Canadian teenagers are among the largest consumers of cannabis worldwide. The damaging effects of this illicit drug on young brains are worse than originally thought, according to new research by Dr. Gabriella Gobbi, a psychiatric researcher from the Research Institute of the McGill University Health Centre. The new study, published in Neurobiology of Disease, suggests that daily consumption of cannabis in teens can cause depression and anxiety, and have an irreversible long-term effect on the brain.

“We wanted to know what happens in the brains of teenagers when they use cannabis and whether they are more susceptible to its neurological effects than adults,” explained Dr. Gobbi, who is also a professor at McGill University. Her study points to an apparent action of cannabis on two important compounds in the brain – serotonin and norepinephrine – which are involved in the regulation of neurological functions such as mood control and anxiety.

“Teenagers who are exposed to cannabis have decreased serotonin transmission, which leads to mood disorders, as well as increased norepinephrine transmission, which leads to greater long-term susceptibility to stress,” Dr. Gobbi stated.

Previous epidemiological studies have shown how cannabis consumption can affect behaviour in some teenagers. “Our study is one of the first to focus on the neurobiological mechanisms at the root of this influence of cannabis on depression and anxiety in adolescents,” confirmed Dr. Gobbi. It is also the first study to demonstrate that cannabis consumption causes more serious damage during adolescence than adulthood.

Dr. Gabriella Gobbi is a researcher at the neuroscience axis of the Research Institute of the McGill University Health Centre and also a psychiatrist and associate professor at the Department of Psychiatry, McGill University.

Funding

This study was funded by a grant from The Canadian Psychiatric Research Foundation (CPRF)

Partners

This article was co-authored by Dr. Francis Rodriguez Bambico; Ms. Nhu-Tram Nguyen, and Mr. Noam Katz from from IR-MUHC and the Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University.

The Research Institute of the McGill University Health Centre (RI MUHC) is a world-renowned biomedical and health-care hospital research centre. Located in Montreal, Quebec, the institute is the research arm of the MUHC, the university health center affiliated with the Faculty of Medicine at McGill University. The institute supports over 600 researchers, nearly 1200 graduate and post-doctoral students and operates more than 300 laboratories devoted to a broad spectrum of fundamental and clinical research. The Research Institute operates at the forefront of knowledge, innovation and technology and is inextricably linked to the clinical programs of the MUHC, ensuring that patients benefit directly from the latest research-based knowledge. The Research Institute of the MUHC is supported in part by the Fonds de la recherche en santé du Québec. For further details visit: www.muhc.ca/research [1]

The McGill University Health Centre (MUHC) is a comprehensive academic health institution with an international reputation for excellence in clinical programs, research and teaching. Its partner hospitals are the Montreal Children's Hospital, the Montreal General Hospital, the Royal Victoria Hospital, the Montreal Neurological Hospital, the Montreal Chest Institute and the Lachine Hospital. The goal of the MUHC is to provide patient care based on the most advanced knowledge in the health care field and to contribute to the development of new knowledge. www.muhc.ca [2]

About the MUHC Redevelopment Project Guided by its mission and its role as co-leaders of the McGill integrated university hospital network, the MUHC is carrying out a $2.2-billion Redevelopment Project that will help the Government achieve its vision for academic medicine in Quebec. Excellence in patient care, research, education and technology assessment will be fostered on three state-of-the-art campuses—The Mountain, the Glen and Lachine—and through strong relationships with healthcare partners. Each LEED®-registered campus will be designed to provide patients and their families with “The Best Care for Life” in a healing environment that is anchored in best sustainable development practices, including BOMA BESt guidelines. www.muhc.ca/construction [3]