Today, I want to tackle the argument that “Cannabis causes schizophrenia”. This argument is a fundamentally misleading and untrue assessment of the clinical data.
The global prevalence for Schizophrenia has remained at the same steady 1% for decades, in spite of Cannabis consumption continuing to rise throughout the world’s population since its reintroduction into the popular consciousness in the mid-1960’s.
If, as is claimed by cannabis disparagers in the media with headlines about “Skunk psychosis”, that smoking Cannabis indeed does cause Schizophrenia and one puff will make you insane, then where is this increase in the number of patients?
Assessing the impact of cannabis use on trends in diagnosed schizophrenia in the United Kingdom from 1996 to 2005.
A recent systematic review concluded that cannabis use increases the risk of psychotic outcomes independently of confounding and transient intoxication effects.
…The study cohort comprised almost 600,000 patients each year, representing approximately 2.3% of the UK population aged 16 to 44. Between 1996 and 2005 the incidence and prevalence of schizophrenia and psychoses were either stable or declining. Explanations other than a genuine stability or decline were considered but appeared less plausible. In conclusion, this study did not find any evidence of increasing schizophrenia or psychoses in the general population from 1996 to 2005.
Read more: https://www.ncbi.nlm.nih.gov/pubmed/19560900
As is strongly suggested by the data in the study above, cannabis does not cause Schizophrenia. Yes, cannabis can precipitate a psychotic event/break much in the same way as alcohol, amphetamines, cocaine or any narcotic that has a psychoactive component may do, but so can trauma arising from something like a car accident, or even a particularly bad relationship/break up.
Do we seek to prohibit these possible trauma-inducing experiences? No! of course not.
So why should we with Cannabis?
The “evidence” that has been used to mislead the general public by various media outlets (deliberately) is actually based on outdated, unverifiable and often manipulated studies that can be funded by groups that have a vested interest in keeping Cannabis illegal e.g. Tobacco lobbyists, Big Pharma, etc.
So, how serious can we take these studies?
Simply put we cannot, the only relevant material to this subject matter should come from medical and scientific institutions.
In fact, recent studies have even shown a potential link between smoking tobacco and psychosis. We need more research done in this area, but it is worth mentioning here as it shows just how misled some of our sources can be when selectively picking studies to link cannabis and psychotic illness, often ignoring important factors, e.g., did these cannabis users also consume tobacco?
The Institute of Psychiatry, Psychology and Neuroscience at King’s College London recently conducted a study showing that after meta-analysis of some 61 studies, 57% of people surveyed at mental health services following their first psychotic episode were tobacco smokers, suggesting that although the results didn’t prove causality, the tobacco-psychosis link should not be dismissed.
So even though it has always been understood that sufferers of psychotic illnesses often more likely to smoke [Tobacco], it had been previously theorised that these patients were “self-medicating” to help mitigate the severe symptomatology that accompanies psychotic disorders like Schizophrenia.
Were this theory to be true then researchers would have found smoking rates only increased after an individual had displayed with psychosis. But this was not the case, suggesting that smoking tobacco itself may be playing an active role in the development of psychosis.
“While it is always hard to determine the direction of causality, our findings indicate that smoking should be taken seriously as a possible risk factor for developing psychosis” Dr James MacCabe, clinical senior lecturer in psychosis studies at King’s IoPPN.
Now, for the interesting part.
Did you know that the figures used in the UK by the British Medical Association (BMA) to quantify data about patients presenting with “Cannabis psychosis” do not separate whether the patient mixes their Cannabis with Tobacco?
Why does that matter? Because apparently, up to 80% of British Cannabis smokers use the drug in conjunction with Tobacco.
Recently scientists in the UK finally began warning us of the dangers of mixing tobacco and cannabis.
With studies like this suggesting causal links between smoking itself and schizophrenia, it is even more ridiculous that this has been the basis of an argument which many people in the UK still believe, hyped up by our tabloid media.
Cannabis does not cause schizophrenia, and if more studies are ever done on cannabis and psychotic illness, then they need to take all other factors into account to judge the results accurately.