Positive life events and mood disorders: longitudinal evidence for an erratic lifecourse hypothesis.

BACKGROUND An unresolved issue in psychiatry research concerns the assumption that detrimental effects of negative life events on mental health may be buffered by a multitude of positive life events. However, there is clear lack of empirical evidence for this assumption, and one may even argue that positive life events act as additional stressors and thus increase (and not decrease) the risk for affective disorders. METHODS Data were used from 4796 adults aged 18-64, who participated in 2 waves (i.e., 1997 and 1999) of NEMESIS, a prospective-epidemiological study. Measures were based on diagnoses of DSM-III-R mood disorders, and a life events questionnaire employed in the NEMESIS study. RESULTS Although the prevalence of mood disorders correlated positively with both the number of negative and positive life events experienced, a multivariate path analysis (Mplus) demonstrated that only negative life events longitudinally predicted mood disorders. Positive life events predicted subsequent mood disorders only when in the same time period a high number of negative events were experienced. CONCLUSIONS Positive life events do not buffer the detrimental impact of negative ones, but instead may function as additional stressor, in the context of highly erratic life course patterns that may be typical for depressed individuals.