Hard neurologic signs and psychopathology in relatives of schizophrenic patients.

Previous research found more hard neurologic signs (i.e., signs that have localizing significance and exclude likely artifacts) in the nonschizophrenic relatives of schizophrenic patients than in control subjects, and in the psychiatrically normal relatives of schizophrenic patients compared with their ill relatives. Using interview-based DSM-III-R diagnoses and standard clinical neurological examinations on new samples, we found a trend to more hard signs in the 52 nonschizophrenic relatives of schizophrenic patients than in 20 control subjects, and significantly more signs in psychiatrically normal relatives than in ill ones. When pooled with previous data, signs were significantly higher in (1) relatives vs. controls and (2) normal vs. ill relatives, suggesting neurologic signs reflect an etiologic factor that often runs in families of schizophrenic patients.