Neuropsychological performance of psychotic patients in community care: results from the UK700 study.

Objective: To compare cognitive performance in chronic schizophrenic and affective psychotic patients maintained in community care. Method: We studied a sample of community-based patients (n=707) with chronic psychotic disorders. Neuropsychological assessment was completed using the National Adult Reading Test (NART) and the Trail Making Test (TMT). Results: Affective psychotic patients had higher premorbid IQ than schizophrenic patients before adjustment for confounding factors (P=0.03); however, after adjustment for ethnic group and social class this became non-significant (P=0.19). There were no significant differences between groups on the TMT, parts A or B. Conclusion: Unlike studies suggesting that schizophrenic patients are more cognitively impaired than affective psychotic patients, our study suggests a degree of cognitive homogeneity between those patients who develop a chronic illness. Measures of premorbid IQ suggest that this cognitive homogeneity exists prior to the onset of illness.