A comparison of placebo and no-treatment during a hypnotic clinical trial

Objective: Sleep parameters commonly improve during placebo treatment in insomnia clinical trials. We examined whether the improvement seen with placebo was related to taking pills or other non-specific factors. Method: 95 insomniacs took either a placebo pill (pill⁺) or no pill (pill^-) on nights of their choosing over 12 weeks. Results: Pills were consumed on about half of the nights. Consistent improvement was seen with reduced reported sleep latency, wakefulness after sleep onset, number of awakenings, and total sleep time over the 12 weeks for both the pill⁺ and pill^- condition. A difference between pill⁺ and pill^- was detected only for total sleep time, and this difference favored pill⁺. Conclusions: This study suggests that improvement seen during placebo treatment is more related to non-specific factors of participating in clinical trial than to pill taking behavior.