Dementia is a neuropsychiatric disorder characterized by cognitive impairment and behavioral and psychological symptoms. The efficacy and tolerability of risperidone for treating dementia-associated psychological and behavioral disturbances were evaluated in a study of 135 patients aged 60-85 years with DSM-IV diagnoses of Alzheimer's disease. All were treated with risperidone at a starting dose of 0.5 mg once daily at bedtime. After the first 3 days of therapy the dosage was increased to 1 mg in 2 doses (morning and evening), then a further 0.5 mg was added (alternatively in the morning and in the evening) every three days until attenuation of the psychiatric symptoms. The response to treatment was evaluated for a period of 12 weeks by the Neuropsychiatric Inventory (NPI) and the Behavioral Pathology in Alzheimer's Disease Rating Scale (BEHAVE-AD). Both NPI and BEHAVE-AD were administered at the baseline visit, and after 4 and 12 weeks of therapy. Tolerability was assessed by the incidence of clinically evident side effects. The mean dose at endpoint was 1 mg/day of risperidone. The mean NPI score was 28.80+/-13.92 at start, 15.55+/-11.25 after 4 weeks and 8.30+/-7.00 at endpoint. The reduction in mean scores at 4 and 12 weeks was statistically significant in most of the Neuropsychiatric Inventory items, except for appetite disorders (p<0.0001). The mean BEHAVE-AD score was 20.44+/-3.92 at start, 13.50+/-11.39 after 4 weeks and 8.03+/-7.80 at endpoint. All the items showed a statistically significant improvement after 4 and 12 weeks (p<0.0001). The results were better at 12 than at 4 weeks. In our elderly patients with dementia low-dose risperidone was well tolerated and associated with reductions in BPSD, in particular agitation, aggression, irritability, delusions, sleep disorders, anxiety and phobias.