This essay addresses the challenges of clinical trials to develop treatments for Alzheimer's Disease (AD). The issues covered are enrolling subjects, defining clinically meaningful endpoints, and making the claim that a drug slows the progression of the disease. The perspective to address these challenges is that dementia research should embrace a biopsychosocial model for drug development. In this model, the patient and caregiver are seen as interrelated subjects of both treatment and research and outcome measures reflect biomarkers of the disease, the functional morbidity of AD and the distress of caregiving.