Determinants of depressive mood states in everyday life: an experience sampling study

This study tests relative contributions and time-course of proposed risk/protective factors (e.g., stress, coping, and lack of social interactions) for influencing depressed mood states in daily life. Seventy-three participants completed baseline measurement of major depressive disorder symptomatology, followed by smartphone app-based monitoring of momentary experiences of depressed mood and risk/protective factors for 7 days. All predictors had deteriorating impacts on mood as lag increased, and the optimal lag appears to be less than 120 min. Linear decay in effect sizes was found for physical activity, social interaction, and tiredness, whereas exponential decline in effect sizes was found for stress and coping ability. Stress, coping, and depressed mood at the prior time-point were the best predictors of subsequent mood. These effects did not differ as a function of trait depressive symptom severity. Findings highlight the influence of spacing of assessments in identification and magnitude of predictors of mood states, and provide insights into key drivers of change in mood and their time-course.