Cardiff depression study. A sib-pair study of life events and familiality in major depression

Abstract

Background: An excess of both depression and undesirable life events in first-degree relatives of probands with depression as compared with controls has been reported. This association may have reflected a familial factor in common.

Aims: To examine the familiality of life events and depression and whether there may be a common familial factor influencing vulnerability to depression and the experiencing of life events.

Method: In a sib-pair design, 108 probands with depression and their siblings were compared with 105 healthy controls and their siblings for psychopathology and life events.

Results: The lifetime relative risk of depressive disorder in the siblings of depressed subjects as compared with siblings of controls was 9.74, although these groups did not differ in the life events measures. Several categories 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 familial effects on life events were largely explained by shared experiences. There was no evidence for a common factor influencing both depression and life events.