Chronic insomnia: effects of tryptophan, flurazepam, secobarbital, and placebo

This study compared the effects of l-tryptophan (1 g), secobarbital (100 mg), flurazepam (30 mg), and placebo on sleep in 96 serious insomniacs. Each treatment was given nightly for 7 nights in a separate-group design. Outcome measures were subjective estimates by subjects of a number of sleep parameters during the week of treatment and for 1 week after, and an overall evaluation made by subjects and investigators at the end of the 2 weeks. During the treatment week, flurazepam produced significant improvement on several sleep measures compared to placebo, while tryptophan and secobarbital did not. Flurazepam and secobarbital produced withdrawal symptoms during the post-treatment week, while tryptophan and placebo did not. Sleep latency was not significantly improved by tryptophan during the treatment week, but continued to improve during the post-treatment week, resulting in a significant difference between tryptophan and baseline in week 2.