Association for Public Policy Analysis & Management

Legalization of marijuana, for either medicinal or recreational use, is one of the most controversial issues in state and Federal drug policy.  To date, 23 states and the District of Columbia have passed laws legalizing access to medical marijuana. Those who support legalization of medical marijuana tout its potential to offer a larger range of treatment options for patients suffering from chronic health conditions, although there are few clinical studies to support or refute this claim.  In this paper, we ask whether MMLs are positively impacting older adults, a group with a high prevalence of chronic pain, which is the most common way patients qualify for medical marijuana.

We use panel survey data from the 1992 - 2012 waves of the Health and Retirement Study (HRS) to estimate the effect of state medical marijuana laws on pain and labor supply among older adults aged 50 and above.  We estimate differences-in-differences regressions of respondent-level outcomes on state law changes, exploiting within-state variation in the timing of MMLs to study the impacts of expanded legal access to marijuana for medical use. We consider the impact of any MML and we also examine law heterogeneity as measured by home cultivation and legal protection for medical marijuana dispensaries.

We find that providing legal access to medical marijuana through home cultivation or legal dispensaries reduces pain among respondents with one or more health conditions that would qualify them to participate in medical marijuana programs (any pain, -2.8 percentage points, p < 0.05; moderate to severe pain, -2.2pp, p < 0.01; pain limits activity -1.7pp, p < 0.01).  Reductions in pain are more pronounced for men.  Legal access to medical marijuana also increases labor supply on the intensive margin for the full population (2.0 percentage point increase in full-time work, p < 0.01; 4.2% increase in hours worked, p < 0.05), with evidence that work increases both for medical marijuana-eligible adults and those whose labor supply was reduced by caregiving. Our results are robust across a number of sensitivity analyses including use of individual fixed effects, alternative measures of law passage, and an event study design.

Our results suggest medical and economic benefits to medical marijuana legalization, at least among older adults.  Policymakers should account for these benefits when evaluating medical marijuana legislation.