Researchers at McGill University Health Centre and McGill University in Montreal and the University of British Columbia in Vancouver said that as the use of cannabinoid medications increases, so do concerns about their potential to cause "adverse events."

Dr. Mark Ware of the McGill University Health Centre said the analysis reported 31 separate clinical studies of cannabinoid medications conducted between 1966 and 2007. Adverse events were categorized as either serious or non-serious; with serious adverse events defined as those leading to death, hospitalization or disability.

"Overall, we found an 86 percent increase in the rate of non-serious adverse events among the patients treated with cannabinoids compared to the patients in the control groups," Ware said in a statement. "The majority of events were mild to moderate in severity."

The majority of non-serious adverse events observed involved dizziness and drowsiness, the researchers said.

The findings were published in the Canadian Medical Association Journal.