The study confirms previous research by Imperial College London, that psilocybin, a naturally occurring compound present in “shrooms”, stimulates new brain cell growth and erases frightening memories. Mice conditioned to fear electric shock when hearing a noise associated with the shock “simply lost their fear”, says Dr. Juan Sanchez-Ramos, who co-authored the study. A low dose of psilocybin led them to overcome “fear conditioning” and the freeze response associated with it faster than the group of mice on Ketanserin (a drug that counteracts the receptor that binds psilocybin in the brain) and a control group on saline.

An estimated 5 percent of Americans – more than 13 million people – have PTSD at any given time, according to the PTSD Alliance. The condition more often associated with combat veterans, is twice as likely to develop in women because they tend to experience interpersonal violence (such as domestic violence, rape and abuse) more often than men.

PTSD is not just psychological. Common symptoms, such as hyper-vigilance, memory fragmentation, flashbacks, dissociation, nightmares and fight or flight responses to ‘triggers’, are generally thought to be psychological and therefore treatable by learning to change thought processes. But new research suggests that they may in fact be the result of long term physiological mutations to the brain.