Background
Anxiety and post-traumatic stress disorder (PTSD) are qualifying psychiatric conditions for medical marijuana (MM) treatment in Pennsylvania. This study examined baseline prevalence and changes in prescription anxiety medication use three months following MM treatment initiation among individuals with these qualifying conditions.

Methods
The study sample was comprised of 108 adults with anxiety or PTSD as a referring condition; they were enrolled in a longitudinal study evaluating biopsychosocial outcomes in new MM patients. Consenting participants completed an assessment battery at baseline and Month 3 (n = 94, 87 % follow-up rate) that included a measure of anxiety severity and questions about current anxiety medication prescription and desired (baseline) and actual (Month 3) reductions in medication use.

Results
Findings indicated that 59 % of participants reported prescription medications for anxiety, with 70 % reporting at least a moderate desire to reduce medication use. Overall and within the medication sub-sample, participants displayed significant reductions in anxiety severity from baseline to Month 3 (p’s <0.0001). Furthermore, 32 % reported actual reductions in medication use at Month 3, and reductions were more likely among patients prescribed benzodiazepines than other drug classes.

Conclusions
Results suggest that a significant number of MM patients with anxiety and/or PTSD diagnoses are currently being prescribed antianxiety medications and that MM may help to reduce their use of these medications.

Limitations
Limitations include the observational study design and the lack of a PTSD-specific measure. More controlled longitudinal studies are necessary to better understand the role of MM in the treatment of anxiety and PTSD.