Clinical Guidance: Cognitive Effects of Second-Generation Antipsychotics in Alzheimer's Disease
Patients with moderate to severe Alzheimer's disease who receive olanzapine, quetiapine, or risperidone for the indication of agitated behavior or psychosis experience a decrement in cognitive function greater than occurs with placebo. Vigen et al. (p. 831) estimate that the decrement ascribable to the antipsychotic is equivalent to 1 year's progression of illness. Devanand and Schultz in an editorial (p. 767) point out that adverse effects in Alzheimer's patients are quite dose dependent, e.g., occurring with risperidone doses greater than 2 mg/day or olanzapine doses greater than 5 mg/day. Alternative medications, such as benzodiazepines, also have adverse cognitive effects.