thus of psychological or psychotherapeutic interventions.
Happiness is regarded as comprising self-experienced satisfac-
tion with life and the relative amounts of positive and negative
affect. It is close to the concept of subjective well-being (SWB).
High SWB also arises from the experience of more positive
than negative affect and a satisfaction with life (Andrews &
Whitey, 1984). According to Diener, Suh, Lucas and Smith
(1999), SWB can be the result of bottom-up and top-down
processes, i.e., a cumulation of singular events of happiness or
an attitude of the subject to experience events in a positive way,
respectively. In addition, teleological theories assume that SWB
is the result of the attainment of a specific state or an important
personal goal. In contrast, other theories assume that happiness
is not the goal of human activity but results from specific ac-
tions, as assumed by the flow concept (Csikszentmihalyi,
As mentioned, the ratio of positive and negative affect is a
main constituent of SWB and thus happiness. Evidently, the
preponderance of positive affect over negative affect is related
to more SWB and happiness. Recent theories assume that posi-
tive and negative affect are not merely the poles of a single
(bipolar) dimension, but are independent factors (Watson &
Clark, 1997). Thus, the experience of positive affect may not
merely indicate a lack of negative affect. Rather, both may be
concurrent, i.e., a person may experience high positive affect
and, concomitantly, high negative affect. Likewise, the reduc-
tion of negative affect, as in the treatment of depressive patients,
may not automatically result in an increase of positive affect.
On the other hand, there is some profound criticism of the as-
sumption that positive and negative affect are independent fac-
tors (Green, Goldman, & Salovey, 1993; Russel & Carrol,
1999). This controversy may hint at the fact that in a short-term
perspective there may be a high correlation between both (bi-
polarity), while in a long-term perspective they can be regarded
as independent (Diener & Emmons, 1984). Positive affect can
R. PIETROWSKY, J. MIKUTTA
induce a specific way of thinking, feeling and acting and thus
facilitate SWB and happiness. As Lyubomirsky, King and Die-
ner (2005) have shown, positive affect is related to personality
factors such as optimism, self-efficacy, activity, flexibility, and
a functional coping with stress. Thus, positive affect—in a
long-term perspective—may be the result of personality factors
like optimism and resilience.
Optimism is a capacity that fosters positive affect. It can be
defined as expecting the best and that goals will be reached and
dreams and hopes will come true. Optimism can be regarded as
a disposition in terms of a personality trait (Scheier & Carver,
1985) and as an attributional style (Buchanan & Seligman,
1995). Optimism leads to a functional tracking of goals, which
itself is an important predictor of satisfaction and the use of
adaptive and problem-oriented coping strategies (Scheier &
Carver, 1992). A low or missing optimism can be regarded as
an important factor to elicit a depression (Schueller & Seligman,
Another factor that may contribute to happiness is grateful-
ness. Gratefulness means to consciously attend to the happy
things of one’s life, to appreciate them and to be thankful for
them. By this means gratefulness is an important factor in im-
proving SWB (Bryant, 1989). Gratefulness results from the
understanding that positive things that happen to oneself have a
cause, and this understanding can imbue the things one is doing
or that happen to one with meaning (McCullough, 2002).
Moreover, gratefulness is incompatible with the feeling of
negative affect (McCullough, Emmons, & Tsang, 2002).
Gratefulness is thus an important factor that strengthens resil-
ience, which by itself is a major determinant of well-being,
satisfaction with life, and happiness.
Positive Psychology Interventions
Since the ratio of positive to negative affect, optimism, and
gratefulness can be regarded as important factors for happiness
and SWB, PP interventions thus are intended to induce positive
affect and minimize negative affect and to enhance optimism
and gratefulness in order to increase SWB and happiness. An
intervention task used by PP to increase positive affect and
optimism is the so-called “Best Possible Self” (BPS), in which
the intent is to think of the future in a positive way and to be-
lieve that personal goals can be reached. This technique was
introduced by King (2001) and is derived from expressive
writing. In a study by Sheldon and Lyubomirsky (2006) prac-
tice of this task for six weeks led to more positive affect in
psychology students compared to a control task. In a further
study, Lyubomirsky, Dickerhoff, Boehm and Sheldon (2011)
could demonstrate in a student sample that the BPS task also
increased optimism when performed for eight weeks compared
to a control task. Likewise, Peterson, Flink, Boersma and Lin-
ton (2010) could demonstrate that positive affect and optimism
increased in a student sample following this task compared to a
control task. Moreover, these authors showed that the increase
in optimism was independent of the increase in positive affect.
Tasks that are suitable to increase gratefulness are the “Count-
ing one’s blessings” (COB) and the “3 Good Things” (3GT). In
the COB, the participants are instructed to write down what
they are thankful for. Emmons and McCullough (2003) showed
that COB enhanced gratefulness, life satisfaction and optimism
as compared to a control task. In the 3GT, subjects write down
three things every evening that have gone well and why these
things went well. In an internet-based randomized study,
Seligman, Steen, Park and Peterson (2005) could demonstrate
that the 3GD was capable of increasing happiness and reducing
depressive symptoms in a one-week treatment. Likewise, a
combination of 3GT and COB was shown to induce grateful-
ness and enhance life satisfaction and positive affect in teachers
Assessment of the Target Factors
The target variables of PP such as SWB, positive and nega-
tive affect, and optimism can be assessed using specific ques-
tionnaires. Well established questionnaires, which were also
used in the above-mentioned studies, are the Satisfaction with
Life Scales (SWLS) (Diener, Emmons, Larsen, & Griffin, 1985)
used to assess satisfaction with life, the Positive and Negative
Affect Schedule (PANAS) (Watson, Clark, & Tellegen, 1988)
used to assess positive and negative affect, and the Life Orien-
tation Test (LOT) (Scheier, Carver, & Bridges, 1994) used to
assess optimism. These three variables are indicators of SWB.
To our knowledge, there is no established questionnaire to as-
sess gratefulness. Accordingly, gratefulness was assessed by
the feeling of relatedness to other people (Emmons & McCul-
lough, 2003) or derived from positive affect or feelings of hap-
piness (Seligman et al., 2005). In our opinion, resilience as a
personality feature that describes the “acceptance of the self
and life” covers some aspects of gratefulness. Thus, we decided
to assess resilience, which has rarely been assessed in PP re-
search, as a further indicator of PP effects, mainly on personal
competence, acceptance and also gratefulness.
Rationale of the Present Study
While there are numerous studies that showed effects of PP
interventions in non-clinical samples (e.g., Sin & Lyubomirsky,
2009), only a few studies have investigated the effects of PP in
clinical samples of depressive patients. While in these studies
the PP interventions have been rather extensive and in the form
of an individualized therapy (e.g., Seligman, Rashid, & Parks,
2006), the present study served to investigate the effects of a
short PP intervention in a group of depressive patients, who
were provided only with instructions concerning the PP tasks.
Thus, interference with effects from current psychotherapy or
unspecific therapeutic effects was avoided. In a randomized
manner the patients received either two PP tasks (BPS, 3GT) or
two control tasks for a three week period. We expected the PP
tasks to enhance satisfaction with life, the ratio of positive to
negative affect, optimism and gratefulness (as assessed by a
resilience scale) and to reduce depression.
Methods and Materials
Seventeen depressive participants (8 male, 9 female) took
part in the study. Patients were recruited from a larger sample
of 43 participants who were on the waiting list for the psycho-
therapeutic outpatient clinic at the University of Düsseldorf,
Germany. Inclusion criteria of this sample were a BDI-II score
greater than 19. From this sample, 15 patients were excluded
due to the exclusion criteria while 11 patients were not inter-
ested in participating in the study. Exclusion criteria were sui-
cidal tendencies, comorbid psychiatric diseases, and start of
Copyright © 2012 SciRes.
R. PIETROWSKY, J. MIKUTTA
psychotherapy during the course of the study. The remaining 17
patients were randomly assigned to either the experimental (N
= 9) group, which received a Positive Psychology treatment (PP)
or the control group (CG; N = 8), which received treatment as
described below. Two patients of each group dropped out dur-
ing the treatment, however their data were included in the
analysis due to an Intend-To-Treat analysis (see below). Mean
age was 43.75 years (SD: 8.84) in the PP group, years after
34.11 (SD: 8.43; t(15) = 2.57, p < .05) in the control group. In
each group 5 participants were under medication with antide-
pressants. Medication was stable over the duration of the study.
Informed written consent was obtained from each participant.
The study was approved by the ethics committee of the Univer-
sity of Düsseldorf.
All participants underwent three sessions. In the first session
the participants were informed about the study and the treat-
ment they would receive and filled out the questionnaires for
the pre-testing as well as the written informed consent. Then
the first task (see below) was explained. This session took
about one hour. In the second session one week later, which
took also about an hour, the practise of the first task was dis-
cussed and the participants reported what they had written
down in the first task. They were encouraged to continue this
task during the next two weeks. Then the second task was ex-
plained and the time fixed for a short phone interview in one
week. This phone call served for a short test of the practise of
the second task. The third session took place two weeks after
the second session (i.e. one week after the phone interview) and
served to talk about the practise of the second task. Then the
questionnaires for the post-measurement were filled out. This
session took about 45 minutes.
Participants who received the PP treatment did the BPS task
as the first intervention for one week (from session 1 to session
2). Instructions for the BPS task were given according to Shel-
don and Lyubomirsky (2006). Participants were instructed to
think about their best possible self and to write down their
thoughts and feelings about that. In detail, they were instructed
that to think about the best possible self means that they should
imagine their future when whatever happened was as good as
possible. For example, they have worked hard and have been
successful in realising all their goals. They should imagine they
had realised all their life dreams and their own potential. In that
case, they should describe the best possible way how things
should happen in their life to guide them to make decisions in
the present. Participants were instructed to take 30 min of the
next day at a quiet place to think about their BPS and to write
down their thoughts on a sheet of paper. These recordings
should be read by them once again during the week.
In the second and third week, PP participants did the 3GT
task. Instructions for this task were given according to Selig-
man et al. (2005). Participants were told that people dwell too
much on things that go wrong and too little on things that go
well in their life. Of course, sometimes it may be helpful to
analyse things that went wrong to avoid mistakes. Nonetheless,
people tend to think about bad things most of the time. A way
to prevent this may be to increase our ability to think about the
good things in our life. However, this is not easy, because we
are usually not experienced in that. Thus, this ability takes time
to practice. Therefore the participants were asked to take 10
minutes of time each evening for two weeks to write down in a
diary three things that went well that day and why these things
went well. The diary was given to the participants in session 2
and was requested to bring it with them for session 3.
As controls for the BPS task, participants in the controls
group were given the task of writing about the future of man-
kind in the first week. To parallel with the task in the PP group,
the participants in the CG also had to think about the future of
mankind for 30 min each day in a quiet place and to write down
their thoughts. Their task to think about the future of mankind
means that they should think that all things will go well for
mankind. People have worked hard and have been successful in
attaining their goals. This should be seen as a realisation of
their dreams and the potential of mankind. They should imagine
the way how things could happen in the future to help the peo-
ple and how this would affect their decisions in the present.
This instruction also served to encourage the participants to
think about good possible things, but in contrast to the BPS task,
not with the focus on the own person and the self.
To control for the 3GT task, participants in the CG were re-
quested to think about early memories. As a parallel with the
task in the PP group, they were instructed to think about early
memories and write them down in a diary for 10 min each eve-
ning for the following two weeks. They were to bring the diary
with them in the third session.
Depression was assessed using the Beck Depressions Inven-
tory, 2nd edition (BDI-II) (Beck, Steer, & Brown, 1996; Ger-
man version by Hautzinger, Keller, & Kühner, 2006). The
BDI-II is a standardized and widely used self-response ques-
tionnaire to assess depressive symptoms. Depressive symptoms
during the last two weeks are assessed by 21 items with state-
ments reflecting different degrees of agreement with an item,
ranging from full disagreement (0) to full agreement (3). Sum
scores < 13 indicate no depression, 14 - 19 indicates a mild de-
pression, 20 - 29 indicates a moderate depression, and a sum
score > 30 indicates a severe depression.
Satisfaction with life was assessed by the Satisfaction with
Life Scales (SWLS) (Diener et al., 1985; German version by
Schumacher, Klaiberg, & Brähler, 2003). The SWLS is a self-
response questionnaire consisting of five statements (e.g., “I am
satisfied with my life”) to which the participant has to agree or
disagree according to 7 alternatives ranging from full agree-
ment to full disagreement. The scores are added to a sum score.
Higher sum scores indicate a greater satisfaction with life, with
a score of 20 indicating a neutral value. Thus, scores higher 20
indicate satisfaction with life, while scores lower 20 indicate
dissatisfaction with life. The reliability of the SWLS is Cron-
bach’s α = .87 and the discriminative validity is given to posi-
tive and negative affect as well as to optimisms (Lucas, Diener,
& Suh, 1996).
Positive and negative affect were assessed using the Positive
and Negative Affect Schedule (PANAS) (Watson et al., 1988;
German version by Krohne, Egloff, Kohlmann, & Tausch,
1996). The PANAS is also a self-response questionnaire, con-
sisting of 20 adjectives, 10 for positive affect and 10 for nega-
tive affect (e.g., enthusiastic, inspired, irritable, distressed), to
Copyright © 2012 SciRes. 1069
R. PIETROWSKY, J. MIKUTTA
which the participant has to agree or not agree if the respective
adjective describes his feeling during the last days. Answers are
given to five alternatives ranging from full disagreement to full
agreement. The ratings on each subscale (positive affect, nega-
tive affect) are added to a sum score with higher values repre-
senting higher positive or higher negative affect, respectively.
The reliability (Cronbach’s α) is .88 for the positive affect-scale
and .85 for the negative affect-scale (Krohne et al., 1996). Ex-
ternal validity was shown by comparisons with reports on emo-
Optimism and pessimism were assessed using the Life Ori-
entation Test-Revised (LOT-R) (Scheier, Carver, & Bridges,
1994; German version by Glaesmer, Hoyer, Klotsche, & Herz-
berg, 2008). The self-response questionnaire consists of 10
items (statements), of which three items measure optimism (e.g.,
I see my future always optimistic), three measure pessimism
(e.g., I do not expect that something good will happen to me),
and four are filler items. Answers to the statements are given to
five alternatives ranging from full disagreement to full agree-
ment, scored from 0 to 4. The scores of the three items for op-
timism and the three items for pessimism are added, resulting in
sum scores for optimism and pessimism, respectively. Higher
scores indicate greater optimism or pessimism. Based on a fac-
tor analysis, it was shown that optimism and pessimism as as-
sessed by the LOT-R are not opponent poles of one dimension
but are independent factors, i.e., a person may have at once a
low optimism and low pessimism or a high optimism and a
high pessimism (Glaesmer et al., 2008). Reliability (Cronbach’s
α) for the German version is .69 for optimism and .68 for pes-
simism. External validity is given by positive correlations to the
concept of self-mastery and negative correlations to anxiety
(Scheier et al., 1994).
Resilience was assessed using a short version (RS-11) of the
Resilience Scale (RS) (Wagnild & Young, 1993; German ver-
sion by Schumacher, Leppert, Gunzelmann, Strauß, & Brähler,
2005). It consists of 11 statements (e.g., If I have plans, I pur-
sue them; Usually I can regard a situation from several perspec-
tives) to which agreement in general is rated on a 7-point Likert
scale (1 = full disagreement, 7 = full agreement). The scores of
the 11 items are added, resulting in a sum score, with high
scores indicating strong resilience. Reliability of the German
version is good (Cronbachs’s α = .91) and validity is given by
high positive correlations to self-efficacy (Schumacher et al.,
Data were analysed according to an Intention-to-Treat analy-
sis, i.e., the data from subjects who refused to start with the
treatment or that dropped out during the intervention period
were also taken into consideration. Accordingly, the data from
those participants were treated following a “last observation
carried forward” (LOCF) protocol with the pre-measures also
taken for the post-measure. This procedure is rather conserva-
tive and implies that no improvement has taken place due to the
Statistical analysis was based on an analysis of variance
(ANOVA) with the between-group factor Treatment (PP vs.
CG) and the repeated measures factor Time (pre vs. post) for
each of the dependent variables (depression, satisfaction with
life, positive and negative affect, optimism, resilience). Prior to
each ANOVA, a test for homogeneity of variances was applied.
A p-value ≤ .05 was regarded as significant.
Depression ratings of both groups as assessed by the BDI-II
were not significantly different prior to treatment (CG 28.25,
PP 25.22; t(15) = 0.36, n.s.; Table 1). Depression ratings de-
clined over the course of the study in both groups (Time:
F(1,15) = 10.29, p < .01). Although the Treatment × Time in-
teraction in the ANOVA failed to reach statistical significance
(F(1,15) = 1.92, n.s.), depression declined more in the PP (t(8)
= 2.88, p < .05) than in the CG (t(7) = 1.61; n.s.). There was no
significant main effect for Treatment (F(1,15) = 1.75, n.s.).
Satisfaction with Life:
Satisfaction with life was not affected by Time or by Treat-
ment (Table 1).
Positive and negative affect:
Positive affect tended to be higher in the PP compared to the
CG (24.67 vs. 19.65; Treatment: F(1,15) = 3.04, p = .1). It also
tended to increase during the study interval (pre: 21.24, post:
23.32; Time: F(1,15) = 3.58, p < .1). The increase of positive
affect was more pronounced in the PP than in the CG (Table 1),
but this effect did not reach statistical significance (Treatment ×
Table 1. Means (±SD) of the different dependent measures for de-
pressive patients receiving either 3 weeks of Positive Psychology
interventions (PP) or 3 weeks of a control treatment (CG).
Pre 25.22 (2.99) 28.25 (9.19) n.s.
Post 17.67 (7.62) 25.25 (13.41) n.s.
Satisfaction with life
Pre 16.44 (4.77) 15.88 (4.32) n.s.
Post 17.67 (5.61) 15.88 (2.59) n.s.
Pre 22.44 (5.86) 19.88 (6.62) n.s.
Post 26.89 (6.35) 19.75 (5.92) p < .05
Pre 26.33 (7.00) 25.25 (6.63) n.s.
Post 21.89 (5.26) 24.50 (8.12) n.s.
Pre 5.56 (2.01) 4.88 (3.09) n.s.
Post 5.89 (2.42) 4.25 (3.00) n.s.
Pre 5.56 (1.67) 6.25 (2.12) n.s.
Post 5.33 (1.80) 7.63 (2.33) p < .05
Pre 45.78 (13.72) 36.25 (11.08) n.s.
Post 51.22 (10.21) 36.88 (10.23) p < .05
Copyright © 2012 SciRes.
R. PIETROWSKY, J. MIKUTTA
Time: F(1,15) = 4.01, p < .1). Positive affect was significantly
higher in the PP compared to the CG at the end of intervention
(26.89 vs. 19.75; t(15) = 2.39, p < .05).
Negative Affect tended to decline across the study period
(main effect Time: F(1,15) = 4.34, p < .1; Table 1). There was
no significant effect of the intervention or a Treatment × Time
Optimism and Pessimism:
Optimism was not affected by Time or Treatment (Table 1).
Pessimism was significantly higher in the CG compared to the
PP group at the end of the intervention (7.63 vs. 5.33; t(15) =
2.29, p < .05).
Resilience was generally higher in the PP compared to the
CG (48.50 vs. 36.57; Treatment: F(1,15) = 4.92; p < .05). It
also increased during the study interval (pre: 41.29, post: 44.47;
Time: F(2,30) = 4.70, p < .05). The Treatment × Time interac-
tion tended toward statistical significance, indicating a more
pronounced increase of resilience in the PP compared to the CG
(F(1,15) = 2.96, p = .1; Table 1). This resulted in a significantly
higher resilience in the PP group compared to the CG at the end
of the intervention (51.22 vs. 36.88; t(15) = 2.89, p < .05).
In the present study a short intervention of three weeks, not
embedded in psychotherapy, was compared with a control in-
tervention in depressive patients. The results show that PP was
superior to the control intervention, i.e., all measures in the PP
group improved, while this was not the case in the control
group. Specifically, depression ratings, positive affect, and
resilience increased markedly in the PP group compared to the
control group, although these increases reached only marginal
statistical significance. The fact that the differences between
both groups after the three-week interventions were only mar-
ginally significant (i.e., p < .1) may be due to the small sample
size of the present study, with nine depressive patients in the PP
group and eight in the control group.
As expected, the depression ratings prior to the intervention
did not differ significantly between the two groups. The de-
pression ratings as assessed by the BDI-II were in the range of
19 to 45, indicating moderate to severe depression. During the
three-week intervention the depression ratings declined in both
groups, but the decline was more pronounced in those patients
receiving PP interventions. Although this difference was not
displayed in a significant interaction in the ANOVA, subse-
quent t-tests were performed separately for each group; the
t-tests confirmed a significant decline of depression ratings in
the PP group but not in the control group. Following the inter-
vention period, the mean depression ratings in the PP group
were below the criterion for a moderate depression, while they
remained above that score in the control group, which had
started from a slightly higher level, it must be said. These re-
sults do not confirm a significant amelioration of depressive
symptoms in patients with major depression as reported by
Seligman et al. (2006). However, in their study, the patients
received 14 therapy sessions in a personal instruction, while in
the present investigation there was no concomitant therapy
except for the explanation of the PP tasks.
Satisfaction with life as assessed by the SWLS was not af-
fected by the intervention. Although the SWLS scores margin-
ally increased following the PP intervention while remaining
stable in the control group, this small effect did not reach statis-
tical significance. On the one hand, this result is in contrast to
the study reported by Seligman et al. (2006), who found a sub-
stantial improvement in SWLS ratings following a six-week PP
intervention in mild to moderate depressive students. However,
in their study the duration and intensity of the PP intervention
was longer and greater than in the present study. On the other
hand, the items of the SWLS describe a general satisfaction
with life (i.e., “I have attained the main things that I wished for
my life”), thus it is not too surprising that there are only small
effects after the three weeks intervention in the present study,
which may have been too short to alter satisfaction with general
Positive affect, as assessed by the PANAS, was improved by
the PP intervention and even declined marginally in the control
group. Since the PANAS assessed affect during the last few
days, this questionnaire seems suitable to assess short-term
changes in affect as caused by the intervention. As expected,
three weeks of PP interventions enhanced positive affect in the
depressive patients. This result is in line with other studies that
showed that PP interventions enhanced positive affect (Peters et
al., 2010; Sheldon & Lyubomirsky, 2006). Negative affect de-
clined marginally across the three weeks intervention in both
groups. Thus, there was no specific effect of PP on negative
affect compared to the control intervention.
Contrary to our expectation, optimism was not affected by
the intervention. Although the statements of the LOT-R de-
scribe general appraisals of a person and the own life (i.e., “I
see my future always optimistically”), we expected that these
appraisals could be changed by the PP interventions. Especially
the technique of the best possible self was expected to increase
optimism due to the optimistic beliefs that are supposed to be
evoked by that intervention. Accordingly, a number of previous
studies did obtain positive effects of the BPS and an enhance-
ment of optimism (Peters et al., 2010; Sheldon & Lyubomirsky,
2006). Pessimism as assessed by the LOT-R was significantly
higher in the control group at the end of the intervention period.
Since the optimism and pessimism subscales of the LOT-R can
be regarded as independent factors, it should have been possible
that pessimism was reduced by the intervention irrespective of
an effect on optimism. In fact, pessimism increased to a small
extent in the control group, resulting in a significant difference
at post measurement, while there was no effect on optimism. It
may thus be concluded either that the PP interventions in the
present study were too short or that the study group was too
small (see below).
Resilience increased across the study with a more pro-
nounced increase in the PP group. This effect was expected and
may be predominantly caused by the “3 good things” intervene-
tion, which is supposed to focus on the mastery of things and
problems even in situations in which the patients see things that
go wrong instead those that go well. This ability to focus on the
good things, even when they are embedded in bad things, is a
basic factor of resilience (and of PP) and also reflects grateful-
ness. The effects on resilience are in line with previous studies
which showed positive effects of the COB and 3GT tasks on
gratitude (Chan, 2010; Emmons & McCullough, 2003; Selig-
man et al., 2005). In addition to effects on gratitude, the in-
crease in resilience of course also hints at a higher resilience
due to the PP interventions.
The patients in the present sample were recruited from the
waiting list of a psychotherapeutic outpatient clinic. Since one
Copyright © 2012 SciRes. 1071
R. PIETROWSKY, J. MIKUTTA
inclusion criterion was a BDI-II score > 19, they all had de-
pression scores that indicated at least moderate depression (>19
on the BDI-II) prior to the intervention. On average, the control
group had higher depression scores than the PP group, but this
difference was not statistically significant. However, the higher
depression score in the control group appears to be due to a
single patient who had a BDI score of 45 prior to the interven-
tion. With respect to clinical symptoms, four patients in each
group shifted from moderate to mild depression during the
course of the intervention, whereas the BDI scores increased in
two patients from the control group. No such increase in the
BDI score was observed in the PP group. These data also con-
tain the two patients in each group whose pre-measures were
also taken as post-measures and thus could not indicate any
Although the effects in the present study were of marginal
significance, the relatively small sample size must be consid-
ered. Due to the large F-values in the ANOVAs for the respect-
tive Treatment × Time interactions, it can be assumed that the
observed effects are strong and that given a larger sample of
patients, they would have become statistically significant.
Moreover, the PP intervention was of rather short duration
(three weeks) and not guided by the therapist. In fact, the pa-
tients got only the instructions for the PP interventions and then
practiced by themselves at home. In the second session, the
experiences with the first intervention were discussed. Thus, the
results indicate that even the instructions for the use of PP in-
terventions with subsequent self-guided practice have remark-
able effects. In contrast, in some other PP studies in which the
PP interventions were included in a full and regular psycho-
therapy, effects of the same magnitude were observed (e.g.,
Seligman et al., 2006).
An additional factor that may account for the weak effects in
the present study may be the use of an Intent-to-Treat analysis
(ITT). Since two patients of each group dropped out during the
intervention period, we used their pre-measures also as post-
measures, which is a conservative procedure, since it does not
account for effects due to the intervention. Although the ITT
was applied to two patients in each group, it cannot be sup-
posed that their effects simply cancel out, since on our hy-
potheses we expected a more pronounced effect in the PP than
in the CG. Thus, the ITT should affect the PP group more than
the CG. This may be a further indication that the potency of PP
was underestimated in the present study.
In summary, the present study showed weak but consistent
effects of PP interventions in a sample of patients with moder-
ate depression. These effects are of particular relevance since
the patients received no other form of psychotherapy during or
prior to the intervention. Thus, the positive effects on depres-
sive symptoms, positive affect and resilience can be attributed
only to the self-guided PP interventions of a short duration of
three weeks. The results thus add to the increasing evidence for
the positive and helpful effects of Positive Psychology in the
treatment of different forms of psychological disturbances,
including depression, and they show that PP interventions can
be effective even without a concomitant psychotherapy.
We thank Helen-Rose Cleveland for language editing of the
Financial disclosures: The authors have no conflict of interest
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