New Research Reveals Age Plays Key Role in Cannabis‑Related Psychiatric Risks

A new study undertaken by researchers at Johns Hopkins University has discovered a link between cannabis use disorder and development of psychiatric disorders in young adults.

CUD Linked to Increase Risk of Serious Mental Illness

The study found that young adults who suffer from cannabis use disorder (CUD) are more likely to develop psychiatric disorders compared to those of the same age suffering from other substance abuse disorders. CUD is defined by the Cleveland Clinic as “a complex condition that involves a problematic pattern of cannabis (marijuana) use…CUD exists on a spectrum and may be mild, moderate or severe. It typically involves an overpowering desire to use cannabis, increased tolerance to the cannabis and/or withdrawal symptoms when you stop taking it.” The clinic added: “CUD can significantly impact your health, relationships and overall quality of life. It’s crucial to seek help as soon as you develop signs of it.”

Young adults aged 17 and under who suffer from cannabis use disorder are at a 52 percent higher chance for developing schizophrenia, according to the study. They are 30 percent more likely to be diagnosed with major recurrent depression, and 21 percent more likely to develop anxiety disorders. However, adults 18 and older with cannabis use disorder were found to be less likely to be diagnosed with a psychiatric condition.

“Is cannabis use a unique risk factor compared to the use of other substances such as alcohol, opioids, or cocaine? That’s the question we addressed in this study, and our findings suggest that that relative risk depends on the user’s age,” said study co-author Johannes Thrul, an associate professor in the Department of Mental Health at the Bloomberg School.

Cannabis use by adults aged 21 and over is now legal in 24 states and the District of Columbia. The study suggests that cannabis use in the United States exceeds alcohol consumption. “Much of our interest in this came from the recent legalization of recreational cannabis in Maryland, in 2023, and other states,” said Ryan Nicholson, aresident at Johns Hopkins University School of Medicine. “We wanted to understand cannabis-related psychotic disorders clinicians are seeing in the context of other substance-related psychotic disorders."

Cannabis Use in Adolescents Is Exceedingly Dangerous

The results of the study are consistent with a link between heavy cannabis use and a predisposition to schizophrenia and other serious psychological disorders that may not otherwise develop. This so-called “acceleration effect” could potentially make these illnesses less likely to develop at later stages of life, though researchers stipulate this is in comparison to other recreational drugs.

The results are consistent with the idea that heavy cannabis use predisposes young people to subsequent schizophrenia and some other psychiatric disorders that they might not develop otherwise. Thrul notes that this acceleration effect could make these illnesses seem less likely at later ages, thus appearing to lower the risk in adults, at least in relation to other recreational drugs.

“There are still many unknowns on that question, but I would never recommend that teenagers use, especially not the high-potency cannabis products that are on the market now,” Thrul said.