Is Mississippi's prescription-only precursor control law a prescription to decrease the production and raise the...

In 2010, Mississippi became the second state to require a prescription to purchase pseudoephedrine-based medications. Proponents of "prescription-only" laws argue that they are necessary to disrupt methamphetamine markets, but critics note the costs to legal consumers of cold medications may offset some of the laws' intended benefits.

We evaluated the effect of prescription-only restrictions for methamphetamine precursors on state-level methamphetamine lab seizures and methamphetamine prices.

We used a synthetic control approach to create a control state comparable to Mississippi and then used permutation testing to determine if the resulting difference was statistically significant.

We found that Mississippi's prescription-only law removed 2637 small methamphetamine labs in the two years after the law became effective, which represents a 77% reduction in small labs relative to the synthetic counterfactual. We found no evidence that the law impacted methamphetamine prices.

We conclude that while prescription-only laws can reduce the number of domestic small methamphetamine labs in operation, methamphetamine availability is unlikely to be materially impacted.