Young men who use marijuana heavily are at an increased risk of schizophrenia, according to a new study by the National Institutes of Health.
The study examined people suffering from “cannabis use disorder.” Cannabis use disorder is loosely defined as heavy marijuana use or as the inability to stop using marijuana despite the negative consequences that it causes.
The study estimated that as many as 30% of schizophrenia cases among men between the ages 21 and 30 might have been prevented by not using marijuana.
In a press release, the NIH wrote,
Previous studies indicate that rates of daily or near daily cannabis use, cannabis use disorder, and new schizophrenia diagnoses are higher among men than women, and that early, frequent cannabis use is associated with an increased risk of developing schizophrenia. . . .
This study also adds to existing evidence(link is external) suggesting that the proportion of new schizophrenia cases that may be attributed to cannabis use disorder has consistently increased over the past five decades. The authors note that this increase is likely linked to the higher potency of cannabis and increasing prevalence of diagnosed cannabis use disorder over time.
The study itself noted that THC levels in marijuana have “increased dramatically” since 2009, and that THC may trigger or worsen schizophrenia.
This is not the first time that researched have found a connection between marijuana use and serious mental health problems. For example:
- A 2022 study published in The Lancet determined that using marijuana with high levels of THC was linked to an increased risk of psychosis.
- A 2021 report published in the Journal of the American Medical Association found self-harm rates rose 46% among men ages 21 to 39 in states where commercial marijuana sales were legalized.
- A 2019 study published in The Lancet found using marijuana with THC levels exceeding 10% increased the odds of a person suffering a psychotic episode.
Research increasingly ties marijuana use to other serious health problems as well.
In April the American Heart Association said that marijuana use is “scientifically linked” to deadly cardiovascular diseases, heart attacks, and strokes.
A recent study presented at the American College of Cardiology’s Annual Scientific Session found people who used marijuana daily were 34% more likely to develop coronary artery disease compared with people who have never used marijuana.
In February, a survey of more than 2,500 teens and young adults led by the American Heart Association found that vaping THC was associated with self-reported symptoms of depression and anxiety.
A study by the Roswell Park Comprehensive Cancer Center recently found that vaping CBD — a substance found in marijuana — can cause more severe lung damage than vaping nicotine.
A study published in the Canadian Medical Association Journal found adults under age 45 who frequently use marijuana are roughly twice as likely to suffer from a heart attack as adults who do not use marijuana.
A study published last year in the journal of the Radiological Society of North America found marijuana smoke may be more harmful to lungs than cigarette smoke, after researchers examined some 150 lung scans from marijuana smokers, tobacco-only smokers, and nonsmokers.
A 2019 study found that regular marijuana use increased the risk of heart problems for young people, and a 2017 study reported marijuana smokers were three times more likely to die of hypertension.
The list goes on and on and on.
All of this underscores what we have said for years: Marijuana may be many things, but “harmless” simply is not one of them.
