To the Editor: We have some concerns about the design of the randomized controlled trial in which Dr Morin and colleagues1 studied the effect of CBT, singly and combined with medication, for persistent insomnia. First, the placebo effect was not investigated. At the first stage, placebo medication was not administered in the group that received only CBT for the first 6 weeks, so the specific effects of zolpidem could not be assessed. Regarding the second stage, according to the expectancy theory of placebo effects,2 patients who received CBT plus daily zolpidem for 6 weeks and extended CBT alone for 6 months may have anticipated that, if after the first 6 weeks' treatment their insomnia had been controlled well, they could maintain the outcomes without the pills. The group that received CBT plus daily zolpidem for 6 weeks and extended CBT plus zolpidem as needed for 6 months may have ascribed good outcomes to the medicine, which may influence the results of the trial. Furthermore, during the acute treatment, combination of zolpidem and placebo may achieve the same or better results compared with using zolpidem alone,2,3 reducing the overall exposure to zolpidem.
Yang Y, Miao D, Sun Y. Cognitive Behavioral Therapy Alone and With Medication for Persistent Insomnia. JAMA. 2009;302(10):1053-1054. doi:10.1001/jama.2009.1283