Long-term course of cognitive impairment in schizophrenia.

The aim of this study was to examine the long-term course of cognitive impairment in people with schizophrenia. Forty-three people with schizophrenia were followed up over an average of 33 years along with a control group of 12 matched individuals free from psychosis. Cognitive function was assessed at baseline and follow-up. The participants with schizophrenia were found to show impairment in verbal and non-verbal intelligence at baseline compared with estimated premorbid scores, this was not found in the control group. At follow-up there was a significant decline in non-verbal intelligence over time in participants with schizophrenia compared with controls (P=0.007). This differential change over time was not seen in verbal intelligence (P= 0.318).