Sleep and mental health are closely related. The DSM (Diagnostic and Statistical Manual) which categorizes mental disorders contains countless references to sleep as a symptom. Various mental disorders can involve both insomnia and hypersomnia (a tendency to sleep too much). There are also references to nightmares and disturbed dreams. On the other side, long-term sleep issues can predispose those without a current mental health disorder to getting one later. Thus, the relationship between sleep and mental health is bidirectional- when one aspect is improving, so does the other. When one aspect worsens, so does the other.
Mental health has been a growing issue in the US and elsewhere for decades. Even before the COVID pandemic, mortality rates were increasing around a cluster of causes known as diseases of despair. These include depression, suicidality, substance abuse, etc. Very recent pollings show that the coronavirus and its sequelae are hightening these trends.
In the remains of this articles, we will take a deeper dive in each of the broad categories of mental illness which most highly correlate to disturbed sleep.
Mood Disorders: These include Major Depressive Disorder/Bipolar Disorder, along with more minor variants – dysthymia, cylocthymia, Seasonal Affective Disorder (SAD). Some 75% of depressed patients complain of either insomnia or hypersomnia (excess sleep drive). They also complain of frequent arousals, disturbing dreams, and generally non-restorative sleep. On the EEG (electro-encephalogram) we can see reduced slow wave sleep (the most restorative type) and decreased delta power, which is thought to reflect abnormal regulation of homeostasis.
There is a major connection between insomnia and mood disorders. Insomnia patients have a ninefold increased liklihood of depression, and the worse the insomnia generally the worse the depression. Inasomnia can also act as a warning signal for a major depressive episode or manic phase (sidenote – it can also predict postpartum depression). Unfortunately, the symptoms of insomnia often persist even with the remission of other mood symptoms.
A word on suicide, which is the 4th leading cause of death and which has increased over the past several years. Insomnia and nightmares are predictive for suicidal ideations and attemps.
There may be some hormonal factors at play as well. 50% of depressed patients show endocrine imbalance. They also see increased cortisol (also known as the stress hormone), which has been linked to more awakenings and damage to the hippocampus. Studies also show a reduction in growth hormone related to the drop in slow wave sleep.
We also see REM (rapid eye movement) sleep issues in depression. REM is important for learning and memory consolidation. Depressed (and manic) patients show a reduced time to enter REM, a longer first REM, more density of the actual eye movements, and more total REM sleep as a percentage of overall architecture. Interestingly, REM density (the number of eye movements per minute) predicts the severity of a mood disturbance. Another surprising finding is that first degree relatives of depressed patients show a reduced REM latency, even if they are not themselves depressed.
Functional MRIs (fMRIs) below show changes in brain metabolism in depressed patients versus controls. Basically, the brains of depressed patients are less able to chill out (literally- glucose metabolism should reduce) in non-REM sleep and they’re more wound-up in REM sleep. One exception is that depressed patients have increased metabolism in the areas of the brain related to emotional regulation (i.e. the amygdala, hippocampus and thalamus). Even when they are awake, it seems their brain is less active than controls, suggesting that it’s more than just a feeling or emotion which can cause lethargy – it’s absolutely physiological.
|NREM||Decreased metabolism||Smaller decrease|
|REM||Normal metabolism||Increased metabolism|
|Wake||Normal metabolism||Decreased metabolism|
Another interesting feature is EEG Coherence, which describes the similarity of rhythm throughout the cortex (brain). Increased coherence indicates optimized functionality and communication between brain regions. In depressed patients, we see decreased coherence. And again, children of depressed patients can show this even if they aren’t themselves depressed. For this reason, it has been suggested that EEG coherence could be considered a bio-marker in depression screenings.
What about the relationship of anti-depressant medications to sleep? The most common class of SSRIs (selective serotonin reuptake inhibitors) increase serotonin and also normalize sleep architecture (the balance of various sleep stages). Below is a nice table summarizing the impacts of various classes of medications.
Increased N2 (a kind of throw-away sleep)
Major REM suppression
NREM eye movements (“Prozac eyes”)
Can worsen restless legs/periodic limb movements/REM behavioral disorder
NREM eye movements
You may notice that all of these suppress REM sleep (which you will recall is excessive in depressed patients). Insomnia is also a common side-effect and the exacerbation of insomnia can cause some patients to become non-compliant with medications. Many of these drugs can also cause hypersomnia (excess sleeping).
One interesting idea is that sleep deprivation may actually be a treatment for depression. Early studies show it can reduce symptoms within hours for 30-60% of patients. This often gives only a short-term effect, though it can supplement other treatments that may take longer to reach effective levels. Unfortunately for bipolar patients, it can also flip the switch on their symptoms. As my mom has bipolar, I know this all to well. It’s almost 100% predictive that if she had a night with minimal or no sleep, she will develop a manic episode within 24-48 hours.
Another cool potential technology is trans-cranial magnetic stimulation (TCM). This is a novel, non-invasive therapy already approved for extreme depression. The treatment involves passing a wand which sends a weak electromagnetic current to target brain regions, causing depolarization of neurons. Researchers (including at my day job) are looking at using this treatment to induce slow wave sleep in patients who need it, with early promising effects. It’s a little crazy to think of a wand causing the brain to react differently, but cool for my inner nerd.
Depression also has a bi-directional relationship with a surprising disorder- sleep apnea. Around 20% of sleep apnea patients have depression and around 20% of depressed patients have apnea. Unfortunately, all antidepressants (and anti-psychotics) can cause weight gain, which increases risk for apnea. Studies show that depression has a dose-dependent response (e.g. increases) with severity of sleep apnea. Conversely, treating sleep apnea correlates to improvements in depression. As many patients are non-compliant with their CPAP machines, this could be a great motivator!
A bit more about mania and sleep. Symptoms of mania included excess talk, inflated ego/grandiosity, flights of ideas, racing thoughts, distractibility, agitation, and excess pleasure seeking (e.g. food, drugs, sex). Manic patients have less sleep (they generally don’t feel the need to sleep as much), increased REM density and sooner REM onset.
While a much rarer disorder, schizophrenia also has important relationships with sleep. Most commonly known for symptoms of delusions and hallucinations, this disorder generally hits in the late teens is prevalent in around 1% of adults. Schizophrenic patients sleep less and worse, and can have both insomnia and hypersomnia as well as restlessness and agitation. They can also show a reversal pattern (daytime sleep and nighttime awakenings). Often, worsening of these symptoms foreshadows worsening periods of psychosis. The also show less slow wave sleep, which may indicate a lack of synaptic pruning (shown below, the brain’s process of tidying up it’s neural connections). This in turn can exacerbate psychotic symptoms.
It may be that the tendancy for poor sleep in schizophrenics worsens their condition. “Neurogenesis (the development of new nerves and synaptic connections) can be inhibited by sleep loss, suggest(ing) that the chronic dyssomnias of schizophrenia might themselves contribute to brain structure abnormalities” – Kathleen Benson.
The impact on antipsychotic medications on sleep is somewhat mixed. Anti-psychotics generally improve sleep quality, but can have undesirable side effects. There are fewer negative effects in the second generation anti-psychotics. Certainly improved sleep seems to help reduce psychotic symptoms. Anti-psychotics can increase the risk for other sleep disorders such as apnea. Some of them (including lithium which is technically a mood stabilizer) increase slow wave sleep which can impair arousal functioning and lead to parasomnias (abnormal behaviors like sleep walking and talking).
|Class||Positive Effects||Negative Effects|
|First Generation/ Traditional||Increased total sleep time |
Increased Sleep efficiency
|Residual insomnia Daytime sleepiness |
Increased risk for obstructive sleep apnea Increased parasomnias Sleepwalking
Increased restless legs/limb movements
|Second Generation/Atypical||Increased total sleep time Increased Sleep efficiency||Residual insomnia |
The sleep-specific side effects can be treated with benzodiazepines (though these are not ideal for patients with apnea or a history of substance abuse), melatonin, and stimulants such as modafinil (though this can cause an increased risk of relapse/exacerbation of psychosis). Interestingly, both treated and untreated schizophrenics show a decreased production of meltonin.
Similar to mood disorder patients, schizophrenics can have an increased risk of apnea, in part because many anti-psychotic medications cause weight gain. Nearly half of schizophrenic patients tested in a sleep study had moderate to severe apnea, and most of them tended towards the severe side. An issues with schizophrenia and apnea is that many patients are poor historians and have fewer bed partners to notice the snoring/breathing abnormalities.
Schizophrenic patients are also at a higher risk for sleep-related movement disorders. There is a common link – dopamine. We see a dopamine deficiency in restless leg disorder and REM-behavioral disorder (where patients act out their dreams). Schizophrenic patients are twice as likely as controls to have restless leg syndrome (21% prevalence), and those with restless legs have been found to have more severe psychiatric symptoms. Unfortunately conventional treatments (dopamine agonists) are contraindicated in schizophrenics. The preferred option is to reduce/change anti-psychotic regimens.
Anxiety Disorders – The major categories of anxiety disorders are Generalized Anxiety Disorder (GAD), Post-Traumatic Stress Disorder (PTSD), Panic Disorder, Obsessive Compulsive Disorder (OCD), and Phobic Disorders. The last two of these are generally less prone to sleep complaints, while the remainder all see significant sleep issues. It’s also worth noting there’s often overlap between anxiety disorders and depression. GAD and PTSD have sleep complaints listed as symptoms in the DSM-IV. Interestingly GAD, is also correlated to increased risk of restless leg syndrome.
|•Chronic worry and tension |
|•Re-experience of trauma |
|•Insomnia •Fatigue||•Insomnia (difficulty initiating/maintaining sleep) •Nightmares with trauma-related content|
Panic attacks arise during sleep around 18% of the time and 1/3 of patients report more panic attacks in sleep versus wake. The attacks generally occur in NREM sleep, often during a transition of stage. Patients with sleep-related panic attacks have been found to have worse severity of symptoms and increased suicidal ideations. Sleep apnea can worsen panic attacks. It make sense – when you stop breathing, it leads to heart pounding and shortness of breath or the sense of being choked. In fact, treating apnea can reduce panic attacks.
PTSD is well known for a link to poor sleep and severe nightmares. The sleep complaints in these patients generally decrease with time, but not in all cases, and sleep symptoms tend to be worse with worse traumas. We see specific REM phenomena in these patients including increased motor activity (the body is supposed to be paralyzed, but it’s not), more actual eye movements, frequent arousals, shorter REM periods. Perhaps this is because they wake up more from nightmares. An increase in the severity of PTSD is associated with more similar dream content to actual trauma. These patients also suffer from more insomnia and show increased sympathetic activation (they can’t chill out/relax).
Studies have been done on the source of trauma and dream content. Below is a table summarizing these findings.
|Nature of Initial Trauma||Typical Dream Content|
|Physical/Sexual Abuse||Attack |
Blood and dismemberment
Dreaming of one’s own death
Faceless men, shadows, demons, serpents, worms
Death of self or others
Misfortune to close family/friends
|Natural Disasters||Loss, grief |
Death of self, others, dead animals
Resurrection of someone who has died
Seeking food, housing, clothing, money
REM sleep is thought to help with trauma processing as well as memory consolidation (which is often spotty in PTSD). An interesting finding is that children in war zones have an inverse emotional relationship between feelings right before sleep and emotional content of dreaming, thought to restore emotional equilibrium.
Sleep and anxiety disorders often have overlapping treatments including medication (especially benzos) and cognitive behavioral therapy (CBT). Unlike in mood disorders, sleep deprivation actually worsens anxiety symptoms.
Take home message: sleep and mental health are closely intertwined. If you struggle with either, you are at risk for both. In these crazy times, it makes it all the more important to prioritize your sleep as part of your overall well being. I’d strongly encourage a nightly meditation practice as described here.
At Integrative Alchemists, we offer sleep coaching (which can be done virtually) and have a range of blogs on sleep topics. Wishing you restful sleep and mental peace, in spite of the many legitimate challenges you may be facing.
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