The efficacy of conventional neuroleptics in the treatment of the negative symptoms of schizophrenia is highly controversial. Clozapine, the leading atypical neuroleptic, has been shown to be effective, in the majority of the controlled studies, on both the positive and negative symptoms of the disease. It appears to be active vis-à-vis both the primary and secondary negative symptoms. However, several weeks (at least 12) are required for the effect on primary negative symptoms to clearly emerge. The position of clozapine in the treatment of patients presenting with a state of deficiency remains more debatable.