Sleep And Mental Health:

What Is The Relationship Between
Sleep and Mental Health?

Key Points

• The relationship between sleep and mental health is a two-way street: Poor sleep can be both a symptom of a mental health condition and a major risk factor for developing one.

• Insomnia is a key risk factor: Long-term insomnia is a powerful predictor for the start of major depression and can worsen the symptoms of nearly all psychiatric disorders, increasing the risk of relapse and suicide.

• Specific sleep patterns are linked to different mental health conditions. Depression is often marked by more intense and earlier dream sleep (REM sleep), while schizophrenia is associated with a lack of brainwave bursts called sleep spindles.

• Treating sleep problems directly is a key part of mental healthcare. Therapies like Cognitive Behavioral Therapy for Insomnia (CBT-I) are very effective and can improve not just sleep, but directly improve psychiatric symptoms and overall quality of life.

Sleep & Mental Health: The Brain Link

The link between how we sleep and mental health, how we feel, is one of the most important relationships in our health. For a long time, sleep problems were often seen as just a side effect of mental illness, just another unfortunate but secondary symptom. Today, however, research makes it clear this view is incomplete.

Disturbed sleep is not just a result of a mental health issue; it is often a predictor of one, a driver of relapse, and a serious risk factor in its own right (Nofzinger, 2022).

This shouldn’t be surprising.

The brain circuits that regulate our sleep states - waking, light sleep, deep sleep, and dreaming - are the very same circuits involved in managing our mood, emotions, and thoughts.

When one system is out of balance, the other is almost always affected.

In this comprehensive overview article, we explore the deep, two-way relationship, between sleep and mental health, looking at how specific sleep disruptions are tied to major psychiatric disorders and what can be done to treat both.

So, let’s start at the start.
How exactly does a lack of sleep begin to affect our emotional stability?

How Does Poor Sleep Affect Our Emotions?

Poor sleep directly harms our ability to manage emotions by disrupting communication between key areas of the brain. This disruption can lead to a short fuse, poor coping skills, and a tendency to view the world more negatively (Beattie & Gumley, 2022).

But how exactly is brain communication disrupted by poor sleep?

How Exactly Does Disturbed Sleep Affect Brain Function?

When we are sleep-deprived, the brain's emotional centers become overactive, while the parts responsible for rational control go offline. A key study showed this by having sleep-deprived individuals look at upsetting images. Their brains showed a 60% stronger reaction in the amygdala, the brain’s alarm center for fear and threat, compared to when they were well-rested (Yoo et al., 2007).

At the same time, the connection to the prefrontal cortex, the brain's logical "CEO" that normally calms the amygdala, was cut off (Yoo et al., 2007).

Without sleep, it’s as if the brain’s emotional alarm system is left on, with no one there to turn it off.

This state of high alert is a common thread linking poor sleep and anxiety.

Some people have a high degree of "Anxiety Sensitivity," a fear of the physical feelings of anxiety itself, like a racing heart or shortness of breath. This heightened awareness of bodily signals makes it much harder to relax, leading to a vicious cycle where anxiety about not sleeping becomes a self-fulfilling prophecy (Rohrs et al. 2020).

So if poor sleep can heighten emotion, does this mean a sleep problem can lead to mental health problems?

Can Insomnia Predict a Mental Health Disorder Like Depression?

Yes, persistent insomnia is one of the strongest predictors for the later development of a mental health disorder, particularly major depression. It is far more than just a symptom; it is an active risk factor that can pave the way for other conditions (Chopra et al., 2020).

While many people experience a few bad nights of sleep, chronic insomnia is a different matter.

A landmark study followed thousands of adults over time and found that those with persistent insomnia had almost 40 times the risk of developing new-onset major depression compared to people with no sleep complaints (Ford & Kamerow, 1989). Even after their insomnia got better, the risk was still higher than normal.

Can Insomnia Predict Mental Health Disorders In General?

This pattern holds true for other conditions as well. For example, having insomnia symptoms before military deployment has been shown to significantly increase the risk of developing PTSD after service members return (Gehrman et al., 2013). This evidence strongly suggests that addressing sleep problems early is a powerful strategy for preventing mental illness.

But what happens when a mood disorder has already taken hold?

Does Sleep Change in Depression and Bipolar Disorder?

In affective disorders, conditions defined by shifts in mood and energy, sleep disruption is a core feature of the illness. These problems are not just side effects; they are deeply woven into the biology of the disorder and can predict its severity and course (Nissen & Hertenstein, 2022).

How Do Sleep Patterns Change in Depression?

In major depression, sleep problems most often show up as insomnia, that is difficulty falling asleep, staying asleep, or waking up too early. Around 90% of people with depression report some form of sleep disturbance (Chopra et al., 2020). A smaller number experience hypersomnia, a need for an excessive amount of sleep (Geoffroy et al., 2018).

These complaints are matched by objective changes in what is called sleep architecture, the nightly pattern of our sleep stages. Using polysomnography (PSG), a test that records brain waves and other signals during sleep, researchers have found a consistent signature of depression:

• Less Deep Sleep: A significant reduction in slow-wave sleep, the most physically restorative stage of sleep.

• Fragmented Sleep: More frequent awakenings throughout the night.

• Intense REM Sleep: People with depression tend to enter their first REM (dreaming) stage much faster than normal (a short REM latency) and have more intense and frequent eye movements during this stage (high REM density). This heightened REM pressure is considered one of the most specific biological markers for depression (Baglioni et al., 2016; Berger & Riemann, 1993).

How Does Sleep Change During Bipolar Disorder?

During a manic episode, a hallmark of bipolar disorder, there is a dramatically reduced need for sleep. An individual may sleep for only a few hours, or not at all, yet feel highly energetic and rested (Dinerman et al., 2020). This is a key feature that distinguishes the sleeplessness of mania from the exhausting, frustrating experience of insomnia.

Is The Body Clock Important in Bipolar Disorder?

The body’s internal 24-hour clock, or circadian rhythm, appears to be deeply involved in bipolar disorder. Many individuals with the condition have an "evening chronotype," a natural preference for staying up late and waking up late, which reflects a misalignment of their internal clock with the external day-night cycle (Melo et al., 2017).

This sensitivity to sleep, light, dark, and circadian rhythm is highlighted by a strange phenomenon: therapeutic sleep deprivation. While staying up all night can temporarily relieve symptoms in some people with unipolar depression, it can be dangerous for those with bipolar disorder, as it carries a significant risk of triggering a switch from depression into mania or hypomania (Wehr et al., 1982).

What is the Link Between Sleep, Anxiety, and Trauma?

For the 70% to 90% of people with anxiety and trauma-related disorders, disturbed sleep is a nightly reality (Rohrs et al., 2020). The state of high alert that defines anxiety directly conflicts with the relaxation needed to fall asleep.

How Is Are Sleep Problems Related To Generalised Anxiety Disorder (GAD)?

In Generalized Anxiety Disorder (GAD), excessive worry is the main problem. The racing thoughts and mental rehearsal of fears make it nearly impossible for the mind to quiet down, and sleep disturbance is an official diagnostic symptom for the disorder (Choi et al., 2022).

Is Sleep Disturbed In Panic Disorder?

In Panic Disorder, sleep can be interrupted by nocturnal panic attacks. These are not caused by nightmares; instead, they are sudden awakenings from non-REM sleep accompanied by intense fear and physical symptoms like a racing heart and shortness of breath (Mellman & Uhde, 1989). This suggests they are driven by a physical process in the body, such as a hypersensitivity to changes in carbon dioxide levels during sleep (Klein, 1993).

How does Sleep Disturbance Show Up In OCD?

Sleep problems are very common in people with Obsessive-Compulsive Disorder (OCD), with a notable link to a specific disruption of the body's internal clock. Studies show that a large portion, around 40% to 50% of individuals with OCD, report major sleep disturbances (Nordahl et al., 2018; Paterson et al., 2013).

Is The Body Clock Involved In OCD?

Beyond general insomnia, OCD is frequently associated with Delayed Sleep Phase Disorder (DSPD), a circadian rhythm condition where a person’s internal clock is shifted much later than normal (Mukhopadhyay et al., 2008; Nota, Sharkey, & Coles, 2015).

This means that individuals with OCD may find it extremely difficult to fall asleep until the early hours of the morning, leading to a chronic cycle of sleep deprivation when they have to meet the demands of a typical school or work schedule.

Why Are Nightmares and Insomnia So Common in PTSD?

About 70% of individuals with PTSD report chronic difficulty falling or staying asleep (Ohayon & Shapiro, 2000). Core symptoms include severe insomnia, hypervigilance that makes it hard to feel safe enough to sleep, and recurrent, distressing nightmares that replay the traumatic event (Brownlow et al., 2020).

The sleep problems in PTSD are thought to come from an overactive norepinephrine system, the brain’s network for the "fight-or-flight" response. This system remains on high alert even during sleep, particularly during the REM stage, disrupting the brain's ability to process traumatic memories in a safe context (Ross et al., 1994).

It is also important to recognize that PTSD has a very high rate of co-existing with Obstructive Sleep Apnea (OSA), a condition where breathing stops and starts during sleep. Untreated OSA can mimic or worsen PTSD symptoms, making a thorough sleep evaluation very important (Krakow et al., 2004).

Are Sleep Problems Common In ADHD?

The relationship between sleep and Attention-Deficit/Hyperactivity Disorder (ADHD) is a complex, two-way relationship, with up to 50% of individuals with ADHD reporting significant sleep problems (Wajszilber et al., 2018).

These issues are often due to co-existing sleep disorders, including sleep-disordered breathing, Restless Legs Syndrome (RLS), and circadian rhythm disorders like Delayed Sleep Phase Syndrome.

The connection works in both directions: broken or not enough sleep can worsen the core ADHD symptoms of inattention, hyperactivity, and emotional dysregulation. At the same time, behavioral traits of ADHD, such as difficulty with impulse control, can lead to bedtime resistance and poor sleep habits, further disrupting sleep.

This overlap can also create diagnostic confusion, as the daytime symptoms of some sleep disorders - such as the restlessness of RLS, the inattention caused by fatigue, or the sleepiness of OSA (in children) - can mimic ADHD itself (Wajszilber et al., 2018).

What Is the Connection Between Sleep and Eating Disorders?

The connection between sleep and eating disorders is a two-way street; poor sleep can drive unhealthy eating patterns, and disordered eating behaviors can lead to significant sleep disturbances (Narahari et al., 2020).

Research shows that short sleep duration and poor sleep quality are associated with increased food intake, a preference for energy-rich foods, and weight gain, a process that appears to be driven more by the brain's reward system than by true hunger (Chaput, 2014). On the other hand, disordered eating behaviors can predict the future development of sleep problems, such as difficulty falling and staying asleep (Bos et al., 2013).

In conditions like Anorexia Nervosa, sleep problems are very common but are often a direct result of not getting enough nutrition; as weight is restored, many of these sleep disturbances improve (Narahari et al., 2020). This link is important for treatment, as persistent poor sleep can predict the future severity of eating disorder symptoms, suggesting that treating sleep is a valuable part of any recovery plan (Lombardo et al., 2015).

Are Sleep Changes Part Of Schizophrenia?

Sleep disturbances are reported in up to 80% of patients and can appear long before the first episode of psychosis, sometimes even predicting when symptoms will worsen (Kaskie et al., 2017; Chemerinski et al., 2002). Research has also identified distinct sleep patterns in schizophrenia, with a lack of "sleep spindles" becoming known as a strong biological marker.

What Are Sleep Spindles, and Why Are They Important?

Sleep spindles are short, powerful bursts of brain activity that occur during Stage 2 non-REM sleep. They are believed to be critical for strengthening memories and protecting sleep from outside noises. One of the most consistent findings in schizophrenia research is a large drop in the number of these spindles (Ferrarelli et al., 2007, 2010).

This deficit is not a result of medication; it is found in unmedicated patients and even in their close relatives who do not have the disorder (Manoach et al., 2014).

This suggests the spindle deficit is a core feature of the illness, reflecting a disruption in the communication circuits between the thalamus, a central relay station in the brain, and the cortex.

Is Poor Sleep A Risk Factor For Suicide?

A growing body of research shows that insomnia, poor sleep quality, and nightmares are all associated with an increased risk for suicidal thoughts, attempts, and death, even when you factor in how severe a depression is (Pigeon et al., 2012; Bernert et al., 2015).

Nightmares, in particular, are a powerful red flag. One study found that people who reported frequent nightmares were much more likely to die by suicide compared to those who did not (Tanskanen et al., 2001).

Poor sleep can fuel feelings of hopelessness, a key psychological driver of suicide, making it an important focus for treatment (Woznica et al., 2015).

What Are the Best Ways to Treat Sleep And Co-occurring Mental Health Issues?

Given the major impact of sleep on mental health, a complete treatment plan must focus directly on improving sleep. Treating the sleep problem is not just a “nice to have”; it is about directly treating the underlying disorder.

What Is The First-Line Treatment for Insomnia?

The most effective and recommended first-line treatment for chronic insomnia is Cognitive Behavioral Therapy for Insomnia (CBT-I).

This is a structured, non-medication program that helps people change the behaviours and thoughts that are getting in the way of their sleep.

CBT-I is highly effective for insomnia that happens alongside depression, anxiety, and PTSD, and has been shown to not only improve sleep but also lessen the psychiatric symptoms (Geiger-Brown et al., 2015).

Are There Specialized Therapies For Nightmares?

Yes. For nightmares associated with PTSD, a specific treatment called Imagery Rehearsal Therapy (IRT) is recommended. IRT, and now a broader treatment for non-PTSD nightmares, CBT-n, are specialised written exposure therapies specifically tailored to nightmares and gaining a sense of control over the dream content. This can reduce how often the nightmares happen and how upsetting they are (Aurora et al., 2010).

Why is Screening For Sleep Disorders So Important When Treating Mental Health Disorders?

It is important to check for sleep disorders when treating mental health conditions as they are:

1) common in people with psychiatric conditions;

2) can block progress if left untreated; and

3) common psychiatric medications disturb sleep and can trigger sleep disorders.

As mentioned, Obstructive Sleep Apnea is highly prevalent in people with PTSD and depression. Treating these underlying conditions is often a necessary first step.

Sleep disorders such as Insomnia, Hypersomnia, and Restless Legs Syndrome (RLS), an irresistible urge to move the legs, can be caused or worsened by certain antidepressant and antipsychotic medications (Au et al., 2020).

What Is The Role of Psychiatric Medications in Treating Sleep Disorders?

Medications can play a role, but they must be used carefully. Some sedating antidepressants can help with sleep, but others can cause insomnia or worsen daytime fatigue symptoms (Alberti et al., 2015).

In people with bipolar disorder, stimulants used to treat hypersomnia must be monitored closely to avoid triggering mania (Dinerman et al., 2020). In schizophrenia, the use of certain sleep aids like benzodiazepines has been associated with an increased risk of death, highlighting the need for caution (Tiihonen et al., 2012).

Takeaway: Healthy Sleep Is The Foundation for Mental Health

The message from decades of research is clear: sleep is a central pillar of mental health. Sleep is not just a background process, it is the foundation for our mental and emotional well-being.

Sleep can be likened to a vital sign of mental health (a “transdiagnostic process” in the professional mental health jargon), and addressing sleep disturbances directly is one of the most effective ways to promote recovery from a mental health condition, prevent relapse, and improve overall well-being.

When sleep is disrupted, it can set off or worsen a wide range of mental health problems, from depression and anxiety to eating disorders, ADHD, and schizophrenia.

Sometimes, sleep problems come first and increase the risk of developing a mental health condition. Other times, they show up as part of the illness or make recovery harder.

The good news is that sleep problems are treatable. Addressing sleep directly - through evidence-based sleep therapies such as CBT-i, CBT-n (CBT for nightmares), circadian rhythm treatments (and not, not sleep hygiene) or, when absolutely needed, medication (and a supported medication tapering plan) - can directly improve mental health outcomes. For many people, addressing sleep is the turning point in their recovery journey.

What Can You Do To Support Better Understanding Of Sleep And Mental Health?

• Pay attention to sleep: If you or someone you care for is struggling with sleep and mental health, don’t ignore the sleep issues. They are not just a side effect - they are a core part of the problem and the solution.

• Talk to your healthcare provider: Ask about sleep when discussing mental health. If your provider only offers “sleep hygiene” then talk to a sleep clinic or a sleep psychologist that can provide a thorough sleep and mental health assessment that can help identify sleep disorders that may be making things worse.

• Consider sleep therapy: Cognitive Behavioral Therapy for Insomnia (CBT-I) is a proven, non-drug treatment that can help with many types of sleep problems, even when they occur alongside mental health conditions.

• Be cautious with medications: Some medications can help with sleep, but others can make sleep worse or have side effects. Always discuss options and risks with your doctor.

Final Thoughts

Sleep and mental health are deeply connected. We know because we treat both every day. We also see the improvements in mental health that come from treating sleep problems.

By treating sleep as a priority, not an afterthought, we can help prevent mental health problems, support recovery, and improve quality of life. If you’re struggling with sleep and mental health, know that help is available - and that better sleep can be a powerful step toward feeling better.