Background: Positive psychological interventions (PPIs) are known to be effective in alleviating depression. However, the effect of PPIs on positive and negative emotions in depressed participants is not unclear.
Aims: To systematically investigate the effects of PPIs on positive and negative emotions in depressed individuals.
Methods: 6 databases were searched for randomized controlled trials of PPIs in individuals with depressive disorders or depressive symptoms. Hedges' g value was computed using a random-effects model to determine effect sizes.
Results: 14 trials from 13 studies were included. Our meta-analysis showed that PPIs had significant but small effects on improving positive affect (g = 0.33, p = .02), life satisfaction (g = 0.26, p = .03), happiness (g = 0.62, p = .03) and depression (g = -0.32, p = .001), and negligible effects on improving well-being (g = 0.13, p = .24) and negative affect (g = -0.15, p = .31). Subgroup analyses of depression showed that PPIs have experienced benefits in improving depression in most subgroups. In addition, none of the subgroup analyses performed for outcomes other than depression found PPIs to be more effective than controls.
Conclusion: PPIs can improve positive affect, life satisfaction, happiness and depression in depressed individuals, but further studies are needed to validate their effects on well-being, and negative affect.
Keywords: Depression; meta-analysis; negative emotions; positive emotions; positive psychology intervention; systematic review.