Antidepressant Use for Insomnia: Is It Effective?

Low-dose doxepin and trazodone may provide small improvement in sleep quality
Low-dose doxepin and trazodone may provide small improvement in sleep quality

Despite the widespread use of antidepressants for treating insomnia, the evidence for their effectiveness remains limited, according to a new review published in the Cochrane Library.

For this study, researchers identified 23 randomized controlled trials that included a total of 2806 adults with a primary diagnosis of insomnia to examine the relationship between antidepressant use and insomnia improvement. The studies included for analysis compared antidepressant monotherapy (at any dose) with placebo, other insomnia drugs (e.g. benzodiazepines), other antidepressants, waiting list control, or "treatment as usual."

Three of the studies compared selective serotonin reuptake inhibitors (SSRIs) with placebo (N=135).  Improvements in subjective sleep measures at 6 weeks (N=60; P=.03) and 12 weeks (N=27; P<.001) were observed with paroxetine in 2 of the studies, however no differences were seen in the fluoxetine study (low quality evidence). 

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Tricyclic antidepressants (TCA) were compared with placebo in 6 studies (5 with doxepin and 1 with trimipramine; N=812). Pooled results from 4 of these studies indicated a moderate improvement in subjective sleep quality over placebo (standardized mean difference [SMD] -0.39, 95% CI, -0.56 to -0.21). Additionally, TCAs were associated with improved sleep efficiency and increased sleep time, but had very little impact on sleep latency.

With regard to other antidepressants, 3 studies (370 patients) involving trazodone were pooled and indicated a moderate improvement in subjective sleep outcomes (MD -0.34, 95% CI -0.66 to -0.02), however 2 studies which measured polysomnography found little or no difference in sleep efficiency (N=169; MD 1.38 percentage points, 95% CI -2.87 to 5.63).

Most of the studies were small and had short follow-up times which limited the findings. The authors stated that there was too little data regarding SSRIs to draw any conclusions but low-dose doxepin and trazodone use may potentially offer a small improvement in sleep quality. There was also no evidence to support the use of amitriptyline, or for long-term use of antidepressants for insomnia. Due to limited reporting, the authors were unable to make conclusions on tolerability and safety.

"High quality trials of antidepressants for insomnia are needed to provide better evidence to inform clinical practice," the authors concluded. "Additionally, health professionals and patients should be made aware of the current paucity of evidence for antidepressants commonly used for insomnia management."

For more information visit Cochranelibrary.com.