Cannabis use has become more common in recent years, especially in countries where it has been legalized.
While many people see it as a way to relax or cope with stress, new research suggests that increasing cannabis use may be happening alongside rising mental health problems such as anxiety, depression, and thoughts of suicide.
A large study in Canada looked at the health data of about 35,000 people aged 15 and older over a ten‑year period.
The research was led by scientists at McMaster University and used information from two national surveys conducted between 2012 and 2022.
During this time, Canada legalized cannabis, making it easier to buy and use. Researchers wanted to understand how these changes might be related to people’s mental health.
The findings showed that cannabis use and mental health struggles have been increasing together. The study did not prove that cannabis causes these problems, but it found that the link between them has grown stronger over time.
One of the most concerning trends involved anxiety and depression. The number of people reporting symptoms of these conditions nearly doubled during the study period.
By 2022, about 5.2 percent of Canadians reported having generalized anxiety disorder, and 7.6 percent reported a major depressive episode. These conditions can deeply affect daily life, making it harder to work, study, maintain relationships, and enjoy normal activities.
Young people appeared to be especially vulnerable. While the rate of suicidal thoughts and behaviors did not change much among adults, it increased sharply among youth. In fact, suicidality rose by 44 percent among younger Canadians.
Researchers also found that younger people showed some of the strongest connections between cannabis use and mental health problems.
Cannabis use itself also increased during this period. The number of people using cannabis several times a week more than doubled. By 2022, more than one in five Canadians reported using cannabis at least once in the past year. This suggests that cannabis has become a regular part of life for many people.
When researchers compared users with non‑users, they found that people who used cannabis at any level were more likely to experience anxiety, depression, and suicidal thoughts.
Those who used cannabis regularly—two or more times per week—were about five times more likely to report these mental health problems than people who did not use cannabis at all.
Experts say there may be several reasons for this connection. Some people may turn to cannabis to cope with stress, loneliness, or emotional pain.
Others may experience worsening mental health symptoms after using cannabis, especially strong products with high levels of active ingredients. Legalization may also have led to stronger products and greater availability, which could influence how often people use it.
The study highlights the importance of recognizing the relationship between substance use and mental health. Doctors and mental health professionals are encouraged to ask patients about cannabis use when evaluating anxiety or depression.
At the same time, people who use cannabis should be aware of how it might affect their mood and emotional well‑being.
Researchers also call for better prevention programs and easier access to services that treat substance use and mental health issues together. Early support could help reduce the risk of serious problems later in life.
Although cannabis is often seen as harmless, this study suggests that heavy or frequent use may be linked to worsening mental health for some people, especially young users. Understanding these risks can help individuals make informed choices and seek help when needed.
If you care about mental health, please read studies about how dairy foods may influence depression risk, and 6 foods you can eat to improve mental health.
For more mental health information, please see recent studies about top foods to tame your stress, and Omega-3 fats may help reduce depression.
The study is published in JAMA Internal Medicine.
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