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Mental Health

Schizophrenia Can be Linked to Cannabis Use Disorder, Experts Say

— September 12, 2023

Study reveals young men with cannabis use disorder could be susceptible to developing schizophrenia.

A new decades long study involving research on various institutions has found a surprising link between chronic cannabis use disorder and schizophrenia. Cannabis-induced schizophrenia was previously documented as a mental health condition. However, the exact link between the two has long been a subject of debate. The new research, published in the Psychological Medicine journal, shows that addiction to cannabis due to heavy use led to the onset of the condition, especially in young males.

Schizophrenia is a mental health issue that has serious effects on functionality presenting with symptoms and signs of altered perceptions of reality and often impaired social and emotional well-being. Individuals with cannabis use disorders, on the other hand, use the drug in a way that is considered harmful over any given period of time.

The study, which made use of Danish health records, was the single largest epidemiological study focused on cannabis-induced psychosis. It delved into a record of about 6.9 million people diagnosed with schizophrenia over a period of fifty years. Findings showed that up to 30% of cases could have been avoided in young men if they didn’t also have cannabis use disorder.

Schizophrenia Can be Linked to Cannabis Use Disorder, Experts Say
Photo by Kindel Media from Pexels

A comparative study, the present research found prevention rates of 15% among men aged 14– 49 and 4% among women within the same age range. Particularly intriguing is the result that up to 30% of cases could be prevented in men aged 21-30.

“Though the study does not establish a direct causal relationship between cannabis use disorder and schizophrenia, this kind of large scale- study could assume causality,” said lead author Carsten Hjorthøj who is also an associate professor with Mental Health Services located in the Capital Region of Denmark and at the University of Copenhagen.

The National Institute on Drug Abuse (NIDA) collaborated with Mental Health Services in the Capital Region of Denmark to come up with the study design. According to NIDA’s deputy director, Compton, “This is the first time we’ve seen a large-scale study across an entire population that addresses the relationship of cannabis and schizophrenia across different age and sex groups.”

The team also took note of the fact that there has been an increase in schizophrenia cases proportional to increased use of cannabis over the past few decades. Particular emphasis was placed on the fact that demand and access to cannabis continues to expand, and attention should be directed at preventing, screening, and treating cannabis-associated problems.

The progress made by the study to link marijuana and schizophrenia still fails to resolve the existing debates sparked by previous research. In particular, one study conducted at the University of Wyoming argued that cannabis use is just one of the many behavioral problems that may characterize people likely to be diagnosed with psychosis and other mental health disorders and isn’t likely to cause schizophrenia by itself.

NIDA’s deputy director Compton suggested that prevention-oriented educational programs be implemented which a focus on problematic cannabis use as it relates to schizophrenia. In this way, he said, researchers will be more apt to be able to prove a definitive link between the two. In his words, “Scientifically, if you can successfully change the rates of cannabis use, that will test the theory that cannabis causes schizophrenia.” If cannabis use rates decrease and there is a link, the number of schizophrenia cases should also decrease over time.


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