Negative symptoms in schizophrenia: their longitudinal course and prognostic importance.

Negative and positive symptoms were investigated longitudinally in 39 young schizophrenic patients at two followup assessments approximately 2.5 and 5 years after hospital discharge. Negative symptoms, such as flat affect and poverty of speech, which were assessed at the first followup, were found to be effective prognostic signs in schizophrenic patients for predicting later poor role functioning at the second followup. The prognostic importance of negative symptoms was predominantly due to their tendency to occur in patients who were already functioning poorly in social and instrumental areas at the first followup, and who tended to continue doing poorly at the second followup. Contrary to some current hypotheses, positive symptoms, such as delusions and hallucinations, were also found to be prognostic of later deficits in role functioning at the second followup. Negative symptoms appeared to be generally persistent over time, although there was some tendency toward remission. Potential models of the etiology of negative symptoms and their role in schizophrenia are proposed.