How Are Depression And Insomnia Related?

Updated August 27, 2020

Medically Reviewed By: Tonia Cassaday

Both depression and insomnia are common disorders that cause people some disturbance worldwide. When dealing with either of these issues, the person can have difficulty maintaining a good quality of life. Scientists estimate that 40% of Americans will struggle with insomnia at one point in their life, while an estimated 17.3 million U.S. adults will deal with the symptoms of a major depression episode at least once per year. Depression and insomnia are often linked as interrelated disorders, and they are often related in a variety of ways. In fact, some scientists have gone so far as to suggest that medical practitioners should be wary of diagnosing depression without evidence of sleep complaints by the individual. So, how are depression and insomnia related?

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It has been proven that as many as 75% of individuals with depression suffer from insomnia, suggesting that the two disorders often appear in tandem with each other. About 40% of depressed patients may also struggle with hypersomnia—a disorder that is characterized by excess sleep. It is clear that many who have experienced depressive episodes have also experienced sleep issues, but the relation between the two is influenced by a variety of factors. These factors can be categorized into two groups: insomnia and sleep disorders as subsequent symptoms of depressive episodes or insomnia and sleep disorders as antecedent symptoms or precursors to depressive episodes. However, many researchers theorize that it is actually a combination of the two that creates a vicious cycle that is difficult to break.

Insomnia as a Subsequent Symptom

According to Harvard Health, 69% of people with insomnia also struggled with depression later on. In another study, 21% of individuals reported that they struggled with a combination of hypersomnia and insomnia. These two studies suggest that depressive episodes may cause insomnia or hypersomnia. Issues with sleep due to depression can happen in a variety of ways, including changes to sleep regulation processes or side effects of prescription medication. This, in turn, may exacerbate symptoms of depression, but experts in a U.K. study note that depressive disorders without insomnia or other sleep disorders are increasingly rare.

Disturbances in Sleep Regulation

Over the past 35 years, research has determined the existence of two sleep regulation mechanisms: the circadian process and the homeostatic process, also known as the recovery process. The circadian process is the mechanism that drives individuals to sleep on a regular basis during nighttime hours. In individuals without sleep disorders, the circadian process begins at around 11 p.m. and peaks at 4 a.m. It subsequently fades around waking hours. The recovery process is another mechanism that drives sleep, but it is directly dependent on the amount of time that has passed since an individual has last slept. The difference between the two is that the circadian process regulates sleep at relatively set times each night, while the recovery process may drive an individual to sleep at an irregular time if they have spent too much time without sleep. This mechanism is what drives the body’s need for a midday nap after an individual stays awake for the entire night.

In individuals without depression or insomnia, these two mechanisms interact for a regular sleeping schedule of about seven to eight hours each night, from about 11 p.m. to 6 a.m. The brain activity that regulates these processes is called slow-wave activity and shows up most prevalently at the onset of sleep. In individuals who do not have sleep disorders, slow-wave brain activity helps an individual to fall asleep quickly and easily. It also aids them in staying asleep for the entire night. However, those who struggle with depression and sleep disorders are also found to have disrupted circadian and homeostatic processes. In these individuals, slow-wave activity is much lower. Therefore, the drive to sleep is much less powerful for individuals without depression and insomnia, as the person struggles to sleep within a regular rhythm. This disruption in sleep processes is why insomnia is much more common than hypersomnia in individuals with depressive disorders. Depression is shown to disrupt sleep mechanisms and make it much harder for an individual to fall or stay asleep on a regular basis.

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Effects from Prescription Medications

Many people struggling with depression take anti-depressant prescription medication to help them control their symptoms. While medication can be helpful in aiding depressed patients to combat mood shifts, lethargy, and other symptoms of depression, it may also induce or increase sleep disorders, especially insomnia. There are two main types of medication geared towards those with depression—medication with “activating” properties and medication with “sedative” properties. Medication with activating effects is geared towards improving energy levels and raising the moods of those with depression. Sedative medications are mainly used to regulate the moods of those with bipolar disorder and relieve anxiety. While many of these medications work wonders to relieve these symptoms, they can negatively affect a depressed patient’s sleep as well.

Activating medication can use fluoxetine or venlafaxine, which are agents that can make an individual feel more alert and reduces the urges to sleep at a regular interval. Sedative medication may have the opposite effects—medication using doxepin and mirtazapine can cause an increased need to sleep, much like prescription or over the counter sleep medication. While good for short-term use, it can cause many problems in long-term sleep regulation and make it even harder for the individual to sleep at normal intervals and for regular lengths.

Insomnia as an Antecedent Symptom

In the UK study described earlier, while 68% of individuals with depression described their insomnia symptoms as appearing at or after their depressive disorder began, 16% reported that their sleep problems began long before they experienced changes or shifts in mood. While this is a minority category, it seems to suggest that those with insomnia can develop depression as a result. This is backed up by the mood changes that come with depression as well as the studies that prove how people with insomnia can result in increased or relapsed symptoms of depressive disorders.

Insomnia and Risk of Developing Depression

While some may categorize insomnia and other sleep disorders as symptoms of a depressive disorder, research has proven that they may actually be antecedents to depressive episodes—suggesting that depression could actually be categorized as a symptom of insomnia. For younger adults along with middle-aged individuals, insomnia was found to lead to a two to four-fold increased risk for having a relapsed depressive episode later in life.

In addition, researchers have posited that complaints of episodes of insomnia almost every night for two weeks or more could be a useful indicator to predict a major depression episode for those who have struggled with depression in the past. The link is not only reserved for those who have struggled with past depression, however. In fact, research studies show that 14% of individuals who struggled with insomnia at one date developed new major depression one year later, suggesting that for some individuals, insomnia can lead to new depressive disorders and not simply exacerbate old ones.

Sleep Disorders and Mood Changes

There is no contest that major depression causes a variety of mood shifts. Mood changes and an overall feeling of lethargy are the primary symptoms of depression. The mood changes caused by insomnia may explain why individuals struggling with a variety of sleep disorders may develop depressive thoughts or habits. In general, insomnia is linked to a reduced quality of life by enhancing anxiety, frustration, hopelessness, exhaustion, and issues with concentration. Certain studies have researched how different age groups may react to insomnia and other sleep disorders and have found that many symptoms of insomnia coincide with symptoms of depression. These findings suggest that those struggling with insomnia begin to take on symptoms of depression as well and can eventually develop one of many depressive disorders.

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In the same study, there were some concerning findings revolving children and adolescents with insomnia. In adolescents, poor sleep quality has been linked to decreased performance in school as well as an increased risk of self-harm and suicidal ideation. These are two symptoms of depression that may be brought about in the first place by an adolescent’s lack of sleep. In adults, insomnia has been discovered to cause a decreased health-related quality of life, mortality, inflammation, and a greater risk for other chronic diseases, such as chronic depression.

Sleep disorders do not just cause nighttime impairments with falling and staying asleep, but daytime impairments as well. These impairments can severely lower an individual’s ability to concentrate, self-motivated, perform to peak abilities in school or work environments, initiate projects, or solve problems. The daytime impairments that individuals struggling with insomnia face may lead to low self-esteem and a decreased quality of life. These two factors can quickly lead to anxiety depression, and further exacerbate the symptoms of sleep disorders.

The Link Between Depression and Insomnia

Sleep disorders and their link to depressive disorders are varied and complex. Scientists and psychologists have determined that while there is an undeniable link between depression and insomnia, there is very little way to determine if sleep disorders present as a precursor to depression or if they are caused by depression. While research studies have shown that most depressed patients develop symptoms of insomnia after they develop depression, individuals who experience the opposite cannot be overlooked. Most likely, the two go hand in hand.

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Depression can inhibit slow-wave activity that disrupts circadian and homeostatic rhythms which regulates sleep, but the resulting insomnia can exacerbate other symptoms of depression such as anxiety, lethargy, and irritability. Luckily, due to the prevalence of these two disorders, there are many options available for individuals struggling with both depression and insomnia. Medical professionals have developed many treatments to simultaneously treat depression and insomnia and help individuals get back to the peak of health. If you are struggling with depression, consider scheduling meetings with a counselor. A licensed counselor, such as one from BetterHelp, can assist you in managing your major depression symptoms, which may be linked to better sleep quality.


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