Extensive research: cannabis use increases the risk of mental disorders at a young age

The result was that adolescent cannabis use was associated with an increased risk of developing psychosis, bipolar disorder, depression or anxiety as a young adult.

The study was published At Jama Health Forum. More than 463,000 young people between the ages of 13 and 17 were monitored. Their mental health status was monitored until they were 26 years old.

Cannabis use was confidentially surveyed as part of regular health checks. The young people were later followed from electronic medical records until early adulthood.

The strongest an association was seen with psychosis and bipolar disorder, the risk of which was approximately double.

The weight of the study is increased by the fact that it did not only look at heavy use or addiction.

The use preceded the psychiatric diagnosis by about two years on average. It reinforces the notion that adolescent cannabis use may play a role in the development of later mental health disorders.

Although the most striking finding was related to psychosis and bipolar disorder, the link was also seen in the risk of depression and anxiety. In them, the connection was weaker, but still clear.

Depression and anxiety, the association was strongest in younger teenagers and weakened with age. According to the researchers, it supports the idea that adolescence can be a particularly sensitive stage of development.

US researchers also point out that current cannabis products are stronger than years or decades ago.

Thc, or tetrahydrocannabinol, is the main intoxicant in cannabis. It is not only intoxicating, but also affects the systems central to the development of the brain.

THC content of cannabis flower in Northern California often exceeds 20 percentsuch as research Scientific Reports – science journal in 2025 found. Cannabis concentrates can contain up to 95 percent thc.

Research does not openly claim that cannabis alone causes mental health disorders.

According to the researchers, the relationship can also be two-way, so that some young people can use cannabis to ease their symptoms. There may also be common risk factors in the background.

However, the connections remained, even when previous psychiatric disorders, other substance use and other explanatory factors were taken into account in the analysis.

The researchers’ interpretation is that cannabis not only follows problems, but can also make them worse or increase their likelihood.

to cannabis is treated more leniently in Finland now than a few years ago.

The long term of the Institute of Health and Welfare (THL). based on the time series the risks of Finnish cannabis use are considered lower than before.

Also attitude the legalization of cannabis has eased. The majority is already opposed to punishing use, and an increasing number also accept the legal availability of cannabis, at least for medicinal use.