Lymphocytopenia and thrombocytopenia during treatment with risperidone or clozapine.

The atypical antipsychotic clozapine is associated with several well-known abnormalities of blood cell count, whereas only rare reports are associated with the neuroleptic risperidone. This report describes lymphocytopenia and thrombocytopenia under treatment with risperidone which continued after changing to clozapine without other clinically significant abnormal hematological parameters. Within one week after discontinuation of both neuroleptics abnormalities of blood cell count reversed to the initial values. Abnormalities of lymphocytes or thrombocytes are rare side-effects under treatment with risperidone or clozapine.