Steroid Dexamethasone Facilitates Fear Extinction
A 2017 article by Vasiliki Michopoulos and colleagues in the journal Psychoendocrinology reports that the potent steroid dexamethasone reduced the fear-potentiated startle response in patients with post-traumatic stress disorder (PTSD) but not in healthy controls. Dexamethasone acts on glucocorticoid receptors to suppress the body’s secretion of cortisol.
In the study, participants both with and without PTSD were taught to associate a picture of a blue square or a purple triangle with an uncomfortable short blast of air to the larynx (voicebox) and a loud burst of broadband noise in the participants’ headphones.
Some participants were given a placebo the night before the study, while others received a 0.5 mg dose of dexamethasone. Those who received dexamethasone the night before the study acquired a startle response to the blue square or purple triangle as much as other participants.
People without PTSD were easily able to eliminate their fear of the visual symbol when it was no longer linked to the noise and the blast of air, regardless of whether they had taken dexamethasone. However, among those with PTSD, only those who received dexamethasone were able to eliminate this fear-potentiated startle response and properly discriminate between safe and unsafe signals. People with PTSD who received the placebo maintained the fearful response to the blue square or purple triangle and startled in response to safe symbols.
People with PTSD may have difficulty learning to inhibit their fearful responses to stimuli that are no longer dangerous. In this study, the patients with PTSD continued to startle even after repeated presentations of the visual symbol without any accompanying air blast, while the controls showed excellent extinction of the response. After dexamethasone, but not placebo, patients with PTSD were just as successful in extinguishing the fear potentiated startle response as the controls. The authors conclude that dexamethasone could help facilitate extinction-based interventions used in PTSD, such as exposure therapy delivered during cognitive behavioral therapy or virtual reality exposure therapy.
Acute Steroid Injection May Ward Off PTSD
Low cortisol after a trauma is a risk factor for developing chronic post-traumatic stress disorder (PTSD). Researcher Joseph Zohar studied has been researching the effects of steroids on the development of PTSD and presented some findings at the 2014 meeting of the International College of Neuropsychopharmacology.
Twenty-five patients who experienced a traumatic event and showed acute stress symptoms were given either a single high-dose injection of hydrocortisone (100–140 mg) or a placebo within six hours of the trauma. Follow-up evaluation took place after two weeks, one month, and three months. Those who received this single high dose of hydrocortisone had lowered stress symptoms and less subsequent PTSD compared to those who received placebo.