Obstetrical complications and trail making deficits discriminate schizophrenics from unaffected siblings and controls

Numerous studies have reported that both obstetrical complications (OCs) and deficits on the Trail Making Test show elevated prevalences in schizophrenics. Trail Making deficits have also been reported to be more common in schizophrenics' relatives than in controls, suggesting poor trail Making performance may be a behavioral indicator of a familial risk factor for schizophrenia. Few studies, however, have investigated how these two variables co-vary in samples of schizophrenics and non-schizophrenics. In this study, DSM-III-R diagnoses, OCs noted in birth records, and Trail Making performance were independently assessed in 30 subjects: 9 schizophrenics, 8 of their non-schizophrenic siblings, and 13 comparison subjects with neither a personal nor a family history of schizophrenia. Results supported two key predictions of a two-factor etiologic model of schizophrenia: (a) the combination of perinatal OCs and poor Trail Making performance discriminated schizophrenics extremely well from non-schizophrenics, including their own non-schizophrenic sibs, and (b) perinatal OCs and Trail Making errors manifested a significant inverse association among schizophrenics' non-schizophrenic sibs, but not among other subjects.