Wow, that was fast, good job!
Clearly, there is not a simple answer and whatever that answer is goes far beyond drug laws and sentencing guidelines in each state or even county or parish.
Unemployment rates may show a stronger correlation, but even that would not always correlate as there are states with similar unemployment rates on that map, but OD rates are far different.
I don’t think California drug laws are twice as harsh as Pennsylvania’s, but Pennsylvania OD rates are twice that of California.
Texas and Florida typically have similar unemployment rates but their OD rates are not similar.
It could be as simple as medical examiners from county to county having different (political) standards for ruling a death an OD or drug trafficking regimes that result in drug quality control issues in certain areas of the country.
Like many other issues, the nation’s drug problem is extremely complex and there are no easy or singular solutions.