Cognitive functioning and anhedonia in subjects at risk for schizophrenia

This study investigated the performance of individuals with familiar loading of schizophrenia (healthy siblings of schizophrenic inpatients) on three neuropsychological tasks assumed to require frontal lobe functions: Trail Making Test (TMT), verbal fluency and Wisconsin Card Sorting Test (WCST). Healthy siblings of schizophrenics differed in performance from healthy controls not only on the WCST, but also on the Trail Making Test and the verbal fluency task. Furthermore, scores of physical anhedonia, assessed in a self-report rating scale (Chapman et al., 1976) were also significantly higher in the high risk group than in the control sample. However, healthy siblings of schizophrenics did not differ from controls with regard to experiences of perceptual aberrations, measured by the same method (Chapman et al., 1978). Neuropsychological performance and elevated anhedonia scores in the high risk group were interpreted under the conceptual framework of vulnerability markers: they were supposed to represent a trait shared by family members of schizophrenic probands. Amongst the neuropsychological tests, there were significant correlations between the physical anhedonia score and WCST and Trail Making test performance in the group of healthy siblings of schizophrenics, but not in the control group.