The objective was to assess the effect of a structured intervention on caregiver stress and the institutionalization rate of patients with dementia and problem behaviors. Caregivers contacting the Federazione Alzheimer Italia (AI) to receive help, advice, or information in relation to problem behaviors of outpatients were enrolled. Eligible caregiver-patient dyads were randomized to receive either a structured intervention or the counseling AI usually provides (control group). After basal assessment, families were reassessed at 6 and 12 months. Problem behavior (particularly agitation) was the only variable significantly correlated (P = 0.006) with the baseline caregivers' stress score. Thirty-nine families completed the 12-month follow-up; the mean problem behavior score was significantly lower in the intervention than the control group (p < 0.03); the time needed for care of the patient increased by 0.5 +/- 9.7 hours/day in the control group and decreased by 0.3 +/- 4.1 in the intervention group (p = 0.4, Wilcoxon test). The main determinant of institutionalization seemed to be the level of caregiver stress (p = 0.03). In patients of the intervention group, there was a significant reduction in the frequency of delusions. This pilot study suggests that caregiver stress is relieved by a structured intervention. The number of families lost to follow-up, the relatively short duration of the study, and the ceiling effect due to the severity of the clinical characteristics of patients probably all partly dilute the observed findings.