Sleep and Depression: An Endless Cycle

A common symptom of many sleep disorders is depression. Those with depression report having difficulty sleeping. This correlation represents that both sleep and depression affect and are affected by each other. It is not certain whether one disorder is more dominant; however, sleep deprivation affects mood and a negative mood affects sleep, making an endless cycle of mood and sleep disorders.

Because sleep disorders are so closely related to depression, misdiagnosis is very common. Misdiagnosis makes treatment difficult and costly as trial and error with expensive medications can add up with little relief from symptoms. This correlation also makes it so that some treatments for depression work for certain sleep disorders such as prescription medication that treat depression and cause drowsiness.

Many of the same neurochemical and physiological processes involved in regulating sleep are also used in regulating mood. Women and older individuals are more likely to experience depression.  These groups are also amongst those that report the most difficulty sleeping. Those with depression also commonly report fragmented sleep and early morning awakening before fully rested. 

Common sleep disorders that list depression as a main symptom include:

• Narcolepsy
• Insomnia (chronic and irregular): Those with insomnia are ten times as likely to become depressed.
• Restless legs syndrome: Forty percent of those diagnosed with RLS experience symptoms of depression if a sleep disorder were not already considered.
• Obstructive sleep apnea: Those with depression are five times more likely to develop OSA based on a European study; however, with regular use of a CPAP (continuous positive airway pressure) machine, both OSA and depression symptoms were suppressed.

It is not certain if depression causes sleep disorders or sleep disorders cause depression, but it is clear that the mind is truly affected by sleep deprivation. Because some sleep disorders influence the ability to do certain tasks and can affect activities while awake, it is reasonable to believe that depression could stem from this added difficulty in life. Additionally, it had been shown that depression and related trouble sleeping could be genetically related just as restless legs syndrome and obstructive sleep apnea are thought to be genetic.

Studies have also shown that those experiencing symptoms of depression tend to have decreased amount of slow wave sleep (SWS) and increased brain activity during rapid eye movement sleep (REM sleep).  Therefore, those with depression experience more dreams.

Though the depth of the connection between sleep and depression is not yet certain, one thing is evident: Do not undervalue sleep. It is vital to well-being and happiness and can make the difference in living a fulfilled life. Taking steps to improve sleep hygiene and sleep environment can help to ease the symptoms of both depression and sleep disorders and stop the endless cycle of sleep and mood disruption.

Bibliography:

1. Carskadon, Mary A. Encyclopedia of Sleep and Dreaming. New York: Macmillan Pub., 1993.

2. National Sleep Foundation—Depression and Sleep; http://www.sleepfoundation.org/article/sleep-topics/depression-and-sleep