Cardiff Depression Study - A sib-pair study of life events and familialityin major depression

Background An excess of both depression and undesirable lire events ii firs t-degree relatives of probands with depression as compared with controls ha s been reported. This association may have reflected a familial factor in c ommon. Aims To examine the familiality of life events and depression and whether t here may be a common familial factor influencing vulnerability to depressio n and the experiencing of lire events. Method In a sib-pair design, 108 probands with depression and their sibling s were compared with 105 healthy controls and their siblings for psychopath ology and life events. Results The lifetime relative risk of depressive disorder in the siblings o f depressed subjects as compared with siblings of controls was 9.74, althou gh these groups did not differ in the life eve:nts measures. Several catego ries of events showed significant sibling correlations. but this was due to the same event affecting both members of the pair. Conclusions Although depressive disorder was strongly familial, the familia l effects on life events were largely explained by shared experiences. Ther e was no evidence for a common factor influencing both depression and life events. Declaration of interest The study was funded by a project grant from the We lcome Trust.