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Sleep Disorders And Mental Illness: Causes And Consequences

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Sleep and mental health are closely related. If one is disrupted, the other deteriorates as well. It is not uncommon for mental illness to cause sleep problems, but sometimes sleep problems occur first and a mental illness occurs within a few months or years.

If a person treats mental illness with prescribed medications or other therapies but pays no attention to sleep problems, it is very likely their hard work will not pay off and the symptoms will quickly return. Insomnia and disrupted sleep worsen mood, attention, and can trigger a manic episode in bipolar people.

Learning about the importance of good sleep, techniques on how to relax and make the most out of nightly rest can greatly help a mentally ill person feel better and treat their illness more successfully.

What is a mental illness?

One definition of mental illness is: “a health condition that changes a person’s thinking, feelings, or behavior (or all three) and that causes the person distress and difficulty in functioning.” Depending on the severity of illness, it may cause slight or extreme difficulty in the daily functioning of a mentally ill person.

Some sources make a distinction between mental illness and mental disorder, but it is very hard to define them as different. Most sources, however, use the terms synonymously and so will we in this article.

What are the different types of mental illnesses?

These are the most common categories of mental illnesses:

  • Anxiety disorders (panic disorder, post-traumatic stress disorder (PTSD), obsessive-compulsive disorder, social anxiety)
  • Mood disorders (depression, bipolar disorder)
  • Neurodevelopmental (attention-deficit/hyperactivity disorder – ADHD)
  • Psychotic disorders (schizophrenia, delusional disorder, schizotypal personality disorder)
  • Dementia (Alzheimer’s, Parkinson’s, vascular dementia)
  • Eating disorders (binge-eating disorder, bulimia).

Mental illnesses and sleep disturbances

Each illness carries a high risk of sleep problems. Anxiety disorders usually prevent people from relaxing before bedtime with recurring stressful thoughts. They may also wake up frequently due to nightmares.

Mood disorders are closely related to sleep problems – sleep deprivation is likely to cause depression, and depression may cause insomnia. Those with bipolar disorder usually don’t sleep in the periods of mania and often complain of sleep problems when having episodes of depression.

ADHD has recently been reevaluated – when all of the findings are put together, they clearly show a close connection between ADHD and sleep disturbances. Proper treatment of sleep problems can greatly decrease ADHD symptoms and many authors today agree that ADHD might actually be caused by early sleep disturbances.

The majority of people with schizophrenia suffer from sleep problems; including insomnia, sleep apnea, and circadian rhythm problems (causing them to sleep and wake at very unusual times, and not get a sufficient amount of sleep).

Dementia is mainly related to circadian rhythm sleep disorders (CRSDs), which can cause insomnia and hypersomnia (sleepiness or falling asleep at inappropriate times). It mostly occurs with the elderly.

Even eating disorders are related to sleep problems. Insomnia and sleep deprivation are known to cause disbalance in hormones that regulate hunger and satiety (ghrelin and leptin). Insomnia can cause eating disorders, and eating disorders, in turn, can lead to poor, non-restorative sleep.

Sleep and mental health

Figure 1. Sleep and mental health – the vicious circle. Source: Voices and Choices

Do many people suffer from mental illnesses?

This chart below shows that about one in five people suffer from a mental illness in the US, and about one in four young people aged between 18-25 currently has a mental illness.

Mental Illness Among US Adults
Figure 2. Mental Illness Among US Adults. Source: Mental Illness. National Institute of Mental Health.

Women are more likely to have sleep problems and any type of mental illness, whereas men tend to be less affected. The majority of mentally ill people also have some kind of sleep disorder, and having a sleep disorder is often a symptom (or a cause) of another illness.

Mental illnesses and sleep problems – the relationship

A vast majority of people with mental illnesses also have one or more sleep disorders. And those who only suffer from sleep disorders are likely to develop a mental illness because the brain doesn’t get to process emotions and memories properly. We can’t deal with daily stresses, make good and rational decisions or understand life events correctly when we are chronically tired and our brain cells are overworked.

People with a mental illness, who also struggle to fall asleep or have other sleep problems also tend to spend most of their time in light sleep (due to stress or frequent awakenings). They miss out on REM (rapid eye movement) sleep and the restorative, deep sleep.

These two sleep stages are crucial for feeling rested and energized. Our emotions and memories are processed in REM sleep and in deep sleep and our brain and body go through regeneration and restoration. Human growth hormone is released, the immune system is strengthened and the brain refreshed. When we are deprived of either of those stages we suffer from a bad mood, low energy, forgetfulness, and bad overall health.

Anxiety disorders

Over half of people with anxiety disorders suffer from insomnia. Anxious thoughts and stressful events keep visiting them when they go to sleep, which keeps them awake for hours.

People with generalized anxiety disorder have long sleep latency (it takes a lot of time to fall asleep), and they wake up many times a night. They don’t lack REM sleep, but they do spend significantly less time in slow-wave sleep (deep sleep) and more time in light sleep.

Those who suffer from post-traumatic stress disorder (PTSD), like military veterans, also mainly suffer from insomnia – whether because anxiety keeps them up, or nightmares wake them up after which they can’t go back to sleep. Sometimes the cause of their insomnia is pain or tinnitus (loud buzzing noise in the ears).

PTSD sufferers may also have a periodic limb movement disorder (when their limbs move throughout sleep time) and sleep apnea (periodic breathing cessation, usually after loud snoring). All these problems result in excessive daytime sleepiness and fatigue.

Mood disorders

Depression may include insomnia or hypersomnia. About 90% of people with major depression suffer from some kind of sleep disorder. Apart from insomnia; they also have poor quality sleep, they may have nightmares, and are overly sleepy during the day.

On polysomnography, their sleep is unusual due to quickly reaching REM sleep and having more eye movements during this stage, more REM sleep time overall and short deep sleep.

Bipolar people typically have sleep disorders, although these disorders may vary depending on their episode – manic or depressive. In mania, they have a decreased need for sleep and may go for days without sleeping. A period of mania is usually followed by a period of depression, in which some have insomnia problems, but most complain about hypersomnia (they sleep for extremely long periods of time). However, even when they are not in any of the episodes, bipolar people usually experience non-restorative sleep. Polysomnography shows that they have similar sleep to that of depressed people.


ADHD is characterized by restless sleep, easy awakenings, and long sleep latency. However, it is usually difficult for them to wake up in the morning and shake off the morning grogginess. They can also suffer from obstructive sleep apnea, various sleep-related movement disorders, and circadian rhythm disorder. In children, ADHD and sleep deprivation have many of the same symptoms – inattentiveness, emotional instability, and hyperactiveness.

Schizophrenia and psychotic disorders

People with schizophrenia mostly have a delay in the circadian rhythm – they tend to be active at night and sleep through the day. They also don’t sleep long enough, and have an overall short slow-wave sleep – however, their slow waves have a lower amplitude compared to people who don’t have this illness.

They also tend to suffer from other illnesses like sleep apnea and periodic limb movement disorder.


People with different types of dementia generally experience insomnia problems, delayed circadian rhythm, hypersomnia, REM sleep behavior disorder (body movement during REM sleep), restless leg syndrome and sleep apnea.

They also experience ‘sundowning’, that is; irritability, anxiety, and increased confusion as the sun sets. This is probably related to their circadian rhythm (biological clock).

Eating disorders

If someone has a binge-eating disorder and has large meals late at night, their action will suppress melatonin (sleep-inducing hormone) and keep them awake for a long time. Big meals also negatively influence sleep quality. Poor sleep also leads to disbalance in hunger hormones and insulin resistance, which, paired with an increase in food intake, can easily lead to obesity or in more difficult cases, diabetes.

Improving sleep can improve mental health

It is difficult to break the vicious circle of poor sleep and mental health issues, but cognitive behavioral therapy (CBT) seems to be very useful in helping patients change their behavior and learn how to sleep better without any prescription drugs.

CBT consists of making a healthy sleep-wake schedule for an individual. First, you may be asked to keep a sleep diary and answer some questions about your sleep habits. Your clinician will look at the notes and recognize any non-recommendable behaviors that may be aggravating your condition. Then you will learn about good sleep habits and will be required to stick to them.

Even online CBT helps

A UK study was designed to test an online program called Sleepio – which is a website course that provides cognitive behavioral therapy online. Sleepio is also available for US residents. More than 150 adults with insomnia were chosen to complete a course of six sessions. The website gave them an animated therapist; but they could also browse articles, read through session content or access a community of users.

The sessions were so successful that not only their sleep kept improving weeks after the trial, but their depression and anxiety levels steadily decreased.

Sleep quality improvement after CBT

Figure 3. Sleep quality improvement after an online CBT course. Source: Sleepio

How to sleep better with a mental illness?

Taken that insomnia is the main problem with all mental illnesses, cognitive behavioral therapy for insomnia (CBT-I) is one thing everyone can try.

Minding your sleep hygiene should alleviate sleep problems. If your racing thoughts or worrying is what keeps you up, try to ‘declutter’ your mind prior to sleep. Avoid any disturbing thoughts and focus on relaxation.

Do progressive muscle relaxation – tense and relax one by one group of muscles. People with anxiety usually have muscle tension and relaxing them can help sleep come more quickly.

Technology is not your friend at night. Social media can increase anxiety and depression, while bright screen lights can delay your sleep by suppressing melatonin. If you already have a delayed circadian rhythm, avoid technology and LED lights hours before sleep time.

Don’t have coffee or alcohol in the evening – they are disturbing your sleep. Even though alcohol may be sedating and relaxing, it disrupts your sleep architecture. Refrain from big meals before bed. Instead, have a light snack and a cup of relaxing tea (chamomile, nettle, mint).

Expose yourself to bright light in the morning and afternoon and do physical exercise during the day.

Those suffering from depression or circadian rhythm problems can benefit from light therapy – having a strong, bright lightbox on at mornings and throughout the day. It improves mood and sleep. If paired with melatonin supplements in the evening, this therapy can quickly reset your body clock.

Set a strict sleep-wake schedule and stick to it. However hard it may be, try to follow the schedule. If you suffer from bipolar disorder; change your schedule slowly, because sleep deprivation can trigger a manic episode.

Another thing people with bipolar disorder should avoid is using a CPAP machine for obstructive sleep apnea. Although this machine greatly helps anyone else by providing constant air pressure, bipolar people can become manic.

The information on this website is not intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice. Read our full medical disclaimer.

Additional resources

  1. Krystal A. Psychiatric Disorders and Sleep. Neurologic clinics. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3493205/ Accessed April 27, 2019.
  2. Sleep and mental health. Harvard Health Publishing. https://www.health.harvard.edu/newsletter_article/sleep-and-mental-health Accessed April 27, 2019.
  3. Allison K. C, Spaeth A, et al. Sleep and Eating Disorders. Current Psychiatry Reports. https://www.ncbi.nlm.nih.gov/pubmed/27553980 Accessed April 27, 2019.
  4. Mental Illness. National Institute of Mental Health https://www.nimh.nih.gov/health/statistics/mental-illness.shtml Accessed April 27, 2019.
  5. Nutt D, Wilson S, et al. Sleep disorders as core symptoms of depression. Dialogues in Clinical Neuroscience. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3181883/ Accessed April 27, 2019.

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