A family study of outpatients with borderline personality disorder and no history of mood disorder.

While several studies have examined psychiatric disorders in the relatives of individuals with borderline personality disorder, many of these studies have not employed a family study methodology and suffer from other methodological shortcomings. Thus, the conclusions from family data addressing the validity of borderline personality disorder, its relation to other conditions, and its distinction from mood disorders, continue to be debated. The present investigation employed a family study design with direct interviews with relatives, structured diagnostic interviews with both probands and relatives, and blind assessment of relatives. Rates of psychiatric disorders were examined in 563 relatives of outpatients with mood disorders (n = 119), 54 relatives of outpatients with borderline personality disorder and no history of mood disorder (n = 11), and 229 relatives of never psychiatrically ill controls (n = 45). Results indicate increased rates of mood disorders and personality disorders in the relatives of borderline probands compared with never psychiatrically ill controls. Familial aggregation of psychiatric disorders was generally similar for borderline personality and the mood disorder comparison group. The results suggest there may be common etiological factors between borderline personality disorder and mood disorders.