Neuropsychological functioning among the nonpsychotic relatives of schizophrenic patients: a diagnostic efficiency analysis.
Numerous studies suggest that the relatives of schizophrenic patients exhibit neuropsychological impairments that are milder yet similar to those seen among schizophrenic patients. The authors assessed 35 nonpsychotic relatives of schizophrenic patients and 72 normal controls using a clinical and experimental neuropsychological test battery. Three neuropsychological functions met criteria for risk indicators of the schizophrenia genotype: abstraction, verbal memory, and auditory attention. These findings could not be attributed to parental socioeconomic status, education, general visual-spatial ability, or psychopathology. Furthermore, exploratory analyses were performed to determine whether the diagnostic efficiency of the indicators could be adjusted to meet the needs of genetic linkage analyses. These analyses suggest that psychometric considerations may help to create measures for genetic linkage studies.