Conventional psychotropic medications may be used to treat behavioral disturbances and psychotic symptoms in patients with dementia and they are the drugs of choice for treating delusions and hallucinations. However the sensitivity to side effects in these patients often restricts the use of these agents (2, 3). Although, atypical antipsychotics have some advantages compared with conventional neuroleptics, they also are associated with side effects (5, 6).

Cholinesterase inhibitors (ChEIs) enhance neuronal transmission by increasing the availability of acetylcholine in muscarinic and nicotinic receptors. According to findings of some researchers ChEIs have psychotropic effects and may play an important role in controlling neuropsychiatric and behavioral disturbances in patients with Alzheimer's disease (7-10). These agents may also contribute to the management of other disorders with cholinergic system abnormalities and neuropsychiatric symptoms such as visual hallucinations (11).

Donepezil is a piperidine-based reversible, noncompetitive ChEI, which is indicated in the management of patients with Alzheimer's disease of mild to moderate severity (12-14). Preliminary observations suggest the possible value of ChEIs in the amelioration of psychotic symptoms in patients with dementia of the Alzheimer's type (DAT), dementia with Lewy bodies and patients suffering from Parkinson's disease (11-18).

The results of our study (18) indicate that the addition of donepezil to perphenazine resulted in qualitatively superior clinical gains compared to higher doses of neuroleptic therapy without donepezil.

The finding of the pilot study although impressive, stem from data regarding a rather small sample. The present (second) phase of the study will include a larger sample of patients. We now intend to examine 80 inpatients, aged 65-90 years old, suffering from DAT.