FRIDAY, May 26, 2023 (HealthDay News) — Heavy marijuana users may be at increased risk for bipolar disorder and depression, a new study suggests.
The analysis of more than 6.6 million Danish individuals found that having a cannabis use disorder doubled or even tripled the risk of most forms of depression or bipolar disorder. Specifically, with regard to bipolar disorder, “a cannabis use disorder was associated with a higher risk of psychotic than nonpsychotic subtypes of bipolar disorder,” the researchers noted.
However, these results cannot prove that marijuana use was the cause of these conditions, the researchers said.
“Our results are compatible with the idea that cannabis may increase the risk of developing depression or bipolar disorder, but we cannot prove this with certainty because we are working with observational data,” said lead researcher Dr. Oskar Jefsen of the psychosis research. department at Aarhus University in Denmark. “Unambiguous evidence would require a randomized controlled trial, but this would be unethical.”
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Still, one expert noted that while the study cannot prove that cannabis was the cause of bipolar disorder or depression, it adds to the growing evidence that the drug is not harmless.
“This is a powerful and well-conducted study that adds to the emerging evidence of the additional risk of regular cannabis use for the development of serious mental health disorders,” said Beatriz Carlini, director of the Cannabis Research and Education Program and an acting associate professor of psychiatry and behavioral sciences at the University of Washington School of Medicine.
As marijuana legalization spreads in the United States, people need to recognize that cannabis use is not benign, she said.
“While we should celebrate moving away as a society from the stigmatization of cannabis users and the widespread exaggeration of the risks associated with cannabis use, we should be concerned about our current cultural moment, where cannabis is portrayed as a harmless substance. ,” Carlini said.
This study raises the question of whether bipolar disorder and depression make cannabis abuse more likely, rather than causing these problems, said Paul Armentano, deputy director of NORML, which advocates for the legalization of marijuana.
“It is well established that people predisposed to or suffering from bipolar disorder and other similar conditions tend to consume all controlled substances, not just cannabis, at a much higher rate than the general population,” he said. “This is especially true for tobacco use.”
Still, there’s little support for the idea that cigarette smoking causes psychiatric illness or that it should be criminalized for adults to benefit mental health, he said.
“Studies often show that the relationship between cannabis use and many psychiatric conditions is bidirectional, meaning that in many cases a diagnosis predicts later cannabis use,” Armentano said. “In short, these relationships are most likely correlative, and they are often complex, multidirectional, and they are far from unique to cannabis.”
However, some populations are more vulnerable to the effects of cannabis, especially when the substance is used frequently or at a younger age, Armentano noted.
“Those who suffer from bipolar disorder, schizophrenia and certain other mental health problems, or who are predisposed to these events, probably fall into this category and should probably approach cannabis and other substances with a greater degree of caution,” he said.
The report was published online May 24 in the journal JAMA Psychiatry.
For more information on the effects of marijuana, see the U.S. Centers for Disease Control and Prevention.
SOURCES: Oskar Jefsen, MD, psychosis research unit, Aarhus University Hospital-Psychiatry, Aarhus University, Denmark; Paul Armentano, Deputy Director, NORML; Beatriz Carlini, PhD, MPH, director, Cannabis Education and Research, and acting associate professor, psychiatry and behavioral sciences, University of Washington School of Medicine, Seattle; JAMA PsychiatryMay 24, 2023, online