How Do Sleep and Depression Influence Each Other?

Introduction

Sleep disorders occur in most patients suffering from depression. Some doctors even hesitate to diagnose depression if the patient does not report a sleep problem. The quality of sleep and depression influence each other − lack of sleep can contribute to the onset of depression, and conversely, depression typically leads to worsening sleep quality. For patients with depression, it is often difficult to fall asleep or stay asleep throughout the night; they may sleep too much or feel very sleepy during the day. Sleep problems can worsen depression, and if persistent, they increase the risk of relapse in patients who are successfully treated for depression. 

Which sleep disorders are associated with depression and why do they occur?

Sleep disorders associated with depression include insomnia, which occurs in about 75% of patients, obstructive sleep apnea, and hypersomnia, which affect around 20% and 15% of patients, respectively. In many patients, different types of sleep disorders may even alternate within one depressive episode, such as insomnia turning into hypersomnia. Sleep disorders are likely related to changes in the functioning of the neurotransmitter serotonin and can trigger the activation of the stress axis, disrupt circadian rhythms, and increase the risk of developing depression. 

Diagnosing and treating depression with regard to sleep disorders

Proper understanding of the relationship between depression and sleep is essential for improving sleep quality and choosing appropriate therapy. The attending physician can monitor the improvement or worsening of the patient's condition and symptoms using various tests. They can also refer the patient to a sleep specialist to determine if the patient shows signs of sleep apnea or restless legs syndrome, which can cause or worsen depression symptoms. 

Fortunately, effective treatment options are currently known. These include antidepressants, which effectively treat depression and positively influence sleep. Psychotherapy, especially cognitive-behavioral therapy (which can be directly targeted at insomnia), and interpersonal therapy play important roles in the therapy. Ideally, treatment includes both pharmacological and psychological approaches. Patients themselves can support treatment by changing their lifestyle.

Practical recommendations for patients

The following recommendations can be provided by specialists to patients with depression who suffer from sleep disorders.

• Visit a psychotherapist. The therapist can teach the patient mechanisms to cope with problematic nights, in addition to using the mentioned psychotherapeutic methods.
• Maintain a consistent sleep and wake time. For patients with depression, it is often difficult to maintain a daily routine. Establishing a daily routine before bedtime allows the body to calm down in the evening and prepare for sleep.
• Adhere to proper daytime sleep duration. Lack of sleep or poor-quality sleep may lead to the need for daytime naps. Studies have shown that a daytime nap, known as a power nap, can help regulate emotions, reduce sleepiness, and lead to overall performance improvement. The ideal duration is 10−20 minutes − a power nap lasting longer than 20 minutes could interfere with falling asleep at night, while a nap shorter than 10 minutes is not long enough to produce desirable results.
• Avoid alcohol. Studies have shown that drinking alcohol before sleep worsens falling asleep and maintaining sleep throughout the night, disrupts the sleep cycle, and shortens the REM sleep phase. 
• Spend time outdoors. Exposure to sunlight helps the body set the circadian rhythm. After sunset, the hormone melatonin, which promotes sleep and facilitates falling asleep, begins to be produced.
• Exercise regularly. Research shows that light and dynamic exercise is associated with very good or good sleep quality. Exercise should ideally take place in the morning; evening exercises could interfere with the ability to fall asleep.

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Source: Newsom R. Depression and sleep. Sleep Foundation, 2021 May 19. Available at: www.sleepfoundation.org/mental-health/depression-and-sleep