Background: We investigated whether family history had prognostic significance in depression in a study which addressed some of the methodological shortcomings of previous studies.
Method: We collected family history data on a consecutive series of 89 patients admitted with RDC major depression, blind to the outcome of the proband. This comprised 116, 283 and 120 first-degree relatives examined with the SADS-L, FH-RDC and case note data, respectively. The outcome of 74 of these probands (83%), previously categorised into four operationally defined groups, was then examined.
Results: A positive family history of severe psychiatric illness (i.e. a relative with a history of either a psychosis, hospitalised depression or suicide) was associated with poor outcome in the proband. This association persisted after controlling for variable family size, age structure and gender. As family history was correlated with neither Kendell's neurotic/psychotic index nor the proband's neuroticism score, an individual with high scores an all three would have a greatly increased chance of having a poor outcome.
Conclusions: A family history of severe psychiatric illness in a first-degree relative may be useful as one of the vulnerability factors for predicting poor long-term outcome in depression.