The stronger the Cannabis in a city, the more psychosis


Canada, several US States, South Africa and Uruguay: more and more countries adopt the Cannabis Prohibition. Critics warn that the legalization of the health risks increased. In this direction, a recent study shows: The more that is in a town that is circulating on the Cannabis, the more likely to be diagnosed with psychosis, researchers report in the journal “Lancet Psychiatry”.

For the study, the researchers had analysed data from eleven European countries. Most clearly the effect in London and Amsterdam, where Cannabis is widely used with a high content of psychoactive Tetrahydrocannabinol (THC) far index.

It implies that Cannabis use is actually for psychosis responsible, in Amsterdam estimated half of all newly diagnosed cases of psychosis on the daily consumption of strong Cannabis, around a third, in London. As strong, the researchers Cannabis designated with a salary of more than ten percent THC.

The clear evidence that Cannabis promotes psychosis, is not able to provide the study. The researchers have only observed a statistical correlation, but no cause-and-effect relationship, says Suzanne Gage from the University of Liverpool, who was not involved in the study. Although there is a correlation between the use of Cannabis in a city, and a higher number of psychosis – whether this is actually due to the use of the drug or other, still unknown factors, it remains ultimately unclear.

“Legalization has devastating consequences,”

Nevertheless, the study give reason to intensify the education about psychosis-risk, says Rainer Thomasius, medical Director of the German centre for addiction issues of the child and adolescent (substance use) at the University hospital Eppendorf (UKE) in Hamburg. “The study is further proof that the legalization of Cannabis in terms of health has devastating consequences.”

In the survey, Cambridge (UK), Gouda, and Voorhout (the Netherlands), Paris and Puy-de-Dôme (France), Madrid and Barcelona (Spain), as well as Bologna and Palermo (Italy) were included in addition to London and Amsterdam. German cities were not there.

The results of the study were transferable to Germany, says the Hamburg-based expert Thomasius, who himself was not involved in the analysis. According to the drug and addiction report by 2018, the THC content was in this country for an average of hashish in the case of almost 15 percent, and for the inflorescences of the hemp plant in the case of a good 13 percent. According to estimates, almost nine percent of 12 – to 17-Year-olds in Germany have consumed at least Once in their lifetime.

For the current analysis, the researchers estimated to Marta Di Forti, of King’s College London, the incidence of psychoses in the respective cities. The data come from the regional health authorities. Were evaluated all psychoses were diagnosed between 2010 and 2015, for the first time in patients. The data the researchers compared with a representative control group from the respective city. Were recorded, among other things, data on the consumption of Cannabis and other drugs.

Almost 30 percent of people with a diagnosis of psychosis reported daily Cannabis consumed in the control group, there were nearly seven per cent. Consumers with psychosis are far more (37 per cent) users to use strong Cannabis than in the control group (19 percent).

THC content of up to 67 percent

In the middle of the eleven European cities is an estimated was three times as high risk for psychosis in people with daily cannabis consumption, with the use of products with a high THC content up to five Times higher compared with people who consumed never Cannabis. One of the five psychosis-cases, this was due to daily cannabis use, estimate the researchers.

Unlike the past, today’s varieties often contain significantly higher amounts of the intoxicating substance THC. At the end of December published a study of data from the EU, Norway and Turkey came to the conclusion that the average THC content has doubled in the case of marijuana and hashish from 2006 to 2016, about. Consumers to smoke but often a similar amount of Cannabis, as before, and thus take much more THC than a user once.

The THC content is, according to the study in the Dutch varieties of Nederwiet in up to 22 percent, in the case of Nederhasj even up to 67 percent. In London Cannabis dominates, therefore, with an average THC content of 14 percent. In countries such as Italy, France and Spain, especially Cannabis would be consumed, as varieties with a THC content of less than 10 percent.

There is no Cannabis with a high THC content more, would fall on the extrapolation according to the psychosis Rates in Amsterdam from almost 38 to just 19 cases per 100,000 inhabitants a year, in London, from almost 46 to almost 32 cases.

Anxiety and depression?

The current study, however, also has weaknesses. The Information on whether and how much the Cannabis the subjects consumed only by their own data. Urine, blood or hair analysis. In addition, the researchers considered only the THC content, not the content of Cannabidiol (CBD). CBD is considered to be hardly psychoactive.

That some people develop as a result of daily use of Cannabis with a high THC content with a higher risk for psychosis, had the analyses shown, however, on several occasions, Gage. Against the Background that the consumer will currently legalized increasingly, or at least tolerated, and the number of consumers increases, therefore, probably, it is important to clarify which people have a higher risk.

Experts have been warning for some time prior to that, the risks of cannabis use. According to a study from the year 2015, people who regularly consume THC-rich Cannabis have an increased risk for psychosis. In the case of low-THC Cannabis, the effect could not be observed, even with daily use.

In addition, the only possible consequences of cannabis use are not psychoses. “The present study focuses on the incidence of psychoses,” says Ursula Havemann-Reinecke of the Department of psychiatry and psychotherapy of the University medical center Göttingen. It is also interesting data would be to other mental problems such as anxiety and depressive disorders. The analysis will show how many other studies it is clear that Cannabis is not a harmless substance. “Cannabis should not be legalized and the economy regulated.”

Summarized: According to a recent study, in cities where Cannabis with a high THC content, courses, and more psychosis. Whether this is actually due to the use of the drug or to other factors, remains unclear. Previous observational studies had shown that there is a statistical correlation between THC-rich Cannabis and psychosis.