Prolonged exposure therapy is a typical treatment for PTSD. Patients are exposed repeatedly to their traumatic memory in a bid to determine that the memories no longer indicate imminent danger.
The effects of prolonged exposure therapy are limited and associated with the return of fears over time. To address this, researchers have evaluated a medicine that could enhance the treatment.
Supplied by Pfizer, the drug targets the body’s endocannabinoid system, which regulates fear and stress-related behaviours.
It increases the levels of anandamide in the brain regions that control fear and anxiety. The inhibition of FAAH, which breaks down anandamide, causes this increase.
The randomised, placebo-controlled and double-blind trial by Linköping researchers compared the drug to placebo in a total of 45 healthy volunteers.
Following a treatment period of ten days, participants received various psychological and physiological tests.
One test coupled a highly unpleasant sound with a visual cue.
Once participants learned to respond with fear to the visual cue, they were repeatedly re-exposed to it without the unpleasant sound, to facilitate unlearning of the fear memory.
When compared, volunteers treated with the FAAH inhibitor were observed to remember the fear extinction memory more successfully.
Linköping University senior post-doctoral fellow and study lead investigator Leah Mayo said: “We have used a medication that blocks the way the body breaks down its own cannabis-like substances, or ‘endocannabinoids’.
“Our study shows that this class of medications, called FAAH inhibitors, may offer a new way to treat PTSD and perhaps also other stress-related psychiatric conditions. The next important step will be to see if this type of medication works in patients, particularly those with PTSD.”
Partial funding of the study came from the Swedish Research Council and the Canadian Institutes of Health Research.