Depression and mood disorders are frequently associated. They can be described as a part of schizophrenic symptomatology, observed as post-psychotic depression, be a part of a schizoaffective disorder or be a consequence of neuroleptic treatment. Suicide is the main risk of evolution in young schizophrenics and is often associated to depression. Despite methodological difficulties, a few studies demonstrate the efficacy of clozapine, one of the first atypical antipsychotic, in the treatment of depressive symptomatology in schizophrenics and schizoaffectives. This action remains controversial in the treatment of post-psychotic depression. This drug also contribute to reduce suicidality in a sample of chronic schizophrenics in an open study. This action has to be considered when we evaluate the risk-benefit of the prescription of clozapine.