Genetics, and the Pathophysiology of Schizophrenia

Impaired attention is commonly observed among schizophrenia patients and those at genetic risk for the disease. This article re-views over 40 studies that used various versions of the Contin-uous Performance Test (CPT) as the primary measure of attention. These studies of normal subjects, affected patients, and various at-risk populations demonstrate that the CPT is a psychometrically sound procedure that consistently discriminates affected patients from controls. Sufficiently diffi-cult versions of this task have also demonstrated that impaired attention is (1) evident in schizo-phrenia patients regardless of clinical state, (2) detectable be-fore illness onset, (3) apparently heritable, (4) specific—in terms of distinct profile patterns—to schizophrenia, and (5) predictive of later behavioral disturbances in susceptible individuals. Se-lected studies are also discussed that examine the role of atten-tional deficit in the pathophysi-ology of schizophrenia and its potential consequences for per-sonality development. With re-spect to pathophysiology, pre-liminary data suggest that subcortical brain dysfunction has an important role in the atten-tional deficits tapped by the CPT. With respect to personality, an association between chron-ically impaired attention and de-ficient social skills has been found. It is concluded that the CPT is a cost-effective measure of the attentional deficit com-monly found in affected schizo-phrenia subjects and those at risk for the disorder, and is therefore a potentially valuable screening device for preventive intervention programs