The prognostic significance of negative symptoms in schizophrenia

A review of research on the negative symptoms of schizophrenia reveals confusing variations in experimental methodology and diagnostic criteria, as well as inconsistent results. Negative symptoms are usually defined by blunted mood and emotions (affect), poverty of speech and slow movement. Studies of the prognostic or predictive value of negative symptoms assessed during an acute schizophrenic episode have been inconclusive. However, studies that have looked at symptoms occurring during nonacute or posthospitalization periods have found negative symptoms to be strong predictors of poor overall functioning at two- and five-year follow-up evaluations. This may be because negative symptoms during postacute episodes are less likely to be secondary symptoms related to neuroleptic (antipsychotic) medication side-effects, or responses to psychosis. Studies examining social withdrawal and functioning deficits prior to first schizophrenic hospital admission suggest a moderate ability to predict the eventual development of negative symptoms. The overall prognostic utility of negative symptoms in evaluating illness outcome is much more moderate than previously thought. Studies also suggest that more changes occur in negative symptoms over time than previously expected. We still do not know whether or not negative symptoms stabilize or become more predominant during the later course of illness, but the degree of symptom instability demonstrated by recent studies argues against a model relating all negative symptoms to brain abnormalities. (Consumer Summary produced by Reliance Medical Information, Inc.)