As a practical strategy for reducing agitation in schizophrenia, low-potency neuroleptics have been commonly used as an adjunct in combination with high-potency neuroleptics that seem superior in reducing positive symptoms. There is no evidence, however, that giving more than one antipsychotics at a time enhances therapeutic effects. Antipsychotic polypharmacy has been rather considered an unproven and potentially harmful practice .
The low-potency neuroleptic levomepromazine has been in common use for agitated patients with schizophrenia in Europe and Japan [2,3], because of its markedly sedative property. In order to clarify whether levomepromazine as an adjunct to high-potency neuroleptics are beneficial or harmful, therefore, we compared the efficacy of the combined therapy with levomepromazine and high-potency neuroleptic haloperidol with the monotherapy with haloperidol for patients with acute exacerbation of schizophrenia.