'Fear Gene' Could Unlock Triggers of Post-Traumatic Stress Disorder

A new study links a particular gene that invokes fear to the cause of post-traumatic stress disorder. However, a treatment technique that could help aid the problem may not be far off. 

Statistics show that approximately 3.5 percent of U.S. adults suffer from PTSD in varying degrees, with one in three cases considered "severe." This can be a particularly difficult issue for soldiers who are returning home from the war. In fact, nearly 20 percent of Iraq and Afghanistan veterans have been diagnosed with PTSD, according to the Congressional Research Service.

The Mayo Clinic notes that post-traumatic stress disorder (PTSD) is a mental health condition triggered by a terrifying event, with symptoms that include flashbacks of horrific events, nightmares and severe anxiety.

According to the U.S. National Institute of Health, about half of those suffering from PTSD in the general population receive treatment, compared to more than 57 percent of members in the military who've been diagnosed with PTSD. Unfortunately, the organization notes that both groups only receive minimally adequate treatment.

Researchers note that blocking areas of the amygdala where fearful memories are housed, can possibly prevent the development of the condition, all together.

"This early intervention would be especially appropriate for individuals at higher risk for PTSD after trauma, such as those with a history of previous trauma or those carrying genetic polymorphisms that have been associated with PTSD risk," the researcher said, according to the study.

They immobilized laboratory mice to a wooden board, measured fear responses and increased heart rate so the fear response would be present. This technique caused stress symptoms to increase in the mice analogous to PTSD symptoms in humans, relating to long-term impaired declarative memory and enhanced anxiety.

Following this, colleagues examined gene expression changes in mice, to find that the OPRL1 gene in the amygdala gives off the molecule nociceptin. The study notes that a drug that targeted this receptor blocked the development of fear in the memories of the mice.

However, researchers caution that other studies must be conducted to determine if this gene is responsible for the consolidation of fear within the brain. "Our data suggest that early intervention - shortly after fear learning - with a selective, centrally acting [drug] reduces fear memory consolidation," the researchers wrote, according to the study. "In humans, this may translate to the ability to prevent the likelihood of developing PTSD in the aftermath of trauma."

The findings for the study were published Wednesday in the journal Science Translation Medicine.