It's no secret that studies show that sexually diverse youth - in particular, lesbian, gay and bisexual (LGB) youth - use more cannabis and experience more mental health challenges than their heterosexual peers.

But what about the changes that occur in the rates of cannabis use: do they precede those related to mental health or is it the other way around? A new study from Université de Montréal offers some answers.

In the Journal of Abnormal Psychology, Kira London-Nadeau, a doctoral student and CIHR Vanier Scholar in the Department of Psychology at UdeM and the CHU Sainte-Justine Research Centre, provides an update.

In her study, conducted under the direction of Professor Natalie Castellanos-Ryan and with the support of Professors Jean Séguin and Sophie Parent, London-Nadeau analyzed data collected from 1,548 adolescent boys and girls - including 128 LGB adolescents - as part of the Longitudinal Study of Child Development in Quebec supported by CIHR and the Institut de la Statistique du Québec.

Participants were followed from the age of five months and the study was based on their responses to questionnaires collected at ages 13, 15 and 17. Although there was an association between depressive symptoms at age 15 and increased cannabis use at age 17 in the general sample, the association was five times stronger among LGB youth.

According to London-Nadeau, this relationship may signal a practice of LGB youth self-medicating with cannabis to cope with depressive symptoms. The use of cannabis for these purposes could also indicate that other sources of support for depressive symptoms are lacking or inadequate for the realities of LGB youth.

Unexpectedly, the study also found that anxiety symptoms among LGBs at age 15 predicted reduced cannabis use at age 17. This finding thus seems to run counter to the finding of an association between depression and cannabis use in the LGB group.

The difference between the depression-cannabis relationship and the anxiety-cannabis relationship could indicate different realities that LGB youth would experience, particularly with respect to their public display of their minority sexual orientation."

Kira London-Nadeau, Doctoral Student and CIHR Vanier Scholar, Department of Psychology, UdeM

hus, the researcher believes that social factors related to the experience of a minority sexual orientation would play an important role in both cannabis use and mental health challenges and the relationship between the two among adolescents.

In this regard, London-Nadeau emphasizes the need for youth services, particularly mental health services, to be better equipped to understand the issues specific to sexual diversity communities.

"As a teenager, you're constantly trying to figure out your identity as a person, which in itself is pretty difficult," said the young researcher, who identifies herself as gay. "When you add the discovery of a minority sexual orientation to that identity development, things get even more complicated."

"Now it's a matter of digging deeper into the why of these associations and making sure to include other communities that may be having similar experiences, including trans and non-binary teens, as well as sexually and gender diverse young adults," she continued.

"These results will be crucial for these communities, as they will allow us to better target their needs to ultimately achieve a more equitable level of parity in their health."