The differential effects of tetrahydrocannabinol (THC) versus cannabidiol (CBD) on cognition in persons with MS

Start Term
End Term
Funding Amount
$49,590
Affiliation(s)
London Health Sciences Centre Research
Geographic Region(s) / Province(s)
Ontario
Researcher(s)
Dr. Sarah A. Morrow
Research Priorities
Cognition and mental health
Impact Goal(s)
Advance Treatment and Care

Summary:

  • As cannabis products are increasingly being used among people with MS, it is important to understand both the benefits and harms of use. 
  • Dr. Sarah Morrow and team will examine the effect of cannabis on cognitive outcomes in people with MS through a pilot study. The researchers will evaluate both components, THC and CBD, and what dose of cannabis negatively affects cognition. 
  • This research will be important in informing decisions and practices regarding cannabis use in people with MS. 

Project Description:  

Use of cannabis and cannabis-based products is increasing in Canada, including among people with MS. Previous studies have shown that cannabis can affect cognition. MS can also result in cognitive impairments affecting 40-65% of people with MS. 

Cannabis has two main components, tetrahydrocannabinol (THC) and cannabidiol (CBD). THC is thought to be the component responsible for the ‘high’ of cannabis, while CBD is not. Preliminary studies suggest THC is the component that negatively impacts cognition, while CBD alone does not. However, little is known about the doses of THC or CBD that may have negative effects. 

Dr. Sarah Morrow and team aim to examine the effect of THC and CBD on cognition in people with MS. The researchers will conduct a pilot study in people with MS using cannabis to treat bladder symptoms. People with MS will be randomly and blindly assigned to either THC or CBD treatment for 15 weeks. Participants will report on bladder symptoms, cognitive symptoms, and complete cognitive tests before and after the use of THC or CBD. The researchers will also evaluate the dose of THC or CBD and its affect on cognition in people with MS. 

Potential Impact: The findings of this research will provide both healthcare providers and people with MS information on the harms and benefits of cannabis use, so they can make informed decisions. A larger confirmatory study will be designed based on the results of this initial study.

Project Status: In Progress