One frequently cited symptom of depression is the inability to fall or stay asleep. Unsurprisingly, this insomnia can be extremely frustrating to the individual and therefore perpetuate or exacerbate depressive symptoms. There are many hypotheses as to why this may be, including:

• Insomnia may lead to a decreased overall quality of life or decreased performance in school or work, which could worsen depression.
• Inability to fall asleep may lead to depressive rumination during the nighttime, especially while lying awake in the dark.
• Losing control of sleep may fester feelings of helplessness or hopelessness, common symptoms in depression (Taylor, 2008).

Seemingly counterintuitive to this point, antidepressant medications may contribute to insomnia. Sleep deprivation typically results in poor mood upon awakening due to feelings of grogginess and frustration from lack of sleep the night before. However, a specific stage of sleep, known as rapid eye movement (REM) may have different effects on mood in depressed individuals. Studies have actually shown an improvement in mood following REM deprivation.

A group of popularly prescribed antidepressants are selective serotonin reuptake inhibitors (SSRIs) and these medications have been shown to inhibit REM sleep, therefore possibly contributing to mood enhancement. Rapid eye movement (REM) sleep is the stage of sleep in which the eyes move rapidly, muscle tone is diminished, and the body is in a state of paralysis. This stage of sleep is typically characterized as the stage in which we dream. Although there are many theories on whether or not REM sleep is critical, we do know that after a night of REM deprivation, the body will enter a REM rebound the following night, increasing the density of REM sleep seemingly to make up for the lack of REM received the night before. This suggests the importance of REM, which would lead us to believe that SSRIs inhibiting this stage of sleep would not be beneficial. But, in depressed individuals, REM sleep may prove detrimental, especially in regards to mood. This begs the question, is REM sleep harmful to individuals with depression? And if so, why is this the case?

It is well established that dreaming occurs during REM sleep. Although the exact purpose of dreaming has not yet been agreed upon, it has been hypothesized to be a time for processing affect, which may then affect mood upon waking dependent on the dream content (Beauchemin & Hays, 1996). For example, if during waking, a depressed individual is consumed by negative emotions and thoughts, his dreams may be plagued with negativity and result in a similar feeling the next morning.

Antidepressants may aid depressed individuals in treating their insomnia, however they tend to affect sleep architecture as well. Specifically, SSRIs, are known to inhibit REM sleep. This class of antidepressant works by blocking the reuptake of serotonin in the synapse, thus increasing the amount of serotonin available to bind to the postsynaptic cell. Those with depression have lower than normal levels of serotonin, which is ameliorated by SSRIs. Specifically in regards to sleep architecture, serotonergic activity is almost silent during REM sleep (Drago, 2008). Thus, SSRIs increasing of serotonin in the synaptic cleft would suppress REM sleep by increasing the amount of Non-REM via serotonin activity.

My dad has clinical depression and is plagued by insomnia night after night. He medicates with benzodiazepines, a class of drugs that act on GABA-A receptors that also suppress REM sleep. He wakes up feeling groggy and frustrated after not being able to sleep. It is therefore difficult to tell if suppression of REM sleep had any effect on mood because it is impossible to discriminate the effects of his insomnia from that of the benzodiazepines. More research is therefore needed to determine if REM deprivation truly improves mood in depressed individuals and why this may be the case. It is often extremely difficult for those with depression to get out of bed in the morning. The clinical implications of this research could be life changing for those individuals by improving their mood upon wakening and encouraging them to take on the day.

References:

Beauchemin, K.M., & Hays, P. (1996). Sunny hospital rooms expedite recovery from severe and refractory depressions. Journal of affective disorders, 40 (1-2), 49-51.

Drago, A. (2008). SSRIs impact on sleep architecture: Guidelines for clinician use. Clinical Neuropsychiatry, 5 (3), 115-131.

Taylor, D.J. (2008). Insomnia and depression. Sleep, 31 (4), 447-448.

Further reading:

Vogel, G.W., Vogel, F., McAbee, R.S., & Thurmond, A.J. (1980). Improvement of depression by REM sleep deprivation. New findings and a theory. Archives of General Psychiatry, 37(3), 247-253.