Sleep and Depression

Why is good sleep important, especially for people who have depression?

Getting a good night’s sleep has multiple benefits.  One of the key benefits is the biological repair that occurs during sleep.  This repair contributes to immune system regulation, body cell work, blood cell repair and cardiovascular fitness.  These biological mechanisms are functions of sleep and if you are chronically sleep-deprived, the repairs your body needs are not fully completed.  Sleep disturbance increases the risk for cardiovascular disease and heart attack, and even susceptibility to the common cold.  The loss of one to two hours of sleep, three or four nights a week, can cause chronic or long-term sleep deprivation. 

Patients with depression tend to experience sleep disruption, poor sleep quality and insomnia, and those with major depression can suffer from perpetual sleep loss.  This can have a cascading effect because an increase in sleep disruption can lead to a decrease in effective responses to treatments for depression.  It can also mean an increase in depression-related episodes over a lifetime and greater time spent ill during those episodes.  Even more concerning, those with chronic sleep disturbance are more likely to develop treatment resistant or difficult to treat depression.

Can poor sleep cause depression?

We think of sleep as a core biological risk factor for depression in much the same way that high cholesterol is a risk factor for a heart attack.  Not everyone with high cholesterol will progress to a heart attack, but it increases risk and very often requires an aggressive approach with statin agents to reduce cholesterol.  In much the same way, sleep disturbance is an important biological risk factor for depression and often requires an aggressive approach to treatment.  While not everyone whose sleep is chronically disturbed will develop depression, the risk is estimated to be three to ten times greater than for those who do not experience persistent sleep problems.  It is important to intervene early to improve sleep and reduce the risk of depression.

It is possible to develop depression without ever having had a sleep disturbance, although ninety percent of depressed patients report a sleep problem.  Sleep disturbances seem to herald an episode of depression and tend to get significantly worse before an episode of depression—the longer the history of sleep disturbances, the greater the risk of depression.  Severe sleep disturbance in young children is one of the best predictors of the onset of depression in later childhood and adolescence.  Some depressed patients also sleep excessively.

Can chronic sleep problems cause other disorders or co-morbid illnesses with depression?

Sleep problems can be a risk factor for a multitude of ailments.  Chronic sleep loss can cause insulin resistance, a precursor for diabetes and obesity.  In turn, diabetes can lead to an increased risk for depression.  Sleep problems are also strongly linked to substance abuse, especially alcoholism.  It is critical that patients get help for both their sleep problems and co-occurring illnesses such as depression, diabetes or substance abuse.  These illnesses are closely linked, and treating one illness and not the others can sabotage a full recovery.  In addition, it is important that we, as a culture, reevaluate our relationship with sleep.  People tend to try to function with less and do not make the time for adequate, restful and restorative sleep.  However, healthy sleep is very important to our daily lives and long-term health—it is as important as heart health.  You would never hear someone say, “I'll be fine with less heart function.”