The harms of cannabis outweigh its benefits. This is the exhaustive conclusion of the largest analysis that has been carried out so far on this issue and which was presented this Thursday at the Clínic hospital in Barcelona. Although cannabinoids “can improve some medical conditions in epilepsy, chronic pain, sclerosis or intestinal inflammation, the harms outweigh.”

These are the words of doctors Eduard Vieta and Joquim Raduà, who participated in this international study, published in a reference medium, the British Medical Journal. Researchers have analyzed all previous work on the benefits and harms of this psychoactive substance, which they consider especially dangerous in those under 25 years of age due to the risk of psychosis, schizophrenia and bipolar disorders.

Because? “Because the brain of young people is maturing and cannabis interferes with this process,” explain these specialists, who believe that in the same way that the law prohibits the consumption of alcohol for those under 18 years of age, the protection of those under 25 from cannabis and take it into account when, for example, smoking clubs. Its adverse effects do not end there.

The research also warns of the danger of consumption in pregnant women, drivers and people with a predisposition or mental health disorders. If cannabis were an iceberg, the tip would be the benefits and the harms would be the immense mass of ice under the sea, but even so it must be taken into account that the benefits can also entail side effects for these patients.

Head of Psychiatry and Psychology at the Clinic and of the bipolar and depressive disorders group at IDIBAPS, Dr. Vieta is a CIBERSAM researcher and professor of Psychiatry at the University of Barcelona (UB). The IDIBAPS or Instituto de Investigaciones Biomédicas August Pi i Sunyer is a referent in biomedicine, integrated by the Clinic, the UB, the Generalitat and the Consejo Superior de Investigaciones Científicas.

For its part, the Mental Health Network Medical Research Center or CIBERSAM is linked to the Carlos III Health Institute, another national and international reference in medical research and public health. Joaquim Raduà, the second Spanish specialist who has participated in the work, is head of the imaging group for disorders related to mood and anxiety at IBIBAPS.

Dr. Raduà is also a CIBERSAM researcher and associate professor at the UB. The study in which he and his partner participated was led by researchers from Linköping University (Sweden), the University of Ottawa (Canada) and Yonsei University (South Korea). All of these experts have evaluated the associations between cannabis, cannabinoids, medications and health.

Important detrimental effects are evident in certain groups, the study maintains: increased risk of psychosis in young people, adolescents and people with a predisposition to having a mental health problem. And also “low baby weight in babies of pregnant women consumers”, as well as “increased risk of car accidents”. Drowsiness and gastrointestinal problems are other side effects.

The study, the participants indicate, “clearly indicates that the use of cannabis and derivatives must be prevented in people at risk, which are young people under 25 years of age, pregnant women and drivers.” His conclusion is blunt: “All these people should not consume cannabis in any way.” In fact, this substance should not be consumed, “except in specific cases in which a clinical benefit has been demonstrated.”

These benefits are restricted to people with epilepsy, chronic pain or sclerosis. Not all young people who use will develop psychosis or other mental problems, but the risk is high and is determined by genetic factors that are not yet known. In the case of pregnant women, as in the case of drivers, all psychoactive substances are contraindicated, including alcohol.