Combined serotonin‐5‐HT₂ and dopamine‐D₂ antagonism in schizophrenia: Clinical, extrapyramidal and neuroendocrine response in a preliminary study with risperidone (R 64 766)

Abstract

Abstract Previous studies suggested a therapeutic action of the selective serotonin 5‐HT 2 ‐antagonist ritanserin on negative symptoms of schizophrenia and on neuroleptic‐induced parkinsonism. In this open trial the effect of risperidone, a combined serotonin‐5‐HT 2 ‐and dopamine‐D 2 ‐antagonist, was studied on a sample of 31 schizophrenic outpatients with an unsatisfactory response to conventional neuroleptic treatment, predominance of negative symptoms, together with troublesome extrapyramidal side‐effects. After 28 days of oral treatment (2–6 mg daily) the patients showed a significant improvement as measured by means of the Brief Psychiatric Rating Scale and the Scale for the Assessment of Negative Symptoms. It is possible that the 5‐HT 2 receptor antagonist properties of risperidone may improve negative symptoms. In addition, confirming previous studies, extrapyramidal symptoms showed a reduced incidence compared to previous neuroleptic treatment, suggesting a serotonin‐‐dopamine interaction in the basal ganglia. No electrocardiographic, cardiovascular or laboratory abnormalities were observed.