How Effective is Sleep Restriction Therapy?
In this brief report, I will be summarizing a scientific review of the effectiveness of Sleep Restriction Therapy (SRT). Readers of the SomniSkills Workbook are familiar with SRT, which is basically the same procedure as Sleep Episode Rationing (SER), described in Chapter 12. We call it Sleep Episode Rationing because we think it describes the procedure more accurately. As you read on, keep in mind that SRT and SER are interchangeable.
In the SomniSkills Workbook, we state that SER is “one the most powerful” techniques and “our favorite SomniSkill because it is so effective.” As you will see, the scientific review described below strongly supports our enthusiasm.
It is important to know that the reviewers only looked at Randomized Clinical Trials, which provide the strongest test of a treatment’s effectiveness. They searched the scientific literature and identified eight high-quality Randomized Clinical Trials. Together, these studies included 533 participants who suffered from insomnia. About half received SRT, while the other half were in a control group.
The reviewers examined whether people who received SRT slept better than those in the control group. Specifically, they looked at the following measures of sleep: Sleep Onset Latency (how long it took to fall asleep), Mid-Sleep Awakenings, Total Sleep Time, and Sleep Efficiency. Readers of the SomniSkills Workbook will be familiar with each of these sleep measures because they are included in the SomniLog. The reviewers also analyzed scores on the Insomnia Severity Index (ISI), a questionnaire designed to measure the overall severity of a person’s insomnia.
What did the reviewers find? They found “evidence of large treatment effects for SRT versus control” on all the measures listed above except Total Sleep Time. Moreover, they concluded that the benefits of SRT are “comparable in magnitude” to those reported for a full program of CBT-I. Those are impressive results!
Do these results mean you only have to practice Sleep Restriction Therapy (or Sleep Episode Rationing) and forget about the rest of CBT-I? Well, not quite. It turns out that nearly all of the studies had the participants practice Sleep Hygiene along with SRT. As readers know, the SomniSkills Workbook stresses the importance of Sleep Hygiene. Sleep Hygiene alone may not solve your sleep problems, but we think it is an essential component of an effective sleep program. Other techniques described in the SomniSkills Workbook are also likely to improve your sleep. Each person is different. You should try all the techniques recommended by the Formulator to see what works best for you. But based on the strength of the scientific evidence, you should definitely include Sleep Episode Rationing.
You may be wondering why SRT did not improve Total Sleep Time. This finding is not surprising. The goal of CBT-I is to improve the quality of sleep, not necessarily the quantity. The positive effect on Sleep Efficiency captures the improvement in sleep quality. Better Sleep Efficiency means that a person falls asleep faster and wakes up less often and for shorter periods of time. Better Sleep Efficiency leads to greater sleep satisfaction, which shows up in higher ISI scores.
In summary, Sleep Restriction Therapy, or as we call it, Sleep Episode Rationing, is certainly one of the most powerful techniques used in the SomniSkills Workbook. It is in your best interest to be aware of the power of this technique. At the same time, keep practicing Sleep Hygiene (and other CBT-I techniques that have helped you). In most cases, no technique alone will help enough, but several together should have a powerful positive effect on improving your sleep.
Maurer LF, Schneider J, Miller CB, Espie CA, Kyle SD. The clinical effects of sleep restriction therapy for insomnia: A meta-analysis of randomised controlled trials. Sleep Med Rev. 2021 Aug;58:101493. doi: 10.1016/j.smrv.2021.101493. Epub 2021 Apr 21. PMID: 33984745.