Objective: The primary purpose of this article was to determine if cognitive abilities decline, remain unchanged, or modestly improve throughout the course of schizophrenic illness.
Method: Forty-two patients with a first hospitalization for schizophrenia or schizophreniform disorder and 16 normal comparison subjects had a battery of neuropsychological tests and a magnetic resonance imaging (MRI) brain scan at approximate yearly intervals for the first 2 to 5 years of illness. Summary rating scales for language, executive, memory, processing speed, and sensory-perceptual functions were constructed.
Results: Patients with schizophrenia scored 1 to 2 standard deviations below normal comparison subjects on neuropsychological test measures during the course of the study. Patients exhibited less improvement than comparison subjects on measures of verbal memory. In general, improvement in positive symptoms over the time interval was associated with improvement in cognition. No changes in regional brain measurements were correlated with cognitive change in the patient group.
Conclusions: Patients with schizophrenia have considerable cognitive dysfunction in the first 4 to 5 years of illness, which is stable at a level of 1 to 2 standard deviations below that of comparison subjects. There is little evidence for deterioration of cognitive abilities over the first few years of illness, with the exception of verbal memory, which shows significantly less improvement in patients over time relative to that of comparison subjects.