A new publication has claimed that using cannabis can hasten the onset of psychotic illnesses. The study by Dr. Matthew Large has sparked great debate over the supposed correlation between cannabis use and psychosis.
The key finding within the study, which has been posted on YouTube and all over the internet, is that “psychosis associated with cannabis use appears to come on 3 years earlier to psychosis related to other causes”.
The Beckley Foundation believes that it is of the utmost importance to listen to the scientific evidence relating to harms associated with any drug. However, careful evaluation of ‘new’ studies must be carried out to guarantee that a misrepresentation of scientific data is not being used to advance prohibitionist agendas.
Dr Large’s central conclusion was that “The results…confirm the need for a renewed public health warning about the potential for cannabis use to bring on psychotic illness.” However, the scientific evidence for such a very bold statement is absent from the paper. The study provides no new data. It consists of a recalculation of data from 83 previous studies. It’s all correlation and association, and correlation does not equal causation. Dr Large provides no evidence of a causal relationship between cannabis use and psychosis whatsoever.
Further examination of the “meta-analysis” shows that the majority of subjects already had a predisposition towards psychosis (usually by genetics). Additionally, as well as being consumers of cannabis, participants were also regular users of tobacco and other psychoactive substances, including cocaine, heroin and amphetamines. Therefore Dr Large’s claim that it is cannabis specifically that caused psychosis in these patients is illogical and un-scientific. 90% of diagnosed schizophrenics smoke cigarettes – but nobody is claiming tobacco causes schizophrenia.
This study would appear to be pure subjective science. It advances the prohibitionist agenda – and would seem to be closely connected to Dr Large’s future funding and career path. The question must be raised as to why this study was launched by a press conference and why, for that matter Jan Copeland, the director of the Australian National Cannabis Prevention and Information Centre, presented alongside Dr. Large? was sat next to him there
The Beckley Foundation is dedicated to providing original and scientifically validated research into illegal drugs and disseminating the findings, regardless of what they might be, to inform users about the potential harms associated with drug use. Studies, like Dr Large’s, which misinform and can be used as propaganda for underlying prohibitionist views, are dangerous in their attempts to sway public opinion with misinformation. They undermine faith in the scientific community and risk damaging their reputation as unbiased reporters of the facts regarding the real harms of drug use.