The Army’s top doctor is skeptical that the first-ever federally-approved study will show that marijuana can help U.S. veterans suffering from post-traumatic stress disorder. “It’s been found that using marijuana has a lot of adverse health effects,” Lieut. General Nadya West says. In April, the federal government approved a three-year study to try to determine if actual marijuana, not merely chemicals extracted from it, can help those with PTSD.

Many veterans say smoking marijuana has eased their symptoms of PTSD. Like the Army, the Department of Veterans Affairs has doubts about its effectiveness. Proponents, the Army surgeon general adds, too often emphasize the benefits without acknowledging the downsides. Marijuana “is more dangerous, with some of the carcinogens that are in it, than tobacco,” West says. “So to make it sound as if it’s perfectly safe, the impact that it has long-term on certain areas of the brain, especially young people developing, that’s been proven: irreversible damage to the hippocampus and things like that that can really have impacts on individuals long-term.”

Lieut. General Nadya West, the Army surgeon general U.S. Army

The Army’s existing PTSD treatments ease symptoms in 80% of soldiers, the three-star officer tells TIME, and any soldiers try to self-medicate with pot will be disciplined. “The Army policy is still that [marijuana] is an illegal substance,” she says.

But some veterans aren’t waiting for the government’s, or anyone else’s, stamp of approval.

Jose Martinez knows trauma. As a U.S. Army infantryman in Afghanistan, he lost both legs, his right arm and his left index finger to a land mine in 2012. Recovery was challenging. “In my eyes, I had pretty much failed when I stepped on a bomb and lost three limbs,” he says. “I was going insane because I did not understand why I was still alive.”

Then, last December, he broke his maimed left arm, his lone remaining limb, when his car flipped over after hitting black ice in the high desert near his Apple Valley, Calif., home. It’s no surprise, then, that he also knows PTSD. Doctors plied him with pills after both calamities. “I started taking so many prescription pills,” he recalls, “I was numb to the world.”

Over time, he ended up replacing those pills—up to 150 a day, he says—with marijuana. While Martinez says he smoked pot occasionally before enlisting in the Army in 2010, he obeyed the military’s prohibition against it before that bomb blast near Kandahar.

He says marijuana has stayed his pain and tamed his demons. “My brain’s telling me to freak out because I’m missing my limbs, but when I’m on cannabis, it tells me to calm down, you’re O.K., you’re fine,” Martinez says. Not only does it soothe the phantom pain of his missing limbs, but it also eases a racing and apprehensive mind riven with PTSD. “It relaxes me and helps me sleep at night,” he says. “I’m so super-vigilant, and it really calms my anxiety, which can shoot up when I’m around a lot of people I don’t know.”

Back home, Martinez, 28, is once again a frontline soldier, now in a new battle—to prove that the ancient herb can help veterans like him who suffer from PTSD, a signature wound of the wars in Afghanistan and Iraq. But marijuana’s checkered legal, medical and social history make it a controversial treatment. The federal government estimates that as many as 500,000 of the 2.7 million troops who served in those countries may have some kind of PTSD.

Despite her misgivings, West, the Army’s top doctor, endorses the research. “I don’t know if we need to have the full spectrum of what’s in marijuana as its typically administered, if that’s necessary, she says. But “we should always, at least, have an open mind to look at things in an evidence-based way for something that could be useful for our soldiers.”

Subscribers can read the entire story here, or in the Aug 29 issue of Time Magazine.

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