Prediction of Relapse After Discontinuation of Antipsychotic Treatment in Alzheimer's Disease: The Role of Hallucinations

Objective: In Alzheimer's disease, antipsychotic medications are often used for a period, with relief of symptoms, and then discontinued, after which relapse may occur. The authors sought to determine which neuropsychiatric symptoms predict relapse.

Method: In the Antipsychotic Discontinuation in Alzheimer's Disease trial, 180 patients with Alzheimer's disease and symptoms of agitation or psychosis were treated with risperidone for 16 weeks, after which patients who responded (N=110) were randomly assigned to continue risperidone for 32 weeks, to continue risperidone for 16 weeks followed by switch to placebo for 16 weeks, or to receive placebo for 32 weeks. As reported previously, discontinuation of risperidone was associated with a two- to fourfold increased risk of relapse over 16-32 weeks. In planned post hoc analyses, the authors examined associations between the 12 symptom domains in the Neuropsychiatric Inventory (NPI) and relapse in the first 16-week phase after randomization.

Results: Compared with patients with mild hallucinations or no hallucinations, patients with severe hallucinations as a presenting symptom at baseline had a higher likelihood of relapse (hazard ratio=2.96, 95% CI=1.52, 5.76). This effect was present for the subgroup with auditory hallucinations, but not the subgroup with visual hallucinations. Among patients with baseline hallucinations, 13 of 17 (76.5%) who discontinued risperidone relapsed, compared with 10 of 26 (38.5%) who continued risperidone (p<0.02). This group difference remained significant for severe (77.8%) compared with mild (36%) hallucinations. NPI domain scores after the initial open-treatment phase were not associated with relapse.

Conclusions: Patients with severe baseline hallucinations were more likely to relapse after randomization, and the presence of baseline hallucinations was associated with a higher risk of relapse after discontinuation of risperidone compared with continued risperidone treatment. For patients with hallucinations, particularly auditory hallucinations, antipsychotic discontinuation should be approached cautiously because of high relapse risk.