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  • Updated 11.24.2023
  • Released 12.23.1994
  • Expires For CME 11.24.2026

Sleep and depression



There is increasing interest in the connection between sleep disturbances and psychiatric disorders. It has been established that 4.4% to 20% of the general population suffers from a major depressive disorder, which is frequently associated with insomnia and evening circadian preference (61). Disturbances of circadian rhythms are a cardinal feature of psychiatric dysfunctions, including major depressive disorder, suggesting that biological clocks may play a role in their pathophysiology. In addition, the habit of sleeping at a time that is out of phase with the body's other biological rhythms is a common finding in patients with depression (61; 55). Depression is associated with longer sleep latency, frequent and long awakenings, or early morning awakening associated with poor sleep satisfaction. Depression treatment studies indicate poorer outcomes for those with comorbid sleep disturbances because even if half of adults with major depression receive pharmacotherapy, at least a quarter of them do not experience remission. In addition, pharmacotherapy including the selective serotonin reuptake inhibitors and duloxetine, associated with unpleasant side effects, increased sleep disturbances. In this chapter the author describes the most common sleep disturbances observed in depression, focusing on the link between the presence of sleep disorders and greater depressive symptom severity, worse treatment outcomes, and greater risk of relapse.

Key points

• Sleep disorders are common in depression.

• Symptoms of insomnia exceed 80% in those who are concurrently depressed.

• Insomnia predicts the onset, course, and reoccurrence of unipolar depression.

• Insomnia can lead to depression, or common causalities underlie both disorders.

• Prevention of sleep disturbance is best achieved by preventing the onset of depression.

Historical note and terminology

Sleep disturbance in depression has been described at least as far back as the ancient Greeks. Throughout history there have been great numbers of famous people who are known to have suffered from insomnia and depression. It is a well-known fact that for most of his life Winston Churchill suffered from insomnia and depression that persisted until old age. Churchill referred to this depressive state as his "black dog." The famous British mathematician, astronomer, and philosopher, Sir Isaac Newton, one of the leading pioneers of scientific discovery, was also known to have suffered from inability to sleep and depression.

Mood disorders, including depressive disorders and bipolar disorders, are commonly associated with sleep disturbances. Major depressive disorder or unipolar depression is diagnosed in people who have experienced one or more major depressive episodes. The essential feature of a major depressive episode is a period of at least 2 weeks during which there is depressed mood or a loss of interest in pleasure, together with at least four of the following symptoms: (1) weight gain or significant weight loss when not dieting; (2) insomnia or hypersomnia; (3) psychomotor agitation; (4) fatigue or loss of energy; (5) feelings of worthlessness or excessive or inappropriate guilt; (6) diminished ability to think or concentrate; (7) recurrent thoughts of death, suicidal ideation, or a specific plan to commit suicide. The Diagnostic and Statistical Manual of Mental Disorders (DSM-V) criteria for major depressive episode include insomnia or hypersomnia nearly every day.

Insomnia is seen in 80% to 85% of patients with depression and it is bidirectionally related to anxiety and depression. People with insomnia have significantly higher levels of depression than people not having insomnia; increased insomnia frequency and increased numbers of awakenings are related to increased depression and anxiety, which is also among adolescents and university students.

Less frequently, in about 15% to 20% of cases, patients with depression complain of hypersomnia, with prolonged sleep episodes at night or increased daytime sleepiness and fatigue. Co-occurring insomnia and hypersomnia appear to be a unique risk factor for greater functional impairment and use of treatment (89).

Depression may be also associated with other sleep disturbances, such as restless legs syndrome, obstructive sleep apnea syndrome (47; 72), narcolepsy (01), and REM sleep behavior disorder (85).

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