Meta-analysis of benzodiazepine use in the treatment of insomnia

Objective: To systematically review the benefits and risks associated with the use of benzodiazepines to treat insomnia in adults. Data sources: MEDLINE and the Cochrane Controlled Trials Registry were sear ched for English-language articles published from 1966 to December 1998 tha t described randomized controlled trials of benzodiazepines for the treatme nt of insomnia. Key words included "benzodiazepines" (exploded), "randomize d controlled trial" and "insomnia." Bibliographies of relevant articles wer e reviewed for additional studies and manufacturers of benzodiazepines were asked to submit additional randomized controlled trial reports not in the literature. Study selection: Articles were considered for the meta-analysis if they wer e randomized controlled trials involving patients with insomnia and compare d a benzodiazepine with placebo or another active agent. Of the 89 trials o riginally identified, 45 met our criteria, representing a total of 2672 pat ients. Data extraction: Data were extracted regarding the participants, the settin g, details of the intervention, the outcomes (including adverse effects) an d the methodologic quality of the studies. Data synthesis: The meta-analyses of sleep records indicated that, when com pared with placebo, benzodiazepines decreased sleep latency by 4.2 minutes (non significant; 95% confidence interval [CI] -0.7 to 9.2) and significant ly increased total sleep duration by 61.8 minutes (95% CI 37.4 to 86.2) Pat ient-reported outcomes were more optimistic for sleep latency; those random ized to benzodiazepine treatment estimated a sleep latency decrease of 14.3 minutes (95% CI 10.6 to 18.0). Although more patients receiving benzodiaze pine treatment reported adverse effects, especially daytime drowsiness and dizziness or lightheadedness (common odds ratio 1.8, 95% CI 1.4 to 2.4), dr opout rates for the benzodiazepine and placebo groups were similar. Cogniti ve function decline including memory impairment was reported in several of the studies. Zopiclone was not found to be superior to benzodiazepines on a ny of the outcome measures examined. Interpretation: The use of benzodiazepines in the treatment of insomnia is associated with an increase in sleep duration, but this is countered by a n umber of adverse effects. Additional studies evaluating the efficacy of non pharmacological interventions would be valuable.