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Valerian for insomnia

Review
Results
Comment

Valerian is a herbal medicine that has been promoted for improving sleep. Does it work? A systematic review [1] of randomised trials provides very limited evidence for its effectiveness. It also demonstrates how clinical trials using different extracts, different outcomes, different subjects and different periods of use can produce a real mess of data.

Review


It sought randomised, placebo-controlled double-blind studies examining the effects of valerian preparations on sleep, without restriction of language up to May 1999. It used a range of electronic databases, including the Cochrane Library.

Results


Nine trials were identified. Three examined valerian over a period with consecutive use from 8 to 28 nights. Six looked at single night effects. Quality scores were generally two or less (using a score of up to five points), but were five in three trials.

One study with a quality score of five investigated 121 patients with non-organic insomnia over 28 days, with an ethanolic valerian extract of 600 mg daily. Clinical global impression was rated as good or very good by 66% of patients taking valerian compared with 26% taking placebo.

Two studies with quality scores of five investigated valerian over individual nights. One with eight volunteers with mild insomnia showed benefits from valerian over placebo. The other with 128 volunteers also showed benefits of valerian over placebo, especially in those who considered themselves habitually poor or irregular sleepers.

Comment


The problem is simple. There is limited evidence. Trials were often of short duration, used volunteers or patients with different criteria, and were usually methodologically poor. The positive aspect was that the three studies of high methodological quality all seemed to demonstrate some beneficial effects of valerian, though this still doesn't add up to anything like an overwhelming case. Some adverse effects were reported.

The methodological issues are beautifully dealt with, and this is another paper that could usefully be used to train people about clinical trials and systematic reviews.

The message for consumers is that the evidence on valerian for insomnia is sparse.

References:

  1. C Stevinson, E Ernst. Valerian for insomnia: a systematic review of randomized clinical trials. Sleep medicine 2000 1: 91-99.
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