RESUMEN
OBJECTIVE: This study's first objective was to confirm that patients with schizophrenia and their nonmentally ill siblings share the same impaired executive function when compared to healthy control subjects. The second objective was to study the relation between Wisconsin card sorting task (WCST) performance and the persistence and severity of clinical symptoms, as well as different clinical dimensions. METHOD: Ninety subjects were involved in this study, divided in 3 groups of 30 each: one group of patients with schizophrenia, one group of their siblings, and a control group. Symptom severity was assessed with the Positive and Negative Syndrome Scale (PANSS), and social functioning was measured by the Global functioning scale (GFS). The WCST was administered to all 3 groups. RESULTS: Patients with schizophrenia and their siblings had a significantly lower WCST performance than control subjects. Statistical analysis showed that the patient group had a significantly greater impaired WCST performance than the 2 other groups. Siblings also had a significantly lower performance than the control subjects. Furthermore, no significant relation was found between WCST performance and other variables, including age, gender, education, illness duration, treatment, and different PANSS and GFS scores. CONCLUSION: Patients with schizophrenia and their nonmentally ill siblings share the same impaired executive function. These findings suggest that WCST performance can be considered a schizophrenia vulnerability marker in siblings of patients with schizophrenia.