John Evans insists that calling post-traumatic stress a disorder is like cutting yourself and calling the blood a disorder.

“It is a natural reaction to an unnatural event,” says Evans, director of support group Veterans 4 Freedom. Not only military veterans, but women who have suffered domestic abuse or sexual assault, hospice workers, EMTs, firefighters, police officers and even those affected by natural disasters can have post-traumatic stress, he believes.

Evans is a vocal member of the growing contingent of advocates demanding public health officials add medical marijuana to Colorado’s approved list of PTSD treatments. Ten other states have passed similar measures. The Medical Marijuana Scientific Advisory Council, tasked by the Colorado Department of Public Health and Environment with reviewing petitions based on their scientific merits, recommended a yes vote. The state’s chief medical officer Dr. Larry Wolk endorsed the proposal.

“There’s certainly evidence cannabis helps with muscle spasms, anxiety...