Unveiling the Link Between Sleep and Mental Health

Author: Dr Yagna Prasanna Kondadadi, BDS (Bachelor of Dental Surgery). 

Reviewed by: Dr Azuka Ezeike, MBBS, FWACS (Obstetrics and Gynaecology), FMCOG, MSc (Public Health)

Highlights

• Sleep and mental well-being are closely linked, influencing each other in a cycle.
• Poor sleep increases the risk of anxiety, depression, and other mental health issues.
• The body regulates sleep through the internal clock (circadian rhythm) and sleep drive.
• Sleep deprivation harms memory, decision-making, focus, and emotional stability.
• Mental health conditions like anxiety, depression, and PTSD can disrupt sleep.
• Good sleep hygiene, consistent sleep schedules, limiting blue light, and relaxation techniques improve sleep quality and mental well-being.

Introduction

Sleep is mysterious and can affect our lifestyle and mental well-being. Not having enough sleep interferes with our mental well-being; whereas mental distress disrupts sleep patterns. Hence, sleep and mental well-being could mutually reinforce each other.

According to the Centers for Disease Control and Prevention, one-third of US adults report sleeping less than the recommended amount, and approximately 20% live with a mental illness.[1]

Sleep has often taken a backseat in today’s world, with everyone swamped chasing their dreams and striving to meet their needs. Sleep has lost its priority amidst the chaos. Whether it’s a young mother balancing childcare with work deadlines or a dedicated professional striving for career success to provide a better life for their family, many sacrifice sleep to meet their goals. However, sleep deprivation comes at a cost. In the relentless pursuit of our ambitions, we often compromise our mental and physical well-being.

A good laugh and a long sleep are the best cures in the doctor’s book.

• An Irish proverb
  

The sleep-mental wellbeing connection

Sleep and mental health are mutually linked to each other. Both sleep problems and mental health issues have become global health concerns.

• Individuals with poor sleep are more likely to experience depression and anxiety than those without sleep problems. 
• Similarly, poor sleep might be, in turn, the result of stress, anxiety, eating disorders, and experiences such as delusions and hallucinations.
• Sleep deprivation is scientifically and medically linked to hormonal imbalances and diseases like Alzheimer’s’.[2]
• Research has found that sleep disorders like sleep apnea, circadian rhythm disruption, restless leg syndrome, excessive daytime sleepiness, sleepwalking, and nightmares are all more prevalent in those experiencing mental health difficulties.[3]

Mental health and sleep could be the cause and consequence of one another.

The human body is resilient to small changes in the sleep cycle. But when sleep deprivation becomes chronic, it affects the brain and body functions.

The science behind sleep

Sleep is critical for the body to balance and regulate its vital functions. Many factors play a role in preparing the body to fall asleep and wake up. There are two powerful drives in our 24-hour body clock.

These include:

• Internal body clock
• Drive for sleep.

Internal body clock

The internal body clock has a 24-hour resting rhythm called the Circadian rhythm. 

Two processes control the circadian rhythm:

•  One is the coordination of the body with certain environmental cues such as light and darkness. 
• Second is an increase in sleep-inducing chemicals like Adenosine and Melatonin. These chemicals slow your breathing and relax your muscles allowing you to sleep better.

Drive for sleep

Drive for sleep, also known as sleep pressure, is the body’s natural urge or need for sleep as long as you are awake. For example, if you are awake for a longer time, your body gets tired and feels the need to sleep. This gives the signal to your brain to get some sleep. As soon as you are asleep, the drive to sleep slows down. This is controlled by a chemical called adenosine. Whenever you don’t sleep for long hours, or your body needs sleep, the chemical called adenosine, sends signals to the brain, to promote sleepiness. This sleep drive is also a kind of regulating mechanism for the sleep-wake-up cycle.

Stages of sleep

• Sleep is regulated by the circadian rhythm, or body clock, located in the hypothalamus (a region of the brain).

There are 4 stages of sleep that the body experiences in cycles throughout the night.

•  Stage 1 & Stage 2 - Non-rapid eye movement
•  Stage 3 - Delta sleep stage
•  Stage 4 - Rapid eye movement sleep

Stage 1 and Stage 2 

These are the non-rapid eye movement stages. This is the transition from staying awake to falling asleep. Heart rate and breathing begin to slow. Body temperature falls and muscles may twitch.

Stage 3 

This is the delta sleep stage. This is because of the slow delta brain waves released during this stage. This is the first stage of deep sleep, where the pituitary gland produces growth hormones for the muscles and cells, allowing the body to repair during sleep.

Stage 4 

This is the rapid eye movement stage. This is where we begin to dream. The brain exhibits high activity in this stage, just like when we are awake except our eyes are closed. 

How sleep affects mental health

Sleep is a biological process that is key to development and growth. The Centers for Disease Control and Prevention and the American Academy of Sleep Medicine recommend getting adequate sleep, which is 7 or more hours per night. .[1]Anything less than this amount may lead to chronic mental illnesses like anxiety, depression, and other psychological illnesses.[1]

• Not having proper sleep or poor quality of sleep is linked with an increased risk of mental health illnesses. 
• While lack of sleep has been identified as a consequence of mental health disorders, sleep problems can also be a cause of psychiatric disorders like anxiety and depression. 
• Poor sleep can cause irritability, mood swings, and short-temperedness.
• Chronic sleep deficiency has also been linked to depression, suicide, and risk-taking behaviour.
• Sleep deprivation in children may lead to problems in paying attention at school and they may get low grades and feel stressed.
• Sleep-deficient children may feel angry and impulsive, have mood swings, or be depressed.
• During sleep, the brain works to process the information required to consolidate positive memories. Lack of sleep may interfere with the function of the brain in securing positive memories and may affect the ability to think, learn, and understand things.
• Sleep deficiency results in mood disorders, emotional reactivity, mental health disorders, and even suicidal tendencies.
• Lack of adequate sleep or poor quality of sleep may result in stress and worry, anxiety and depression, declining mental health, and feelings of fatigue.

Does mental health affect sleep?

Absolutely. Mental health and sleep share a bidirectional relationship. Mental health disorders can affect sleep in several ways.

Anxiety:

•  Anxiety is a feeling of worry and uneasiness. 
• It is normal to feel anxious at times in response to stressful situations, but when it becomes chronic, it is associated with sleeplessness or poor-quality sleep.
• Insomnia (lack of sleep) is a common symptom of anxiety disorders.
•  People with anxiety are much more likely to have sleep problems during stress.

Depression: 

• Depression is a feeling of sadness or hopelessness, not having any interest in anything, and not being focused well enough. 
• People with signs of depression show excessive daytime sleepiness.

Post-traumatic stress disorder: 

• Post-traumatic stress disorder is a mental health condition that is caused either by experiencing or witnessing a stressful or disturbing event. 
• This is characterized by nightmares, anxiety, and unusual worry or fear. 
• The brain cells will be in a state of hyperactivity during the REM stage of sleep and people will have dreams, replay negative events in their minds, likely be alert, and stay awake at night.

Other disorders that may affect sleep include Schizophrenia and bipolar disorder.

Sleep and Cognitive Intelligence

Cognitive intelligence is the human ability to understand, think, learn, solve problems, and make decisions effectively. Sleep is important for learning and memory. When we sleep, the brain will process what happened to us today at work, at home, or a study place. Here is how sleep deprivation affects cognitive intelligence:

Memory impairment:

• Lack of sleep disrupts ability to recall and memory retention
• Chronic sleep deprivation may result in serious conditions like dementia. Dementia is a term for conditions that affect memory, thinking, and the ability to perform daily activities.
• Dementia is characterized by loss of memory, among many others. Alzheimer’s is the most common form of dementia and contributes to 60-70% of cases.[4]

Problem-solving and logical thinking:

• Lack of adequate sleep results in the inability to think, learn, understand, solve problems, and make decisions effectively.

         Poor attention and focus:

• Sleep deprivation leads to decreased focus and poor understanding and processing of information.  
• Tasks that require attention for long periods, such as studying, become challenging.

Emotional dysregulation:

•       Sleep deprivation leads to increased stress hormone levels, leading to anxiety, depression, and mood swings.
• A decline in emotional regulation further interferes with social interactions and decision-making.

Lowered IQ and reduced cognitive efficiency:

• According to studies,[5] sleep-deprived patients have shown deficits in functioning, apart from attention and memory tasks. 
• Patients who were acutely sleep-deprived for just 30 hours showed a decrease in verbal fluency, creative thinking, logical thinking, decision-making, and nonverbal planning. Sleep deprivation leads to decreased focus and poor understanding and processing of information. [5]

Poor decision-making:

• Sleep deprivation results in poor judgment and impulsiveness.
• Emotional stability is weakened leading to irritability.

Thus, chronic sleep deprivation impacts cognitive intelligence, lowering IQ, reducing memory retention, and impairing focus. Prioritizing sleep is essential for both optimal cognitive performance and long-term brain health.

Ways to Achieve Better Sleep

Sleep is not merely a period of rest for the body. It is a crucial process for the body and brain to grow and develop. It is also important to understand that sleeping for long hours is not enough but the quality of sleep matters as well. The human growth hormone is produced during sleep, which accelerates healing regeneration, and growth of muscles.

There are many ways to achieve good sleep. Integrating them into your routine would help you achieve a broader spectrum of physical and mental well-being. Setting up sleep hygiene by integrating daily habits and sleep-inducing behaviour in your environments would help you achieve the desired goal of quality sleep.

The strategies to achieve better sleep include:

• Maintain a consistent sleep schedule, sleeping and waking up around the same time every day, irrespective of holidays or weekends.
• Set your bedtime such that you get 7 hours of sleep every day.
• Cultivate a bedtime routine to make it relaxing and easier for the transition.
• Avoid blue light or any kind of screen time 2 hours before bedtime.
• Dim your bedroom lights, wear eye masks, or use blackout curtains to darken the room. This promotes the production of melatonin.
• Cultivate good lifestyle habits like exercise and a balanced diet.
• Avoid alcohol, tobacco, and caffeine before bedtime.
• Practice relaxation techniques like meditation before bedtime.
• Listen to the feedback your body gives each day and sleep accordingly. Wait until you feel sleepy before you go to bed.
• Include foods rich in tryptophan in your diet.
• Keep a gap of 2-3 hours between bedtime and last meals.

A call to action:

Sleep is a biological process that is essential for everyone irrespective of age, and gender for the body to rest, repair, rejuvenate, and eliminate toxins.Promoting mental and physical health requires the active involvement of public health organizations, policymakers, healthcare providers, and community leaders. This can be achieved through:Education: 

• Include awareness campaigns and sleep education in mental health awareness on the importance of sleep in maintaining mental health and emotional well-being.

Support services:

• Focus on providing health, and free consultations for individuals struggling with sleep-related issues.

Therapeutic interventions:

• Expand access to behavioural therapies like cognitive behavioural therapy in public health centres.

Conclusion

Sleep is the new magic pill that works against weight loss, hormonal imbalance, mental illness and lifestyle diseases. A good night’s sleep allows detoxification in the body. 

Different stages of the sleep cycle are correlated with different functions ranging from repair, regeneration, detoxification of cells, and good health. It’s important to understand that missed sleep for a day or two cannot be fully recovered by sleeping later.. Poor quality of sleep results in a compromised immune system, irritability, difficulty in concentration, and other disorders.

While more research is needed to understand the direct association between sleep and mental health, sleep is important to maintain the integrity of physical health. mental, and cognitive abilities. It is extremely important to incorporate sleep hygiene in daily practice.

References

1. Blackwelder A, Hoskins M, Huber L. Effect of inadequate sleep on frequent mental distress. Preventing Chronic Disease 2021;18(18). Available from: https://pubmed.ncbi.nlm.nih.gov/34138697/

2. Lv Y-N, Cui Y, Zhang B, Huang S-M. Sleep deficiency promotes Alzheimer’s disease development and progression. Frontiers in Neurology 2022;13. Available from: https://pubmed.ncbi.nlm.nih.gov/36588906/

3. Scott AJ, Webb TL, Martyn-St James M, Rowse G, Weich S. Improving Sleep Quality Leads to Better Mental health: a meta-analysis of Randomised Controlled Trials. Sleep Medicine Reviews [Internet] 2021;60(60):101556. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8651630/

4. World Health Organization. Dementia [Internet]. World Health Organization. 2023; Available from: https://www.who.int/news-room/fact-sheets/detail/dementia5. Deak MC, Stickgold R. Sleep and cognition. Wiley Interdisciplinary Reviews: Cognitive Science [Internet] 2010;1(4):491–500. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5831725/

Published : February 28, 2025