Canada: Pot Smokers Recruited To Study Effects Of Cannabis On Cognition

Photo Credit: Darryl Dyck

If you have smoked five joints a week, every week, for the past year, then science needs you.

A research collaboration between Alberta Health Services, the University of Alberta and MacEwan University is studying 120 healthy Edmontonians aged between 18 and 35 to understand the short and long-term effects of cannabis use and its residual effects on cognition, motor skills and sensory skills.

It will also look at how people with mental illness are affected by cannabis.

Principal investigator Scot Purdon, with the neuropsychology department at Alberta Hospital Edmonton, admits it will be a small sample group, but calls it a good starting point to help fill the void in scientific literature surrounding the use of cannabis.

“There’s literature out there, but it’s highly ambiguous, with as many positive results as negative,” he said. “We don’t have long-term data; it’s just a big gap.”

There has been no shortage of patients who use a minimum of one gram of marijuana a week willing to spend several hours with researchers to answer questions about their substance use history and undertake short cognitive tests such as remembering words and drawings.

Volunteers receive $30 for their troubles.

“We thought we’d have difficulty recruiting, but what we found was that people use quite a bit more,” he said.

As of Tuesday, 56 people had taken part in the study at a rate that could move the release of the final results forward from August to as earlier as April or May.

Considering recreational marijuana is set to be legalized across the country July 1, the project could not be more timely, Purdon said.

“This research is just a drop in the bucket with what we need to find out about the effects of cannabis,” he said.

The $30,000 in funding for the project came from the Hotchkiss Brain Institute at the University of Calgary and the Neuroscience Institute at the U of A.

Anyone wishing to be involved in the project can email: