Diagnoses of the relatives of schizotypal outpatients

Relatives of 22 schizotypal probands were evaluated for lifetime psychiatric diagnoses. Forty-four (N = 44) of the 97 available relatives were interviewed directly using the Diagnostic Interview Schedule. The rates of psychiatric diagnoses were compared with those of sixty-six (N = 66) of 140 relatives of 30 depressed patients. Family history of mental illness was ascertained by the informant method on the remainder of relatives of both proband groups. The rate of depression found in the relatives of schizotypal patients was 52% in those directly interviewed and 25.7% when informants' reports on unavailable relatives are pooled with direct interview data. These rates were not significantly higher than those found for the relatives of depressed probands (34.8% by direct interview and 21% including reports from informants). The high rates of depression in the relatives of schizotypal probands may indicate that schizotypal personality is associated with affective disorder and not only with schizophrenia. However, the high rates may be due to the presence of depressive character traits in relatives, which inflate the rates of dysthymic disorder and other chronic depressive disorders in the relatives of borderline patients.