Insomnia demystified: a sleep psychologist’s guide (Part 3)

Insomnia demystified: a sleep psychologist’s guide (Part 3)

How cognitive-behavioural therapy for insomnia (CBT-I) works: stimulus control, sleep restriction and cognitive restructuring.

How cognitive-behavioural therapy for insomnia (CBT-I) works: stimulus control, sleep restriction and cognitive restructuring.

Dr Julian Lim, PhD

Lead Sleep Psychologist

Published 1 Dec 2023 · Updated 17 Oct 2026 · 4 min read

Illustration of a tangled purple line that straightens into a smooth line ending at a soft light.

This is the third in a series of four articles explaining how chronic insomnia develops and what you can do to get relief from it.

If you are struggling with getting a good night’s sleep, you’re (unfortunately) in good company. Insomnia is a very common problem in developed countries. In the previous article in this series, I explained how chronic insomnia develops over time. In this installment, we’ll get some insights into how psychologists work on insomnia using cognitive-behavioural therapy (CBT).

Why psychotherapy?

In the first instance, it may appear odd to some people to use psychotherapy to solve what seems to be a physiological problem. If a natural biological process has gone wrong, it seems logical to use a medical approach to try and fix it.

Many of the clients I see have indeed gone to a GP or psychiatrist as their first port of call. Most of them were prescribed sleeping pills. These can be a source of great relief if you’re desperate for a night of sleep, but the problem with trying to fix insomnia with medication is that it often comes back when the pills run out.

As we learned last time, chronic insomnia has a substantial psychological component. Even though it can feel like something has gone wrong with the body, the source of sleeplessness is really in the mind. Worrying about sleep and changing one’s sleeping habits to try and get more of it creates a vicious cycle that can perpetuate insomnia over months or even years. Unlearning these habits is the key to recovery while sedation with drugs often only provides temporary relief.

How does cognitive-behavioural therapy for insomnia (CBT-I) work?

CBT-I has several components, and a skilled psychologist will know how to prioritize these to maximize your chance of success. Three of the core components of the therapy are stimulus control, sleep restriction, and cognitive restructuring.

1. Stimulus control

Stimulus control is at the heart of CBT-I and is often its most important element. Despite its slightly exotic-sounding name, it is in essence a very simple concept – your bed should be reserved for just two activities: sleep and sex.

Insomnia sufferers often spend many hours lying awake in bed waiting for sleep to come. Many of them also use the bed for other activities while winding down for the night, for example, reading, watching TV, or using a laptop. All these behaviours reinforce an association between the bedroom and wakefulness (and often anxiety as well). Not the best conditions for restful sleep.

In therapy, I develop a strategy with my clients for eliminating the wakeful and restless periods in bed. We work together on figuring out another place in the home they can retreat to when sleep is not coming, and relaxing activities they can engage in while waiting for sleepiness to arise. We also talk about recognizing these physical signs of sleepiness so that they know when to go back to bed. Finally, we troubleshoot some of the problems that they frequently have in sticking to this routine to maximize the probability of success.

2. Sleep restriction

Sleep restriction is a counterintuitive but powerful strategy for getting the sleep patterns of an insomnia sufferer back on track. Being sleep-deprived ramps up the urge to fall asleep, making it much easier to fall asleep quickly and stay asleep for the duration of the time in bed – the perfect antidote for the usual tossing and turning that one suffers through during insomnia.

“Quality over quantity” is the principle in the short term. It’s better to have six hours of sleep in a concentrated window rather than the same amount fragmented over nine or ten hours.

For many people, sleep restriction is the toughest part of CBT-I: no one likes to hear that they are being prescribed less opportunity to sleep when they are looking for help getting more of it! The good news is that this sacrifice in the short run is the foundation for building long-term gains. There is even a bit of an upside: sleep restriction can give you the chance to catch up on fun activities you normally don’t have time for!

3. Cognitive restructuring

Another useful tool in the CBT-I psychologist’s kit is knowing how to challenge the unhelpful thoughts or beliefs that insomnia sufferers can have about sleep (I mentioned a few of these in the previous article).

I like to explain this exercise to clients as putting them in the role of junior scientists. Their job in this role is to test their own beliefs about sleep, trying to find evidence for and against them.

For example, if someone believes that having a bad night of sleep will be devastating for work performance the next day, we might keep records of what they accomplished after bad (and good) nights of sleep to get at the truth. In doing this exercise, many people start to realize that poor sleep might have some negative effect on productivity, but that this is far from catastrophic. Imagined consequences are often quite different from reality.

In combination, stimulus control, sleep restriction and cognitive restructuring, together with education on good sleep hygiene are a potent remedy for chronic insomnia. It commonly takes just 4 weeks of disciplined adherence to the therapy before clients start seeing results.

If you know of someone suffering from long-term sleep difficulties, help is at hand in Singapore through trained providers of CBT-I. For more information, do get in touch and let us know how we can be of assistance!

1:1 THERAPY

Work one-to-one with a sleep psychologist

CBT-I and mindfulness-based therapy, in person or online. Initial consultation from S$310.

This article is general information, not medical advice. Talk to your doctor before changing any medication.

Sources

ABOUT THE AUTHOR

Dr Julian Lim, PhD

Dr Julian Lim, PhD is Somnus’s Lead Sleep Psychologist and a co-founder. A former Assistant Professor at Duke-NUS and NUS, he has published more than 40 peer-reviewed papers.

ABOUT THE AUTHOR

Dr Julian Lim, PhD

Dr Julian Lim, PhD is Somnus’s Lead Sleep Psychologist and a co-founder. A former Assistant Professor at Duke-NUS and NUS, he has published more than 40 peer-reviewed papers.

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Start with a free 15-minute call.

Reading about sleep is a good start. If your nights still aren’t improving, tell us a little about them and we’ll arrange your call.

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GET STARTED

Start with a free 15-minute call.

Reading about sleep is a good start. If your nights still aren’t improving, tell us a little about them and we’ll arrange your call.

Enter your first name.

Enter your last name.

Enter an email address like name@example.com.

We’ll call or WhatsApp you on this number.

Enter a mobile number we can call or WhatsApp.

No need for medical details. We’ll ask on the call.

Keep it under 500 characters.

Your request didn’t send. Please try again, or WhatsApp us on +65 8920 0930.

By sending this, you agree to us using your details to arrange your call. See our Privacy Policy.

© 2026 Somnus Sleep Wellness Pte Ltd. All rights reserved.

As featured in The Straits Times, CNA and The Business Times.

Dr Julian Lim, PhD holds a doctorate in Psychology from the University of Pennsylvania. It is an academic qualification, not a medical or dental qualification.

© 2026 Somnus Sleep Wellness Pte Ltd. All rights reserved.

As featured in The Straits Times, CNA and The Business Times.

Dr Julian Lim, PhD holds a doctorate in Psychology from the University of Pennsylvania. It is an academic qualification, not a medical or dental qualification.

© 2026 Somnus Sleep Wellness Pte Ltd. All rights reserved.

As featured in The Straits Times, CNA and The Business Times.

Dr Julian Lim, PhD holds a doctorate in Psychology from the University of Pennsylvania. It is an academic qualification, not a medical or dental qualification.