The association between positive affect and depressive symptoms in individuals with diagnosed or probable major depressive disorder: A systematic review and meta-analysis

Background: A number of theories propose that positive affect is negatively associated with depressive symptoms, but this claim has only been examined in meta-analyses of non-clinical samples and it remains unclear whether the association holds in clinical populations. Objective: To obtain evidence-based estimates of the cross-sectional and prospective associations between positive affect and depression severity measures in individuals with clinical depression by conducting a systematic review and meta-analysis. Methods: We performed a systematic search on PsychINFO, MEDLINE, and Google Scholar and included studies reporting estimates of the association between positive affect and depressive symptoms in clinical populations. A correlational (r) effect size based on cross-sectional measures was estimated using a random-effects meta-analysis. Results: From 1,930 unique records, we identified 17 eligible manuscripts, reporting 20 effect sizes from 1,665 individuals with diagnosed or probable major depressive disorder. The results of the omnibus model indicated a significant moderate association between cross-sectional positive affect and depressive symptoms (r =-.38, 95 % CI [-0.45,-0.30]); heterogeneity of effect sizes was low to moderate (I2 = 45.79 %). None of the included studies reported prospective relationships between the variables outside of a treatment context. Conclusion: The results are in line with theoretical models on the cross-sectional association between positive affect and depressive symptoms in major depressive disorder. More research is needed to develop a deeper understanding of the overlap and temporal directions between positive affect and depressive symptoms in clinical populations.