Effects of supidimide in schizophrenic inpatients undergoing neuroleptic maintenance therapy with haloperidol

Forty schizophrenic inpatients, on constant low-dosage maintenance therapy with haloperidol, entered a superimposed, double-blind, placebo-controlled clinical trial with supidimide 2 x 200 mg per day. The double-blind phase lasted 5 days and was preceded and followed by single-blind base line and washout periods, respectively, during which all patients received matching placebos. The therapeutic effects were evaluated by BPRS, NOSIE, a post-sleep questionnaire, and, in a subgroup of patients, by objective monitoring of movements during sleep. Supidimide substantially relieved sleep disturbances, as demonstrated by subjective (p less than 0.05; n = 20) and objective (p less than 0.1; n = 3) measurements. In addition, the following drug-related effects (p less than 0.05 versus base line and placebo) on daytime behaviour were observed: a decrease in "somatic concern" (BPRS), items related to agitation (BPRS), "irritability" and "manifest psychosis" (NOSIE), and a slight increase in "retardation" (NOSIE). No adverse effects attributable to supidimide were detected. It is concluded that supidimide exerts beneficial effects on day-time behaviour and sleep in agitated schizophrenic patients undergoing low-dosage maintenance neuroleptic therapy.