Nithsdale Schizophrenia Surveys 20 - Cognitive function in a catchment-area-based population of patients with schizophrenia

Background Cognitive deficits are a core aspect of schizophrenia but there has been no study of cognitive function in a catchment-area-based population of patients with schizophrenia. Aims To assess cognitive function ina population of patients with schizophrenia, and relate it to community functioning. Method All patients with schizophrenia in Nithsdale, south-west Scotland, were identified (n=182). Measures of assessment were: National Adult Reading Test (NART), Mini-Menial State Examination (MMSE), Rivermead Behavioural Memory Test(RBMT), Executive Interview (EXIT), FAS Verbal Fluency and Health of the Nation Outcome Scales (HoNOS). Results We assessed 138 patients, mean age 48 years (standard deviation (s.d.) 15). Only 14% were in-patients. The mean premorbid IQ as assessed by NART was 98 (s.d. 14); 15% of patients had significant global cognitive impairment (MMSE); 81% had impaired memory (RBMT); 25% had executive dyscontrol (EXIT); and 49% had impaired verbal fluency (FAS). Scores on the functional impairment sub-scale of HoNOS correlated with all measures of cognitive impairment. Conclusions Cognitive dysfunction is pervasive in a community-based population of patients with schizophrenia.