Neuropsychological risk indicators for schizophrenia: a preliminary study of female relatives of schizophrenic and bipolar probands.
Evidence of subtle neuropsychological deficits in relatives of schizophrenic probands (REL-SZs) suggests that these are risk indicators for schizophrenia, but little is known about whether neuropsychological performance in REL-SZs differs from that in other groups of relatives. We compared neuropsychological function in female REL-SZs (n = 39), relatives of primarily psychotic bipolar disorder probands (REL-BPs; n = 15), and a normal control group (n = 44). After adjustment for expected intellectual ability (based on reading recognition), REL-SZs showed deficits in verbal and visual memory (Wechsler Memory Scale-Revised logical memories, visual reproductions), and auditory attention (dichotic digits) compared with either REL-BPs or control subjects. Memory, but not dichotic listening differences remained significant after adjusting for current IQ; however, average effect sizes after controlling for either reading or IQ were roughly comparable for these three parameters (d = 0.80, 0.71, and 0.69, respectively). REL-BPs and control subjects showed little difference. Although both schizophrenic and bipolar patients often manifest neuropsychological dysfunction, these preliminary findings indicate subtle neuropsychological deficits only in REL-SZs. Such differences suggest different underlying processes; neuropsychological impairment may, in part, reflect an expression of genetic liability to schizophrenia but not bipolar disorder. Replication with a larger REL-BP sample and with male relatives is needed to evaluate the generalizability of the results.
Kremen
W S
WS
Department of Psychiatry, University of California, Davis School of Medicine, Sacramento 95817, USA. wskremen@ucdavis.edu
Faraone
S V
SV
Seidman
L J
LJ
Pepple
J R
JR
Tsuang
M T
MT
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology; D001714:Bipolar Disorder / Q000235:genetics / Q000523:psychology; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D003072:Cognition Disorders / Q000235:genetics*; D004198:Disease Susceptibility; D005192:Family Health; D005260:Female; D006801:Humans; D008569:Memory Disorders / Q000235:genetics*; D001523:Mental Disorders / Q000150:complications / Q000235:genetics; D008875:Middle Aged; D009483:Neuropsychological Tests; D012559:Schizophrenia / Q000235:genetics*; D012565:Schizophrenic Psychology