Hazardous cannabis use in MS linked to anxiety, depression

SEATTLE – A small new study suggests that patients with multiple sclerosis (MS) who use cannabis in a hazardous way are more likely to suffer from symptoms of anxiety and depression, although it is not clear whether there is a cause-and-effect relationship. “We highly recommend screening for hazardous cannabis use in clinical settings,” said study lead author and rehabilitation psychologist Abbey J. Hughes, PhD, an assistant professor at Johns Hopkins University, Baltimore, in an interview. She spoke prior to the presentation of the study findings at the annual meeting of the Consortium of Multiple Sclerosis Centers.

According to Dr. Hughes, research suggests that patients with MS are using cannabis more now than in the past, especially for medical reasons. It is not clear, however, how cannabis is affecting neurobehavior in patients with MS who use it, said Dr. Hughes, who works with patients with MS.

For the new study, researchers gave surveys to 100 patients with MS (76% female; mean age, 46 years) who sought outpatient care at an MS center. Of those, 31 said they had used cannabis within the past month.

The patients were screened via several tools: the Cannabis Use Disorders Identification Test–Revised (CUDIT-R) Fatigue Severity Scale; Patient Health Questionnaire–8; Generalized Anxiety Disorders Scale–7; and Brief International Cognitive Assessment for Multiple Sclerosis.

Subjects were considered to have a problem with “hazardous cannabis use” if they met or exceeded the CUDIT-R’s clinical cut-off of 8 points. The test asks about topics such as hazardous behavior while using cannabis, problems with memory or concentration after using it, and inability to stop using it. Twelve participants met this criteria, and they were more likely to have more symptoms of depression (beta = 0.32; P less than .01) and anxiety (beta = 0.24; P = .02), after researchers controlled for age, years of education, and MS subtype.

They also were slightly more likely to have more severe fatigue (beta = 0.20; P = .07) and poor sleep (beta = 0.20; P = .07).

The researchers found no link between cannabis use and scores on the cognitive test, although Dr. Hughes noted that other research has suggested such a link.

The study is cross-sectional and does not offer insight into cause and effect, Dr. Hughes said. She noted that it is possible that patients used cannabis because they had higher levels of anxiety and depression.

No study funding was reported and the authors report no relevant disclosures.