Am J Psychiatry 1993; 150:66-71
Copyright © 1993 by American Psychiatric Association
Psychiatric illnesses in families of subjects with schizophrenia- spectrum personality disorders: high morbidity risks for unspecified functional psychoses and schizophrenia
G Thaker, H Adami, M Moran, A Lahti and S Cassady
Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore 21228.
OBJECTIVE: The authors determined morbidity risks for psychiatric illnesses
in the families of probands with schizophrenia-spectrum personality
disorders. METHOD: Subjects were recruited from the community through
newspaper advertisements. Subjects were identified as having
schizophrenia-spectrum personality disorders (N = 30) if they met at least
three, four, or three DSM-III-R criteria for schizoid (N = 14), schizotypal
(N = 20), and/or paranoid (N = 15) personality disorder, respectively. The
comparison subjects had no psychiatric diagnoses (N = 8) or had other
personality disorders (N = 12); none of the subjects in either group had
any DSM-III-R axis I diagnosis. Trained interviewers collected family
history information about the relatives of the two groups; the interviewers
were blind to the probands' diagnoses. RESULTS: The risks for
schizophrenia, other functional psychoses, and schizophrenia-spectrum
personality disorders were significantly higher in the relatives of
subjects with schizophrenia-spectrum personality disorders than in the
families of the comparison subjects. CONCLUSIONS: The high rate of
schizophrenia in the families of probands with schizophrenia-spectrum
personality disorders is consistent with the previous findings of higher
than normal rates of these personality disorders in the biological
relatives of schizophrenic patients. The significance of the high rate of
unspecified functional psychoses is unclear. Use of the family study
method, by which valid differential diagnosis of psychoses is possible, is
indicated. The results from the current study do not rule out the
possibility that the schizophrenia-spectrum personality disorders are
related to psychoses in general rather than specifically to schizophrenia.
