Family history of depression in clinic and community samples.

Because most published family studies of depression ascertained subjects from treatment settings, the reported familial aggregation of depression could be an artifact if a family history of depression increased the likelihood of seeking treatment. To investigate this possibility, we compared the family history of depression in three groups of probands aged 18-44; 54 women randomly selected from the community with depression in the prior year, 41 women who entered a clinical trial for depression and 37 women randomly selected from the community who had not been depressed in the prior year. The presence of depression in the parents and siblings of the probands was assessed by the family history method and quantified via family history scores which took the age, gender and number of relatives into account. Depressed probands ascertained from clinical sources had markedly higher family history scores of depression than other two groups (P < 0.00005 in each instance). In the absence of direct interviews with relatives, we cannot exclude the impact of differential reporting. A family history of depression might be associated with an increased probability of treatment or the differential reporting of family history. It is thus possible that the familial aggregation of depression observed in probands from treatment settings is an artifact.