Multiple Sclerosis Health Center

Medical Marijuana May Impair Thinking of MS Patients

Medical Marijuana Debate

The researchers say larger studies are needed to confirm their findings.

Neurologist Lily Jung Hensen, MD, of Seattle’s Swedish Neurosciences Institute, tells WebMD that the findings make a strong argument that the cognitive risks associated with marijuana use outweigh potential benefits for MS patients.

Morgan Fox of the Marijuana Policy Project notes that the researchers did not consider other medications that the study participants might have been taking and he said the study had other limitations that could have affected the findings.

”No study has been able to show long-term, permanent cognitive damage in adult marijuana users, only temporarily decreased abilities,” he tells WebMD.

Fox noted that all medications have side effects, but decisions about whether or not to use them should be left to patients and their doctors.

Williams agrees, adding that a review of 15 medical marijuana studies conducted over the last 20 years showed no evidence of long-term cognitive decline. The review, conducted by researchers from the University of California’s Center for Medicinal Cannabis Research, was reported in February 2010.

“Marijuana is not going to work for everybody, but no pain medication on the planet does,” he says. “But if my doctor can write me prescriptions for morphine and for OxyContin, he should certainly be able to write me a prescription for this drug.”