This is a historic decision in the world of cannabis. The Drug Enforcement Administration has approved the first ever study on the efficacy of cannabis in the treatment of post-traumatic stress disorder.

This study will be the first of its kind, utilizing smoked cannabis in a placebo-controlled clinical trial. It will examine the effectiveness of strains varying in THC and CBD content in treating the debilitating condition.

The study has actually been in the works since 2010, facing many unexpected setbacks; one of these setbacks was the termination of the study author Dr. Sue Sisley from her position at the University of Arizona in 2014.

The clinical trials has been paid for by the Colorado Department of Health and Environment, who also allocated more than $2 million to fund the study in February 2015 from fees paid by applicants to the state’s medical marijuana program.

Researchers are now beginning the process of enrolling the 76 military veterans required for the study at clinics in Phoenix and Baltimore. This process could still take two years, or more.

Read more about cannabis and PTSD.