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Research project: Can cannabis trigger schizophrenia?


Cannabis use increases the risk of schizophrenia
In Germany, a law was passed just a few days ago that makes seriously ill people easier to access cannabis as a medicine. An international team of researchers is now reporting that consuming marijuana poses health risks. Accordingly, smoking pot increases the risk of developing schizophrenia.

Marijuana helps against many diseases
A few days ago, when the German Bundestag passed a law that makes it easier for the seriously ill to buy medical marijuana, health experts have increasingly pointed out which diseases cannabis helps with. However, the consumption of the intoxicant can also harm health. According to an international study, marijuana use increases the risk of developing schizophrenia.

Relationship between cannabis use and risk of schizophrenia
Earlier research had indicated that excessive cannabis use could lead to psychosis. However, as British researchers reported, a certain gene is crucial whether stoners develop psychoses.

Numerous studies have already dealt with the connection between marijuana use and schizophrenia. A study by Dutch scientists years ago indicated that cannabis use can make schizophrenic.

However, a recent study by researchers at the University of Bristol concluded that cannabis smoking is not a trigger but a result of schizophrenia.

Influence of a risk factor
A new study of epidemiological data from over 40 years has now again provided evidence that there is a connection between cannabis use and the risk of schizophrenia, reports the APA news agency. Accordingly, no study has previously been able to prove that smoking pot can also be directly responsible for the occurrence of the disease.

With the new investigation, in which the University Hospital Lausanne (CHUV) was involved in Switzerland, this has now been achieved. According to the information, the study is based on a method called "Mendelian randomization".

It can be used to examine the influence of a risk factor - such as cannabis use - on the occurrence of diseases - in this case schizophrenia. This avoids false conclusions, for example that the effect is mistaken for the cause - for example, that an increased risk of schizophrenia could be the reason for greater cannabis use. (see study from Great Britain mentioned)

37 percent increased risk of schizophrenia
In order to arrive at the results that were published in the journal “Molecular Psychiatry”, the scientists first evaluated data from a publication from 2016 that showed a connection between certain gene variants and cannabis use among 32,000 study participants.

The same genetic markers were then searched for in a separate data set that included genetic information from 34,000 patients and 45,000 healthy individuals. By combining this information from two separate sources, the researchers concluded that marijuana use was associated with a 37 percent increased risk of schizophrenia.

Tobacco use has no effect
Earlier observational studies had shown similar numbers. It is said that the relationship is not influenced by other factors, such as tobacco use.

"These robust results complement the numerous studies in this area and show that the connection between cannabis use and an increased risk of schizophrenia is a causal factor," said student author Julien Vaucher from CHUV.

They are also important to inform about the risks of smoking. Precisely because this substance is currently experiencing a wave of liberalization and is increasingly being used for therapeutic purposes, a precise understanding of the mechanisms of action is required.

According to the expert, further studies could make it possible, for example, to formulate warnings for groups at high risk for schizophrenia or other disorders.

According to Vaucher, the method used in the study does not allow the risk to be determined depending on the amount consumed, the type of cannabis, the form of administration or the age of the users. (ad)

Author and source information


Video: Significant increase in cannabis-induced psychosis, mental health charity warns (September 2021).