Neuropsychological deficit in siblings discordant for schizophrenia.

This study was aimed, first, at detecting neuropsychological markers that assess vulnerability to schizophrenia in siblings of patients with schizophrenia, and second, at exploring possible relationships between markers. For these purposes, performances were assessed in 18 clinically stabilized patients with schizophrenia, 18 of their unaffected full siblings, and 15 controls on attentional abilities (the Degraded Stimuli-Continuous Performance Task [DS-CPT] and the Span of Apprehension [SOA] task) and on executive functions (the Wisconsin Card Sorting Test [WCST]). Both patients and siblings were impaired on the three tasks, leading to the conclusion that these poor performances may represent markers of genetic vulnerability to schizophrenia. Furthermore, significant relationships were found between DS-CPT and WCST performance in patients only, suggesting a possible implication of prefrontal brain areas for the two tasks. In spite of the lack of similar relationships between DS-CPT and WCST in siblings, this raises the question of a putative role of prefrontal areas in vulnerability to schizophrenia.