Study design
agitation, insomnia
BLIND
All eligible patients were randomly allocated to four groups: (i) benzoate 500 group (fixed dose at 500 mg/day); (ii) benzoate 750 group (500 mg/day for the first 4 weeks, 750 mg/day from the fifth week to the 24th week); (iii) benzoate 1000 group (500 mg/day for the first 4 weeks, 1000 mg/day from the fifth week to the 24th week); and (iv) placebo group. Two hundred and fifty milligrams of sodium benzoate or placebo were packed with identical capsules provided in coded containers. Patients were randomized through a computer‐generated randomization table to receive placebo or benzoate treatment in a 1:1:1:1 ratio. Non‐blinded pharmacists dispensed appropriate medication for treatment according to the randomization table. Patients, caregivers, and investigators, except the investigational pharmacist, were all blind to the assignment. Patient medical adherence and safety were closely monitored by caregivers and research physicians, and pill‐counting was monitored by the study staff.During the study, limited use of benzodiazepines (up to 4‐mg/day lorazepam) was allowed as concomitant medication for agitation or insomnia. In case of side‐effect intolerance or clinical worsening, the patients could be withdrawn earlier.