Negative symptoms in schizophrenia: assessment of the effect of risperidone

This article reviews the definitions of negative symptoms and the deficit syndrome of schizophrenia, rating scale criteria (the Scale for Assessment of Negative Symptoms and the Positive and Negative Syndrome Scale), Crow's Type II syndrome, and Carpenter's deficit syndrome in relation to the DSM-IV. The effectiveness of conventional neuroleptics against negative symptoms is still in question. Improvement in negative symptoms may occur in tandem with improvement in the florid symptoms of schizophrenia, but negative symptoms may be difficult to discriminate from the extrapyramidal side effects that are caused by conventional neuroleptics. In a multicenter trial comparing the novel antipsychotic risperidone with haloperidol and placebo in symptomatic schizophrenia, negative symptoms (assessed using the Positive and Negative Syndrome Scale) were reduced more by risperidone at a dose of 6, 10, and 16 mg/day than by placebo. Haloperidol at a dose of 20 mg/day was not significantly better than placebo. Risperidone 6 mg was the lowest dose that produced substantial change in negative symptoms and no increase in extrapyramidal symptoms and antiparkinsonian medication use.