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Difficulties Studying Medical Marijuana

CU School of Medicine


AURORA, Colo. – Studies of marijuana use to treat inflammatory bowel disease (IBD) are hampered by a lack of scientific evidence, public perception of the drug’s safety and legal prohibitions making it difficult to design research studies, according to an article by researchers at the University of Colorado School of Medicine. 

“Our understanding of the potential anti-inflammatory mechanisms of cannabis is relatively poor,” said Edward Hoffenberg, MD, professor of pediatrics at the CU School of Medicine and director of the Center for Pediatric Inflammatory Bowel Diseases at Children’s Hospital Colorado. 

“And that’s because there are a wide array of biologically active components in cannabis and there are legal prohibitions that make it challenging for academic researchers who want to study health effects of cannabis,” said Hoffenberg.

The paper, “Cannabis and pediatric inflammatory bowel disease: change blossoms a mile high,” appears in the current issue of the Journal of Pediatric Gastroenterology and Nutrition. Hoffenberg is the lead author.

Hoffenberg, who has a grant from the Colorado Department of Public Health and Environment to study the benefits of marijuana in pediatric and adolescent IBD, and his colleagues conducted a pilot study in 2013 to measure marijuana use by 65 pediatric patients with IBD and 100 subjects without chronic illness.

The study found that 55 percent of the patients with IBD who used marijuana reported using weekly or more often for treatment of physical symptoms. That compared with 26 percent of those without chronic illness using marijuana on a weekly or more frequent basis.

The researchers could find no studies that evaluate marijuana for treatment of IBD in children and data for adults are limited. There are three observational studies of about 300 adult subjects, suggesting that marijuana is associated with subjective relief of IBD symptoms. These studies found that patients feel cannabis could potentially alleviate nausea, stool frequency and abdominal pain, while improving appetite and weight gain.

But there is a lack of scientific evidence that the drug has any direct impact on the underlying disease, legal uncertainty due to conflicts between state and federal law, and public perception that marijuana is safe to use regularly, Hoffenberg said.

Hoffenberg and his colleagues write that federal laws require most universities implement programs to prevent unlawful possession, use and distribution of illicit drugs by students and employees and to have policies that will subject employees to institutional and criminal sanctions. Because marijuana is a Schedule 1 drug under federal law, those prohibitions create “a challenging environment for academic researchers who want to study health effects of cannabis.”

While advocates have touted marijuana as beneficial for many ailments, heavy use can cause memory impairment and lead to withdrawal symptoms and addiction risk, Hoffenberg and his colleagues write. “These negative effects have both immediate and long term implications, leading the American Academy of Pediatrics and the Academy of Child and Adolescent Psychiatry to officially oppose the legalization of marijuana.”

Hoffenberg’s co-authors are Heike Newman, MS, Colm Collins, PhD, Kristina Leinwand, DO, and Sally Tarbell, PhD of the University of Colorado School of Medicine on the Anschutz Medical Campus.