OBJECTIVE: The purpose of this study was to examine the efficacy and side effects of haloperidol, chlorpromazine, and lorazepam for the treatment of the symptoms of delirium in adult AIDS patients in a randomized, double-blind, comparison trial. METHOD: Nondelirious, medically hospitalized AIDS patients (N = 244) consented to participate in the study and were monitored prospectively for the development of delirium. Patients entered the treatment phase of the study if they met DSM-III-R criteria for delirium and scored 13 or greater on the Delirium Rating Scale. Thirty patients were randomly assigned to treatment with haloperidol (N = 11), chlorpromazine (N = 13), or lorazepam (N = 6). Efficacy and side effects associated with the treatment were measured with repeated assessments using the Delirium Rating Scale, the Mini-Mental State, and the Extrapyramidal Symptom Rating Scale. RESULTS: Treatment with either haloperidol or chlorpromazine in relatively low doses resulted in significant improvement in the symptoms of delirium as measured by the Delirium Rating Scale. No improvement in the symptoms of delirium was found in the lorazepam group. Cognitive function, as measured by the Mini-Mental State, improved significantly from baseline to day 2 for patients receiving chlorpromazine. Treatment with haloperidol or chlorpromazine was associated with an extremely low prevalence of extrapyramidal side effects. All patients receiving lorazepam, however, developed treatment- limiting adverse effects. Although only a small number of patients had been treated with lorazepam, the authors became sufficiently concerned with the adverse effects to terminate that arm of the protocol early. CONCLUSIONS: Symptoms of delirium in medically hospitalized AIDS patients may be treated efficaciously with few side effects by using low-dose neuroleptics (haloperidol or chlorpromazine). Lorazepam alone appears to be ineffective and associated with treatment-limiting adverse effects.Abstract Teaser