Positive relations mediate the bidirectional connections between depression and anxiety symptoms

Introduction: Major depressive disorder (MDD) and generalized anxiety disorder (GAD) co-occur at high rates, often preceding and predicting one another over long durations. Interpersonal theories propose that relationships with others may contribute to the longitudinal connections between MDD and GAD. Therefore, the current study examined the mediational effect of positive relations with others in these connections over 18 years. Methods: Community-dwelling adults (n = 3294) participated in data collection at three time-points (Time 1 [T1], Time 2 [T2], and Time 3 [T3]) spaced about nine years apart. MDD and GAD symptoms were assessed using the Composite International Diagnostic Interview-Short Form. Positive relations was measured with the Psy-chological Well-Being Scale-Positive Relations with Others subscale. Structural equation mediation modeling was used for data analysis. Results: Results indicated that lower T2 positive relations significantly mediated the relationship between higher T1 MDD severity predicting more severe T3 GAD symptoms (d = 0.375) and explained 10.7% of the variance. T2 positive relations also had a significant mediational effect in the association between T1 GAD symptoms posi-tively predicting T3 MDD severity (d = 0.360), accounting for 12.2% of the variance of this connection. These mediational effects were significant after adjusting for age, gender, education, and T1 symptoms (d = 0.277-0.677). Conclusions: Supporting interpersonal theories, lack of positive relations with others mediated the bidirectional connections between MDD and GAD symptoms across 18 years. Future research should continue to explore the influence of positive relations on mental health and whether treatments that enhance interpersonal functioning could improve treatment for depression and anxiety.