Patients with multiple sclerosis (MS) who smoke marijuana regularly have more cognitive deficits
than patients with MS who do not smoke marijuana,
according to research published May 27 in Neurology.
Marijuana use may be associated with impairments
in information processing speed, visual memory, and
working memory among these individuals.
In a cross-sectional study, cannabis users had more
diffuse cerebral activation during a test of working
memory, compared with nonusers. The cannabis users also had increased activation in parietal and anterior cingulate brain regions implicated in working
memory, relative to nonusers.
But investigators found no differences in brain
structure between the study groups, and this find-
ing is consistent with the results of cannabis imaging
studies in healthy subjects.
Subjects Underwent Imaging
and Neuropsychologic Tests
Bennis Pavisian, research assistant at Sunnybrook
Hospital in Toronto, and colleagues recruited 39 patients (ages 18 to 60) with a confirmed diagnosis
of MS for their study. They enrolled 20 participants who regularly used cannabis and whose urine
tested positive for cannabis metabolites. The investigators asked participants not to use cannabis for
12 hours before the trial. Nineteen patients with
MS who had never used cannabis were matched
to the other participants using demographic and
disease-related variables.
Does Cannabis Impair Cognition
Among Patients With MS?
Serving the Neurology Community Since 1993
FOLLOW US ON Find us on
facebook
continued on page 4
Rare Diseases Are Not
5 So Rare in Neurology
News Briefs From the
10 Annual Sleep Meeting
Brain Reserve May Protect
14 Against Cognitive Decline in MS
News Briefs From the
15 CMSC/ACTRIMS Meeting
Study Details Adverse Health
20 Effects of Marijuana Use
MS Researchers Debate Risks
23 and Benefits of Alemtuzumab
How Safe Are Opioids for
Inside This Issue
©Ol
iv
er
Berg
/C
orbi
s