Does Cortisol Affect Depression?

The Relationship Between Stress, Cortisol, Stress, and Depression

woman appearing distressed with blurry view of city in background
What is the role of cortisol in depression, and how does this relate to serotonin levels and stress?. Ronald Regidor/Moment/Getty Images

What is the relationship of cortisol, serotonin, stress, and depression? We have known for a long time that people with depression tend to have reduced levels of serotonin in the brain and elevated levels of cortisol in their bloodstream, but what does this mean?

What is Cortisol?

Cortisol is an important hormone produced by the adrenal glands, small endocrine glands that sit on top of our kidneys. Cortisol is secreted by the body in response to stress, and is one of the hormones our bodies secrete in what is known as the "fight or flight response." Cortisol, in turn, plays an important role in everything from how our bodies use glucose (sugar), to our blood pressure, to the function of our immune systems.

In small doses, cortisol secretion has many benefits. It prepares us for challenges, whether physical or emotional, provides us with bursts of energy in the face of trauma, and bursts of immune activity when confronted with infectious diseases. Following this cortisol induced activation state, however, our bodies go through a necessary relaxation response.

The problem appears when we are exposed to continuous or prolonged stress, resulting in the continuous production of cortisol. Prolonged elevated levels of cortisol can result in high blood sugar, high blood pressure, reduced ability to fight infections, and increased fat storage in the body.

In other words, in the short term an increase in cortisol secretion may aid in survival, but long term elevations may do the opposite.

Cortisol Levels Tend to be Higher in Depressed People

It is known that in people who are not depressed the level of cortisol in the bloodstream peaks in the morning, then decreases as the day progresses.

In people who are depressed, however, cortisol peaks earlier in the morning and does not level off or decrease in the afternoon or evening. The resultant elevation in afternoon and evening cortisol levels have been found in roughly half of people living with depression. Although the exact mechanism that may lead to depression is uncertain, clinical studies suggest that chronically elevated cortisol may induce clinical depression by somehow affecting the way serotonin, a neurotransmitter that influences mood, is transmitted.

Regardless of whether or not cortisol has a direct role in depression, however, we know that chronic stress can lead to elevated cortisol levels, which in turn is connected with conditions such as metabolic syndrome.

Cortisol and Depression Treatment

While we are still uncertain about if and how cortisol affects serotonin levels or other aspects of depression, cortisol is important in another way as well for those with depression. It's been found that people with elevated cortisol levels are less responsive to treatment with psychotherapy. This would imply that therapies which may reduce cortisol levels, such as stress management, would be an important part of a depression treatment regimen.

How Stress Affects the Brain

When we are under stress, our brains tell our bodies to start putting out stress hormones, such as cortisol and adrenaline, to try to cope. While these stress hormones can be helpful in moderation, having them operating throughout the day for most of the day because of ongoing stress is exhausting and may cause the neurotransmitters in our brains, like serotonin, to stop functioning correctly, potentially sending us into depression.

Natural Ways to Increase Serotonin

Serotonin is a neurotransmitter in the brain that appears to influence mood, appetite and sleep, among other things.

It is the neurotransmitter that has been affectionately coined our body's "feel good" chemical. There are some natural ways that may boost your serotonin levels beyond just antidepressant. These include:

  • Exercise. While it has been clearly demonstrated that physical exercise boosts mood, many studies have also shown that it increases serotonin levels in the brain.​
  • Sleeping well. Getting enough sleep and keeping a regular sleep pattern also helps stave off depression and improves mood.​
  • Light exposure. Sunlight is preferable, but especially in winter months, even getting light by way of a therapy light can help. ​
  • Watch the caffeine. Caffeine may lower serotonin levels, so consider decreasing or even stopping your intake. 

​​Ways to Reduce Stress

In addition to boosting serotonin, reducing your stress can help mellow out the effects of depression (perhaps by reducing chronically elevated cortisol levels.) Here are some good ways to reduce your stress:

  • Meditation. Using meditation has been proven to reduce stress and anxiety, boost mood and even help physical ailments like headaches.​
  • Relaxation. Make sure you take some time every day, even if it's just a few minutes, to completely relax your body and your mind.​
  • Take your pet for a walk. As noted above, exercise is good for your mood and helps you feel good about yourself, plus interacting with your beloved pet will also help you relax.​
  • Get a massage. Massage has proven benefits to relieve stress, anxiety and tension.​
  • Indulge in some art therapy. Coloring, painting, drawing, photography...whatever your pick, engaging your inner artist can help drive away stress.​
  • Keep a journal. Giving yourself a place to let it all out can be not only freeing, but help you deal with stress you may not have even realized you had.​ Learn more about using journaling as a stress management tool.
  • Do something you love every day. Even if it's just for ten minutes, being able to read the next chapter of that novel you're absorbed in or playing your guitar will help you blow off some steam.

If you're still feeling stressed, check out these 25 ways to begin relieving stress today.

Bottom Line on Cortisol, Stress, Serotonin and Depression

There are many ways cortisol may contribute the development of depression, either by affecting serotonin levels or through other endocrine pathways (though we did not address the specific molecular pathways that have been postulated here.) What is most important is to understand that elevated cortisol levels can hamper effective depression therapy, and the best way to lower cortisol levels is not through a few quick stress reduction exercises but through adopting a stress management lifestyle. Learn what is meant by a stress management lifestyle today whether you're living with depression or not.

Sources:

de Kloet, E., Otte, C., Kumstra, R., Kok, L., Hillegers, M., Hasselmann, H., Kliegel, D., and M. Joels. Stress and Depression: A Crucial Role of the Mineralocorticoid Receptor. Journal of Neuroendocrinology. 2016. 28(8).

Peacock, B., Scheiderer, D., and G. Kellermann. Biomolecular Aspects of Depression: A Retrospective Analysis. Comprehensive Psychiatry. 2016. 73:168-180.

Fischer, S., Strawbridge, R., Herane Vives, A., and A. Cleare. Cortisol as a Predictor of Psychological Therapy Response in Depressive Disorders: Systematic Review and Meta-Analysis. British Journal of Psychiatry. 2016 Dec 1. (Epub ahead of print).

Zorn, J., Schur, R., Boks, M., Kahn, R., Joels, M., and C. Vinkers. Cortisol Stress Reactivity Across Psychiatric Disorders: A Systematic Review and Meta-Analysis. Psychoneuroendocrinology. 2016. 77L25-36.

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