Assessing the prospect of donepezil in improving cognitive impairment in patients with schizophrenia.

INTRODUCTION: Even though cognitive impairment is manifested in almost all patients with schizophrenia, the Clinical Antipsychotic Trials for Intervention Effectiveness (CATIE) study showed no significant difference between first- and second-generation psychotropic drugs in improving cognitive abilities. Discovering new drugs that can improve impaired cognition, thus, is an attractive treatment target for patients with schizophrenia. AREAS COVERED: This article briefly reviews about donepezil, a highly selective (IC(50) = 6.7 nM) centrally acting reversible acetylcholinesterase inhibitor that has been approved by FDA for treating cognitive deficit states such as in Alzheimer's disease and its uses in clinical trials for the treatment of schizophrenia. The literature search included PubMed and Cochrane library with the following words: donepezil, schizophrenia and cognitive impairments. EXPERT OPINION: The results of several clinical trials utilizing donepezil as an adjunct to second-generation antipsychotic drugs targeting cognitive deficits in schizophrenia subjects have been disappointing and would not lead clinicians to consider this as a potential treatment option. While longer randomized controlled trials, increase dosage and selected groups of patients at different stage of cognitive impairment may provide a better understanding of the potential for this drug in addressing cognitive deficits, results to date have not been encouraging.