While anecdotal reports support the benefits of medical marijuana in treating the disorder, evidence from clinical research has been lacking.

But now, scientists from the University of Michigan, Harvard Medical School and the University of Illinois at Chicago have confirmed that THC affects the storage and extinction of fearful memories in human subjects.

Published in October 2013 in the journal Neurobiology of Learning and Memory, the team suggests that marijuana pathways in the brain, which make up the cannabinoid system, could be a target for future PTSD treatments.

"Ultimately, the cannabinoid system may serve as a promising target for innovative intervention strategies in PTSD and other fear learning-related disorders."

In the study, researchers performed brain scans on 14 healthy individuals, who were given THC pills (Marinol) or a placebo before being exposed to a fearful stimulus. After 24 hours, individuals who received THC showed increased activity in areas of the brain involved with overcoming past negative memories.

While animal studies also support a role of cannabinoids in overcoming bad memories, the authors note the study was the first to show this effect in humans.

"Together, these findings provide the first evidence that pre-extinction administration of THC modulates the underlying neural circuits involved in fear extinction in humans."

The authors conclude: "these results prompt future investigation to test if cannabinoid agonists can rescue or correct the impaired behavioral and neural function during extinction recall in patients with PTSD."

The study received funding from the National Center for Research Resources and the National Institute of Mental Health

Source: LeafScience.com