In a big win for medical marijuana advocates, the US senate approved an amendment Tuesday allowing veterans to receive medical marijuana recommendations from VA doctors in MMJ-friendly states and municipalities, according to The Drug Policy Alliance. Previously, VA doctors were prohibited from such actions by federal law, preventing the nation’s veterans from receiving the full scope of medical treatment that could be available to them.

While numerous chronic conditions afflicting veterans can be treated by medical chronic, the key syndrome at play here is post traumatic stress disorder (PTSD), a condition which affects roughly 30 percent of all military veterans of Afghanistan and Iraq, according to the Chicago Sun Times and the Department of Veterans Affairs.

Self-medication for PTSD became popular during the Vietnam war, but only began to be scientifically substantiated in the early 21st century, when researchers discovered the link between PTSD and the cannabinoid system. According to NPR, “For decades, researchers have suspected that marijuana might help people with PTSD by quieting an overactive fear system. But they didn’t understand how this might work until 2002, when scientists in Germany published a mouse study showing that the brain uses chemicals called cannabinoids to modulate the fear system, Dr. Kerry Ressler of Emory University says.”

The bipartisan-backed Veterans Equal Access Amendment to the FY2016 Military Construction and Veterans Affairs Appropriations Bill was approved 18-12 by the Senate Appropriations Committee.

The Drug Policy Alliance issued the quote, passed on from TJ Thompson, a disabled Navy veteran, in statement after the bill was passed:

“On this eve of Veterans/Armistice Day where we remember those who served in the military and the treaty agreement to reach peace concluding WWI, we see this victory as a step toward a peace treaty with the government we volunteered to defend with our lives and as a step toward restoring our first amendment rights and dignity as citizens of the United States.”