Life events and depression in a community sample of siblings

Background. The overall aim of the GENESIS project is to identify quantitat ive trait loci (QTLs) for anxiety/depression, and to examine the interactio n between these loci and psychosocial adversity. Here we present life-event s data with the aim of clarifying: (i) the aetiology of life events as infe rred from sibling correlations; (ii) the relationship between life events a nd measures of anxiety and depression, as well as neuroticism; and (iii) th e interaction between life events and neuroticism on anxiety/depression ind ices. Methods. We assessed the occurrence of one network and three personal life- event categories and multiple indices of anxiety/depression including Gener al Health Questionnaire, Anhedonic Depression, Anxious Arousal and Neurotic ism in a large community-based sample of 2150 sib pairs, 410 trios and 81 q uads. Liability threshold models and raw ordinal maximum likelihood were us ed to estimate within-individual and between-sibling correlations of life e vents. The relationship between life events and indices of emotional states and personality were assessed by multiple linear regression and canonical correlations. Results. Life events showed sibling correlations of 0.37 for network events and between 0.10 and 0.19 for personal events. Adverse life events were re lated to anxiety and depression and, to a less extent, neuroticism. Trait-v ulnerability las indexed by co-sib's neuroticism, anxiety and depression) a ccounted for 11% and life events for 3% of the variance in emotional states . There were no interaction effects. Conclusions. Life events show moderate familiality and are significantly re lated to symptoms of anxiety and depression in the community. Appropriate m odelling of life events in linkage and association analyses should help to identify QTLs for depression and anxiety.