Research finds compelling links between insomnia and greater mood instability, increased stress, and the exacerbation of existing mental illnesses including depression.

By Jeff Rodgers, DMD, DABDSM, DASBA

Insomnia is the most common sleep disorder, and of those who have the condition, about 33% experience it chronically.1 Due to its prevalence, people with insomnia may disregard their symptoms as “annoying but normal” and neglect addressing them—but insomnia is a significant health issue that can greatly impact a person’s day-to-day life, especially their mental health. Just a few of the negative mental health consequences related to untreated insomnia include greater mood instability, increased stress, and the exacerbation of existing mental illnesses. Over time, such consequences can cause a great deal of tension and undesirable outcomes in the person’s interpersonal relationships, on the job, and to their overall quality of life.

Greater Mood Instability & Less Impulse Control

Acute sleep deprivation can create disruptions in a person’s mood and lower their ability to effectively handle even minor conflicts. This happens because lack of sleep causes a person to experience heightened anger while simultaneously impairing the brain’s ability to adapt to frustrating circumstances.2 For those with chronic insomnia, these issues may become exacerbated, making them a constant in their life.

Additionally, sleep deprivation can lower the brain’s ability to control impulses because the prefrontal cortex, the brain’s center for complex tasks, is impaired. One study found that sleepiness caused an increase in impulsive behaviors including gambling and Internet addiction.3

Compound this over time, and a person with chronic insomnia is likely to experience serious difficulties in relationships and problems associated with poor decision making, both of which can significantly decrease their quality of life.

Increased Stress

Stress is our body’s response to the challenges of life. Some stress, such as acute stress, can be beneficial for getting through a tough situation. A person may experience acute stress after missing an important deadline or losing a valuable item, for example. It is short-term and generally manageable.

But some types of stress cause damage to the body and mind. For example, chronic stress, in which a person has high levels of stress for an extended period, can lead to a host of health conditions.

Insomnia and chronic stress are intrinsically connected. Chronic stress can cause insomnia, and the resulting insomnia can make stress even worse. The two are so interconnected that they can create a puzzling chicken-and-egg situation: did long-term insomnia cause the chronic stress condition or vice versa? The truth is there are a variety of causes and circumstances that can contribute to both insomnia and stress.

The important thing when it comes to these two conditions is to get treatment. Untreated chronic stress can increase risk for a number of health concerns, including high blood pressure, obesity, heart disease, and a weakened immune system. Similarly, there are many serious health implications for chronic untreated insomnia, including stroke, diabetes, inflammation, and shortened life expectancy.4

Exacerbation of Existing Mental Illnesses

The bidirectional relationship between sleep and stress is just one instance that underscores just how connected mental health is to sleep. Bipolar disorder and depression, for example, both have insomnia as a key part of their DNA.

Sleep disturbance is a core symptom of bipolar disorder.5 During manic periods, 69% to 99% of patients experience a reduced need for sleep. Even in between episodes, sleep deprivation can increase risk for relapse and suicide attempts.6

For individuals with depression, the statistics and risks are similar: nearly three-quarters have insomnia symptoms, with 40% of depressed young adults and 10% of older patients experiencing hypersomnia (excessive sleepiness or drowsiness).7 Such sleep disorders can cause significant distress and are a strong risk factor for suicide.


Jeff Rodgers, DMD, DABDSM, DASBA

The connection between insomnia and mental health conditions calls for successful management of sleep as a key treatment component for those living with mental illness, to improve quality of life and reduce the risk for condition exacerbation and resurgence.

Treating insomnia requires a deep dive into its underlying causes. Patients seeking help for the condition should be presented with questions about their mental health and physical health. In addition, working with the patient to identify negative sleep habits that may be contributing to insomnia and offering methods of course-correction is crucial. Cognitive behavioral therapy can also be helpful to identify and replace thoughts and actions that may be contributing to sleep deprivation with those that promote sleep.

Treating insomnia may be a long game for some patients, but it is a worthwhile endeavor. Correcting sleep in most cases will lead to better mental health outcomes, and ultimately, greater quality of life.

Dental sleep medicine practitioner Jeff Rodgers, DMD, D-ABDSM, D-ASBA, has been in private practice for over 20 years. He practices at Sleep Better Georgia in Dunwoody.


1. Bhaskar S, Hemavathy D, Prasad S. Prevalence of chronic insomnia in adult patients and its correlation with medical comorbidities. J Family Med Prim Care. 2016;5(4):780-4.

2. Krizan Z, Hisler G. Sleepy anger: Restricted sleep amplifies angry feelings. J Exp Psychol Gen. 2019 Jul;148(7):1239-50.

3. Grant JE, Chamberlain SR. Sleepiness and impulsivity: Findings in non-treatment seeking young adults. J Behav Addict. 2018;7(3):737-42.

4. Cappuccio FP, D’Elia L, Strazzullo P, Miller MA. Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies. Sleep. 2010;33(5):585-92.

5. Harvey AG, Talbot LS, Gershon A. Sleep disturbance in bipolar disorder across the lifespan. Clin Psychol (New York). 2009 Jun;16(2):256-77.

6. Sylvia LG, Dupuy JM, Ostacher MJ, et al. Sleep disturbance in euthymic bipolar patients. J Psychopharmacol. 2012 Aug;26(8): 1108-12.

7. Nutt D, Wilson S, Paterson L. Sleep disorders as core symptoms of depression. Dialogues Clin Neurosci. 2008;10(3):329-36.

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