Journal of Consulting and Clinical Psychology

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1 Journal of Consulting and Clinical Psychology An Online Optimism Intervention Reduces Depression in Pessimistic Individuals Susan Sergeant and Myriam Mongrain Online First Publication, January 13, doi: /a CITATION Sergeant, S., & Mongrain, M. (2014, January 13). An Online Optimism Intervention Reduces Depression in Pessimistic Individuals. Journal of Consulting and Clinical Psychology. Advance online publication. doi: /a

2 Journal of Consulting and Clinical Psychology 2014 American Psychological Association 2014, Vol. 82, No. 2, X/14/$12.00 DOI: /a An Online Optimism Intervention Reduces Depression in Pessimistic Individuals Susan Sergeant and Myriam Mongrain York University Objective: Interest in online positive psychology interventions (OPPIs) continues to grow. The empirical literature has identified design factors (e.g., variety and duration of activities) and moderators (e.g., personality traits) that can influence their effectiveness. A randomized controlled trial tested an empirically informed OPPI designed to promote self-efficacy and an optimistic outlook. Pessimism was included as a trait moderator. Method: Participants (N 466) were English-speaking adults interested in becoming happier. They were randomly assigned to complete either an OPPI cultivating optimism or a control condition writing about daily activities for 3 weeks. Follow-up assessments occurred 1 and 2 months following the exercise period. Results: A hierarchical linear model analysis indicated that the optimism intervention increased the pursuit of engagement-related happiness in the short term and reduced dysfunctional attitudes across follow-ups. Pessimistic individuals had more to gain and reported fewer depressive symptoms at post-test. Conclusions: These findings support the conclusion that empirically informed online interventions can improve psychological well-being, at least in the short run, and may be particularly helpful when tailored to the needs of the individual. Keywords: pessimism, online intervention, positive psychology, depression, optimism Positive psychology research has shown that psychological well-being can be cultivated through brief interventions aimed at developing individual strengths and resources. Sin and Lyubomirsky (2009) surveyed the results of 49 studies of positive psychology interventions (PPIs) designed to cultivate positive feelings, behaviors, or cognitions. With an average r effect size of.29 (medium effect; Cohen, 1988), 96% of the studies reviewed reported improvements in psychological well-being following positive interventions. The researchers also analyzed 25 studies that assessed depressive symptoms and found that 80% of the studies reported a decrease in depressive symptoms after using PPIs. The average r effect size for change in depressive symptoms was moderate (r.31, medium effect; Cohen, 1988), and the authors concluded that PPIs are effective strategies for enhancing quality of life. Critics of positive psychology research have argued that it is too simplistic to conclude that all people stand to benefit from these exercises. Lazarus (2003) noted that the research to date ignores the variability in outcomes that exists within groups in favor of presenting results as simply improvement or no improvement for the whole group. As a result, individuals who are not helped by such interventions go unacknowledged. Norem and Chang (2002) took this notion a step further, arguing that there are costs and Susan Sergeant and Myriam Mongrain, Psychology Department, York University, Toronto, Ontario, Canada. This project was funded by a grant to Myriam Mongrain from the Social Sciences and Humanities Research Council of Canada. Correspondence concerning this article should be addressed to Myriam Mongrain, Psychology Department, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada. mongrain@yorku.ca 1 benefits to every intervention that may differ across individuals and contexts. For example, practicing optimism can lead to poorer outcomes when it is naïve or unrealistic; conversely, the use of defensive pessimism can lead to higher rates of goal achievement (Norem & Illingworth, 1993). In one study, PPIs did not fare any better than a positive placebo intervention and had limited value in relieving depressive symptoms (Mongrain & Anselmo-Matthews, 2012). Finally, needy individuals have been found to report deterioration in functioning from online PPIs (Sergeant & Mongrain, 2011). Such findings suggest that a fruitful direction for future research on PPIs would involve improved methodological designs and a special attention to moderators of outcome including personality variables (Lyubomirsky & Layous, 2013). A number of PPIs have been developed utilizing the Internet as the medium for delivery (e.g., Mitchell, Stanimirovic, Klein, & Vella-Brodrick, 2009; Mongrain, Chin, & Shapira, 2011; Seligman, Steen, Park, & Peterson, 2005; Sergeant & Mongrain, 2011; Shapira & Mongrain, 2010). There is growing interest in these online PPIs (OPPIs) given their vast potential in cost-effectiveness and accessibility. Unfortunately, most Internet studies are characterized by high attrition rates and lower effect sizes compared to interventions involving in-person contact (Mitchell, Vella- Brodrick, & Klein, 2010). Sin and Lyubomirsky (2009) noted self-administered PPIs tend to have lower effectiveness compared to individual therapy and group-administered formats. The lack of interpersonal contact and feedback in OPPIs may be contributing to these lower effect sizes. What is unclear is whether there is a subset of individuals who are able to flourish using the self-administered format typical of OPPIs. The present study was specifically designed to extend our knowledge on moderator variables in the outcome of those interventions. Additionally, a novel approach to PPI development was adopted. The PPIs used in most studies to date stemmed from

3 2 SERGEANT AND MONGRAIN various models of happiness and how to lead the good life. For example, Seligman et al. (2005) surveyed over 100 interventions purported to improve happiness from sources ranging from Buddhist teachings, the human potential movement of the 1960s, the work of Michael Fordyce, and the self-improvement industry of the 1990s. They developed PPIs based on these interventions by distilling key elements into a form that was replicable and capable of being presented in a manual (Seligman et al., 2005). This method of PPI development is informative for determining whether common practices of PPIs hold any efficacy for improving well-being. However, it is not able to parse out the full potential of PPIs for improving well-being under optimal conditions. Efforts have been made in recent years to identify the specific design factors that predict greater effectiveness across several different PPIs (e.g., duration of the PPI, variety of activities; Lyubomirsky & Layous, 2013). We propose that second generation PPIs can be developed, representing modified versions of existing PPIs that incorporate these optimizing design factors. Research to date has identified several factors that influence the effectiveness of PPIs. For example, greater effectiveness has been found when descriptions of the interventions are crafted carefully to be generally persuasive (Layous, Nelson, & Lyubomirsky, 2013; Lyubomirsky, Dickerhoof, Boehm, & Sheldon, 2011). Other known predictors of greater effectiveness include enjoyment of the exercise (Schueller & Parks, 2012), sustained effort (Lyubomirsky et al., 2011; Sheldon et al., 2010), exercise variety (Schueller & Parks, 2012), and low to moderate exercise difficulty (Sheldon et al., 2010). In theory, an exercise that capitalizes on all of these factors should demonstrate enhanced effectiveness. Optimism-Based PPI The aim of this study was to develop a successful PPI with a strong theoretical and empirical foundation that can address the weaknesses and limitations of previous work, as well as increase participant compliance. A wealth of research supports the cultivation of optimism as an individual skill that can improve psychological well-being. Optimism involves a positive outlook on life, both during times of success and struggle (Segerstrom, 2006). Optimistic people believe that good things will happen to them in the future and that their goals are achievable. Optimism is strongly correlated with positive affect and better coping in a wide variety of stressful situations (Carver, Schier, & Segerstrom, 2010). It is also associated with fewer mental and physical health symptoms (Lench, 2011), increased motivation and effort, and increased engagement with one s goals (Segerstrom, 2006). Taken together, research suggests that being optimistic is associated with various indices of positive functioning. While trait optimism appears to be particularly beneficial for improving well-being, there is also some evidence that optimism is malleable and can be cultivated successfully. Compared to other personality traits, heritability estimates are notably lower for optimism (e.g., positive affectivity; see Jang, McCrae, Angleitner, Riemann, & Livesley, 1998; Plomin et al., 1992; Tellegen et al., 1988). Some optimism PPIs involving the mental visualization of a positive future have been studied to date, all of them reporting some success at improving psychological well-being (King, 2002; Layous et al., 2013; Peters, Flink, Boersma, & Linton, 2010). Clearly, there is potential for optimism exercises to produce improvements in psychological well-being. Segerstrom (2006) noted that fantasizing about one s future self without consideration of the action required to achieve such outcomes may have limited value. Optimism involves an actionoriented and realistic mindset that is associated with high selfefficacy and problem-focused coping (Carver et al., 2010). In line with this conceptualization, Shapira and Mongrain (2010) modified the ideal-self protocol by also having participants give themselves concrete advice for how to achieve an ideal future and found that the combination was effective at reducing depressive symptoms and improving happiness. This study suggests that cultivating the action-oriented aspects of optimism alongside the purely cognitive aspects (i.e., positive beliefs about oneself and one s ability to succeed) may produce superior results. The findings from studies to date suggest PPIs are most effective when there is a good fit between the activity and the individual characteristics of the user. Lyubomirsky, Sheldon, and Schkade (2005) described this matching hypothesis as the notion that people respond more favorably to activities that fall in line with their own needs or goals (e.g., people with high social needs may benefit more from PPIs that emphasize social interaction). Existing research also suggests that activities tend to be more effective for individuals who lack proficiency in the skill being cultivated. For example, Fordyce (1983) studied 14 different activities and observed greater improvements in psychological well-being when participants engaged in exercises targeting an area of weakness for them. More recently, Sergeant and Mongrain (2011) observed that highly self-critical individuals benefitted more from a gratitude exercise (acknowledging good things in their lives) than from a music-listening exercise designed to enhance general mood. This pattern was also observed with an optimism intervention, where highly self-critical individuals reported greater improvements in psychological well-being perhaps due to improvements in confidence engendered by the exercise (Shapira & Mongrain, 2010). Present Study This study was designed to test the hypothesis that an empirically based optimism exercise administered online can produce stronger and lasting effects on psychological well-being than a control condition with a similar structure but no emphasis on building optimism skills (i.e., a neutral diary-writing exercise). Optimism was chosen as the skill to cultivate due to its correlations with other aspects of psychological well-being and relative malleability compared to other positively oriented personal traits. Additionally, trait pessimism was chosen as a moderator variable to determine whether the exercise may be of particular value to those with deficits in this area. Pessimistic individuals tend to have negative expectations for the future and lack confidence in their abilities to meet their goals (Scheier, Carver, & Bridges, 1994). The optimism exercise was expected to be particularly beneficial for those individuals who lack a positive outlook on life and who lack a sense of efficacy in meeting their goals. Both the optimism exercise and the control exercise were designed with the following parameters: (1) participants were given a credible rationale for the usefulness of the exercise, (2) the exercise was relatively easy to complete and consisted of an enjoyable variety of activities, (3) participants were only asked to

4 PESSIMISTS PRACTICING OPTIMISM 3 complete an exercise every second day with no penalties for missed exercises, and (4) regular reminders to practice the exercise were sent to participants. The study s hypotheses were threefold: (1) Participants in both the optimism and control conditions were expected to report significant improvements in psychological well-being following the completion of the exercise period. Psychological well-being was operationalized as low levels of depressive symptoms and dysfunctional beliefs, and the endorsement of having a pleasurable, meaningful, and engaging life. The predicted improvements associated with the control condition were based on literature demonstrating that positive expectancies are associated with small but significant improvements in psychological well-being outcomes (Mongrain & Anselmo-Matthews, 2012). (2) With the addition of active ingredients, the optimism condition was expected to produce significantly greater and longer lasting improvements than the control condition. (3) Dispositional pessimism was expected to be a significant moderator of the relationship between exercise condition and psychological well-being over time. Highly pessimistic individuals were expected to exhibit the greatest benefit from the optimism intervention. Method Sampling Procedure and Participant Characteristics To test the study s hypotheses, a general community sample was recruited via the Internet between April 2010 and January Recruitment ceased once the sample size became large enough to ensure adequate power for the statistical analyses. The study was advertised world-wide through a variety of venues, including Listserv s, postings on social networking and psychologyrelated websites, and, most importantly, through Google. It was presented as a study involving activities designed to develop personal strengths and psychological well-being. All participants were required to be at least 18 years of age, be English-speaking, and have regular access to the Internet. All communication with participants was done through the study s website ( and . The resulting sample consisted of 466 participants (see Figure 1 for a diagram of participant flow). The majority of the sample was between 20 and 45 years of age (M 32.75, SD 12.23), female (65%), and had at least some post-secondary education (85%). Specifically, 15% completed some college, 14% had a college diploma, 31% had a bachelor s degree, 9% completed some postgraduate education, and 16% had a post-graduate degree. A high school degree was the highest level of education obtained by 10% of the sample, and 5% did not complete high school. The majority of participants (60%) reported an annual income of $20,000 or less. The most prevalent ethnic backgrounds were Caucasian (44%) and Asian (35%). Most of the participants resided in Asia (37%), Canada (35%), or the United States (17%). Past and/or present depression was reported by 55% of participants, and 50% of participants reported past and/or present anxiety. Other past and/or present illnesses were infrequent: 8% for bipolar disorder, 2% for schizophrenia, and 12% for substance abuse. Involvement with psychotherapy in the past or present was endorsed by 37% of the sample, and 34% of participants reported taking medication for a psychological problem at present or in the past. Participants on average reported experiencing mild to moderate depressive symptoms on the Centre for Epidemiological Studies Depression Scale (CES-D; Radloff, 1977) at baseline (M CES-D 21.79, SD CES-D 13.06). Survey Methodology This study was conducted in compliance with the York University Research Ethics Board. After registering on the study website, participants received a description of the study requirements and expressed their informed consent by clicking on an I Agree box. At the beginning of the project, participants (N 466) completed a series of baseline psychological well-being measures before being randomly assigned by a computer algorithm to one of two conditions: an optimism exercise (n 253) and a control exercise involving neutral diary-writing activities (n 213). Additional information about these two conditions is provided below. Every other day for approximately 3 weeks, they were instructed to complete a 5 10-min exercise (12 exercises in total). This duration gave participants the time necessary to develop familiarity with their exercise while avoiding excessive repetition. After the 3-week intervention period, participants completed another set of psychological well-being measures. Follow-up assessments were also offered 1 and 2 months later in order to determine whether there were any enduring effects. As an incentive, entry into a $1,000 draw was offered to participants following completion of each follow-up assessment. Participation at each follow-up session was independent that is, participants were allowed to complete questionnaires at any of the follow-up sessions regardless of whether they had completed questionnaires at prior follow-up sessions. After completing the baseline measures and being randomly assigned to a condition, participants were presented with a description of their exercise and a brief rationale for why it may help to develop personal strengths and psychological well-being. The rationales for the two conditions were matched for length, complexity, and affective tone. The control condition was also matched for activity duration, timing, and participant expectation. The equivalence of both the control and experimental condition was corroborated by three independent investigators in this research area. Participants were instructed to begin their first exercise on the following day. Each exercise was available for completion on the study website for 48 hr. The number of times participants logged on to the website to complete their exercise was recorded as an indicator of adherence. Experimental Condition (Optimism) The experimental condition consisted of two alternating exercises providing training in key components of optimism: (a) a cognitive bias toward focusing on and recalling positive experiences in one s life, and (b) a tendency to view one s goals as achievable and worthwhile (Segerstrom, 2006). Specifically, on the first day of the 3-week intervention period, participants were asked to list five things that made them feel like their life was enjoyable, enriching, and/or worthwhile, and then list three things that could help them see the bright side of a difficult situation. On the next exercise day (48 hr later), participants described briefly a goal that they would like to achieve in the next day or two, and

5 4 SERGEANT AND MONGRAIN Baseline Assessment (n = 466) Randomization Optimism group (n = 253) Control group (n = 213) Post-Test Assessment Completed (n = 93) Did not complete (n = 160) 1 Month Follow-Up Completed (n = 90) Did not complete (n = 163) 2 Month Follow-Up Completed (n = 66) Did not complete (n = 187) Analysis (Using ITT) (n = 253) Figure 1. then described the steps they would take to meet this goal. Participants would then alternate between completing these tasks every other day for the remainder of the 3-week intervention period. Control Condition (Daily Activities) 3 Week Intervention Period Participants in the control condition also alternated between two exercises designed to match the requirements of the experimental task while refraining from inducing the key components of optimism as described above. They were presented as activities designed to increase self-awareness with clear statements on the improvements expected from these exercises. In the first exercise, participants described their experience of the last 24 hr as if they were writing a report for a newspaper (including what they were doing, how long the activities lasted, and who they were with). In the second exercise, participants described what they thought the next day would be like (including where they would go, what they would do, who they would see, and what goals they had). As with the optimism condition, the tasks alternated over the 3-week intervention period. Similar exercises involving the fact-based description of daily activities have been used successfully as control conditions in previous PPI studies (e.g., Boehm, Lyubomirsky, & Sheldon, 2011; Lyubomirsky et al., 2011). Measures Post-Test Assessment Completed (n = 73) Did not complete (n =140) 1 Month Follow-Up Completed (n = 79) Did not complete (n = 134) 2 Month Follow-Up Completed (n = 49) Did not complete (n = 164) Analysis (Using ITT) (n = 213) Participant flow through the study. ITT intent-to-treat. Centre for Epidemiological Studies Depression Scale (CES-D; Radloff, 1977). The CES-D is a 20-item measure developed to identify depressed mood in the general population. Each item reflects a common depressive symptom, such as During the past week, I thought my life had been a failure. Respondents are asked to rate how frequently they experienced each symptom over the past week on a 4-point scale (rarely or none of the time, less than 1 day 0, most or all of the time, 5 7 days 3). With total scores ranging from 0 to 60, a score of 16 has been recommended as a cutoff score for the presence of significant depressive symptomatology. The CES-D has good reliability, as demonstrated by a coefficient alpha of.85 and test retest reliability over 6 months of

6 PESSIMISTS PRACTICING OPTIMISM 5.54 (Radloff, 1977). In the current sample, the average Cronbach s alpha across four sampling times was.92. The CES-D is strongly correlated with other indices of depressive symptomatology and is sensitive to the detection of depressive symptoms (Radloff, 1977; Santor, Zuroff, Ramsay, Cervantes, & Palacios, 1995). Demographics questionnaire. The demographics questionnaire was constructed exclusively for use in this study and was adapted from a similar questionnaire used by Sergeant and Mongrain (2011). Participants reported basic demographic information including age, gender, level of education completed, income, relationship status, ethnicity, and country of residence. The questionnaire also included items regarding self-reported history of psychopathology and treatment with psychotherapy. Dysfunctional Attitude Scale 14 (DAS-14; Mongrain & Zuroff, 1989). The DAS-14 is an abbreviated version of the Dysfunctional Attitude Scale (Weissman & Beck, 1978), which is a reliable and well-validated self-report measure of maladaptive beliefs characteristic of depressed individuals. Respondents are asked to rate their agreement at the moment with 14 pessimistic beliefs, such as I am nothing if a person doesn t love me, and If I fail partly, it is as bad as being a complete failure on a scale ranging from 1 (completely disagree) to7(completely agree). Total scores range from 14 to 98, with higher scores indicating a greater degree of dysfunctional attitudes and increased vulnerability to depressed affect. In the current sample, the average Cronbach s alpha across four sampling times was.91. Life Orientation Test Revised (LOT-R; Scheier et al., 1994). The LOT-R, a revised version of the Life Orientation Test (Scheier & Carver, 1985), measures dispositional optimism and pessimism. Respondents rate their agreement with 10 statements, such as Overall, I expect more good things to happen to me than bad on a scale ranging from 1 (I disagree a lot) to5(i agree a lot). Four of the items are non-scored filler statements designed to increase the validity of the measure by disguising its purpose. The sum of the remaining six items represents the respondent s level of optimism. Low scores are indicative of a pessimistic disposition. The LOT-R has good internal consistency (Cronbach s.78) and good test retest reliability (r.68 at 4 months, r.60 at 12 months). Scores on the LOT-R are moderately correlated with measures of anxiety, self-esteem, and neuroticism (Scheier et al., 1994). In the current sample, the average Cronbach s alpha across four sampling times was.82. Orientations to Happiness (OTH; Peterson, Park, & Seligman, 2005). The OTH is an 18-item measure of self-reported endorsement of three ways to be happy: pleasure (maximizing pleasant feelings and minimizing pain), engagement (participating in engaging activities that produce flow), and meaning (succeeding through use of valued skills and talents). Test-takers rate the degree to which items such as For me, the good life is the pleasurable life, I am always very absorbed in what I do, and My life has a lasting meaning apply to them on a scale ranging from 1 (not like me at all) to5(very much like me). OTH scales have high reported internal consistencies ( s all greater than.70) and significant positive correlation with both life satisfaction and state happiness (Peterson et al., 2005; San Martín, Perles, & Canto, 2010). In the current sample, the average Cronbach s alpha across four sampling times was.85 for the Meaning subscale,.80 for the Pleasure subscale, and.69 for the Engagement subscale. Statistical Methods Hierarchical linear modeling is a common method for analyzing longitudinal data sets with significant dropout over time (Christensen, Griffiths, & Farrer, 2009; Raudenbush & Bryk, 2002). Using restricted maximum likelihood estimation (REML), it maximizes data retention in the presence of variable attrition over multiple time points. This approach also accounts for withinperson, between-persons, and between-conditions variability. Thus, hierarchical linear modeling takes into account the effect of individual trajectories while analyzing differences across groups. Alpha was set at.05 for all tests of significance. A hierarchical linear model was constructed for each outcome measure (CES-D, DAS-14, OTH-Meaning, OTH-Pleasure, and OTH-Engagement). In cases where the distribution of residual scores was skewed, hierarchical generalized linear models based on a Poisson distribution were used. Level 1 included the random effects of Time. Level 2 effects for between-group differences included demographic variables to improve the generalizability of the findings beyond the characteristics of this particular sample. Condition (fixed effect) and the Condition Time interaction term tested the effectiveness of the optimism intervention. Condition was listed as a class variable so that all estimates involving Condition reflect the effect for participants in the optimism condition relative to the participants in the control condition (rather than the absolute effect of the Condition variable). This method allows for the direct interpretation of how participants in the optimism condition performed compared to those in the control condition. Cohen s f 2 was calculated to determine whether the size of each effect was small (f ), moderate (0.15 f ), or large (f ) (Cohen, 1988). Observation of the trajectories for scores over the study period indicated that changes in the dependent variables did not follow a simple linear pattern. Rather, the trend for the individual trajectories involved relatively large changes between baseline and posttest scores at 3 weeks, and then a more gradual linear change across the two follow-up assessment points. To enhance the accuracy of the predictive models, Exercise Completion (EC) was added as an additional Level 1 fixed effect with baseline time coded as 0 and all post-test time points coded as 1. This variable effectively captured the degree of change between baseline scores and those at post-test. The general composite model is as follows: Y ij [ EC ij 20 Time ij 01 X demographic where 02 Condition ij 12 (EC ij * Condition i ) 22 (Time ij * Condition i )] [ 0i 1i Time ij ij ], 0i 1i N 0 0, To perform the moderation analyses, the basic models were repeated with the addition of LOT-R scores. Significant three-way interactions were investigated using plots of mean scores and pairwise comparisons of score changes over time within each condition. For ease of interpretation, LOT-R scores were re-coded (1)

7 6 SERGEANT AND MONGRAIN into three groups for the pairwise comparisons: low trait pessimism (scores greater than one standard deviation above the condition s mean), medium trait pessimism (scores within one standard deviation of the condition s mean), and high trait pessimism (scores below one standard deviation of the condition s mean). Thus, scores were compared between subsequent time points (i.e., baseline vs. post-test, post-test vs. 1 month follow-up, 1-month vs. 2-month follow-up) separately for participants characterized by low, medium, and high pessimism in the optimism condition and then the control condition. Based on findings from previous studies using OPPIs (e.g., Mitchell et al., 2009; Sergeant & Mongrain, 2011; Shapira & Mongrain, 2010), a significant amount of attrition and missing data was expected. The presence of missing data for some participants can have implications for the validity of the statistical analyses if it is found to be related to some systematic cause. For example, participants may have been more likely to drop out if they reported being more depressed. These participants may not have profited from the OPPI, but this effect would be missed in the hierarchical linear models. To provide additional information about the generalizability of the findings from the hierarchical linear models, a set of intent-to-treat (ITT) analyses were also conducted to test whether the same pattern of results would have emerged if dropouts had completed the study protocol. The ITT analyses consisted of recalculating the hierarchical linear models with imputed values for all missing data to reveal patterns that would have emerged with no attrition. If findings in the ITT analyses indicate that missing values occurred randomly (i.e., the results do not deviate from the findings from the original analyses), the analyses using the original data set would be considered valid representations of a general response pattern (Chakraborty & Gu, 2009). In order to provide the most reliable estimation of missing data, the multivariate imputation by chained equations (MICE) method was used to impute values. MICE operates by creating a regression model predicting each variable with missing data conditioned upon all other variables in the data set (Azur, Stuart, Frangakis, & Leaf, 2011). These models are then used to impute predicted values into cases of missing data. The process is repeated several times to account for random error. This approach was selected over other imputation methods, such as the last observation carried forward (LOCF) because it requires fewer assumptions to be made about the nature of missing data. Furthermore, it has demonstrated effectiveness at maintaining accurate standard error estimates in data sets with a large quantity of observations and variables (Schafer & Graham, 2002). Results Investigating Attrition With most longitudinal studies, particularly those conducted over the Internet, attrition is an important variable to consider for contextualizing the data obtained. High points of drop-out occurred (a) over the course of the 3-week intervention period and (b) at the 2-month follow-up. Of the 466 participants who began the 3-week intervention period, 166 completed the post-test outcome measures. The sample size at the 1-month follow-up did not change notably; however, at the 2-month follow-up, only 115 of the original 466 participants provided outcome data. A series of t-tests and chi-square tests were used to determine whether completers of the entire study differed from those with missing data. Higher attrition rates occurred for participants who were male, 2 (1) 10.13, p.002; living outside of Canada or the United States, 2 (1) 19.15, p.001; and of non-caucasian ethnicity, 2 (1) 10.04, p.002. Participants with no history of psychotherapy were also more likely to drop out, 2 (1) 8.26, p.004. Non-completers reported higher baseline levels of orientation to happiness through engagement, t(452) 2.53, p.012 (M completer 2.86, M non-completer 3.10). There were no significant differences based on completion status for baseline levels of the other outcome variables, including the CES-D, t(454) 1.79, p.074; DAS-14, t(455) 0.89, p.371; OTH-Meaning, t(452) 0.00, p.997; and OTH-Pleasure, t(452) 0.58, p.564. Finally, dropout rates did not differ across conditions, 2 (1) 0.30, p.583, indicating that exercise type was not related to attrition. Correlations Between Study Variables As can be seen in Table 1, several characteristics were significantly correlated with scores on the psychological well-being measures at baseline. Specifically, baseline CES-D scores were higher (reflecting greater depressive symptoms) for participants who were younger, in a lower income bracket, and single. Baseline DAS-14 scores were higher (reflecting greater maladaptive cognitive beliefs and attitudes) for participants who were younger, male, in a lower income bracket, living outside of Canada or the United States, and of a non-caucasian ethnicity. Surprisingly, greater endorsement of happiness pursuits through meaning, pleasure, and engagement were observed for participants who were in a lower income bracket, living outside Canada or the United States, and of a non-caucasian ethnicity. Additionally, greater endorsement of happiness through pleasure was associated with being younger, and greater endorsement of happiness through engagement was associated with being male. The correlated demographic variables were included in the respective models of change over time as covariates to improve the generalizability of the findings beyond the specific characteristics of this sample. Hierarchical Linear Modeling The cross-level Condition Time interaction effects for models including the four outcome measures and related descriptive statistics are presented in Table 2. The initial model of CES-D scores produced residuals with a negatively skewed distribution. To establish more accurate results, a CES-D hierarchical generalized linear model was constructed with the assumption of a Poisson distribution of residual values rather than a normal distribution. The CES-D model indicated that depressive symptoms over time did not differ by condition. In terms of random effects for depressive symptoms, individuals differed significantly in baseline score, Z 5.73, p.01; covariance between baseline score and change over time, Z 3.04, p.00; and in their pattern of change over time, Z 11.43, p.01. The DAS-14 model included a significant Time Condition interaction effect (see Table 2). The model predicted a 2.74-point greater decrease in dysfunctional attitudes over the course of the

8 PESSIMISTS PRACTICING OPTIMISM 7 Table 1 Correlation Matrix of Demographic Variables, Baseline Scores on Measures of Psychological Well-Being, and Adherence Variable Age Female versus male a Income b North America versus Asia c Relationship status d Ethnicity e Hx psychopathology f Hx psychotherapy f LOT-R BL CES-D BL DAS BL OTH-Meaning BL OTH-Pleasure BL OTH-Engagement Adherence Note. Hx history of; LOT-R Life Orientation Test Revised; BL baseline; CES-D Centre for Epidemiological Studies Depression Scale; DAS-14 Dysfunctional Attitude Scale 14; OTH-Meaning Orientations to Happiness Meaning subscale; OTH-Pleasure Orientations to Happiness Pleasure subscale; OTH-Engagement Orientations to Happiness Engagement subscale. a 1 male, 2 female. b 1 $10,000, 2 $10,000 $20,000, 3 $20,000 $30,000, 4 $30,000 $40,000, 5 $40,000 $50,000, 6 $50,000 $60,000, 7 $60,000 $70,000, 8 $70,000 $80,000, 9 $80,000 $90,000, 10 $90,000 $100,000, 11 $100,000. c 1 Canada or United States, 2 other. d 1 single, 2 in a relationship. e 1 Caucasian, 2 non-caucasian. f 1 no history, 2 yes history. p.05. p.01. study in the optimism condition. Cohen s f 2 indicated this was a small effect size. In terms of random effects, individual differences were evident in DAS-14 trajectories over time, Z 9.81, p.01, but there were no significant differences between participants baseline DAS-14 scores, Z 0.39, p.35, nor the covariance between participants baseline DAS-14 scores and change over time, Z 0.39, p.69. There was a significant interaction effect for the Engagement subscale of the OTH. The model indicated that after completing the 3-week intervention period, those in the optimism condition reported a 0.21-point greater increase in engagement in life than those in the control condition (see Table 2). As indicated by Cohen s f 2, this was a small effect size. This difference between conditions was not evident when progress across the entire course of the study was considered. Significant individual differences were found for baseline scores, Z 2.07, p.02, and score changes over time, Z 9.97, p.01, but not the covariance between baseline scores and change over time, Z 0.28, p.78. Together, these findings indicate there was a significant amount of variability between individuals on outcome above and beyond the group-level effects. There were no notable effects of Exercise Completion Condition or Time Condition on predicted OTH-Meaning or OTH- Pleasure scores. Thus, participant reports of their pursuit of happiness through meaning or pleasure over time did not differ across conditions. Significant individual differences were present in both models for baseline scores (Meaning: Z 3.13, p.01; Pleasure: Z 1.94, p.03) and score changes over time (Meaning: Z 12.99, p.01; Pleasure: Z 10.41, p.01), but the effects for covariance between baseline scores and change over time were non-significant (Meaning: Z 1.14, p.25; Pleasure: Z 0.36, p.72). Hierarchical Linear Modeling: Moderation Analyses The three-way interaction effects between dispositional pessimism, treatment condition, and time are also presented in Table 2. The CES-D model produced a significant three-way interaction effect between Trait Pessimism, Exercise Completion, and Condition. The effect size was moderate and indicated that the effectiveness of the active intervention at post-test varied according to levels of Trait Pessimism. A significant Trait Pessimism Time Condition interaction indicated that differences between conditions in CES-D scores across the entire study also varied according to Trait Pessimism. The size of this effect was also moderate. As depicted in Figure 2, pessimists reported a significant reduction in depressive symptoms following Exercise Completion when they were in the optimism condition, t(71) 2.06, p.04. Their scores did not change significantly at the 1-month follow-up, t(99) 0.87, p.39, nor from the 1-month to the 2-month follow-up, t(99) 0.24, p.81. Conversely, pessimists in the control condition did not report a significant reduction in depressive symptoms following exercise completion, t(58) 0.46, p.65, or the follow-up period [post-test to 1-month follow-up, t(76) 0.13, p.90; 1-month follow-up to 2-month follow-up, t(76) 1.20, p.23]. Figure 2 also depicts minimal change in depressive symptoms for individuals low in pessimism, and none of the pairwise comparisons were statistically significant over time [optimism baseline to post-test: t(71) 1.88, p.06; optimism post-test to 1-month follow-up, t(99) 0.41, p.68; optimism 1-month follow-up to 2-month follow-up, t(99) 0.05, p.96; control baseline to post-test: t(58) 1.24, p.22; control post-test to 1-month follow-up, t(76) 1.30, p.20; control 1-month follow-up to 2-month follow-up, t(76) 0.33, p.74]. It is worth noting that

9 8 SERGEANT AND MONGRAIN Table 2 Descriptive Statistics and Hierarchical Linear Model Tests of Psychological Well-Being Measures by EC, Time, Condition, and Trait Pessimism (LOT-R) Time Optimism Control Hierarchical linear model tests M SD M SD Measure Model effect Estimate 95% CI t df p Cohen s f 2 Baseline CES-D EC Condition , Post-test Time Condition , month LOT-R EC Condition , months LOT-R Time Condition , Baseline DAS-14 EC Condition , Post-test Time Condition , month LOT-R EC Condition , months LOT-R Time Condition , Baseline OTH-Meaning EC Condition , Post-test Time Condition , month LOT-R EC Condition , months LOT-R Time Condition , Baseline OTH-Pleasure EC Condition , Post-test Time Condition , month LOT-R EC Condition , months LOT-R Time Condition , Baseline OTH-Engagement EC Condition , Post-test Time Condition , month LOT-R EC Condition , months LOT-R Time Condition , Note. EC Exercise Completion (score change from baseline to 3-week post-test only); LOT-R Life Orientation Test Revised; CES-D Centre for Epidemiological Studies Depression Scale; DAS-14 Dysfunctional Attitude Scale 14; OTH-Meaning Orientations to Happiness Meaning subscale; OTH-Pleasure Orientations to Happiness Pleasure subscale; OTH-Engagement Orientations to Happiness Engagement subscale. moderately pessimistic individuals experienced reduced depression symptoms in the short run (from baseline to post-test) in both the optimism condition, t(71) 2.26, p.03, and the control condition, t(58) 2.61, p.01. However, no statistically significant changes were observed across the follow-up period for moderately pessimistic participants [optimism condition: post-test to 1-month follow-up, t(99) 0.47, p.64; 1-month follow-up to 2-month follow-up, t(99) 1.76, p.08; control condition: post-test to 1-month follow-up, t(76) 1.83, p.21; 1-month follow-up to 2-month follow-up, t(76) 1.73, p.26]. Intent-to-Treat Analyses Using the multiple imputations by chained equations (MICE) procedure, 10 imputed data sets were created to fill in missing data. The results from the hierarchical linear models constructed from these data sets are presented in Table 3. In all but one case, the estimates obtained using imputed values for missing data were very similar to the estimates obtained using observed data. The one exception was the effect for Exercise Completion Condition as a predictor of DAS-14 scores, where the imputed estimate was noticeably smaller than the observed estimate. All of the estimates obtained using the imputed data sets fell within the 95% confidence intervals noted for the observed estimates. 1 Thus, the results of the sensitivity analysis suggest comparable results would have been obtained if there had been no attrition over time. Discussion The goals of this study were to determine whether a secondgeneration optimism-based online intervention would provide superior benefits to a closely matched placebo exercise and whether dispositional pessimism would moderate the effectiveness of the intervention. The results provided partial confirmatory support for both of these hypotheses. The optimism exercise was uniquely associated with a short-term gain in reports of happiness through engagement in life and a long-term reduction in dysfunctional thinking. Thus, consistent with previous research (e.g., Boehm et al., 2011; Shapira & Mongrain, 2010), this optimism intervention was effective at improving multiple aspects of psychological wellbeing. There are a number of possible ingredients in the experimental condition that may have contributed to these positive outcomes, such as the positive reappraisal of life events, practice in productive goal-setting, and feelings of self-efficacy. A fruitful avenue for future research would be to create multiple conditions that manipulate these various ingredients to pinpoint which components are most relevant to producing beneficial changes in well-being. 1 The effects were not statistically significant in the models based on imputed data, but this is likely due to the larger sample size of the intent-to-treat sample (i.e., statistical significance would be more difficult to obtain with a larger sample size).

10 PESSIMISTS PRACTICING OPTIMISM 9 Figure 2. Centre for Epidemiological Studies Depression Scale (CES-D) observed scores over Exercise Completion/Time by Condition and Trait Pessimism ( pessim ). Pessimists (i.e., hi pessim ) reported a greater reduction in depressive symptoms in the optimism condition at exercise completion relative to the control condition and also relative to optimists (i.e., lo pessim ) in the same condition. CES-D scores did not significantly change for pessimists in the optimism condition over the follow-up period (from 3 weeks [3w] to 2 months [2m]). hi high; med medium; lo low. Higher levels of pessimism were associated with a relatively larger decrease in depressed mood following completion of the optimism intervention. Thus, the optimism-based intervention was more beneficial in the short run for pessimistic individuals. These findings parallel previous research that reported greater effects for PPIs when they target an area of weakness for users (Sergeant & Mongrain, 2011; Shapira & Mongrain, 2010). The optimism exercise focused on cultivating a more positive outlook on the future and on taking concrete steps toward goal achievement. This may have encouraged pessimists to shift their thinking toward the natural thought process of more optimistic individuals. This finding has important clinical implications relating to the concern that OPPIs may be contraindicated for individuals vulnerable to psychological problems (Parks, Della Porta, Pierce, Zilca, & Lyubomirsky, 2012; Sergeant & Mongrain, 2011). The evidence suggests that under conditions that target the specific areas of vulnerability, many vulnerable individuals may be able to flourish. One caveat is the fact that well-being reports did not change across the follow-up period, suggesting that significant treatment effects only occurred during periods of active exercise practice. It is also likely that trait moderators are the least likely to reveal long-term changes following brief and rather superficial online interventions. Nonetheless, the addition of the present findings lends further support to the notion that positive psychology interventions may be most effective when they are geared toward building skills in areas of personal deficiency. A unique contribution of the current work may be its data analytic strategy. Time was analyzed in two different ways to capture the non-linear trend in the data. This represents an improvement on traditional strategies, which conceptualize time with a single linear function. By treating the score changes from baseline to exercise completion as a separate variable from change across the entire course of the study, we were able to observe different outcomes in the short- and long-term; the improvements in happiness, depression, and dysfunctional thinking were prominent immediately after completion of the exercises, whereas longterm improvements were only maintained for dysfunctional thinking. These findings suggest there may be differential effects of online interventions in the short-term and long-term that may not be detected by analyses that assume a strictly linear pattern of change over time. As expected, there was evidence of improvement in the control condition as observed consistently in prior online studies. For example, Seligman et al. (2005) observed that all participants, including those in a memory-recall placebo group, reported increased happiness and decreased depression after a week-long intervention period. Mongrain and Anselmo-Matthews (2012) also reported significant benefits for placebo interventions and suggested that positive psychology exercises may not possess specific therapeutic ingredients. Rather, immediate gains may be attributable to expectancies for change. The present study s control condition included a rationale matching the expectancy effects of the optimism condition, which may have contributed to the improvements observed after the exercise period. It is also possible that the placebo exercise included active components found for expressive writing (e.g., King, 2002; Pennebaker, 2004). Nonetheless, the optimism condition did still outperform the control condition in several respects, supporting the role of additional mechanisms present in the optimism exercise. Limitations and Future Directions Rates of attrition at each follow-up test point were similar to other OPPIs and were overall very high (75% by the 2-month follow-up; e.g., Mitchell et al., 2009, 2010). Interestingly, rate of dropout did not differ between the optimism and control condition, suggesting the nature of the activity participants engaged in was not a strong predictor of attrition. Demographic variables were better predictors, such that women, individuals living in Canada or the United States, and individuals of Caucasian ethnicity were more likely to stay in the study. Thus, culture and gender factors appear to influence engagement with OPPIs. Future studies may wish to explore ways to enhance engagement in under-represented demographic groups to improve the generalizability of our findings. Also, those who had been in psychotherapy in the past were less likely to drop out, suggesting that psychological mindedness may be a positive prognostic factor for adherence in such studies. Beyond demographic variables and past participation in psycho-