Eight states and the District of Columbia have legalized cannabis use for recreational purposes, and 28 states plus the District of Columbia have legalized cannabis for medical purposes. Recent studies suggest that 45-80% of individuals who seek cannabis for medical purposes do so for pain management, and an estimated 6%-39% of patients prescribed opioid medication for pain are also utilizing cannabis. Over one-third of patients seeking cannabis for medical purposes list post-traumatic stress disorder (PTSD) as the primary reason for the request. Approximately 15% of Veterans who are treated in Department of Veterans Affairs (VA) outpatient PTSD clinics report recent (past 6 months) cannabis use.