A new study shoots down the notion that medical marijuana laws can prevent opioid overdose deaths.
Researchers repeated an analysis that sparked excitement years ago. It linked medical marijuana laws to slower than expected increases in state prescription opioid death rates.
But the promising connection fell apart when researchers updated the analysis with seven years of recent data.
Authors of the original research welcomed the new analysis.
They had speculated patients might be substituting marijuana for opioid painkillers. But they had warned against drawing conclusions.
The findings were released Monday in Proceedings of the National Academy of Sciences. Researchers say policymakers should look elsewhere for solutions to the opioid crisis.