The Impact of Cannabis Use on the Frequency of Psychosis Across Countries and Time
Featured expert: Dr. Robin Murray FRS
Much evidence demonstrates that cannabis use is associated with subsequent onset of psychosis. Our work shows:
- The more you smoke, the greater the risk.
- Continued use by those with established psychosis is associated with a worse outcome.
- Experimental administration of tetrahydrocannabinol (THC), the active ingredient of cannabis, induces transient psychosis in normal subjects.
Our Trans-European study of 16 sites in six countries demonstrates that daily use of high potency cannabis has a significant impact on the incidence of psychosis. The greatest effects were in the cities where high potency cannabis was most available, Amsterdam and London, where 50% and 32% respectively of first episode cases of psychosis could be attributed to daily use of high potency cannabis. Furthermore, the incidence in London has increased steadily over the past 50 years along with availability of cannabis. The evidence that regular use of high potency cannabis is a component cause of psychosis is now sufficient for public health messages outlining the risk. Furthermore, the findings that decriminalisation and legalisation are associated with increased use and potency, suggest that the incidence of psychosis is likely to increase.
After this one-hour webinar, you will understand:
- The effects of the main constituents of cannabis, THC and CBD.
- In which European countries you are most likely to meet someone who is psychotic.
- The cannabis users who are most likely to develop psychosis.
Robin Murray is Professor of Psychiatric Research at the Institute of Psychiatry (IoP), King’s College London (KCL) and a Fellow of the Royal Society (FRS). His main activity is carrying out research into finding the causes of schizophrenia and bipolar disorder and developing better treatments for these disorders. Robin Murray and colleagues were among the first to demonstrate that prolonged heavy abuse of cannabis can contribute to the onset of psychosis, and that starting early before 15 years and using high potency cannabis (e.g. skunk) particularly increase the risk. He also cares for patients within the National Psychosis Unit at the South London and Maudsley NHS Trust. He has supervised 33 PhDs and 5 MD Theses (with 100% success). He is part of the Psychosis Clinical Academic Group and the NIHR Maudsley Biomedical Research Centre. Murray was knighted in 2011 for his services to medicine.
Email Founder & CEO, Laura Stack, at [email protected].