Many experts believe that sleep deprivation and depression can go hand in hand. Disrupted or dysfunctional sleep can lead to feelings of physical fatigue, cognitive impairment, and depressed mood. Conversely, feelings of depression can make it difficult to fall asleep or stay asleep. Often, disorders that cause sleep impairment, such as restless legs syndrome (RLS) or sleep apnea, can cause depressive symptoms. People suffering from depression often experience an improvement in sleep quality once they receive treatment, and people suffering from sleep disorders may experience enhanced mood if treatment is able to improve their sleep quality.
Patients with depressive symptoms are often carefully screened for disorders that can disrupt sleep, and patients with sleep problems are often tested for depression. Disturbed sleep is considered one of the most definitive symptoms of depression, but physical conditions and psychological stress can cause disturbed sleep as well. Sometimes, a patient's sleep deprivation and depression are so closely intertwined that doctors can't determine which one came first.
Chronic sleep deprivation and depression can often occur together because sleep deprivation can make people moody, snappish, and unhappy. These symptoms can mimic depression so closely that many may be misdiagnosed with a depressive disorder when, in fact, they are suffering from a sleep disorder.
Not everyone who suffers chronic sleep deprivation becomes depressed. Physicians typically believe, however, that adequate sleep is crucial to good physical and mental health. The feelings of physical and mental fatigue brought on by chronic sleep deprivation can make it hard for people with insomnia to enjoy themselves. Fatigue can make exercise difficult, and lowered activity levels can often exacerbate sleep problems. If the situation becomes severe enough, chronic sleep deprivation can lead to health problems, which can further impact mood, since people who feel physically unwell often feel psychologically unwell as a result.
Not everyone who suffers from a depressive disorder develops insomnia. Some people who suffer depressive disorders sleep more than is considered normal. In general, any abnormality with sleep is considered a possible symptom of depression.
Sleep deprivation and depression are so closely linked that, often, treating one of these disorders can improve the other. People suffering from depressive disorders often begin to sleep better as treatment relieves their symptoms of depression. This can occur because the feelings of sadness, guilt, anxiety, and helplessness that often accompany depression can make it hard to fall asleep. Many people with depression find themselves lying awake at night, unable to sleep because they can't relax. By the same token, people struggling with sleep disorders often begin to feel more generally cheerful when they receive treatment and begin to enjoy better sleep.