Changes in health-related quality of life over the first three months of medical marijuana use.

Background: The psychosocial impact of medical marijuana use is not yet known. This study evaluated short-term changes in health-related quality of life (HRQoL) over the first three months of medical marijuana use.

Methods: This prospective, observational, longitudinal study followed adults newly recommended for medical marijuana by a physician for any of the more than 20 qualifying medical conditions in Pennsylvania. Participants (N = 438) provided their clinical status and demographic information, and completed semi-structured interviews prior to medical marijuana initiation (baseline) and at three months. HRQoL was assessed by the Short Form-36 (SF-36). Paired-samples t-tests evaluated changes in HRQoL over time.

Results: Participants (M age = 46.4 years [15.6]; 66.4% female) were mostly commonly referred for medical marijuana to treat anxiety disorders (61.9%) or severe chronic or intractable pain (53.6%). Participants reported rapid and significant improvements in all of the domains of HRQoL from baseline to three months after initiating medical marijuana use (physical functioning, role limitations due to physical health problems, emotional well-being, role limitations due to emotional problems, bodily pain, social functioning, energy/fatigue and general health, P < .001 for all). Age was negatively predictive of level of improvement over time for the physical functioning (P < .0001), role limitations due to physical health problems (P < .001), and pain (P < .0001) domains after controlling for baseline, with older participants displaying less improvement than younger participants.

Conclusions: Gains were observed in all HRQoL domains assessed after three months of medical marijuana use. In several domains, age was a significant predictor of degree of improvement.