Sleep And Depression: Why Insomnia And Poor Sleep Are More Than Just Symptoms
Quick Summary
Approximately 90% of people diagnosed with depression experience some form of sleep disturbance, such as insomnia, hypersomnia (excessive sleeping), or nightmares.
Persistent insomnia is not just a symptom of depression; it is a major risk factor. Studies show that individuals with chronic insomnia have a substantially higher risk of developing major depression later on.
Effectively treating sleep problems can significantly improve depression outcomes. In fact, resolving sleep issues is one of the strongest predictors of remaining in remission from depression.
Poor sleep is a direct and modifiable risk factor for suicidal thoughts and behaviors, independent of the severity of a person's depression.
Sleep Problems And Depression: The Vicious Cycle
It’s a feeling many of us know: you toss and turn all night, and the next day, the world feels gray and heavy. A single bad night of sleep can tank your mood, but for millions, this connection runs much deeper. The relationship between sleep and depression isn't just a bad day; it's a complex, intertwined cycle where each condition can trigger and worsen the other. Understanding this powerful link is the first step toward finding effective treatment and lasting relief for both.
So, why is the bond between a sleepless night and a difficult day so powerful?
Why Are Sleep and Depression So Closely Connected?
Sleep and depression are so closely connected because they are regulated by many of the same systems and chemicals within the brain.
This shared neurobiology means that a disruption in one area, like mood regulation, almost inevitably causes a disruption in the other, like the sleep-wake cycle.
This creates what experts call a bidirectional link: poor sleep can pave the way for depression, and depression can cause debilitating sleep problems (Chopra et al., 2021).
The evidence for this two-way street is compelling. For decades, clinicians have recognized sleep disturbance as a core symptom of major depressive disorder (MDD).
But research now shows the relationship is not that simple. And the evidence for this is striking.
In a landmark study, researchers found that people with persistent insomnia had a nearly 40-times higher riskof developing new-onset depression compared to those without sleep problems (Ford & Kamerow, 1989).
Furthermore, sleep quality is a powerful predictor of recovery and relapse.
Even when other symptoms of depression improve with treatment, lingering insomnia can signal trouble ahead. One study found that two-thirds of patients whose insomnia persisted after depression treatment relapsed within a year.
In stark contrast, 90% of patients who achieved good sleep quality remained well, even after discontinuing their medication (Reynolds et al., 1997). This suggests that restoring healthy sleep is not just a side benefit of treating depression - it is central to achieving a stable, long-term recovery.
So, what exactly is happening inside the brain to create this powerful bond?
What Happens in the Brain to Link Poor Sleep and Depression?
The link between poor sleep and depression involves disruptions in the brain's chemical messengers, stress hormone systems, internal body clocks, and even its ability to grow and repair itself. These are not separate issues but parts of an interconnected network that governs both how we feel during the day and how we rest at night (Chopra et al., 2021).
How do brain chemicals play a role in sleep disruption and depression?
Key brain chemicals that regulate mood, known as neurotransmitters, are also essential for managing our sleep cycles.
In depression, the brain's serotonin and norepinephrine systems don't function as they should - and because these same systems act as a brake on REM sleep, the result is dream sleep that arrives too early, runs too long, and becomes more intense than normal.
This is why many antidepressants, which work by increasing the availability of serotonin and norepinephrine, often suppress REM sleep and can sometimes disrupt our sleep patterns (Chopra et al., 2021).
Does stress affect both sleep and mood?
Yes, the body's primary stress-response system, the hypothalamic-pituitary-adrenal (HPA) axis, is often overactive in depression, leading to high levels of stress hormones that disrupt deep, restorative sleep.
About half of all patients in a major depressive episode show excessive activity in the HPA axis, resulting in elevated levels of corticotropin-releasing hormone (CRH) and cortisol.
This state of constant "hyperarousal" is toxic to both mood and sleep. Elevated CRH, in particular, has been shown to reduce the amount of deep slow-wave sleep and increase REM sleep, producing a sleep pattern that closely mirrors what is seen in depression (Chopra et al., 2021).
What is the role of our internal body clock in depression?
Depression is frequently associated with a misaligned internal body clock, or circadian rhythm, which disrupts the natural 24-hour sleep-wake cycle.
Our desire for sleep is governed by two main processes: a homeostatic drive that builds "sleep pressure" the longer we are awake, and a circadian rhythm that dictates the timing of sleepiness and wakefulness.
You can think of it like this: the homeostatic drive is like a 'sleepiness battery' that drains the longer you are awake, making you feel increasingly sleepy. The circadian rhythm is like a timer that signals the best time for your body to recharge that battery. In depression, this timer can become unreliable, signaling your body to sleep and wake at the wrong times.
This misalignment is so central to the condition that treatments designed to reset the body clock, such as bright light therapy, can have significant antidepressant effects (Chopra et al., 2021).
How does brain health and repair factor into the sleep and depression relationship?
A protein essential for brain cell health and growth, called Brain-Derived Neurotrophic Factor (BDNF), is often found in lower levels in people with depression and insomnia.
BDNF is a key molecule involved in neuroplasticity, the brain's ability to form new connections and adapt. Low levels are associated with more severe depression and a higher risk of relapse. Sleep, particularly deep sleep, is critical for processes that support brain health.
It’s no surprise, then, that studies have found a direct link between sleep and BDNF. One study reported that insomnia can be the direct link between feeling stressed and having lower levels of this important brain protein (Giese et al., 2013). Given these profound biological links, how do they actually change the way we sleep?
How Does Depression Change Sleep Stages & The Way We Sleep?
Depression fundamentally alters a person's sleep architecture, the technical term for the pattern of their sleep stages throughout the night. The most consistent changes are a reduction in deep sleep and a significant increase in the amount and intensity of dream sleep (Chopra et al., 2021).
What is different about deep sleep in depression?
People with depression typically experience less slow-wave sleep (SWS), the deepest and most physically restorative stage of sleep. SWS, also known as Stage 3 sleep, is when the body performs essential maintenance functions, like repairing tissues, strengthening the immune system, and strengthening certain types of memories.
The reduction of this deeply restful sleep stage helps explain why people with depression often wake up feeling unrefreshed, no matter how many hours they were in bed.
What happens to dream sleep (REM sleep) in depression?
In depression, REM sleep often starts much earlier in the night, is more intense, and takes up a larger proportion of total sleep time.
Normally, you enter your first period of REM sleep about 90 minutes after falling asleep. In individuals with depression, this period, known as REM latency, is often significantly shorter. Furthermore, the eye movements during this stage are more frequent and dense, a phenomenon called increased REM density.
This combination of shortened REM latency and increased REM density is considered one of the most specific biological markers of major depression (Berger & Riemann, 1993).
But are these symptoms always a direct result of depression, or could another underlying sleep disorder be the root cause?
Could Another Sleep Disorder Be Causing My Depression Symptoms?
Yes, it is very important to consider that a primary sleep disorder, such as obstructive sleep apnea or restless legs syndrome, could be causing or worsening symptoms that look like depression.
Because of the significant overlap in symptoms like fatigue, irritability, and poor concentration, these sleep disorders can be misdiagnosed as depression, and failure to identify them can lead to years of ineffective treatment (Chopra et al., 2021).
What is the connection between depression and Obstructive Sleep Apnea (OSA)?
Obstructive sleep apnea, a condition where breathing repeatedly stops and starts during sleep, is extremely common in people with depression and shares many of the same symptoms.
The frequent drops in oxygen and arousals from sleep caused by OSA lead to severe daytime sleepiness, cognitive problems, and mood changes. The connection is so strong that about one in five patients with OSA also has depression, and conversely, one in five patients with depression has OSA (Ohayon, 2003).
Untreated OSA can make depression highly resistant to standard antidepressant treatments. For these individuals, treating the underlying sleep apnea with a therapy like CPAP (Continuous Positive Airway Pressure) can lead to dramatic improvements in mood and energy.
What is the connection between depression and Restless Legs Syndrome (RLS)?
Restless Legs Syndrome, a neurological disorder characterized by an irresistible urge to move the legs, often disrupts sleep and is more prevalent in people with depression.
The uncomfortable sensations typically occur in the evening or at night while at rest, making it very difficult to fall asleep. This chronic sleep disruption can easily lead to or worsen depressive symptoms.
The relationship is further complicated by the fact that many common antidepressants, particularly those that work on the serotonin system, can trigger or worsen RLS symptoms (Rottach et al., 2008). This makes it very important to screen for RLS before starting certain medications for depression.
Whether the sleep problems are a symptom or a separate disorder, the critical question remains: how can we effectively treat them?
How Can We Treat Sleep Problems in Depression?
Treating sleep problems in depression involves a combination of strategies, including psychotherapy specifically for insomnia, careful medication choices, and addressing any underlying primary sleep disorders.
Because sleep and mood are so interconnected, an approach that targets both simultaneously often produces the best results (Chopra et al., 2021).
Is there a therapy specifically for insomnia?
Yes, Cognitive Behavioral Therapy for Insomnia (CBT-I) is considered the first-line, gold-standard treatment for chronic insomnia and is highly effective for people experiencing it alongside depression.
CBT-I is a structured program that helps you understand how your sleep wake system works and identify and replace behaviours and beliefs about sleep that are perpetuating or worsening your sleep problems.
Studies have shown that adding CBT-I to antidepressant treatment not only resolves insomnia but also significantly improves the overall response of depression, leading to more people recovering from their depression (Manber et al., 2008).
How do antidepressants affect sleep?
Antidepressants have widely varied effects on sleep; some can cause insomnia, while others are sedating and can be used to help with sleep. A large review of many studies on second-generation antidepressants found that medications like bupropion were most likely to cause insomnia, while others like mirtazapine and fluvoxamine were the most sedating (Alberti et al., 2015).
This difference allows clinicians to tailor medication choice to a patient's specific symptoms. For someone with depression and fatigue, a more "activating" antidepressant might be chosen.
For someone with severe insomnia, a more sedating antidepressant like mirtazapine or trazodone might be used, either as the primary treatment or in combination with another antidepressant, particularly in the first few weeks of treatment while waiting for the primary medication to take effect.
Can sleep medications support antidepressant treatment?
Prescription sleep aids, sometimes called hypnotics, can be used as a short-term strategy to improve sleep, especially when insomnia is severe at the start of depression treatment.
Medications like zolpidem (Ambien) and eszopiclone (Lunesta) can help break the cycle of sleepless nights and daytime misery while waiting for an antidepressant or CBT-I to become effective. One study found that patients taking both the antidepressant fluoxetine and eszopiclone experienced a faster and greater improvement in their depression symptoms compared to those taking the antidepressant alone (Fava et al., 2006).
While these treatments offer hope, failing to address sleep issues can have the most serious consequences of all. So what is the ultimate link between poor sleep and suicide risk?
What is the Link Between Poor Sleep and Suicide Risk?
Poor sleep - including insomnia and nightmares - is a significant and independent risk factor for suicidal thoughts and behaviors, even after accounting for the presence of depression. This is one of the most important findings in sleep and mental health research in recent years. It reframes sleep disturbance from being merely a symptom of distress to being an active contributor to suicide risk (Chopra et al., 2021).
A major meta-analysis pooling data from numerous studies confirmed this dangerous link, finding that people with sleep disturbances had a significantly increased risk for suicidal ideation, suicide attempts, and death by suicide (Pigeon et al., 2012). The relationship appears to be independent of depression, meaning that poor sleep adds a separate layer of risk on top of the risk from a mood disorder.
Nightmares are a particularly potent risk factor. In patients with depression, the presence of frequent, frightening dreams is strongly associated with a higher likelihood of suicidal behavior (Agargun et al., 2007). The distress and fear from the nightmares, combined with the resulting broken and interrupted sleep, can contribute to a sense of hopelessness that is a strong psychological predictor of suicide.
The hopeful side of this discovery is that sleep is a risk factor we can change. By specifically and aggressively treating sleep disturbances like insomnia and nightmares, clinicians may be able to directly reduce a person's suicide risk.
So knowing the risks is crucial, but what practical steps can you take to start breaking this cycle today?
Practical Steps to Break the Poor Sleep And Depression Cycle
If you are struggling with depression and poor sleep, it is important to know that you are not alone and that effective treatments are available. Addressing your sleep is not a secondary concern - it is a fundamental part of your recovery.
Speak Up About Sleep: When you talk to your doctor or therapist, be as specific about your sleep problems as you are about your mood. Keep a sleep diary for a week or two to track when you go to bed, when you wake up, and how you feel during the day.
Ask About Screening: Inquire about being screened for primary sleep disorders, especially if you have symptoms of obstructive sleep apnea (loud snoring, gasping in your sleep, severe daytime sleepiness) or restless legs syndrome.
Prioritize Behavioral Therapy: If you are experiencing insomnia, ask for a referral to a provider who specializes in Cognitive Behavioral Therapy for Insomnia (CBT-I). This non-medication approach is the most effective long-term solution for chronic insomnia.
Have a Medication Review: Discuss how your current medications might be affecting your sleep. Your doctor may be able to adjust the timing of your dose or select a different medication that better suits your sleep profile.
Breaking the cycle of depression and poor sleep is possible. By viewing sleep as an active and essential component of mental health, you can take targeted steps to restore rest, improve your mood, and build a foundation for lasting well-being.
Concerned about your sleep? We always advocate talking to your primary care health provider in the first instance.
You can also talk to a NZ behavioural sleep medicine clinic like The Better Sleep Clinic for sleep help. Whether it’s an Auckland sleep clinic, Wellington sleep clinic, Christchurch sleep clinic, Hamilton sleep clinic, New Plymouth sleep clinic or anywhere in NZ, we can help. We specialise in the recommended insomnia treatment - CBT for insomnia. We also have expertise in treating other sleep disorders such as treatments for circadian rhythm disorders such as delayed sleep phase disorder, nightmare disorder, and co-occuring mental health conditions.
Book an assessment (no referral required) or, if you have a specific question, enquire about treatment and get started addressing your sleep problems today.
Frequently Asked Questions About Sleep and Depression
Q1: What is the link between sleep and depression?
A1: The link between sleep and depression is a strong, two-way relationship where each condition can cause and worsen the other. This is because sleep and mood are regulated by many of the same chemical systems and hormones in the brain (Chopra et al., 2021). Approximately 90% of people with depression experience some form of sleep disturbance. This connection means that poor sleep can be both a symptom of depression and a direct risk factor for developing it.
Q2: Can insomnia cause depression?
A2: Yes, persistent insomnia is a significant risk factor for developing depression. Research shows that people with ongoing insomnia have a substantially higher chance of being diagnosed with major depression later in life. In a landmark study, researchers found that people with persistent insomnia had a nearly 40-times higher risk of developing new-onset depression compared to those without sleep problems (Ford & Kamerow, 1989). This shows that insomnia is not just a symptom, but can be a direct pathway to depression.
Q3: How does depression affect your sleep cycle?
A3: Depression changes your sleep cycle by reducing the amount of deep, restorative sleep and increasing the amount of intense dream sleep, also known as REM sleep. It also causes REM sleep to start much earlier in the night than it normally would (Chopra et al., 2021). This reduction in deep slow-wave sleep is why you might sleep for many hours but still wake up feeling tired. The changes to REM sleep, including a shorter time to the first dream period, are considered one of the most specific biological signs of depression (Berger & Riemann, 1993).
Q4: Can sleep apnea be mistaken for depression?
A4: Yes, obstructive sleep apnea (OSA) can easily be mistaken for depression because its main symptoms—fatigue, irritability, and trouble concentrating—are nearly identical. It's estimated that about one in five people with depression also has undiagnosed OSA (Ohayon, 2003). Because OSA disrupts sleep quality and lowers oxygen levels throughout the night, it puts a major strain on the body and brain. If depression isn't improving with standard treatments, it is very important to be screened for OSA, as treating it can lead to significant improvements in mood.
Q5: Do antidepressants make sleep problems worse?
A5: Some antidepressants can make sleep problems worse, while others can help. The effect depends entirely on the specific medication, as some are more "activating" and can cause insomnia, while others are more sedating. For example, a large review of many studies found that medications like bupropion were more likely to cause insomnia, whereas mirtazapine was more likely to cause sleepiness (Alberti et al., 2015). A doctor can choose an antidepressant that best matches a patient's specific sleep issues, such as prescribing a sedating one for someone with severe insomnia.
Q6: What is the best treatment for insomnia when you have depression?
A6: The best first-line treatment for insomnia, even when it occurs with depression, is a specialized form of therapy called Cognitive Behavioral Therapy for Insomnia (CBT-I). CBT-I is a non-medication program that is highly effective at resolving chronic insomnia by addressing the thoughts and behaviors that disrupt sleep. Studies show that when CBT-I is used alongside antidepressant medication, it not only fixes the insomnia but also significantly improves depression outcomes, leading to more people recovering from their depression (Manber et al., 2008).
Q7: Is there a connection between nightmares and suicide risk?
A7: Yes, there is a very strong connection between nightmares and suicide risk, independent of depression. Frequent, distressing nightmares are considered a direct risk factor for suicidal thoughts and behaviors that we can change. The hopelessness and fear caused by nightmares, combined with the broken and interrupted sleep they cause, can be a major contributor to suicide risk (Agargun et al., 2007). Because sleep is something we can treat, addressing nightmares and other sleep problems is a critical part of suicide prevention.
References
Agargun, M. Y., et al. (2007). Nightmares, suicide attempts, and melancholic features in patients with unipolar major depression. Journal of Affective Disorders, 98(3), 267–270.
Alberti, S., et al. (2015). Insomnia and somnolence associated with second-generation antidepressants during the treatment of major depression: a meta-analysis. Journal of Clinical Psychopharmacology, 35(3), 296–303.
Berger, M., & Riemann, D. (1993). REM sleep in depression-an overview. Journal of Sleep Research, 2(4), 211–223.
Chopra, A., Bachu, R., & Peterson, M. J. (2020). Depressive disorders. In A. Chopra, P. Das, & K. Doghramji (Eds.), Management of sleep disorders in psychiatry. Oxford University Press.
Fava, M., et al. (2006). Eszopiclone co-administered with fluoxetine in patients with insomnia coexisting with major depressive disorder. Biological Psychiatry, 59(11), 1052–1060.
Ford, D. E., & Kamerow, D. B. (1989). Epidemiologic study of sleep disturbances and psychiatric disorders: An opportunity for prevention? JAMA, 262(11), 1479–1484.
Giese, M., et al. (2013). The interplay of stress and sleep impacts BDNF level. PLoS One, 8(10), Article e76050.
Manber, R., Edinger, J. D., Gress, J. L., San Pedro-Salcedo, M. G., Kuo, T. F., & Kalista, T. (2008). Cognitive behavioral therapy for insomnia enhances depression outcome in patients with comorbid major depressive disorder and insomnia. Sleep, 31(4), 489–495.
Ohayon, M. M. (2003). The effects of breathing-related sleep disorders on mood disturbances in the general population. The Journal of Clinical Psychiatry, 64(10), 1195–1200.
Pigeon, W. R., Pinquart, M., & Conner, K. (2012). Meta-analysis of sleep disturbance and suicidal thoughts and behaviors. The Journal of Clinical Psychiatry, 73(9), e1160–e1167.
Reynolds, C. F., III, Frank, E., Houck, P. R., Mazumdar, S., Dew, M. A., Cornes, C., Buysse, D. J., Begley, A., & Kupfer, D. J. (1997). Which elderly patients with remitted depression remain well with continued interpersonal psychotherapy after discontinuation of antidepressant medication? American Journal of Psychiatry, 154(7), 958–962.
Rottach, K. G., et al. (2008). Restless legs syndrome as side effect of second generation antidepressants. Journal of Psychiatric Research, 43(1), 70–75.
Written By The Better Sleep Clinic
Reviewed By Dan Ford, Sleep Psychologist
