There's a strong link between anxiety and depression, and sleep problems, and it goes both ways

Good sleep is essential for our mental well-being. Just one night of disturbed sleep can leave us feeling cranky, flat, worried, or sad the next day. So it’s no surprise sleeping problems, like difficulty falling asleep, not getting enough sleep, or regularly disrupted sleep patterns, are associated with anxiety and depression.

Anxiety and depression, which can range from persistent worry and sadness to a diagnosed mental illness, are common and harmful.

Understanding the many interacting factors likely to cause and maintain these experiences is important, especially for developing effective prevention and treatment interventions. And there is growing recognition sleep problems may be a key factor.

Which problem comes first?

The majority of evidence suggests the relationship between sleep problems and anxiety and depression is strong and goes both ways.

This means sleep problems can lead to anxiety and depression, and vice versa. For example, worrying and feeling tense during bedtime can make it difficult to fall asleep, but having trouble falling asleep, and in turn not getting enough sleep, can also result in more anxiety.

Sleep disturbance, particularly insomnia, has been shown to follow anxiety and precede depression in some people, but it is also a common symptom of both disorders.

Trying to tease apart which problem comes first, in whom, and under what circumstances, is difficult. It may depend on when in life the problems occur. Emerging evidence shows sleep problems in adolescence might predict depression (and not the other way around). However, this pattern is not as strong in adults.

The specific type of sleep problem occurring may be of importance. For example, anxiety but not depression has been shown to predict excessive daytime sleepiness. Depression and anxiety also commonly occur together, which complicates the relationship.

Although the exact mechanisms that govern the sleep, anxiety and depression link are unclear, there is overlap in some of the underlying processes that are more generally related to sleep and emotions.

Some aspects of sleep, like the variability of a person’s sleep patterns and their impact on functioning and health, are still relatively unexplored. More research could help further our understanding of these mechanisms.

Sleep interventions

Disentangling which problems come first, and under what circumstances, is difficult. masha krasnova shabaeva/Flickr, CC BY

The good news is we have effective interventions for many sleep problems, like cognitive behaviour therapy for insomnia (CBT-I).

So there is the possibility that targeting sleep problems in people who are at risk of experiencing them – like teenagers, new mothers and people at risk for anxiety – will not only improve sleep but also lower their risk of developing anxiety and depression.

Online interventions have the potential to increase cost-effectiveness and accessibility of sleep programs. A recent study found a six-week online CBT-I program significantly improved both insomnia and depression symptoms. The program included sleep education and improving sleep thoughts and behaviours, and participants kept sleep diaries so they could receive feedback specific to their sleep patterns.

We’re conducting some research to improve and even prevent physical and mental health problems early in life by targeting sleep problems. Using smart phone and activity tracker technology will also help tailor mental health interventions in the future.

General improvements to sleep might be beneficial for a person with anxiety, depression, or both. Targeting one or more features common to two or more mental disorders, like sleep disturbance, is known as a “transdiagnostic” approach.

Interventions that target transdiagnostic risk factors for anxiety and depression, like excessive rumination, have already shown some success.

A good foundation

For many people, treating sleep problems before treating symptoms of anxiety and depression is less stigmatising and might encourage people to seek further help. Addressing sleep first can develop a good foundation for further treatment.

For example, people with a depressive disorder are less likely to respond to treatment and more likely to relapse if they have a sleep problem like insomnia.

Many of the skills learned in a sleep intervention, such as techniques for relaxation and reducing worry, can also be used to help with daytime symptoms of both anxiety and depression. And this is not to mention the physical benefits of getting a good night’s sleep!

If you’re concerned about your sleep or mental health, speak to a health care professional such as your GP. There are already a number of effective treatments for sleeping problems, depression and anxiety, and when one is treated, the other is likely to improve.

And with research in this area expanding, it’s only a matter of time before we find more ways to use sleep improvement interventions as a key tool to enhance our mental health.

Professor Emeritus John Trinder contributed to this article.