Researchers from Nationwide Children’s Hospital and The Ohio State University have published a new study examining the effects of medical marijuana legalization on attitudes and behaviors toward driving after marijuana use (DAMU) in Kentucky and Tennessee.
Using survey data, researchers applied a novel matched design to infer causal relationships while accounting for observational data challenges such as unequal sampling probabilities and potential confounding.
The study, published in the Biometrical Journal, found no evidence linking medical marijuana legalization to increased tolerance of DAMU. This conclusion remained robust even after sensitivity analyses were conducted to evaluate the impact of unmeasured confounding. Unlike previous studies that suggested minor associations between legalization and self-reported DAMU, this research evaluated both behaviors and attitudes using multiple survey items. The study highlighted regional differences, focusing on Southern and Midwestern states, where self-reported DAMU was rare.
Methodologically, the research introduced a matched design that integrated survey weights and propensity scores, allowing for unbiased estimations of population-level effects. While the findings provide valuable insights, the study acknowledged limitations, including reliance on self-reported data, potential response bias, and the short, one-year timeframe of the data. Future research may extend this approach to longitudinal studies and more diverse sampling scenarios.
Overall, the findings challenge the notion that medical marijuana legalization increases risky driving behaviors or attitudes.
For the full text of the study, click here.
