Risk for definite neuroleptic malignant syndrome. A prospective study in 223 consecutive in-patients.

The occurrence of neuroleptic malignant syndrome (NMS) was studied prospectively in two series of consecutive psychiatric in-patients (n = 223). The first group (n = 120) suffered from schizophrenia and was treated only with haloperidol. The second group (n = 103) was treated with diverse neuroleptics. All patients were on a single antipsychotic agent with no anticholinergic drug as prophylaxis. The incidence of full NMS per admission and first neuroleptic exposure was 5/223 (2.2%). Patients with bipolar affective disorder and those treated with injections were significantly over-represented in the NMS group.