This study examines caregiver and patient relationship characteristics in the etiology of behavior problems in Alzheimer's disease. Seventy-two caregivers and patients were assessed twice, 12 months apart. Cross lag panel analysis was used to test for one-way or reciprocal causal links among caregiver variables, patient impairment measures, and patient behavior problems. Caregiver distancing from patients (closeout) predicted increases in the frequency of behavior problems, including activity disturbances, paranoia, and anxiety. These behaviors in turn led to increased closeout of the patient by the caregiver. The reciprocal causal associations found in this study suggest that dysfunctional family interactions may underlie patient behavior problems and caregiver distress.