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Good news for people with specific phobias: Cortisol may increase efficacy of exposure therapy.

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


Originally posted at Field of Science on April 21, 2011, where it was a Research Blogging Editor's Selection.

Earlier this week I shared the story of my specific phobia of vomiting, and today I'm going to blog about an article recently published in PNAS (open access!) about the efficacy of cortisol supplementation during exposure therapy for specific phobias.

Cortisol, which I have bloggedaboutbefore, is a major endocrine involved in the human stress response (corticosterone, a closely-related steroid, serves the same purpose in many other animals). Stressful experiences are also learning experiences for many individuals ("I'll never do that again..." etc.), and cortisol seems to have an impact on the building and retrieval of memories. Specifically, it appears to promote the storage of new memories while simultaneously repressing the retrieval of already stored memories. This makes it a potentially beneficial supplement during exposure therapy, which is based on replacing traumatic memories of objects, events, or situations with repeated non-traumatic exposures to "unlearn" the fear.


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In this study, the authors compared two groups of people undergoing exposure therapy for their fear of heights: a control group that received a placebo and an experimental group that received 20mg of cortisol one hour before their treatment sessions. (The two groups did not differ in baseline levels of cortisol, and the experimental group did have higher levels of circulating cortisol, both validated by saliva samples.)

Exposure therapy reduced self-reported fear in both groups, but the effect was amplified in the cortisol group, both 3-5 days after treatment and at follow-up a month later. This suggests that cortisol supplementation increases the efficacy of exposure therapy in people who have specific phobias of heights. However, more studies need to be done to see if the cortisol treatment has continuing long-term effects in the fear response.

I hesitate to jump for joy because I have no idea if exposure therapy (with or without cortisol) would be effective or even possible for my specific phobia. I am not sure how well these results can be extrapolated to other specific phobias, although previous research suggests it may also be beneficial in arachnophobia and social phobia.


de Quervain, D., Bentz, D., Michael, T., Bolt, O., Wiederhold, B., Margraf, J., & Wilhelm, F. (2011). Glucocorticoids enhance extinction-based psychotherapy Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1018214108

"Life creates [the Force], makes it grow. Its energy surrounds us and binds us. Luminous beings are we, not this crude matter," Yoda explains in The Empire Strikes Back, gesturing to Luke's physical body. This quote is striking because of the apt juxtaposition of the wonder of life with its often disgusting vessel. Like many other animals, we secrete, excrete, expectorate, defecate, flatulate, regurgitate, urinate, circulate, masticate, menstruate, ejaculate, and ventilate. We are filled with gas and feces and blood and guts and mucus and any number of rude things. Life as we know it is possible because of the countless impolite things we do every day. Are we luminous beings? Perhaps, but that's neither here nor there. This blog is about the crude matter that keeps us alive.

Michelle Clement has a B.Sc. in zoology (with a minor in American culture studies) and a M.Sc. in organismal biology from The Ohio State University. Her thesis research was on the ecophysiology of epidermal lipids and water homeostasis in house sparrows. She now works as a technical editor for The American Chemical Society. Her broader interests include weird human and animal physiology, obesity and enteric physiology, endocrinology, sexual and reproductive health, personal genomics, anthropology (physical and cultural), sociology, and science education and communication. She lives in Ohio with her boyfriend and two cats.

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