The new study was carried out in Swedish nursing homes. Subjects were randomized to receive either donepezil or placebo and they were treated for 6 months. The treated group showed slight improvement in tests of mental function and a lower rate of deterioration in basic activities of daily living compared to controls. But before families rush to request donepezil for their relatives, we should consider the intriguing possibility raised by the study’s authors: perhaps what the donezpezil did was to counteract the negative effects of the many other medications these individuals were taking. Virtually all the people in the study (99%) were taking other medications, and 80% were on psychoactive medications intended to control their behavior. We know that the brains of individuals with dementia are very sensitive to chemicals that affect the nervous system—they are very prone to developing delirium, or an acute confusional state. Before concluding that all patients with severe dementia should be given donepezil, we need to study its effectiveness in demented persons who are on no other medications. Only then can we figure out whether we should dole out more donepezil (assuming that the “statistically significant” benefits are in fact clinically meaningful)—or give patients a drug holiday, discontinuing the many potentially toxic medicines they are currently taking.