The counterintuitive insomnia fix: spend less time in bed

Insomnia is one of the most common sleep complaints in adults, and behavioural treatments are usually delivered as multi-part packages that can be time-consuming to access and complete. Sleep restriction therapy is one component of those packages, and it works by deliberately limiting the window a person spends in bed. Whether that single component is effective when delivered on its own is a practical question, because a simpler, stripped-down therapy would be easier to offer at scale. This analysis set out to pool the randomised evidence on single-component sleep restriction therapy for adult insomnia and settle how well it performs by itself.

The researchers searched six databases, including PubMed, EMBASE, OVID, Scopus, the Cochrane Library and Web of Science, for randomised controlled trials published up to 31 July 2024. Study quality was assessed with the Cochrane Collaboration's tool, and results were pooled using models chosen according to how much the trials varied from one another. Nine studies with 1239 participants met the inclusion criteria. Outcomes included insomnia severity, sleep onset latency, sleep efficiency, sleep quality, wake time after sleep onset and total sleep time, measured by sleep diaries and in some cases wrist-worn activity monitors, both at the end of treatment and at longer follow-up.

At the end of treatment, sleep restriction therapy beat control conditions on insomnia severity, on the minutes taken to fall asleep as recorded by diary or activity monitor, and on diary-rated sleep quality. It also improved sleep efficiency, meaning the share of time in bed actually spent asleep, and reduced the minutes spent awake during the night. As an expected consequence of how the therapy works, total sleep time fell significantly compared with control. At longer follow-up, the benefits for insomnia severity, sleep efficiency and night-time waking were sustained, but the advantage in falling asleep faster was no longer present.

The authors conclude that the results confirm the effectiveness of sleep restriction therapy for adult insomnia when used as a standalone treatment, which strengthens the case that this single component carries much of the therapeutic weight. That extends earlier thinking, in which sleep restriction was mainly studied inside larger behavioural packages. The picture over the long term is less tidy, since some benefits persisted while the effect on sleep onset latency did not, and the authors call for further studies on durability. How the initial reduction in total sleep time plays out over months also remains an open question in this analysis.

For anyone who struggles with insomnia, this is a reason to take the seemingly backwards idea of restricting time in bed seriously, since the pooled evidence across nine trials favours it on nearly every sleep measure that matters. It is also a reason not to be alarmed that total sleep initially shrinks, because that reduction is the mechanism doing its work rather than a side effect. The fading of the faster-sleep-onset benefit over follow-up is worth knowing too: the approach looks well supported in the short term, while its lasting effects are still being worked out.