Does cannabis really increase the risk of psychosis?

Anyone who has ever used marijuana has probably heard that cannabis could increase the risk of psychosis. This is a frightening fact, but new research shows that it may not be true after all. That would be good news, as cannabis can also bring many benefits to (mental) health. In this blog, we explain what is known.

Cannabis and its link to psychosis

From new research published in Psychiatry and Clinical Neurosciences shows that no significant link was found between cannabis use and the development of psychosis. This is clearly inconsistent with data from previous studies and claims to the contrary. Often this very fact is used by opponents of cannabis, to make people aware of the “dangers” that cannabis would pose to health.

Yet controversy remains around the subject. Some research suggests that there would be a link between cannabis use and the onset of psychosis. This would be especially true among adolescents and young adults. But whether there really is a causal link remained unclear until recently. The new research seems to shed new light on this

Information on cannabis and psychosis

Many factors come into play when researching the influence of marijuana on mental disorders, including how often a person uses, how much THC the marijuana contains, age and genetics. All of these play a role in your chances of developing psychosis. It is always advised to be very careful with cannabis if there is someone in your family who has psychosis or if you yourself are at risk for this condition.

Also on many Dutch sites with information on drugs, it is always indicated that weed can cause psychosis, especially if you are predisposed to it. You would be more likely to relapse if you suffer from this condition if you start using marijuana.

Cannabis itself can also cause cannabis psychosis. This is acute psychosis, which can occur especially if you use a high dose of marijuana. Usually this is done by eating space cake, where you don’t really know how much cannabis you are ingesting. Symptoms include severe confusion, anxiety and hallucinations. Fortunately, this does not last long and the symptoms disappear on their own, once your body has processed the THC.

When research is conducted on the link between cannabis and psychosis, it should be kept in mind that these are very complex syndromes. It may be that weed symptoms can trigger, especially if you are predisposed to this. But as mentioned, there are many factors involved and you can never be sure if weed was the only trigger. More research has been done on this in recent years and hopefully that can shed some light on the matter.

In this new study, scientists were looking for the link between marijuana use and the vóvance of psychotic disorders in people clinically at high risk for this condition. It charted whether people had previously used cannabis, or were currently still using it. There were 300 individuals estimated to be at high risk of developing psychosis and 67 were healthy.

All participants were followed for 2 years during the study, where they were assessed using the Global Assessment of Functioning Disability scale. Whether they developed psychosis or had persistent psychotic symptoms was also accurately recorded. The data showed that only 16.2% of those at high risk for psychosis developed it. Of those who were not psychotic, 51% had persistent symptoms and 48% had fewer symptoms.

Ultimately, the researchers indicated that there was no significant relationship between cannabis use and the development of psychosis, persistence of symptoms or functioning.

There are also other studies that came to this conclusion. In a paper published in 2023, scientists at the Hospital of the University of Pennsylvania researched medical claims of more than 63 million individuals, between 2003 and 2017. They also found no statistical difference between the rates of psychosis diagnoses, or prescription of medication for psychosis, in states where medical or recreational cannabis is allowed and states where it is prohibited.

Another study (from 2021) looked at the relationship between adolescent marijuana use and the development of psychosis in adulthood. The study was done among twins. No relationship was found between the amount of marijuana used by the twins. Even though one twin used weed more than the other, there was no association with developing psychosis in adulthood.

This, of course, is good news for cannabis advocates. Whether you use marijuana for medical or other reasons, it’s nice to know that you don’t have to worry about potentially developing psychosis. Still, it is always advisable to exercise caution. Cannabis now affects your mood, your emotions and other mental processes. And you can never quite predict how you will react. If you are going to use marijuana for the first time, start with a low dose, and wait to see how it goes first. Make sure you are in a safe and comfortable space, preferably with a close friend (a trip sitter ), so you can always ask for help if needed. This will ensure a positive experience!