More research needed on health effects of recreational marijuana

(Carol Yepes/Getty Images)

This fall, for the third time, South Dakotans are being asked to vote on whether to approve marijuana (cannabis) for recreational use (marijuana use as a medical treatment was approved in 2020 ). In the past, the proposal was approved, declared unconstitutional and then subsequently rejected by voters.

So, what are we to think? What are the facts? Is marijuana safe? Does pot use lead to hard drugs? What about pot smoking during pregnancy? Does use of marijuana increase the risk of other disease?

On each of these questions we have information — and lots of opinion. Unfortunately, the reality is that we really do not have clear cut answers. In spite of decades of experience there is still a serious shortage of reliable, scientifically valid research defining the effects of marijuana on the human body.

Up to this point marijuana has been categorized as a Schedule 1 drug by the federal government, meaning that it had no valid medical use. This meant that it was basically unavailable to medical researchers who were interested in trying to better define its risks and benefits. There is now a federal proposal to recategorize it to Schedule 3. That would make it more available to researchers and give the public much better data about safety and effectiveness.

Even without these changes, however, some legitimate research is available. In the past, the general impression has been that marijuana use is reasonably safe. New information, however, raises genuine safety concerns.

In spite of decades of experience there is still a serious shortage of reliable, scientifically valid research defining the effects of marijuana on the human body.

The American Heart Association recently published a survey showing marijuana use, especially prolonged use, was associated with an increased risk of both heart disease and stroke. A recent study in the Journal of the American Medical Association showed that marijuana use during pregnancy, especially if continued throughout pregnancy, was associated with adverse outcomes. Marijuana use by teen agers has been associated with an increased development of psychotic disorders. It is not clear whether marijuana is actually the causal agent in these situations.

A major explanation for these seemingly conflicting reports is that the drug itself has changed. The marijuana available on the market today — both legal and illegal — is considerably more potent than what was available in years past. Does increased potency make it more dangerous? Again, it is a serious question, and we need more reliable research to make responsible decisions.

Does pot smoking lead to the use of more dangerous “hard” drugs? Surveys have shown that users of hazardous substances such as heroin, fentanyl, etc., very often used marijuana earlier. Whether the progression to more potent substances was a direct result of the marijuana use or whether it simply represents an evolution of people seeking a more powerful experience remains unclear.

Measuring the actual economic impact of marijuana legalization is a complex challenge. Legislators are attracted to a potential new source of tax revenue, but concerns have also been raised about increased social service costs, law enforcement costs, etc. The current ballot proposal contains no direction on these issues. If the measure passes, the rules controlling distribution and the taxing structure would have to be worked out in the next session of the Legislature.

So, what does all this mean? Recent research shows that marijuana use carries risks and raises questions that have not been fully appreciated — or evaluated — in the past. In my view, we need to go slow in allowing wider use of a substance for which the consequences are still poorly defined.

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