Initial and final work performance in schizophrenia: cognitive and symptom predictors

Abstract

Studies have shown that cognitive functioning may limit the rate, tenure, and type of work performed by people with schizophrenia. The present study tested the hypothesis that cognitive abilities needed for initial improvement in work performance would differ from those needed in later vocational development. Ninety-six outpatients with schizophrenia or schizoaffective disorder who participated in a work rehabilitation program were administered neuropsychological testing at intake. Their work performance was evaluated biweekly for 26 weeks. Cognitive test variables were entered into regressions predicting the slope of individual performance curves from weeks 1 to 13 and 13 to 26. Neuropsychological variables accounted for 28% of the variance in slope during the initial period. The strongest predictor was a Continuous Performance Task variable that measures inattentiveness. Other important variables were measures of idiosyncratic thinking, cognitive flexibility, and verbal memory. Neuropsychological variables accounted for 19% of the variance in the slope during the final period. The strongest predictor was verbal learning, while measures of cognitive impulsivity and psychomotor functioning were also significant contributors. There was no relationship between work performance and symptoms for weeks 1 to 13 or 13 to 26. These findings suggest that while attention is more important for initial success, verbal memory becomes more important for sustained improvement. Remediating or accommodating such deficits in a time-sensitive fashion may be a necessary feature for successful rehabilitation.