Statement: The the primary trial placebo group had a over 10% higher mean retention than the donepezil hydrochloride PO QD group.
Primary_evidence: Outcome Measurement:    Retention   Retention is the percentage of participants who stay in the study for 24 weeks.   Time frame: 24 Weeks Results 1:    Arm/Group Title: Arm I   Arm/Group Description: Patients receive donepezil hydrochloride PO QD.   donepezil hydrochloride: Given PO   Overall Number of Participants Analyzed: 31   Mean (Standard Error)   Unit of Measure: percentage of participants  71.0         (8.3) Results 2:    Arm/Group Title: Arm II   Arm/Group Description: Patients receive placebo PO QD.   Placebo: Given PO   Overall Number of Participants Analyzed: 31   Mean (Standard Error)   Unit of Measure: percentage of participants  80.7         (7.2)