Stimulus control for insomnia: A systematic review and meta-analysis

Stimulus control (SC) is commonly viewed as an evidence-based treatment for insomnia, but it has not been evaluated comprehensively with modern review and meta-analytic techniques. The aim of the current study was thus to perform a systematic review and meta-analysis of trials that examine the efficacy of stimulus control for insomnia. A systematic search for eligible articles and dissertations was conducted in six online bibliographic databases. The 11 included studies, with the majority published between 1978 and 1998, were randomised controlled and experimental studies in adults, comparing stimulus control for insomnia with passive and active comparators and assessing insomnia symptoms as outcomes. A random effects model was used to determine the standardised mean difference Hedge's g at post-treatment and follow-up for three sleep diary measures: the number of awakenings, sleep onset latency, and total sleep time. A test for heterogeneity was conducted, forest plots were produced, the risk of publication bias was estimated, and the study quality was assessed. In the trials identified, stimulus control resulted in small to large improvements on sleep onset latency and total sleep time, relative to passive comparators (g = 0.38-0.85). Compared with active comparators, the improvements following stimulus control were negligible (g = 0.06-0.30). Although methodological uncertainties were observed in the included trials, stimulus control appears to be an efficacious treatment for insomnia when compared with passive comparators and with similar effects to active comparators. More robust studies are, however, warranted before stronger conclusions are possible to infer.