Marijuana (Cannabinoids)Multiple Sclerosis

Cognitive effects of street cannabis in MS patients

Given that multiple sclerosis (MS) is associated with cognitive (reasoning) deterioration, researchers at the University of Toronto, in Ontario, determined the neuropsychological effects of cannabis use in these patients.

Listen up, Montel Williams.

First, the details.

  • 50 patients with MS (cannabis users and nonusers) were administered a battery of neuropsychological tests.
  • The findings were adjusted for the effects of age, gender, education, intelligence measured before their disease, disability, and disease course and duration on cognitive function.

And, the results.

  • Cannabis users performed significantly more poorly than nonusers on measures of information processing speed, working memory, executive functions, and visuospatial perception.
  • They were also twice as likely as nonusers to be classified as globally cognitively impaired.
  • There were no differences between groups in depression and anxiety or lifetime psychiatric diagnoses.

The bottom line?

The authors concluded, “Prolonged use of inhaled or ingested street cannabis in patients with MS is associated with poorer performance on cognitive domains commonly affected in this population.”

Somebody show me a well-designed study that supports benefits of smoking pot over mainstream treatments in these patients.

6/18/11 21:08 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.