Pathophysiology and treatment of negative symptoms.

The assessment and clinical characterization of the negative symptoms of schizophrenia are reviewed. While negative symptoms may be secondary to positive symptoms, extrapyramidal side-effects, depressive illness, chronic institutionalization or other factors, they may also be primary, i.e., integral to the disease process itself. Recent literature has suggested that negative symptoms may represent a distinct pathophysiological process mediated in part by serotonergic mechanisms. Atypical neuroleptics, which have dual effects on D2/5-HT2 receptors, have demonstrated clinical efficacy on both negative and positive symptoms of schizophrenia, and might help to clarify the pathogenesis of these symptom clusters.