Antipsychotic Discontinuation in Alzheimer's Disease

This multicenter study (6 academic sites and 2 non-academic sites) involves treating AD patients (assisted living or nursing home patients, and outpatients) using an atypical antipsychotic, risperidone. In Phase A, 180 AD patients with psychosis and/or agitation/aggression receive open treatment with risperidone for 16 weeks. Responders are randomized, double-blind, to one of three arms in Phase B: (1) continuation risperidone for the next 32 weeks, (2) risperidone for the next 16 weeks followed by placebo for 16 weeks, or (3) placebo for the next 32 weeks. The primary hypothesis is that in the first 16 weeks of Phase B, relapse risk will be lower with continuation risperidone (Arms 1 + 2) compared to discontinuation on placebo (Arm 3). The secondary hypothesis is that in the second 16 weeks of Phase B, relapse risk will be lower with continuation risperidone (Arm 1) compared to discontinuation on placebo (Arm 2). For both randomized time periods, the proportions who relapse will be compared for interpretive support. This design provides useful data on the efficacy and side effects of longer term treatment with risperidone, and, in particular, critical information about the time to relapse and likelihood of relapse in patients switched from risperidone to placebo. This information is essential to guide the clinician toward optimal use of such medications in one of the most challenging types of patients: the AD patient with psychosis and/or agitation/aggression. The results of this study will also help to address Federal regulations urging early antipsychotic discontinuation in nursing homes.