Effects of cholinesterase inhibitors on behavioural disturbances in Alzheimer's disease: a systematic review.

Behavioural disturbances, also termed neuropsychiatric symptoms, are a frequent clinical feature of dementia in Alzheimer's disease (AD). Many AD patients receive treatment with cholinesterase inhibitors (ChEIs). This review examines the evidence for behavioural effects of the four ChEIs that have been approved for the treatment of mild to moderate AD. A systematic search of the MEDLINE and EMBASE databases and the Cochrane Library was conducted to identify clinical trials that had a randomised, placebo-controlled design. Studies were included in this review if they enrolled patients who had received a diagnosis of probable AD, involved at least one ChEI, and used an appropriate instrument for the assessment of behavioural disturbances. Fourteen studies that matched the selection criteria were identified in the literature. A statistically significant difference between active treatment and placebo with regard to behavioural symptoms was observed in three of the 14 studies. Treatment effects varied between 2.0 and 6.2 points on the Neuropsychiatric Inventory. ChEIs have moderate effects when used as a blanket treatment for the cluster of behavioural disturbances in AD. With regard to the limitations of the available trials, and in view of the risks that are associated with the use of atypical antipsychotics, the potential of ChEIs for the management of specific neuropsychiatric symptoms in patients with AD should be explored in further studies.