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The Importance of Sleep for Maintaining Optimal Mental Health
Cognitive Health

The Importance of Sleep for Maintaining Optimal Mental Health

Most people have first-hand experience of how a poor night’s sleep can negatively affect their mental and emotional health. Poor quality sleep is a risk factor for depression, anxiety, bipolar disorder, and other mental health conditions.

Living with a mental health disorder can also increase your risk of sleep disorders. Personal experience supports a link between sleep and mental health; researchers are working to better understand the connection.

In one study, over a third of adults reported having insomnia. Other studies reported percentages as high as 50% to 60%. This common sleep disorder is diagnosed when you have distress or impairment from lack of sleep, and it must occur for a minimum of three nights per week for at least three months and not be attributed to another medical or mental health condition.1

According to the Centers for Disease Control and Prevention, about one-third of all adults do not get the recommended amount of sleep each night. Nearly one in five U.S. adults lives with a mental illness, and nearly half of all Americans will be diagnosed with a mental illness or disorder at some point in their lives.2 Sleep disorders and mental health conditions are both public health concerns that significantly impact individuals and society.3

How does sleep affect your mental health?

While it is well established that mental health conditions increase the risk of sleep disorders, there is evidence that sleeping problems can contribute to new mental health disorders or worsen existing ones.2,3  In a large population-based study of U.S. adults, researchers found that inadequate sleep significantly increased the odds of having mental distress, even after controlling for other variables.3

Insomnia and a lack of sleep can increase the likelihood and severity of mental health and emotional conditions, such as:

About half of individuals with major depressive disorder experience insomnia, and a significant proportion (10–20%) of those with insomnia also have major depressive disorder. In one study, researchers found that treating insomnia improved depressive symptoms.4

How does sleep influence brain function and mental health?

Sleep is an active process. Your brain activity fluctuates through the night as you pass through different sleep stages. These stages are divided into rapid eye movement sleep (REM) and non-REM sleep. Non-REM sleep is subdivided into four stages. The first two are characterized as light sleep, and the second two are deep sleep. Throughout the night, your brain passes through four or five sleep cycles.5

Stage 1: This short stage at the beginning of the night is when you transition into sleep.

Stage 2: Most of your sleep time is in stage 2. During this stage, your body’s temperature drops, and your heartbeat, respiratory rate, and brainwaves slow.

Stages 3–4: Deep or slow-wave sleep is when the brain is less responsive to environmental cues and is associated with restoring energy and physical repair. It is also a time to process information and memories, allowing the brain to discard useless information and consolidate new information. Deep non-REM sleep comprises about 10% to 12% of your total sleep time and is more likely to occur in earlier sleep cycles.

REM sleep: REM is associated with vivid dreams and is essential for processing and consolidating memories. It comprises about 20% to 25% of sleep time. REM sleep helps your brain process emotional information, stabilizes learning, and is more common in later sleep cycles.

Sleep is also a time for clearing waste products from the brain that may have accumulated throughout the day.

Deep sleep (non-REM and REM) is essential for the brain to adapt. Neuroplasticity refers to the brain’s capacity to restructure in reaction to various internal and external stimuli, including experiences, behaviors, thought patterns, and responses. Neuroplastic capacities in the brain are reduced during wakefulness and restored during uninterrupted sleep.6 Brain health, mental health, and sleep are interconnected.


How well do you sleep?

The Centers for Disease Control and Prevention and the American Academy of Sleep Medicine emphasize the importance of getting at least seven hours of sleep each night. One way to self-assess your sleep is to take a sleep assessment, such as the Pittsburgh Sleep Quality Index questionnaire (PSQI).

This 19-item clinically validated questionnaire asks about sleep habits, such as:

  • When do you go to bed?
  • How long does it take to fall asleep?
  • When do you get up in the morning?
  • How many hours of sleep do you get each night?

The next section of the questionnaire asks about environmental factors and health conditions that may keep you awake at night. Additional optional questions are provided for your sleeping partner. Scoring instructions for the assessment are provided.7

The questionnaire is designed to assess the following areas:7

  • Subjective sleep quality
  • Sleep latency
  • Sleep duration
  • Habitual sleep efficiency
  • Sleep disturbances
  • Use of sleeping medications
  • Daytime dysfunction

The PSQI assessment is only part of a comprehensive sleep evaluation. Your doctor may also suggest completing a sleep diary and may request diagnostic tests such as an overnight sleep study (polysomnography).

A woman with depression

How can I sleep better for my mental health?

Sleep habits that improve sleep hygiene and can improve your sleep quality include:

  • Avoid caffeine, nicotine, and alcohol use before bedtime.
  • Avoid heavy meals later in the day, especially if you are prone to heartburn.
  • Establish a bedtime routine that does not involve screen exposure in the hour before sleep.
  • Hydrate earlier in the day to reduce nighttime awakenings.
  • If you are concerned that you have obstructive sleep apnea or other sleep disorders, discuss your concerns with your doctor.
  • Safely expose yourself to sunlight first thing in the morning to help regulate circadian rhythms.
  • Set a sleep schedule and follow it even on the weekends.
  • Sleep in a dark, cool room.
  • Reserve the use of the bedroom for sleep and sex.
  • Use meditation, yoga, or deep-breathing exercises to manage stress.
  • Incorporate physical activity into your daily schedule.

Adopting healthy sleep habits can improve sleep quality for some people. However, if you have chronic insomnia or are concerned that you may have a mental health disorder or poor sleep is negatively impacting your mental or emotional health, contact your doctor and ask for a sleep assessment.

Depending on the results of your sleep study and medical history, your doctor may suggest cognitive-behavioral therapy, medications, or another treatment to improve your sleep quality.

A strong association exists between sleep quality and the risk of mental health conditions.8. Before attributing your symptoms to a lack of sleep, talk to your doctor to see if you have any medical conditions or nutritional deficiencies that may be contributing to your sleep difficulties and mental health symptoms. For example, vitamin B12 deficiency affects about 6% of people under the age of 60 and nearly one in five people over the age of 60. Vitamin B12 deficiency symptoms are nonspecific and include fatigue, depression, and neurologic symptoms.9

Get started today with a monthly subscription of Vitamin B12.


While we strive to always provide accurate, current, and safe advice in all of our articles and guides, it’s important to stress that they are no substitute for medical advice from a doctor or healthcare provider. You should always consult a practicing professional who can diagnose your specific case. The content we’ve included in this guide is merely meant to be informational and does not constitute medical advice. 


1. Bhaskar S, Hemavathy D, Prasad S. Prevalence of chronic insomnia in adult patients and its correlation with medical comorbidities. Journal of Family Medicine and Primary Care 5(4):p 780-784, Oct–Dec 2016. | DOI: 10.4103/2249-4863.201153

2. Blackwelder A, Hoskins M, Huber L. Effect of Inadequate Sleep on Frequent Mental Distress. Prev Chronic Dis 2021;18:200573. DOI: icon.

3. Scott AJ, Webb TL, Rowse G. Does improving sleep lead to better mental health? A protocol for a meta-analytic review of randomised controlled trials. BMJ Open 2017;7:e016873. doi: 10.1136/bmjopen-2017-016873

4. Isaac F, Greenwood KM. The relationship between insomnia and depressive symptoms: genuine or artifact? Neuropsychiatr Dis Treat. 2011;7:57-63. doi: 10.2147/NDT.S16267. Epub 2011 Feb 14. PMID: 21430795; PMCID: PMC3056174.

5. Institute of Medicine (U.S.) Committee on Sleep Medicine and Research; Colten HR, Altevogt BM, editors. Sleep Disorders and Sleep Deprivation: An Unmet Public Health Problem. Washington (DC): National Academies Press (U.S.); 2006. 2, Sleep Physiology. Available from:

6. Fattinger, S., de Beukelaar, T., Ruddy, K. et al. Deep sleep maintains learning efficiency of the human brain. Nat Commun 8, 15405 (2017).

7. Buysse,D.J., Reynolds,C.F., Monk,T.H., Berman,S.R., & Kupfer,D.J. (1989). The Pittsburgh Sleep Quality Index (PSQI): A new instrument for psychiatric research and practice. Psychiatry Research, 28(2), 193-213. The detailed scoring instructions are at the end of this journal article.

8. Clement-Carbonell V, Portilla-Tamarit I, Rubio-Aparicio M, Madrid-Valero JJ. Sleep Quality, Mental and Physical Health: A Differential Relationship. Int J Environ Res Public Health. 2021 Jan 8;18(2):460. doi: 10.3390/ijerph18020460. PMID: 33435528; PMCID: PMC7826982.

8. Hunt A, Harrington D, Robinson S. Vitamin B<sub>12</sub> deficiency. BMJ : British Medical Journal. 2014;349:g5226. doi:10.1136/bmj.g5226

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Published: Sep 5, 2023


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