According to planning in the German Parliament, the health ministry bill was to be submitted for a vote in the plenary before Christmas, but it was twice removed from the agenda in short order. The debates were so intense and confrontational that the leaders of the Social Democratic Party (SPD) Central Committee feared that they would be voted against by the Social Democratic MPs themselves.

But this time the risk is controllable. About 15 Social Democrats are expected to vote against it, but doctor and health minister Karl Lauterbach’s flagship bill will pass. Under the coalition government’s plans, possession and cultivation will be allowed to adults within set limits. For many it was a dream. But that doesn’t mean it doesn’t remain controversial.

The risk of psychosis

The goal is not so much to put an end to black market traders. Everyone agrees on this. However, the medical world is concerned about whether young people are sufficiently aware of the dangers of cannabis. The brain matures until the age of 25. And anyone who disrupts this process by frequently smoking weed can suffer lifelong consequences.

The key word is psychosis. It is a psychoactive substance from the cannabis plant, which can cause addiction, either as a cigarette, or as a hash cookie, or in another package. “Dangerous consumption cannot be defined in general terms,” ​​says Stephanie Eckhardt, head of department at the Federal Center for Health Education (BZgA). There are several factors that interact, such as how often cannabis is used, how much, and how high the THC (concentration of the narcotic substance tetrahydrocannabinol, contained in the dried flowers of marijuana and hashish) is. Eckhardt says that consumption in Germany has increased especially among the 18- to 25-year-olds. According to the latest data from the BZgA, half of them had already used cannabis in 2021. It was also the highest percentage recorded since 1973. The reasons for the increase can only be speculated: availability, social environment, social trends , but also the price on the black market.

According to the Ministry of Health in 2022 about 4.5 million adults in Germany used cannabis at least once in 2022, especially between the ages of 18 and 24. For Eckhardt, however, the many joys among teenagers are rather the exception. “1.6% of all young people smoke weed regularly,” he says. “The younger they are, the more dangerous it becomes.” Cannabis is known to bring out stronger moods and emotions. At best it causes relaxation, but sometimes it leads to negative effects. In the short term all of these can lead to anxiety, panic, disorientation, depressed mood, racing heart, nausea and hallucinations. In the long term, however, the risks for teenagers who smoke frequently can be much more threatening, including psychosis and schizophrenia.

“No one knows where it will lead”

According to the bill, the use of cannabis is prohibited until reaching adulthood. Adults will be allowed to possess 25 grams. There is also an age-based model: in cannabis clubs, members will be allowed to grow it together and supply up to a maximum of 50 grams per member, per month. For ages 18 to 21, the quantity is reduced to 30 grams per month, with a content of no more than 10% of the psychoactive substance THC. “It is no longer about the recreational use of cannabis, which leaves us unproblematic,” says Professor Efrosyne Guzouli-Meyfrank, medical director of the LVR Clinic in Cologne and president of the German Society for Psychiatry and Psychotherapy DGPPN. “50 grams a month is enough for several cigarettes a day. Even 30 grams is too much for young adults. Legalization is the equivalent of a field experiment in society,” he says. “In our view, we should not proceed so recklessly at this time. Because no one knows exactly where this road will lead.”

The human body has its own system for so-called “cannabinoid molecules”, responsible for psychotropic reactions. The brain has structures and binding sites for these substances that help regulate appetite, emotions and pain perception, for example . This complex internal system matures slowly in humans until the age of 25. If cannabis is now added, this process can be disrupted. Doctors hypothesize that frequent adolescent smoking of hashish alters the structures of cannabinoids in the brain, and this external effect can have an impact on the whole life. “There is evidence for this from various research studies,” Guzouli-Mayfrank explains. “Those who smoke cannabis early and often have a significantly increased risk of psychosis, even many years later. Another consequence could be greater susceptibility to all kinds of addictions. Cannabis has a different effect only after 25 and the effect is comparable to moderate alcohol consumption,” adds the Greek professor. Once the effect is over, the body returns to its normal state.

Cannabis, legal, but… I prefer broccoli

Health Minister Karl Lauterbach also knows the risks, being a doctor himself. And he agrees that cannabis is particularly harmful to the still-developing brain. But has that message gotten through? “In recent years, the public discussion has become more transparent, regarding the risks. It should no longer be a taboo subject. This is basically very positive”, says Efrosyne Guzouli-Mayfrank, however, maintaining some reservations. “There are opportunities and risks. We have to wait and see.” The message of the Federal Center for Health Education BZgA to young adults is not to smoke hashish. Of course, this also applies to young people under the age of 18, for whom cannabis should remain prohibited by law. “Today’s attention to the issue is associated with both a great deal of uncertainty and a considerable need to reach out to teenagers,” adds Stephanie Eckhardt. According to the BZgA, the change in the law is linked to a greater need for information and education in schools.

A campaign by the Ministry of Health started online last summer. It starts with the catchphrase “Cannabis – legal, but…” and goes on to add “legal, but I prefer broccoli”, or even “legal, but dangerous”. For the Greek psychiatrist Guzouli-Mayfrank, this is not enough. “I expect collateral losses from legalization in Germany,” he says, “I’m afraid it won’t be possible to reliably convey the dangers of cannabis.” That’s why her trade association favors legalization only from age 21 and up. “This would also send a clear message to young adults that smoking weed is problematic for them.”

Studies and opinions

In 2019, a representative study by King’s College London in the journal The Lancet Psychiatry showed that more people suffered from psychosis where cannabis was freely available. This was especially true in cities where the particularly high THC substance was regularly consumed. Researchers from Denmark estimated in the journal “Psychological Medicine” that up to 30% of all cases of schizophrenia in young men can be attributed to problematic cannabis use. Denmark has not legalized cannabis. However, according to the study, the tetrahydrocannabinol content was comparatively high.

The researchers also argue that people with schizophrenia sought cannabis for self-medication. The question then remains which came first, the disease or the addiction? The pros and cons of legalization were laid out at a public hearing before the House Health Committee in early November. This is not an easy decision. The “social experiment” will then be monitored for four years and analyzed in phases.