What cortisol blunting is

Every time I stand up to speak in front of people, something in me expects harm. Nerves is too small a word for it. It is older than that, physical, a sense that the people in front of me are going to hurt me in some way. My heart is in my throat before I have said a word.

And when someone I love says something that cuts, often nothing happens at all. No surge, no tears, no heat in the chest. A flat, slightly distant competence that can hold a conversation for an hour and feel almost nothing.

Same body, two opposite responses. I see versions of this in the women I work with, and there is a body of research on cortisol that helped me understand what is happening.

What cortisol blunting is

Cortisol is the hormone your body releases under threat. When something stressful happens, a chain of signals runs from the brain down to the adrenal glands, cortisol enters the bloodstream, you mobilise, and afterwards the system settles. In a healthy response the rise starts within minutes and peaks around twenty to thirty minutes in.

Blunting means the rise barely happens. The stress arrives and the body does not answer it.

Fries et al. (2005) proposed an explanation that still holds up: low cortisol develops after a long period of the stress system running too hot. Chronic stress keeps the alarm on for years, and eventually the system turns the volume down because the volume has been up too long. They found the pattern across chronic fatigue syndrome, fibromyalgia and PTSD.

The largest test of this against early adversity pooled thirty datasets covering 4,292 people (Bunea et al., 2017). People who had been through early-life adversity showed a blunted cortisol response to stress. The effect was strongest in those who had been maltreated, and stronger in adults than in children, which suggests the effects of a hard childhood may reach their maximum in adulthood rather than fading.

If you grew up with chronic threat, in other words, your stress system may have stopped answering long before you noticed anything was different. From the inside it does not feel like illness. It feels like being hard to rattle.

The evidence cuts both ways

It would be tidy to say childhood adversity flattens the stress response. The research does not support anything that clean.

Heim et al. (2000) found the opposite pattern in women with histories of childhood abuse: their stress systems responded more, not less, and the effect was strongest in women who were currently depressed, with a more than sixfold greater hormonal response than controls. That is sensitisation, not blunting. And a meta-analysis of 37 studies (Meewisse et al., 2007) found no overall cortisol difference between adults with PTSD and controls; differences appeared only under specific conditions, including in studies of physical or sexual abuse and in samples that included women.

So the same kind of childhood can leave one woman's system firing at everything and another's answering nothing. It depends on sex, on the type of adversity, on whether she is currently unwell, even on the time of day the sample was taken. Anyone offering a single rule is flattening data that will not flatten.

Why the flat response is not the lucky one

Blunted reactivity used to be read as the fortunate end of the spectrum. Less reactivity, less wear on the body.

Carroll et al. (2017) reviewed the evidence and found the opposite. Blunted stress responses were associated with depression, obesity, bulimia and addictions, and with what the authors describe as a failure to mobilise: lower motivation, poorer performance on anything requiring effort. A flat response looks like calm from the outside. Underneath, the system has stopped rising to meet challenge, the same way it has stopped rising to meet reward.

Sex matters here, and it matters for the women I work with. Pooling data across psychiatric disorders, Zorn et al. (2017) found that women with current depression or anxiety showed a blunted cortisol response to stress, while men with the same conditions showed an increased one.

In practice that means a woman in acute distress may show less physiological response than a healthy person. She looks steady. She sounds articulate. She is described as coping well.

What it changes in therapy

Cortisol is part of how the brain updates memory, including extinction learning, the process that exposure-based trauma therapy relies on. If the hormone is part of the mechanism, then therapy delivered into a flat physiological state is missing one of its active ingredients.

This has been tested. Patients given cortisol before exposure therapy for height phobia improved more than those given placebo, and held the gains at follow-up (de Quervain et al., 2011). The same direction appeared with spider phobia (Soravia et al., 2014). Yehuda et al. (2015) tried it with veterans in PTSD treatment: the hydrocortisone group improved more, largely because they stayed in treatment rather than dropping out. It was a small pilot and needs replication, but the direction is consistent. And young people with higher cortisol before starting trauma therapy improved more than those whose levels were low (Zantvoord et al., 2019).

None of this means you should order a cortisol panel. These are group-level effects with wide variation, and no one should interpret an individual result from a blog post. What is usable is the observation, and it costs nothing.

Here is what I actually changed. Almost all popular trauma advice points downward: slow the breath, ground, soothe. For a woman whose response to challenge has gone flat, that is more of what her body has already been doing since she was nine. What she needs is the opposite shape: small doses of activation followed by settling, with the change happening in the settling. That only works if something rises in the first place. In a stalled treatment my question now is whether anything moves in her while she speaks, and whether it comes back down afterwards.

It also reframes what looks like resistance. A client who is composed, punctual, insightful and unchanged after two years is often read as avoiding. Sometimes she is. Sometimes too little is coming online for the memory to be updated, and the useful work is building tolerable activation, not reducing it further.

What I am still working out

I hold both of my own responses without trying to reconcile them. The fear before speaking has not reduced with insight, and it may never. The flatness in close relationships is the harder one, because it does not announce itself as a symptom. It announces itself as maturity.

I have learned to ask a smaller question than I used to. Not what does this mean, but did anything move, and did it settle. I am often not sure of the answer in myself. I ask anyway.

References

Bunea, I. M., Szentágotai-Tătar, A., & Miu, A. C. (2017). Early-life adversity and cortisol response to social stress: A meta-analysis. Translational Psychiatry, 7(12), 1274. https://doi.org/10.1038/s41398-017-0032-3

Carroll, D., Ginty, A. T., Whittaker, A. C., Lovallo, W. R., & de Rooij, S. R. (2017). The behavioural, cognitive, and neural corollaries of blunted cardiovascular and cortisol reactions to acute psychological stress. Neuroscience and Biobehavioral Reviews, 77, 74-86. https://doi.org/10.1016/j.neubiorev.2017.02.025

de Quervain, D. J., Bentz, D., Michael, T., Bolt, O. C., Wiederhold, B. K., Margraf, J., & Wilhelm, F. H. (2011). Glucocorticoids enhance extinction-based psychotherapy. Proceedings of the National Academy of Sciences, 108(16), 6621-6625. https://doi.org/10.1073/pnas.1018214108

Fries, E., Hesse, J., Hellhammer, J., & Hellhammer, D. H. (2005). A new view on hypocortisolism. Psychoneuroendocrinology, 30(10), 1010-1016. https://doi.org/10.1016/j.psyneuen.2005.04.006

Heim, C., Newport, D. J., Heit, S., Graham, Y. P., Wilcox, M., Bonsall, R., Miller, A. H., & Nemeroff, C. B. (2000). Pituitary-adrenal and autonomic responses to stress in women after sexual and physical abuse in childhood. JAMA, 284(5), 592-597. https://doi.org/10.1001/jama.284.5.592

Meewisse, M. L., Reitsma, J. B., de Vries, G. J., Gersons, B. P., & Olff, M. (2007). Cortisol and post-traumatic stress disorder in adults: Systematic review and meta-analysis. British Journal of Psychiatry, 191, 387-392. https://doi.org/10.1192/bjp.bp.106.024877

Soravia, L. M., Heinrichs, M., Winzeler, L., Fisler, M., Schmitt, W., Horn, H., Dierks, T., Strik, W., Hofmann, S. G., & de Quervain, D. J. (2014). Glucocorticoids enhance in vivo exposure-based therapy of spider phobia. Depression and Anxiety, 31(5), 429-435. https://doi.org/10.1002/da.22219

Yehuda, R., Bierer, L. M., Pratchett, L. C., Lehrner, A., Koch, E. C., Van Manen, J. A., Flory, J. D., Makotkine, I., & Hildebrandt, T. (2015). Cortisol augmentation of a psychological treatment for warfighters with posttraumatic stress disorder: Randomized trial showing improved treatment retention and outcome. Psychoneuroendocrinology, 51, 589-597. https://doi.org/10.1016/j.psyneuen.2014.08.004

Zantvoord, J. B., Ensink, J. B. M., Op den Kelder, R., Wessel, A. M. A., Lok, A., & Lindauer, R. J. L. (2019). Pretreatment cortisol predicts trauma-focused psychotherapy response in youth with (partial) posttraumatic stress disorder. Psychoneuroendocrinology, 109, 104380. https://doi.org/10.1016/j.psyneuen.2019.104380

Zorn, J. V., Schür, R. R., Boks, M. P., Kahn, R. S., Joëls, M., & Vinkers, C. H. (2017). Cortisol stress reactivity across psychiatric disorders: A systematic review and meta-analysis. Psychoneuroendocrinology, 77, 25-36. https://doi.org/10.1016/j.psyneuen.2016.11.036