Glucocorticoids, including cortisol, are a group of stress hormones that increase after experiencing stress. Cortisol was originally found to be present as a mechanism to protect the body from the physical demands of stress. Later, high levels of cortisol were connected with depression and other stress-related disorders, implying that high levels of cortisol for a long period of time can diminish the psychological capacity to deal with stress.
Following this assumption, drugs such as mifepristone that restrict glucocorticoid activity were tested as treatments for depression. In contrast, separate data suggests high glucocorticoid levels may prevent the occurrence of PTSD.
A new study in Biological Psychiatry supports this hypothesis. Rajnish Rao and his colleagues experimented using an animal model of PTSD proving that high levels of glucocorticoids during episodes of grave stress prevent anxiety-like behaviors by regulating synaptic connectivity in the basolateral amydgala area of the brain.
Dr. John Krystal, editor of Biological Psychiatry comments:
"It seems, increasingly, that the 'trauma' in posttraumatic stress disorder is the impact of stress on brain structure and function. The study by Rao and colleagues provides evidence that glucocorticoids may have protective effects in their animal model that prevent from these changes in synaptic connectivity, potentially shedding light on protective effects of glucocorticoids described in relation to PTSD."
These researchers were able to examine counterintuitive reports stating individuals with lower levels of cortisol are more inclined to develop PTSD and in turn cortisol treatment reduces the main symptoms of PTSD. Additionally, they discovered a possible cellular mechanism in the amygdala, the emotional center of the brain.
These findings are consistent with reports on the protective effects of glucocorticoids against forming symptoms of PTSD brought on by traumatic stress.
During this study, two manipulations were successful together in resetting the number of synapses in the amygdala restoring anxious behavior to normal in rats. Surprisingly, these high and low numbers of synapses emerged as predictors of high and low anxiety levels respectively.
Senior author Professor Sumantra Chattarji from the National Centre for Biological Sciences in Bangalore, India, concludes: "With the increasing costs and suffering associated with PTSD victims, it is our hope that basic research of the kind reported in this study will help in developing new therapeutic strategies against this debilitating disorder."
Written by Kelly Fitzgerald