Familiality of depression in the community; associations with gender and phenotype of major depressive disorder

Although associations between family history and depression have been shown in clinical patients, it is unknown if they also apply to subjects living in the community. The present study considers the relationship between family loading and depression phenotype characteristics in a large community-based sample. In a Dutch representative population sample of 7,076 individuals, lifetime diagnosis of depression was classified according to severity, course and age of onset. A family loading score of depression (FLSD) was computed by taking the proportion of the first-degree relatives for whom a history of depression was reported. There was a strong association between FLSD and lifetime diagnosis of MDD. Severity, recurrence and early onset of depression were the specific phenotypic characteristics associated with familiality. The effects of FLSD and gender were independent. Associations between family history and risk for depression in the community confirm those reported from clinical-based studies using direct interviewing of relatives. A stronger degree of familiality is associated with specific phenotypic characteristics of depression.