Opioid addiction rates across states (and nations) already varies quite wildly, totally independent of weed laws, which were all quite similar some time ago. And the variation is large, far beyond the 5-10% supposed relationship in the paper.
Organisational, legal, social attitudes towards opioids change quite frequently as well - these would be very hard to normalise for.
If someone can validate how they crack the normalisation to achieve causality I'd love to hear about it.
Opioid addiction rates across states (and nations) already varies quite wildly, totally independent of weed laws, which were all quite similar some time ago. And the variation is large, far beyond the 5-10% supposed relationship in the paper.
Organisational, legal, social attitudes towards opioids change quite frequently as well - these would be very hard to normalise for.
If someone can validate how they crack the normalisation to achieve causality I'd love to hear about it.