Effect of donepezil added to atypical antipsychotics on cognition in patients with schizophrenia: An open-label trial

Background: Despite the beneficial effects of atypical antipsychotics on cognition, many schizophrenic patients continue to suffer from cognitive impairment. Postmortem findings suggest that altered cholinergic activity is involved in cognitive impairment in schizophrenia. Objective: This study investigated whether adjunctive donepezil added to atypical antipsychotics can improve cognition in schizophrenic patients. Method: We conducted an open-label trial of donepezil, at doses of up to 10 mg/day for 12 weeks, added to ongoing atypical antipsychotics in 28 stable schizophrenic patients. At baseline and 12 weeks, the patients were evaluated using the Positive and Negative Syndrome Scale (PANSS), Schizophrenia Cognition Rating Scale (SCoRS), and Computerized Neurocognitive Function Test (CNT). Results: Donepezil treatment resulted in significant improvements in attention, memory, psychomotor speed, and mental set-shifting ability. Conclusions: Adjunctive treatment with donepezil improves cognition in patients with schizophrenia who are stabilized on atypical antipsychotics. Further studies controlling for smoking, age, and severity of cognitive impairment of the participants are needed.