• Schizophrenics meeting DSM-III criteria were divided, based on family history of affective disorder in first-degree relatives, into three groups: N-schizophrenics, no relative with affective disorder; U-schizophrenics, a relative with unipolar affective disorder; and B-schizophrenics, a relative with dipolar affective disorder. Although N- and U-schizophrenics displayed similar symptoms during the prodromal, actively psychotic, and remitted stages of their illness, U-schizophrenics were significantly more likely to have a depressive syndrome develop during the follow-up period. Compared with N-schizophrenics, B-schizophrenics were more depressed during the prodrome, were more elated and catatonic when actively psychotic, had fewer residual symptoms when remitted, and were much more likely to have a manic syndrome develop during the follow-up period. Even when DSM-III criteria are met, hesitation is indicated in diagnosing schizophrenia in patients with a first-degree relative with bipolar illness.
Kendler KS, Hays P. Schizophrenia Subdivided by the Family History of Affective DisorderA Comparison of Symptomatology and Course of Illness. Arch Gen Psychiatry. 1983;40(9):951-955. doi:10.1001/archpsyc.1983.01790080033004