Participants in clinical drug trials are often required to discontinue or abstain from other drugs and treatments. With certain drug-responsive diseases or conditions, this can be a serious consideration. However, since there are not yet many highly effective drugs or medical treatments for Alzheimer’s available, this concern is largely eliminated in the case of clinical trials for Alzheimer’s and dementia treatments.
Many clinical drug trials are blind, which means that some participants receive placebos rather than the trial drug, without knowing which they have received. In double-blind studies, researchers also don’t know which participants have received placebos. In all cases, trials are carefully designed to minimize negative impacts on participants receiving the placebo.