Two analysis study populations will be considered in this study, a modified intent-to-treat (mITT) population and a clinically evaluable population. The mITT sample will include individuals deemed eligible for study participation based on the Screening Assessment; who are randomized to study treatment; who are assessed using HVLT-R at the Baseline Visit; and who receive at least one dose of study treatment. The analysis on the mITT sample will be considered the primary analysis. The clinically evaluable population will be a secondary analysis and called the per-protocol population. Inclusion in the per-protocol population will require at least eight weeks of double-blind study treatment, data on primary outcomes at the Outcome Assessment, at least 80% treatment adherence as determined by pill counts on returned blister packs, and no major protocol violations. For the primary outcome HVLT-R Total Trails 1-3, the primary analysis will examine the donepezil effect measured at week 10 using a general linear model (GLM). Because the secondary outcomes are all approximately continuous-type, they will be tested using similar GLM procedures as stated above to estimate and test the effects of donepezil. Additionally, general linear mixed models will be performed to compare the data in the drug and placebo groups, accounting for center effect and other covariables. Side effects data in the form of the frequency of events (drug related/by severity/serious) will be evaluated using a Mantel-Haenszel test. Exact binomial confidence intervals for side effect event frequencies also will be generated.