But the study left one big question unanswered: Since the study's authors — the University of Georgia's Ashley Bradford and W. David Bradford — only looked at Medicare data, they couldn't say for sure whether the findings held for younger patients too.
Specifically, anti-nausea drug prescriptions fell by 17 percent. Antidepressant prescriptions fell 13 percent, while prescriptions for seizure and psychosis drugs fell 12 percent.
Not everyone who has access to medical marijuana opts for it, obviously. But enough do to make a significant dent in the prescription numbers. “Patients and physicians in the community are reacting to the availability of medical marijuana as if it were medicine,” the Bradfords conclude.
Numerous studies have found that opiate abuse and overdose rates fell in states with medical marijuana laws. The Bradfords' research describes the mechanism by which that could happen: the introduction of medical marijuana laws coincides with a drop in painkiller prescriptions.
The Bradfords' data only include prescriptions made under Medicare and Medicaid, but given the totality of their evidence it seems reasonable to assume that similar patterns hold true for patients on private insurance plans.
In the current budgetary environment, no analysis of health care is complete without a discussion of costs. The Bradfords estimate that because of the drops in prescribing rates, a nationwide medical marijuana program would save taxpayers about $1.1 billion on Medicaid prescriptions annually. That's on top of the half a billion in Medicare savings the Bradfords estimated last year.
Those costs don't evaporate into thin air, of course: they would simply be shifted over to seniors and low-income people who would be purchasing medical marijuana outside of their insurance programs.
There's also the open question of how smart it is from a personal health perspective to be self-medicating with pot: “it is plausible that forgoing medications with known safety, efficacy, and dosing profiles in favor of marijuana could be harmful under some circumstances,” the Bradfords warn.
“This decision was made despite the substantial and growing evidence that the requirements for Schedule I status involving 'no currently accepted medical uses' are no longer met by marijuana,” the Bradfords write.