Do Medical Marijuana Laws Increase Disability Benefits Claiming?

     From the abstract of The Impact Of State Medical Marijuana Laws On Social Security Disability Insurance And Workers' Compensation Benefit Claiming by Johanna Catherine Maclean, Keshar M. Ghimire and Lauren Hersch Nicholas:

We study the effect of state medical marijuana laws (MMLs) on Social Security Disability Insurance (SSDI) and Workers' Compensation (WC) claiming. We use data on benefit claiming drawn from the 1990 to 2013 Current Population Survey coupled with a differences-in- differences design. We find that passage of an MML increases SSDI, but not WC, claiming on both the intensive and extensive margins. Post-MML the propensity to claim SSDI increases by 0.27 percentage points (9.9%) and SSDI benefits increase by 2.6%. ...

     A few words of caution in interpreting this:

• The Social Security Act forbids granting disability benefits on the basis of substance abuse disorders, a point which the authors of this study seem not to understand.
• The effect found is small and could have other causes.
• If there is an effect, it may be a little less direct than the authors (who are economists) think. My guess is that if there is an effect, it would be because marijuana lessens the effectiveness of medications given for mental health problems such as bipolar disorder.