For the study, the team involved more than 15,000 lesbian, gay or bisexual youth. The goal of the study was to better understand the risks associated with polysubstance use, or the use of three or more types of drugs, among sexual minority youth.
The data showed that there is a sizeable number of youth, both heterosexual and sexual minority, who don't use any substances at all, Dermody said.
But among those who do, she found that those identified as sexual minority youth were at higher risk of using each type of drug -- alcohol, marijuana and cigarettes -- compared to heterosexual youth.
And within the sexual minority youth population, some groups were at more risk than others for using one, two or all three substances, the researchers found.
Bisexual youth faced the largest increase in risk of polysubstance abuse as well as combinations of two substances, while those who identified as lesbian or gay were only at higher risk for some combinations, the team said.
The disparity may be due in part to stress from discrimination, violence and victimisation rooted in their sexual minority status, Dermody noted.