Today the world is remembering the terrible events of thirteen years ago, when one of the world’s worst terrorist attacks destroyed the World Trade Center in New York. But for some people, the memories don’t just surface every year; they have to live with daily reminders that leave them living in a half-life of trauma and fear.

Some are survivors, some are witnesses, but they share the suffering caused by an anxiety disorder known as Post Traumatic Stress Disorder (PTSD). PTSD, which has only been a recognised medical condition for the past three decades, comprises a broad-ranging symptom cluster including insomnia, nightmares, inability to concentrate, hypersensitivity, detachment from others, severe anxiety, uncontrollable thoughts, and phobias related to anything that reminds them of the fateful day.

After experiencing trauma, the body releases stress hormones and chemicals which normally subside shortly after the event has occurred. In those afflicted with PTSD, these stress responses continue long after the event, sometimes for many years.

Doctors are not sure why PTSD occurs in some people but not in others, but past emotional trauma can increase the risk, as can genetic predisposition.

A study conducted at the Icahn School of Medicine at Mount Sinai in 2011 suggested that blood expression levels of genes targeted by the stress hormones called glucocorticoids could be a physical measure, or biomarker, of risk for developing Post-Traumatic Stress Disorder (PTSD. These findings also made the steroid hormones’ receptor, the glucocorticoid receptor, a potential target for new drugs.

“Our aim was to determine which genes are differentially expressed in relation to PTSD,” said lead investigator Rachel Yehuda, PhD, Professor of Psychiatry and Neuroscience and Director of the Traumatic Stress Studies Division at the Icahn School of Medicine at Mount Sinai. “We found that most of the genes and pathways that are different in PTSD-like animals compared to resilient animals are related to the glucocorticoid receptor, which suggests we might have identified a therapeutic target for treatment of PTSD,” said Dr. Yehuda, who also heads the Mental Health Patient Care Center and PTSD Research Program at the James J. Peters Veterans Affairs Medical Center in the Bronx.

The research team exposed a group of male and female rats to litter soiled by cat urine, a predatory scent that mimics a life-threatening situation. Most PTSD studies until now have used only male rats. Mount Sinai researchers included female rats in this study since women are more vulnerable than men to developing PTSD. The rats were then categorized based on their behavior one week after exposure to the scent. The authors also examined patterns of gene expression in the blood and in stress-responsive brain regions.

After one week of being exposed to soiled cat litter for 10 minutes, vulnerable rats exhibited higher anxiety and hyperarousal, and showed altered glucocorticoid receptor signaling in all tissues compared with resilient rats. Moreover, some rats were treated with a hormone that activates the glucocorticoid receptor called corticosterone one hour after exposure to the cat urine scent. These rats showed lower levels of anxiety and arousal one week later compared with untreated, trauma-exposed rats.

“PTSD is not just a disorder that affects the brain,” said co-investigator Nikolaos Daskalakis, MD, PhD, Associate Research Scientist in the Department of Psychiatry at the Icahn School of Medicine at Mount Sinai. “It involves the entire body, which is why identifying common regulators is key. The glucocorticoid receptor is the one common regulator that consistently stood out.”

A recent study published in the journal Neuropsychopharmacology indicated that marijuana could be a useful tool in the treatment of PTSD. Researchers from Haifa University’s Department of Psychology released the following statement:

“The findings of our study suggest that the connectivity within the brain’s fear circuit changes following trauma, and the administration of cannabinoids (synthetic marijuana) prevents this change from happening."

Sufferers of PTSD often respond negatively to "triggers" that evoke memories of the original trauma, and which can perpetuate the negative effects. Using rats that had been exposed to distressing circumstances, the researchers discovered that their PTSD symptoms disappeared after being injected with synthetic marijuana.

It is believed that the cannabis acts on the two receptors in the brain that are associated with emotional processing.

“The importance of this study is that it contributes to the understanding of the brain basis of the positive effect cannabis has on PTSD and thus supports the necessity to perform human trials to examine potential ways to prevent the development of PTSD and anxiety disorders in response to a traumatic event,” noted the study authors, Nachshon Korem and Irit Akirav, adding:
"This study can lead to future trials in humans regarding possible ways to prevent the development of PTSD and anxiety disorders in response to a traumatic event."

This research appears to be at odds with current medical advice that advises against taking recreational drugs, and also alcohol, as these may exacerbate PTSD symptoms. Other current treatments include talk therapy and anti-depressant drugs, along with exercise and a healthy diet that eliminates caffeine and any potential food allergens. Various nutritional supplements, including Omega 3 fatty acids, Coenzyme Q10 and L-theanine have also been shown to be supportive.

For the rest of us, this day is a time to reflect upon the needless waste of life that occurred thirteen years ago today, and to pray that such an event will never happen again.