Sleep and anxiety are linked in both directions. People who are anxious tend to sleep badly, and people who sleep badly tend to become more anxious. Patients often describe this as one problem, and it is easy to see why. Each one makes the other harder to treat on its own.
How sleep and anxiety influence each other
After a night of lost sleep, the amygdala, a brain area that detects threat, reacts more strongly to negative images. The prefrontal cortex, which helps regulate that reaction, communicates with the amygdala less effectively. The result is that ordinary events feel more threatening than they would after a full night of sleep.
Ben Simon and colleagues (2020) reported that sleep deprivation raised anxiety in healthy adults. They also found that more deep, slow-wave sleep was linked to lower anxiety the following morning. Most of this work used short experiments. It shows what one or two bad nights can do, not what years of poor sleep do.
The reverse direction is just as real. Anxiety keeps the body alert. At bedtime this shows up as racing thoughts, a faster heartbeat and tense muscles. Many people then start to worry about sleep itself, and that worry keeps them awake. A person who lies in bed calculating how many hours remain is usually more awake than before.
Jansson-Fröjmark and Lindblom (2008) followed adults from the general population in Sweden for one year. Insomnia at the start predicted anxiety and depression later on, and anxiety and depression at the start predicted insomnia later on. This was an observational study, so it shows a two-way association. It cannot prove that one problem directly causes the other.
Substances also play a role. Some people use cannabis to fall asleep or to calm down. A recent news report on research in mice described how cannabinoids may raise anxiety by changing the activity of specific neurons in the amygdala, especially under stress. Findings in mice do not transfer directly to people. They do fit what many patients report, which is that cannabis, particularly high-THC products, can leave them more anxious. Stopping regular use can also disturb sleep for a few weeks.
What treatment studies show
If poor sleep feeds anxiety, improving sleep should reduce anxiety, and trials support this. Scott and colleagues (2021) combined results from 65 randomized trials. They found that improving sleep led to better mental health, including lower anxiety. Most of the trials tested cognitive behavioral therapy for insomnia, and the effect on anxiety was moderate.
Cognitive behavioral therapy for insomnia, often shortened to CBT-I, is a structured program that usually runs for several weeks. It teaches a regular sleep schedule, limits the time spent awake in bed and changes unhelpful beliefs about sleep. The European insomnia guideline (Riemann et al., 2023) recommends it as the first treatment for chronic insomnia in adults. Sleeping pills are advised only for short periods.
Treating poor sleep is not something to postpone until the anxiety is under control. It is part of the treatment, and it can make the rest of the treatment work better.
This does not mean that better sleep alone will resolve an anxiety disorder. When anxiety is frequent, intense or interferes with work and relationships, it needs its own treatment, which may be psychotherapy, medication or both. Sleep is addressed alongside it. In my experience, patients are often relieved to hear that sleep is a legitimate target of treatment and not a side issue.
Practical steps for anxious nights
The most useful single habit is a fixed wake-up time, including weekends. A regular rising time makes the body feel sleepy at a more predictable hour. Going to bed earlier to make up for a bad night usually backfires, because extra time in bed tends to mean more time awake.
If you have not fallen asleep after about twenty minutes, get up. Sit in dim light and do something quiet and dull, such as reading a printed book. Return to bed when you feel sleepy. This teaches the brain to connect the bed with sleep and not with worry. Turn the clock face away, since checking the time increases tension.
Set aside ten to fifteen minutes earlier in the evening to write down worries and one possible next step for each. Writing does not solve the problems, but it gives the mind less reason to bring them up at midnight. Do this at a table, not in bed.
Watch what you consume. Caffeine can stay in the body for six to eight hours, so many people sleep better if they stop by noon or early afternoon. Alcohol may help you fall asleep but it fragments sleep later in the night and can increase anxiety the next day. The same caution applies to cannabis, especially in people who already feel anxious.
Seek professional help if trouble sleeping occurs at least three nights a week and lasts three months, which is the usual threshold for chronic insomnia. Do not wait that long if anxiety is affecting daily life, if you wake in panic, or if you have thoughts of harming yourself. In the United States you can call or text 988 at any time.
Before the appointment, keep a simple sleep diary for two weeks. Note when you went to bed, when you woke, how often you woke during the night, and what you drank and took before bed. A clinician can use this record to see whether sleep, anxiety or a substance is the main driver, and to choose the right treatment.
References
- Ben Simon, E., Rossi, A., Harvey, A. G., & Walker, M. P. (2020). Overanxious and underslept. Nature Human Behaviour, 4(1), 100–110.
- Jansson-Fröjmark, M., & Lindblom, K. (2008). A bidirectional relationship between anxiety and depression, and insomnia? A prospective study in the general population. Journal of Psychosomatic Research, 64(4), 443–449.
- Scott, A. J., Webb, T. L., Martyn-St James, M., Rowse, G., & Weich, S. (2021). Improving sleep quality leads to better mental health: A meta-analysis of randomised controlled trials. Sleep Medicine Reviews, 60, 101556.
- Riemann, D., Espie, C. A., Altena, E., Arnardottir, E. S., Baglioni, C., Bassetti, C. L. A., et al. (2023). The European Insomnia Guideline: An update on the diagnosis and treatment of insomnia 2023. Journal of Sleep Research, 32(6), e14035.
