From NPR:

Prescription drug prices continue to climb, putting the pinch on consumers. Some older Americans appear to be seeking an alternative to mainstream medicines that has become easier to get legally in many parts of the country.

Research published Wednesday found that states that legalized medical marijuana — which is sometimes recommended for symptoms like chronic pain, anxiety or depression — saw declines in the number of Medicare prescriptions for drugs used to treat those conditions and a dip in spending by Medicare Part D, which covers the cost on prescription medications.

Because the prescriptions for drugs like opioid painkillers and antidepressants — and associated Medicare spending on those drugs — fell in states where marijuana could feasibly be used as a replacement, the researchers said it appears likely legalization led to a drop in prescriptions. That point, they said, is strengthened because prescriptions didn’t drop for medicines such as blood-thinners, for which marijuana isn’t an alternative.

The study, which appears in Health Affairs, examined data from Medicare Part D from 2010 to 2013. It is the first study to examine whether legalization of marijuana changes doctors’ clinical practice and whether it could curb public health costs.