Impact of stressful life events, familial loading and their interaction on the onset of mood disorders

Abstract

BACKGROUND: Stressful life events are established as risk factors for the onset of mood disorders, but few studies have investigated their impact on the development of mood disorders in adolescents. AIMS: To study the effect of life events on the development of mood disorders in the offspring of parents with bipolar disorder, with respect to the possibility of a decay effect and modification by familial loading. METHOD: In a high-risk cohort of 140 Dutch adolescent offspring of parents with bipolar disorder, we assessed life events, current and past DSM-IV diagnoses and familial loading. To explore their interaction and impact on mood disorder onset, we constructed four different models and used a multivariate survival analysis with time-dependent covariates. RESULTS: The relationship between life events and mood disorder was described optimally with a model in which the effects of life events gradually decayed by 25% per year. The effect of life event load was not significantly stronger in the case of high familial loading. CONCLUSIONS: Independent of familial loading, life events increase the liability to mood disorders in children of patients with bipolar disorder but the effects slowly diminish with time.