, Volume 22, Issue 9, pp 1335-1350

The Efficacy and Safety of Drug Treatments for Chronic Insomnia in Adults: A Meta-analysis of RCTs

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Hypnotics have a role in the management of acute insomnia; however, the efficacy and safety of pharmacological interventions in the management of chronic insomnia is unclear.


The objective of this paper is to conduct a systematic review of the efficacy and safety of drug treatments for chronic insomnia in adults.

Data Sources

Twenty-one electronic databases were searched, up to July 2006.

Study Selection

Randomized double-blind, placebo-controlled trials were eligible. Quality was assessed using the Jadad scale. Data were pooled using the random effects model.

Data Synthesis

One hundred and five studies were included in the review. Sleep onset latency, as measured by polysomnography, was significantly decreased for benzodiazepines (BDZ), (weighted mean difference: −10.0 minutes; 95% CI: −16.6, −3.4), non-benzodiazepines (non-BDZ) (−12.8 minutes; 95% CI: −16.9, −8.8) and antidepressants (ADP) (−7.0 minutes; 95% CI: −10.7, −3.3). Sleep onset latency assessed by sleep diaries was also improved (BDZ: −19.6 minutes; 95% CI: −23.9, −15.3; non-BDZ: −17.0 minutes; 95% CI: −20.0, −14.0; ADP: −12.2 minutes; 95% CI: −22.3, −2.2). Indirect comparisons between drug categories suggest BDZ and non-BDZ have a similar effect. All drug groups had a statistically significant higher risk of harm compared to placebo (BDZ: risk difference [RD]: 0.15; non-BDZ RD: 0.07; and ADP RD: 0.09), although the most commonly reported adverse events were minor. Indirect comparisons suggest that non-BDZ are safer than BDZ.


Benzodiazepines and non-benzodiazepines are effective treatments in the management of chronic insomnia, although they pose a risk of harm. There is also some evidence that antidepressants are effective and that they pose a risk of harm.