ABSTRACT
Objective : To investigate the clinical efficacy and degree of impact of placebo in the patients with primary insomnia. Methods ¡¤ Databases including PubMed, Cochrane, and Embase were searched. The Consolidated Standards of Reporting Trials (CONSORT) was used as a reference standard for enrollment and evaluation. The objective and subjective sleep assessment indicators were collected before and after pla-cebo treatment. Meta-analysis was performed using RevMan 5.3 and Comprehensive Meta-Analysis V2 softwares. Results ¡¤ A total of 17 arti-cles (18 studies) were included in the systematic review, and the total sample size was 1 980. These indicators were analyzed by age subgroups (adults and elderly adults). The objective indicators showed that the number of awaking was only statistically different in elderly adults group (P=0.043), while the latency period of sleep, wakefulness time after sleep onset and total sleep time were statistically different in both groups (P<0.05). The absolute value of total effect range was 0.153-0.414. Subjective indicators showed that the subjective total sleep time, subjective wakefulness time after sleep onset, and subjective number of awaking were statistically different in both groups (P<0.05), while subjective la-tency period of sleep was only statistically different in adults group (P=0.000). The absolute value of total effect range was 0.289-0.474. Con-clusion ¡¤ Placebo in the patients with primary insomnia can improve objective and subjective sleep assessment indicators, but the effect is small.