Double-blind donepezil-placebo crossover augmentation study of atypical antipsychotics in chronic, stable...

Thirteen outpatients with chronic but stable schizophrenia received donepezil and placebo augmentation of their maintenance antipsychotic medication regimen. Each subject received in a randomized, counterbalanced order 1) donepezil 5 mg for 6 weeks then donepezil 10 mg for six weeks and 2) placebo donepezil for 12 weeks. Serial ratings of the Positive and Negative Symptom Scale (PANSS) [Kay, S.R., Fiszbein, A., Opler, L.A., 1987. The positive and negative syndrome scale (PANSS) for schizophrenia. Schizophrenia Bulletin 13(2): 261-276] were performed by a trained rater blind to the donepezil order and condition: at baseline, 12 weeks and 24 weeks. On donepezil as compared to baseline or placebo, there was a significant improvement in PANSS negative scores (p=.018, n=13). These results are discussed with respect to other studies using cholinesterase inhibitors as an augmentation strategy in schizophrenia.