NEUROPSYCHOLOGICAL RISK INDICATORS FOR SCHIZOPHRENIA - A PRELIMINARY-STUDY OF FEMALE RELATIVES OF SCHIZOPHRENIC AND BIPOLAR PROBANDS

Evidence of subtle neuropsychological deficits in relatives of schizop hrenic probands (REL-SZs) suggests that these are risk indicators for schizophrenia, but little is known about whether neuropsychological pe rformance in REL-SZs differs from that in other groups of relatives. W e compared neuropsychological function in female REL-SZs (n = 39), rel atives of primarily psychotic bipolar disorder probands (REL-BPs; n = 15), and a normal control group (n = 44). After adjustment for expecte d intellectual ability (based on reading recognition), REL-SZs showed deficits in verbal and visual memory (Wechsler Memory Scale-Revised lo gical memories, visual reproductions), and auditory attention (dichoti c digits) compared with either REL-BPs or control subjects. Memory, bu t not dichotic listening differences remained significant after adjust ing for current IQ; however, average effect sizes after controlling fo r either reading or IQ were roughly comparable for these three paramet ers (d = 0.80, 0.71, and 0.69, respectively). REL-BPs and control subj ects showed little difference. Although both schizophrenic and bipolar patients often manifest neuropsychological dysfunction, these prelimi nary findings indicate subtle neuropsychological deficits only in REL- SZs. Such differences suggest different underlying processes; neuropsy chological impairment may, in part, reflect an expression of genetic l iability to schizophrenia but not bipolar disorder. Replication with l ager REL-BP sample and with male relatives is needed to evaluate the g eneralizability of the results. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.