A new study published in Psychological Medicine by researchers at the University of Copenhagen has found that up to 30% of schizophrenia cases in young men could be attributed to problematic cannabis use. The study analyzed nearly seven million data sets from five decades in the Danish health register, focusing on the connections between cannabis use disorders and schizophrenia. Previous research has already shown a correlation between cannabis use disorders and serious mental disorders such as schizophrenia, but this study aimed to determine which group is at the highest risk. The researchers collected health data from over 6.9 million male and female individuals, of which more than 45,300 had been diagnosed with schizophrenia. They then examined which gender and age groups had cannabis use disorders and calculated the percentage of all schizophrenia cases that could be associated with such disorders.
The study found that without cannabis use disorders, approximately 15% of all schizophrenia cases in male individuals in Denmark could have been prevented in 2021, while the figure was 4% for female individuals. The most striking finding was the high percentage of up to 30% in men aged between 21 and 30 years. The researchers concluded that cannabis use disorders are a significant risk factor for the development of schizophrenia. However, the study did not provide information on how often and to what extent the affected individuals had consumed cannabis, nor did it indicate the THC content of the cannabis products used.
The researchers also highlighted a potential additional correlation between schizophrenia and cannabis use. Over the years, the number of people suffering from cannabis use disorders has increased, and so has the THC content in cannabis products. In Denmark, the average THC content in cannabis products was 13% in 2006, while ten years later, in 2016, it had risen to 30%. The authors suggest that it would be useful to investigate the reverse relationship of schizophrenia as a risk factor for cannabis use. The study’s findings emphasize the importance of raising awareness of the risks associated with cannabis use, particularly among young men.
