Effectiveness of positive psychology interventions: a systematic review and meta-analysis

A meta-analysis of positive psychology intervention (PPIs) studies was conducted. PPIs were defined as interventions in which the goal of wellbeing enhancement was achieved through pathways consistent with positive psychology theory. Data were extracted from 347 studies involving over 72,000 participants from clinical and non-clinical child and adult populations in 41 countries. The effect of PPIs with an average of ten sessions over six weeks offered in multiple formats and contexts was evaluated. At post-test, PPIs had a significant small to medium effect on wellbeing (g = 0.39), strengths (g = 0.46), QoL (g = 0.48), depression (g = −0.39), anxiety (g = −0.62), and stress (g = −0.58). Gains were maintained at three months follow-up. Individuals in non-western countries with clinical problems, who engaged in longer individual or group therapy programs containing multiple PPIs benefited most. This meta-analysis shows that PPIs have an extensive evidence base supporting their effectiveness.