A new article about therapeutic uses of cannabis suggests that Texans should remain cautious about medical marijuana.

The article, published online in the Journal of the American Medical Association, reviewed recent studies about therapeutic cannabis to determine which conditions it treats effectively. The conditions studied included nausea, seizures, chronic pain, dementia and post-traumatic stress disorder.

The authors’ conclusion: “Evidence is insufficient for the use of cannabis or cannabinoids for most medical conditions.”

The review article appeared three months after a law expanding our state’s “compassionate use” program went into effect. Legislators this year increased the number of dispensing licenses from three to 15. Conditions previously eligible for low-THC cannabis included epilepsy, seizure disorders, ALS, autism, cancer and PTSD. Added this year were chronic pain, traumatic brain injuries, inflammatory bowel diseases and patients receiving hospice care.

Texas has been more prudent than other states, resisting the push to legalize recreational marijuana and wary of claims about medical marijuana’s benefits. In light of the additional information, lawmakers should revisit the most recent expansion of its compassionate use program.

There have always been more claims promoting marijuana’s benefits than hard evidence to back them. Advocates of legalizing marijuana sometimes attribute that to puritanical closed-mindedness or purported conspiracies by pharmaceutical companies to discredit natural products. But many people who attest to marijuana’s therapeutic power endure maladies that resist established treatments. The appeal of cannabis is understandable.

Health policy, though, needs to be research-based and frequently re-evaluated as new data become available. That’s why the JAMA review article is important. It analyzed 124 studies about the uses of cannabis and cannabinoids published between January 2010 and Sept. 15 of this year. It discusses not only its effectiveness, but also how cannabis compares to other drugs or a placebo, side effects, risks and the strength of evidence.

The JAMA review suggested cannabinoids have modest benefits for a few specific conditions, such as chemotherapy-induced nausea and vomiting and a specific seizure disorder. The authors could not recommend for or against it for many other conditions because evidence was insufficient.

It advised against prescribing marijuana or cannabinoids for post-traumatic stress disorder, an eligible condition in Texas, and other psychiatric issues because evidence shows it can provoke or exacerbate mental illness. The article noted that two major medical societies, as well as the U.S. Department of Veterans Affairs, caution doctors against prescribing for PTSD because of its known “psychiatric adverse affects.”

For Texas doctors, the key is knowing patients and their medical histories well enough to distinguish who might benefit from therapeutic cannabis. And lawmakers need to monitor the program, following new research, and revise the law when the Legislature reconvenes.

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