Marine veteran Logan Edwards worried he could become one of the 22 former members of the armed services who, on average, commit suicide every day.

Then, he says, he tried marijuana.

Edwards, who served eight months in Iraq, is one of an unknown number of veterans who have turned to marijuana to manage Post Traumatic Stress Disorder, which may afflict as much as 20 percent of veterans from the wars in Iraq and Afghanistan, according to experts. The Department of Veterans Affairs doesn’t let its doctors prescribe weed, so the former service members buy it illegally, fib to their doctors, accept it as a gift, or grow it themselves.

In Edwards’ case, he says the drug may have saved his life.

“The first time I used it, I wanted to cry. Because it took away my anxiety. Because it did everything for me that the Oxycontin, benzodiazepines and anti-depressants the VA prescribed me for three years did not do,” said Edwards, 26, a resident of Davenport, Iowa. His symptoms -– an unrelenting “hyper-vigilance,” insomnia and nightmares -– emerged “the moment we walked off the plane” in 2008.

“I can function completely fine all day just by using cannabis. I’m back in school. My attendance is good. My grades are good. My relationships have healed,” added the former Marine. “It allowed me to get my life back.”

In a March 12 letter, federal health officials approved a long-delayed study to explore if pot relieves PTSD. But doctors employed by the VA are banned from prescribing medical marijuana – and from completing forms that allow veterans to enroll in medical-marijuana programs. While medical weed is legal in 20 states, only eight states recognize PTSD as a qualifying condition for which physicians can write cannabis prescriptions.

“...Due to the way the federal government and the state want to handle this medical marijuana issue, I still am forced to spend time away from family, treating these wounds of war.”

Across that tangled post-war legal landscape, thousands of combat veterans are tapping underground sources to buy bootleg marijuana to self-treat PTSD. And in 12 states where the drug is legal but prohibited for PTSD, many are lying to doctors that they need medical weed for allowable conditions like chronic pain, advocates assert. Meantime, vast numbers of other veterans can’t find it, can’t afford it, abuse alcohol to self-medicate, or rely on conventional VA drugs.

“My brothers are killing themselves because they’re out of options,” Edwards said. “These VA pharmaceuticals only exacerbate the problem. The listed side effects on (some) of the bottles say: ‘Will increase suicidal ideation.’ So the suicide rate is really what this comes down to.”

U.S. Army veteran Tom Studley, 28, served as a machine gunner in Iraq for 15-months. He returned to civilian life with chronic back pain and was diagnosed with PTSD. Studley was prescribed numerous pharmaceuticals, but he said that by inhaling marijuana with a vaporizer, he's been able to stop using those drugs. Here, Studley stands in the shed where he grows some of the 15 plants he's legally allowed as a medical marijuana patient in Washington state in Nov. 2011. John Brecher / NBC News

With marijuana federally classified as a Schedule I controlled substance (like heroin and LSD), VA physicians “will not provide for use,” said Gina Jackson, a VA public affairs officer. At the same time, veterans who participate in legal, medical-marijuana programs “will not be denied access to care for VA clinical programs but should be assessed for misuse, adverse effects, and withdrawal.”

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The possibility of federal drug monitoring –- plus fears of losing VA benefits and the threat of legal trouble –- has driven scores of veterans to secretly use marijuana for decades to address their PTSD symptoms, several veterans said.

“Us veterans have already conducted tests on pot and PTSD -– and it works!” said Vietnam veteran Bob Walker, 69. “It’s nice to see the feds playing catch up.”

PTSD expert Dr. Harry Croft, a San Antonio-based psychiatrist who has treated veterans for combat-related anxiety and substance abuse, applauds the federally approved investigation.

“We owe it to our veterans with this condition,” Croft said. “Unfortunately, present treatment options are not helpful to many veterans and, therefore, other newer options should be scientifically explored, including medical marijuana.”

At Walker’s home in Northern California, he ingests pot via a vaporizer each night before bed. A Marine veteran grows that marijuana and supplies it free to Walker and a local network of other Vietnam vets. Diagnosed with PTSD, Walker tried VA-prescribed Xanax and anti-depressants but found he could not function on the pharmaceuticals. About 15 years ago, he said, a VA counselor quietly suggested Walker use cannabis to relieve his insomnia, anxiety, stuttering and cold sweats.

“It solved a big problem for me. You feel, well, lighter,” said Walker, a former Army aircraft mechanic who served in Vietnam in 1965 and 1966, watching his best friend die in a chopper crash. “Probably 60 to 70 percent of the vets I know use marijuana for stress reduction and sleep. It’s their baseline medication.”

"I’m back in school. My attendance is good. My grades are good. My relationships have healed. It allowed me to get my life back.”

Near Denver, retired Marine and Iraq veteran Sean Azzariti, 32, sees roughly the same rate of pot use among ex-service members with PTSD. He, too, was diagnosed with the disorder. But in Colorado, PTSD is not a qualifying condition under which private doctors can prescribe cannabis to veterans. So, for four years, Azzariti could not tell his physician the real reason he needed cannabis and instead said the prescription would help treat chronic nausea.

Simply because of that forced ruse, pro-marijuana advocates ensured Azzarti was the first customer in Colorado to buy legal weed on Jan. 1 when the state began allowing anyone 21 and older to purchase pot. He paid $70 for a strain called Bubba Kush and pot-infused candy truffles.

“If veterans had another avenue (to treat PTSD), most would take that and it would save lives. I wouldn’t be talking to you if I didn’t have cannabis,” said Azzariti, who smokes daily to manage his symptoms. “Veterans have been ignored for 30 years, denied what they truly need to heal. Vietnam veterans could have told us this stuff works.

“That’s why I’m open about using it. Sure, there’s a chance I’ll lose my $120-a-month (VA) disability benefits. But that’s a small sacrifice to save one life and potentially change the world,” Azzariti said. “With all of these people coming home from war, (the PTSD and veteran-suicide crises) are only going to get worse. How are we going to treat that? We can’t just keep throwing pills at people.”

Near Seattle, Iraq veteran Tom Studley, 28, stopped swallowing pharmaceuticals for his PTSD symptoms four years ago and instead, he said, gained inner peace by smoking, vaporizing and eating marijuana.

“The anxiety begins to go away pretty quick and stays away for a while,” said Studley, who served as an Army machine gunner.

After returning, he was prescribed muscle relaxants, Percocet and methadone for chronic back pain plus Trazodone, Celexa and hydroxyzine pamoate for sleep and anxiety. On his property, Studley now grows, harvests and uses cannabis from his 15 marijuana plants -– a legal crop in Washington State.

“I feel", he said, “less out of control.”

In Iowa, Marine veteran Edwards is taking control -– but with a painful plan.

In May, he will move to Colorado, away from his girlfriend and 3-year-old daughter. He’s relocating and transferring colleges, he said, for one reason: to legally access medical marijuana to continue managing his PTSD. He’s tired of breaking the law.

“I thought my deployment days, being away from my family, ended when I got out of the Marine Corps. But due to the way the federal government and the state want to handle this medical marijuana issue, I still am forced to spend time away from family, treating these wounds of war,” Edwards said.

“I never thought I would have to leave the state and community I grew up in to get access to medicine that’s working and is better for me than the FDA-approved stuff. I never thought I would end up being a medical refugee.”