Drugs and Kids > Cannabis linked to increased risk of schizophrenia and bipolar disorder in young adults

 

High-Potency Cannabis Linked to Increased Psychosis Risk in Young Adults: Study

Cannabis can be toxic to adolescent brain functioning, increasing the risk of developing psychosis years later.

During breaks from his deployments in the Afghanistan war, Craig turned to smoking cannabis to alleviate stress, just as he had done as a teenager. However, one evening, things took a turn when he barricaded himself and his two young daughters in the master bedroom.

“He thought the house was surrounded by terrorists,” Jennifer Thomas, the girls’ mother, recounted while speaking to The Epoch Times. “That night was bad; he said they were under attack. The other times before that were mostly him seeing auras and aliens talking.”

Military police took Craig to a psychiatric hospital, where he was diagnosed with schizophrenia at 26.

Craig’s story is one among an increasing number of cases, primarily involving men, in which cannabis use has contributed to a schizophrenia diagnosis occurring in one’s 20s.

The Cannabis–Psychosis Link

New UK research shows adults who consumed high-potency cannabis between ages 16 and 18 are twice as likely to experience psychotic episodes such as hallucinations and delusions by their mid-20s compared to those using low-potency strains or abstaining. The longitudinal study, published in Addiction, highlights cannabis’s risks to adolescent brain development.

“Young people using higher-potency forms of cannabis are twice as likely to have experiences associated with psychosis, such as hallucinations and delusions,” lead author Lindsey Hines, a professor from the University of Bath Department of Psychology with a doctorate in epidemiological psychiatry, said in a statement.

Over the past several decades, illicit marijuana products have become significantly more potent. The concentration of tetrahydrocannabinol (THC)—the psychoactive compound in cannabis responsible for the “high” sensation and one linked to psychotic experiences in some people—increased to roughly 14 percent by 2019 from around 10 percent in 2009, according to a scientific review published in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging.

“This is the problem,” Yasmin Hurd, director of the Addiction Institute at Mount Sinai in New York, told The Epoch Times. “Many people don’t realize that the cannabis that is consumed today—the majority or all of it—is high-potency.”

The researchers examined data from the University of Bristol’s Children of the 90s (ALSPAC) study, the most comprehensive birth cohort study of its kind. The study collected information and data from about 14,000 adolescents between 16 and 18. Then, when they were 24, the participants were asked to disclose the types of cannabis they used and any psychotic experiences, such as hallucinations or delusions, they may have experienced.

The study found that 6.4 percent of young people using cannabis had new psychotic experiences, compared to 3.8 percent of nonusers. Furthermore, after starting to use cannabis, 10.1 percent of young people using higher-potency cannabis reported new psychotic experiences, while 3.8 percent using lower-potency cannabis did.

“Importantly, the young people we asked had not previously reported these experiences before starting their cannabis use,” Ms. Hines said. ”This adds to the evidence that use of higher-potency cannabis may negatively impact mental health.”

Stronger THC a Ticking Time Bomb for Mental Health

Cannabis poses a greater psychosis risk than tobacco or alcohol, according to Ms. Hurd, who noted that the new findings align with numerous studies linking cannabis use to psychosis.

A 2017 study in The American Journal of Psychiatry found that people experiencing even one cannabis-induced psychotic episode have a 47 percent higher chance of developing schizophrenia or bipolar disorder, with self-harm after such episodes indicating the highest risk. Of those experiencing substance-induced psychosis, half of them developed schizophrenia within three years, while the other half converted to bipolar disorder within almost 4 1/2 years.

Both schizophrenia and bipolar disorder are thought to involve imbalances in brain chemicals (neurotransmitters) and abnormalities in brain structure and function. These neurological factors may contribute to the development of psychotic symptoms, such as hallucinations and delusions, in both disorders.

A study published in Molecular Psychiatry analyzed genetic markers to assess the cannabis-psychosis relationship and found that “use of cannabis is causally related to the risk of schizophrenia,” meaning that cannabis is a factor influencing the occurrence of the disorder.

A 2023 Danish study reported cannabis use disorder (CUD) as a major schizophrenia risk factor for young males, estimating that 30 percent of cases among men aged 21 to 30 could be prevented by preventing CUD, a diagnosis of problematic cannabis abuse or dependence that affected 14.2 million Americans aged 12 and over in 2020.

While not all young cannabis users develop psychosis, Ms. Hurd said that factors such as starting before 16, frequent use, and higher potency increase risk, potentially triggering conditions in genetically predisposed people, as a 2018 study using 23andMe data found.

The increased psychosis risk from more potent cannabis “must be taken seriously, especially in light of the current mental health crisis,” Ms. Hurd and colleagues wrote in a 2024 commentary in The American Journal of Psychiatry.

The Undiagnosed Issue with Cannabis use

For 50 years I have been watching frequent users of marijuana and have observed a startling symptom that hos not been recognized by the mental health community. That symptom is a complete cessation of the maturing process in a number of people. People who start using pot regularly, say weekly, at 15, will often continue to act, dress, talk, and think like a 15 year old.

I noticed this phenomena long before high-potency pot was available, and can only imagine it getting worse with potencies 3 or 4 times as high as in the 1970s and '80s.

Does Pot make you Crazy?

Challenges Ahead

Despite evidence linking cannabis to psychosis, teen use soared 245 percent between 2000 and 2020, according to research published in Clinical Toxicology. The authors attributed the rise to popular edible products, with legalization making cannabis seem safer and more accessible to teens, even though it is only legal for adults in 24 states and Washington, D.C.

Tax revenue from the cannabis industry must fund prevention strategies to mitigate impacts on developing brains, Ms. Hurd and her colleagues wrote in the commentary.

The U.S. Drug Enforcement Agency (DEA) recently proposed to move cannabis to a Schedule III drug, which would reduce the penalty for selling or delivering the drug in states where it remains criminalized.

The legalization of medical marijuana in more states over the past few years has made cannabis widely accessible. However, Ms. Hurd noted that the current highly addictive strains are not benign. “The adolescent time period is a critical window for CUD risk,” she said, adding that this only makes the need for public health education and intervention more critical.

While “we should not criminalize the use,” she said, the move to make it legal and reduce penalties ignores the fact that the current strains are purposely made to be addictive because “like everything else, it’s a business, and the business is to get more customers.”

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