A blunted response of the hypothalamic-pituitary-adrenal axis immediately after exposure to traumatic events has been proposed as a risk factor for posttraumatic stress disorder (PTSD). Accordingly, administration of hydrocortisone in the aftermath of a traumatic event is indicated. This study consisted of a randomized, placebo-controlled, double-blind trial investigating whether a single intravenous dose of hydrocortisone administered within 6 hours after exposure to trauma would reduce the incidence of PTSD at the 13-month follow-up.

A total of 118 consented patients with acute stress symptoms were administered a single intravenous bolus of hydrocortisone/placebo within 6 hours of the traumatic event. Blood samples were taken before hydrocortisone administration.

At 13 months, the hydrocortisone group did not differ from the placebo group regarding PTSD prevalence or symptom severity. However, a significant interaction between time of the trauma (ie, night, when cortisol’s level is low) and treatment was found. Specifically, a lower prevalence of PTSD was found at the 13-month follow-up in the hydrocortisone night group.

Administration of hydrocortisone within 6 hours of the traumatic event was not effective in preventing PTSD compared to placebo. However, nocturnal administration (when cortisol levels are low) may suggest a new venue for research.