Young men with cannabis use disorder (CUD) are at an increased risk of developing schizophrenia, a new study has found. Researchers estimated that up to 30% of cases of schizophrenia among men aged 21-30 might have been prevented if CUD had been averted.
Previous research has found that the use of THC, the main psychoactive ingredient in cannabis, can trigger or worsen schizophrenia, and that this risk increases along with frequency of cannabis use. This study sought to explore the association between CUD and schizophrenia across genders and ages and to uncover the differences among those cohorts. It found that CUD increases the risk of schizophrenia and worsens symptoms in existing cases in both men and women, and that the effects are greater among men and greatest among young men.
According to the study, 15% of schizophrenia cases among males in 2021 were attributable to CUD, and the number rose as the age of the men decreased. Researchers also attributed about 4% of cases among women to CUD. The association between CUD and schizophrenia among men and women older than 26 were similar, but in the younger age groups there was a marked difference. For 16-20 year olds, the association among men was nearly double that among women. For ages 21-25, the association among men was 50% greater than that among women.
The study was conducted by Danish and American researchers and was based on Danish health registers containing information about nearly 7 million people aged 16-49 between 1972 and 2021. It noted that men tend to fall prey to CUD at younger ages than women, and that men tend to use cannabis at higher rates than women. It also stated that the potency of available cannabis, measured by the amount of delta-9-tetrahydrocannabinol (THC) it contains, has increased considerably in both the United States and in Denmark. At the same time, schizophrenia rates have risen. Researchers theorized that there may be a link between the higher THC content and the link between CUD and schizophrenia.
“Results highlight the importance of early detection and treatment of CUD and policy decisions regarding cannabis use and access, particularly for 16-25 year olds,” the researchers concluded.