Table 1.
Positive psychology intervention meta-analyses.
| References | Title | Sample | Main Effect Findings | Moderator Findings |
|---|---|---|---|---|
| Van Agteren et al. (2021) | A systematic review and meta-analysis of psychological interventions to improve mental wellbeing | 393 studies, 53,288 participants from clinical, non-clinical and physical illness populations in 42 countries | Multi-component PPIs were effective with small to moderate effects on overall well-being for the general population (Hedge’s g = 0.28), mentally ill population (g = 0.37), and physically ill population (g = 0.52). See the article for effects for ACT, Compassion, CBT, expressive writing, mindfulness, multi-theoretical, singular PPI, and reminiscence interventions. | Moderators that increased effectiveness in well-being included: time to follow-up (shorter versus longer, with effect sizes maintained at the 3-month follow-up but dropping at 6 months), as well as comparison groups (waitlist-control or assessment-only design versus placebo). |
| Carr et al. (2020) | Effectiveness of positive psychology interventions: a systematic review and meta-analysis | 347 studies, over 72,000 participants from clinical and non-clinical child and adult populations in 41 countries |
PPIs with an average of ten sessions over six weeks offered in multiple formats and contexts were effective with small to medium effects on well-being (Hedge’s g = 0.39), strengths (g = 0.46), quality of life (g = 0.48), depression (g−0.39), anxiety (g = −0.62), and stress (g = −0.58), with gains maintained at three months follow-up. | Moderators that increased effectiveness of well-being included: life-stage (older versus younger), clinical status (clinical problems versus not), recruitment method (referred versus self-selected), country (individuals in non-western countries versus western), program format (engagement in longer individual or group therapy programs versus self-help), program type (containing two or more PPIs versus one PPI), program duration (longer versus shorter), control group type (no intervention type comparison group versus alternate intervention type), PPI type (e.g., savoring, optimism, and hope versus forgiveness and goal-setting), and alternative intervention type (PPIs versus treatment-as-usual or CBT), study quality (lower versus higher quality), and year of publication (older versus newer). |
| Geerling et al. (2020) | The effect of positive psychology interventions on well-being and psychopathology in patients with severe mental illness: A systematic review and meta-analysis |
16 studies (including 9 RCTs), 729 patients | PPIs in people with severe mental illness were not effective on well-being or psychopathology in comparison to control conditions. However, when only looking at within-group effects, these PPIs were effective with moderate effects on well-being (g = 0.40) and with a large effect on psychopathology (g = 0.70). | Moderators for well-being included diagnosis (patients with major depressive disorder over schizophrenia or mixed samples). Moderators showed no significant differences between sub-groups for treatment duration or format. |
| Heekerens and Eid (2020) | Inducing positive affect and positive future expectations using the best-possible-self intervention: A systematic review and meta-analysis | 34 RCT studies, 4,462 participants | The Best Possible Self interventions were effective PPIs with small effects for positive affect (g = 0.28) and optimism (g = 0.21), with no substantial follow-up effects. | Moderators included: assessment of momentary affect immediately after the intervention and conceptualizing optimism as positive future expectations instead of a general orientation in life. |
| Hendriks et al. (2020) | The efficacy of multi-component positive psychology interventions: A systematic review and meta-analysis of randomized controlled trials | 50 RCT studies in 51 articles, 6,141 participants | Multi-component PPIs (MPPIs) were effective with small effects for subjective well-being (g = 0.34) and depression (g = 0.29), small to moderate effects for psychological well-being (g = 0.39) and anxiety (g = 0.35), and moderate effects for stress (g = 0.48), after taking study quality and outliers into account. | Moderators included region and study quality. Non-Western countries and lower-quality studies found greater effects. |
| Koydemir et al. (2020) | A meta-analysis of the effectiveness of randomized controlled positive psychological interventions on subjective and psychological well-being |
68 RCT studies of nonclinical populations, 16,085 participants | PPIs were effective with small effects for psychological well-being (Cohen’s d = 0.08) and subjective well-being (d = 0.22), with small to moderate effects when targeting both types of well-being (d = 0.43), with evidence for sustained effects at follow-up. | Moderators included: longer interventions (versus shorter), traditional methods (versus technology-assisted methods), and mixed outcomes for age. |
| Tejada-Gallardo et al. (2020) | Effects of school-based multicomponent positive psychology interventions on well-being and distress in adolescents: A systematic review and meta-analysis | 9 studies in 9 articles, 4,898 participants | Multi-component PPIs (MPPIs) were effective with small effects for subjective well-being (g = 0.24), psychological well-being (g = 0.25), and depression symptoms (g = 0.28). | Moderators included: year of publication (more recent over older), study design (non-randomized over randomized), type of intervention (multi-component combined with another type of positive intervention), control group (placebo over waitlist), quality of studies (removing low-quality studies lowered effects for subjective well-being and raised effect size for psychological well-being and depression symptoms), and measurement of follow-up (no-followup over follow-up). |
| Brown et al. (2019) | The effects of positive psychological interventions on medical patients’ anxiety: A meta-analysis | 12 RCT studies with 1,131 participants; 11 non-randomized trials with 300 participants | PPIs were effective with small to medium effects for patient anxiety (g = −0.34), sustained 8 weeks post (g = −0.31). | Moderators included: clinician-led interventions (versus self-administered), longer interventions (versus shorter). |
| Carrillo et al. (2019) | Effects of the Best Possible Self intervention: A systematic review and meta-analysis | 29 studies in 26 articles, 2,909 participants | The Best Possible Self (BPS) interventions were effective PPIs with small effects for negative affect (d+ = 0.192), and depressive symptoms (d+ = 0.115), as well as moderate effects for positive affect (d+ = 0.511), optimism (d+ = 0.334), and well-being (d+ = 0.325). | Moderators included: older participants and shorter (total minutes of) practice. BPS was more effective than gratitude interventions for positive and negative affect outcomes. |
| Donaldson et al. (2019a) | Evaluating positive psychology interventions at work: A systematic review and meta-analysis | 22 studies, 52 independent samples, 6,027 participants from 10 countries | Five workplace PPIs (psychological capital, job crafting, strengths, gratitude, and employee well-being) can be effective with small effects for desirable work outcomes (performance, job well-being, engagement, etc.; g = 0.25) and with small to moderate effects for undesirable work outcomes (negative performance, negative job well-being; g = −0.34). | Moderators for both desirable and undesirable outcomes did not include: type of theory or intervention delivery method. |
| Howell and Passmore (2019) | Acceptance and Commitment Training (ACT) as a positive psychological intervention: A systematic review and initial meta-analysis regarding ACT’s role in well-being promotion among university students |
5 randomized experiments of university students, 585 participants | Acceptance and Commitment Training (ACT) was an effective PPI with small effects on well-being (d = 0.29). | N/A |
| Lomas et al. (2019) | Mindfulness-based interventions in the workplace: An inclusive systematic review and meta-analysis of their impact upon wellbeing |
35 RCT studies, 3,090 participants | Mindfulness-based interventions (MBIs) were effective with moderate effects for stress (Standardized Mean Difference = −0.57), anxiety (SMD = −0.57), distress (SMD = −0.56), depression (SMD = −0.48), and burnout (SMD = −0.36), as well as small to moderate effects for health (SMD = 0.63), job performance (SMD = 0.43), compassion (SMD = 0.42), empathy (SMD = 0.42), mindfulness (SMD = 0.39), and positive well-being (SMD = 0.36), with no effects for emotional regulation. | Moderators for health included: region (higher effects for studies in North America), intervention type (MBSR versus other intervention types), and age (younger versus older). Moderators for positive well-being and compassion included: gender (more women in the intervention group). |
| Slemp et al. (2019) | Contemplative interventions and employee distress: A meta-analysis | 119 studies, 6,044 participants | Contemplative interventions (e.g., mindfulness, meditation, and other practices) were effective in RCTs with small to moderate effects for reducing employee general distress (d = 0.39), sustained at follow-up. More specifically, distress consisted of anxiety (d = 0.58), negative affect (d = 0.50), stress (d = 0.47) depression (d = 0.42), somatic symptoms (d = 0.40), and burnout (d = 0.20). | Moderators included: type of contemplative intervention (highest for general meditation-based interventions, followed by mindfulness-based and ACT-based interventions) and type of control group (no-intervention or comparisons that received no education only versus active control comparisons). Moderators did not include: study quality ratings, overall duration of the programs, or the number of sessions included. Adjustments for publication bias lowered overall effects. |
| White et al. (2019) | Meta-analyses of positive psychology interventions: The effects are much smaller than previously reported | 2 previous meta-analyses (Sin and Lyubomirsky, 2009; Bolier et al., 2013) | When small sample size bias was taken into account, PPIs were effective with small effects for well-being (r = .10), with variable mixed effectiveness for depression. | Study notes need for increasing sample sizes in future studies. |
| Chakhssi et al. (2018) | The effect of positive psychology interventions on well-being in clinical populations: A systematic review and meta-analysis | 30 studies, 1,864 participants with clinical disorders | PPIs were effective with small effects for well-being (g = 0.24) and depression (g = 0.23), moderate effects for anxiety (g = 0.36), and no significant effects for stress, with similar effects 8 to 12 weeks post. | Moderator for well-being included: guided PPIs (versus unguided, such as self-help). Moderator for stress included: control group type (no intervention/waitlist control versus active or treatment-as-usual control). Moderators did not include: population type (psychiatric versus somatic disorders), intervention format (individual versus group), intervention duration (shorter versus longer), or type of PPI (PPI therapy programs versus single PPIs). |
| Curry et al. (2018) | Happy to help? A systematic review and meta-analysis of the effects of performing acts of kindness on the well-being of the actor | 27 studies in 24 articles, 4,045 participants | Kindness interventions (e.g., random acts of kindness) were effective PPIs with small to medium effects for well-being (for the actor of kindness; δ = 0.28). | Moderators did not include: sex, age, type of participant, intervention, control condition, or outcome measure. |
| Hendriks et al. (2018) | The efficacy of positive psychology interventions from non-Western countries: A systematic review and meta-analysis | 28 RCT studies, 3,009 participants | PPIs from non-Western countries were effective with moderate effects for subjective wellbeing (g = 0.48) and psychological wellbeing (g = 0.40), and a large effect on depression (g = 0.62) and anxiety (g = 0.95). | Moderators did not include: study population (clinical or non-clinical), mode of delivery of the PPI (group or self-help), intervention type (single component or multi-component), type of control group (active/placebo or non-active/waitlist), duration of the intervention (≤ 8 weeks or > 8 weeks), or cultural adaptation of the PPI (yes or no). |
| Dhillon et al. (2017) | Mindfulness-based interventions during pregnancy: A systematic review and meta-analysis | 14 articles (some RCT and some non-RCT studies), pregnant (prenatal) participants | Mindfulness-based interventions showed no significant effects for anxiety, depression, or perceived stress in the pooled RCTs, but each showed a significant effect in the pooled non-RCTs: anxiety (SMD = −0.48), depression (SMD = −0.59), and perceived stress (SMD = −3.28). Further, mindfulness as an outcome showed significant effects for both the pooled RCT (SMD = −0.57) and pooled non-RCT studies (SMD = −0.60). | N/A |
| Dickens (2017) | Using gratitude to promote positive change: A series of meta-analyses investigating the effectiveness of gratitude interventions | 38 studies, 5,223 participants | Gratitude interventions can be effective with small to medium effects for well-being, happiness, life satisfaction, grateful mood, grateful disposition, positive affect, and depressive symptoms, with mixed findings for negative affect and stress, and no significant effects for physical health, sleep, exercise, prosocial behavior, or self-esteem. Please see the full paper for effect sizes for each of the comparison group types: neutral, positive, and negative conditions. | Moderators included: adults (versus children or college-aged). Moderators did not include: gender, type of neutral comparison group, duration of the follow-up period. |
| Davis et al. (2016) | Thankful for the little things: A meta-analysis of gratitude interventions | 32 studies in 26 articles | Gratitude interventions were effective PPIs with small effects for psychological well-being (d = 0.31) but not gratitude as an outcome itself (d = 0.20) in comparison to measurement-only controls. However, gratitude interventions were effective with moderate effects for gratitude (d = 0.46) and small effects for psychological well-being (d = 0.17), with no significant effects for anxiety (d = 0.11), in comparison to alternate-activity conditions. | Moderators did not include: type of gratitude intervention or dosage (neither days nor minutes of participation). |
| Weiss et al. (2016) | Can we increase psychological well-being? The effects of interventions on psychological well-being: A meta-analysis of randomized controlled trials | 27 RCT studies, 3,579 participants | Behavioral interventions were effective with moderate effects for psychological well-being (d = 0.44), with small effects at follow-up (d = 0.22). | Moderators included: clinical groups (versus non-clinical) and individual face-to-face interventions (versus self-help or group face-to-face). Moderators did not include: age, number of sessions, measurement instrument, and control group. Lower-quality studies found greater effects. |
| Theeboom et al. (2014) | Does coaching work? A meta-analysis on the effects of coaching on individual-level outcomes in an organizational context | 18 studies, 2,090 participants, organizational context | Coaching was effective with moderate to large effects for goal-directed self-regulation (g = 0.74) and with small to moderate effects for performance/skills (g = 0.60), well-being (g = 0.46), coping (g = 0.43), and work attitudes (g = 0.54), in an organizational context. | N/A |
| Bolier et al. (2013) | Positive psychology interventions: A meta-analysis of randomized controlled studies |
39 RCT studies in 40 articles, 6,139 participants | PPIs were effective with small effects for subjective well-being (SMD = 0.34), psychological well-being (SMD = 0.20), and depression (SMD = 0.23). | Moderators for decreasing depression included: longer duration (four or eight weeks versus as opposed to less than four weeks), recruited as a referral from a healthcare practitioner or hospital (versus recruitment at a community center, online, or at a university), the presence of psychosocial problems, and individual delivery (versus self-help or group). Lower-quality studies found greater effects. |
| Mazzucchelli et al. (2010) | Behavioral activation interventions for well-being: A meta-analysis | 20 RCT studies, 1,353 participants | Behavioral Activation (BA) interventions were effective with moderate effects for well-being (g = 0.52) in both non-clinical participants and those with depressive symptoms, indicating that BA can be useful for non-clinical populations alongside its more common setting as a treatment for depression. | N/A |
| Sin and Lyubomirsky (2009) | Enhancing well-being and alleviating depressive symptoms with positive psychology interventions: A practice-friendly meta-analysis | 51 studies, 4,266 participants | PPIs were effective with moderate effects for well-being (mean r = .29) and depressive symptoms (mean r = .31). | Moderators included: self selection to participate in the PPI, older age (versus younger), depression status, individual therapy (versus group), and relatively longer duration (versus shorter). |
Small to moderate effects were characterized by the following benchmarks for Hedge’s g, Cohen’s d, SMD, and δ: small = 0.2, medium = 0.5, large = 0.8, and for r: small = .1, moderate = .3, and large = .5 ( Cohen, 1988).