Impact of neuroleptic medications on continuous performance test measures in schizophrenia

Abstract

Attentional deficits, as measured by the continuous performance test (CPT), have been reliably detected in schizophrenic patients. Schizophrenic patients show greater impairment on CPT tasks than normal control subjects and subjects with chronic alcoholism or major affective disorder (Nuechterlein and Dawson 1984). The deficits in CPT performance found in remitted (Wohlberg and Kornetsky 1973) and acutely psychotic schizophrenic patients suggest impaired attention may be a core neurocognitive deficit. Impaired CPT performance has also been found in subjects with schizotypal features (Obiols et al 1993) and in children of schizophrenic subjects (Cornblatt and ErlenmeyerKimling 1985), raising the possibility that this deficit may represent a marker of vulnerability to the development of schizophrenia-related disorders. Unfortunately, efforts to delineate the relationship between attentional impairment, as measured by CPT performance, and the pathophysiology, phenomenology, and genetics of schizophrenia have been hampered by a poor understanding of the influence of confounding variables, particularly medication status. Though multiple studies have examined the effects of neuroleptic medication on CPT measures in schizophrenia, results have been contradictory (Medalia et al 1988). Many of these studies used a cross-sectional design and/or failed to examine practice effects. The use of a cross-sectional design for CPT studies with schizophrenic subjects is especially problem-