Cognition and the prediction of functioning in patients with a first treated episode of psychosis: A prospective study

Past research on the role of cognitive performance in predicting later psychosocial functioning for individuals with first treated episode of a psychotic disorder has yielded inconsistent results. Several factors have been suggested as determining the strength of any such relationship including the type of functioning measured, time of the cognitive assessment, covariates included and the use of global versus specific measures of cognitive functioning. In the current study, we examined the importance of these factors in a five year prospective study of individuals with first episode psychotic disorders. Just over 80% of the sample had a schizophrenia spectrum disorder. Cognitive assessments were carried out after initiation of treatment on 113 patients, and at one year for 79 patients. There was evidence that cognition predicted occupational functioning and use of a disability pension, but not a summary index of functioning or use of supervised housing, at follow-up. Overall I.Q. was a more consistent predictor than measures of specific cognitive functions, and there was evidence that cognition assessed after presentation for treatment, particularly after a year of treatment, was more predictive of later functioning than premorbid I.Q. Cognitive functioning, however, did not add to the prediction of outcomes beyond the level possible using past educational achievement or academic premorbid adjustment.