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Marijuana plants are examined under a magnifying glass at Ganja Farms marijuana store in Bogota, Colombia on Jan. 7, 2016. REUTERS/John Vizcaino

In a brand new clinical study that has been in the works for more than four years, a U.S. military veteran was given marijuana to study the effects of the drug and its potential role in treating post-traumatic stress disorder (PTSD).

The first participant of the study was administered cannabis at the Scottsdale Research Institute in Phoenix, Arizona Monday, according to a press release issued by the officials from the Multidisciplinary Association for Psychedelic Studies (MAPS). MAPS is a California-based non-profit research organization focused on “the careful uses” of marijuana, according to its website.

“As this is the first placebo-controlled trial of cannabis for PTSD, we are breaking important ground needed to identify improved treatment options for veterans with PTSD," Marcel Bonn-Miller of the University of Pennsylvania’s Perelman School of Medicine, who is overseeing the project sites, said in the release.

The study being conducted by researchers from MAPS, the University of Pennsylvania, the University of Colorado, Johns Hopkins University and the Scottsdale Research Institute, is being funded by a $2 million grant from the Colorado Department of Public Health and Environment.

The research aims to conduct clinical trials by administrating four different levels of marijuana potency in 76 veterans. The screening for volunteers (adult military veterans who have experienced trauma during military service) began in January.

Participants will finish 17 outpatient visits to one of the two study location clinics — one in Phoenix, led by Dr. Sue Sisley, and another Johns Hopkins University in Baltimore, led by Ryan Vandrey — over a span of 12-weeks, with a follow-up visit in six months. The team will be tracking measurements of PTSD, PTSD symptoms and safety data to dig for “vital information on marijuana dosing, composition, side effects, and areas of benefit to clinicians and legislators considering marijuana as a potential treatment for PTSD. ”