New research reveals that high levels of THC in cannabis can leave distinct marks on DNA, particularly affecting vulnerable teenagers.

A groundbreaking study from King’s College London and Exeter University suggests that DNA testing could one day identify cannabis smokers at risk of developing psychosis. The researchers found that the use of high-potency cannabis—defined as having a tetrahydrocannabinol (THC) content of 10% or more—leaves a unique imprint on the DNA of users, providing critical insights into the drug’s biological impact.

THC, the psychoactive component of cannabis, is known for producing the “high” associated with its use. However, elevated doses can also induce anxiety and paranoia, particularly in certain individuals. While previous studies have established a link between strong cannabis use and an increased risk of psychosis or schizophrenia, the exact nature of this relationship has been a subject of debate.

Adolescents, in particular, are thought to be at heightened risk for psychosis as their brains undergo significant development during this period. Police have noted that much of the cannabis available illegally in the UK is of high potency, characterised by elevated THC levels and reduced cannabidiol (CBD), a compound believed to have antipsychotic properties.

The study’s findings indicate that the impact of cannabis on DNA varies between individuals experiencing their first episode of psychosis and those who have never encountered such mental health issues. This distinction could be vital for future risk assessments and interventions aimed at protecting vulnerable populations.

Researchers hope that as the science of DNA testing evolves, it may serve as a tool for healthcare professionals to identify individuals who could be at greater risk of mental health challenges linked to cannabis use. This proactive approach could help target prevention strategies more effectively, especially among younger users who may not fully understand the implications of consuming high-potency cannabis.

While the findings are promising, the researchers caution that more comprehensive studies are necessary to validate these results and establish clear guidelines for the use of DNA testing in this context. As the conversation around cannabis legality and its associated health risks continues to grow, understanding the genetic factors that contribute to psychosis could play a crucial role in shaping public health policies and educational efforts.