Post-traumatic stress disorder, or PTSD, is not easy to treat. What works for some might not work for others, and the affliction may last for many years.

Estimates are that as many as one in five Iraq and Afghanistan war veterans struggle with PTSD, along with millions of other veterans of military conflicts — and not just those in the U.S. With these sobering statistics in mind, medical experts around the world are trying to develop effective treatment options.

Swedish researchers are aiming at the root cause of the problem: fear.

Our bodies contain fatty acid enzymes called FAAH, which translate feelings of fear, anxiety and stress within our brains. The researchers conducted tests using a drug, originally designed as a pain reliever, that blocks the FAAH enzymes.

Participants were separated into two groups, with one group given the FAAH inhibitor. All the participants then underwent traditional PTSD therapy known as prolonged exposure. In this treatment, traumatic or frightening events are rehashed over and over in the hope that the afflicted person will no longer be traumatized.

Multiple times, they were shown something that frightened them and their reactions were measured. Those who experienced PE while taking the fear-reducing drug fared much better than those without it.

The researchers did not make any conclusions about FAAH, but further studies are planned to examine the effectiveness of the combination of the treatment options.

With the number of military personnel around the world serving in war zones not likely to diminish any time soon, the need for ways to treat the after-effects of conflict continues to be a primary mental health concern worldwide.