When does smoking weed become a problem?

Cannabis is by far the most commonly consumed illegal drug in Switzerland and Europe. Weed is particularly popular among teenagers and young adults. In an HBSC survey (Health Behaviour in School-aged Children) conducted in 2022, around ten percent of 15-year-old Swiss schoolchildren stated that they had smoked pot in the previous month. According to the Federal Statistical Office, this figure is only around four per cent of the average Swiss population up to the age of 65.

«In this country, the age of 15 is regarded as the classic starting age for cannabis use,» explains Boris Quednow, Professor of Pharmacopsychology at the Psychiatric University Hospital Zurich, who has been researching the topic of cannabis and its health consequences for 25 years. «The number of users then rises again significantly up to the age of 20, before falling again slightly,» says Quednow.

When cannabis repeatedly acts as an outlet for everyday problems, it becomes problematic.

Sebastian Züst, social worker

Another study conducted by the Jacobs Centre at the University of Zurich in 2018 found that 15 percent of 20-year-olds in Zurich used cannabis several times a week. These results can certainly be applied to the rest of Switzerland. «Cannabis use is therefore almost a social norm in Switzerland,» says Boris Quednow.

Why do teenagers smoke weed?

«The reason why young people try drugs like cannabis - but also alcohol and nicotine - is mainly curiosity and a certain amount of peer pressure at the beginning, because the others are doing it too,» says Sebastian Züst, social worker and head of Kontakt Uri, a contact point for young people and parents for addiction counselling and prevention in Altdorf UR. «It becomes problematic when cannabis is regularly used as an outlet for everyday problems such as stress and anger or sleeping problems in order to wind down, and then soon you can't do without it.»

The risk of becoming addicted is never as high as between the ages of 15 and 25.

Boris Quednow, pharmacopsychologist

Cannabis has two main cannabinoids, tetrahydrocannabinol (THC) and cannabidiol (CBD), which have a short-term relaxing, calming, mood-enhancing, pain-relieving, appetite-stimulating and nausea-reducing effect. THC also has a psychoactive effect and alters sensory perception and the sense of time. When smoked, these effects usually set in immediately or within a few minutes and last for around one to three hours.

«Humans have their own cannabinoid receptor system in the brain. This is where THC and CBD dock and unfold their effect,» explains pharmacopsychologist Quednow. In addition, the release of dopamine and thus the reward system is activated, which explains the euphoric and mood-enhancing effect.

Consumption is never harmless

When eating cannabis-containing foods, the effect is significantly delayed via the stomach and intestines and is only noticeable after 30 minutes to two hours. «This increases the risk of overdosing because people simply continue to eat before the THC-containing biscuits or jelly babies have developed their full effect,» warns Quednow. «Of course, this can also happen when smoking and inhaling.»

Although not life-threatening, an overdose of THC can cause extremely unpleasant side effects that last for hours, such as severe dizziness, confusion, extreme dry mouth, hallucinations, anxiety and panic attacks or so-called horror trips with delusions of persecution, which should be treated medically.

«There is no healthy or harmless use of cannabis or other drugs such as alcohol and nicotine,» says addiction counsellor Züst. «But there is a form of consumption that is less problematic and can be used to cope with everyday life.» Addiction researcher Boris Quednow adds that most young people only smoke weed occasionally and have their consumption well under control. So-called trial use or occasional use with friends therefore harbours a comparatively low risk of later damage. The two experts agree on this.

But life situations can change dramatically - and so can substance use. In the words of Boris Quednow: «Every consumption harbours the risk of more consumption and therefore also of addiction. At no other time in life is the risk of developing an addiction as high as in adolescence between the ages of 15 and 25.» And it is precisely during the sensitive period of puberty and post-puberty, when the young brain is still developing, that cannabis can cause the greatest damage.

Long-term high cannabis consumption can cause permanent damage to the brain in adolescents.

If you smoke pot every day, you are never sober

According to expert estimates, 20 to 50 per cent of those who use cannabis on a daily basis are already addicted. However, most of those affected are not even aware of this dependence, as they rarely experience physical withdrawal symptoms.

«Unlike other drugs, THC is stored in the body's fatty tissue and is only metabolised very slowly. After a half-life of 24 to 36 hours, just half of the cannabinoid ingested has been metabolised,» says the Zurich-based addiction researcher. «People who smoke pot every day are virtually never sober and also accumulate more and more THC in their bodies.»

However, long-term intoxication has a demonstrably negative effect on cognitive abilities such as memory, learning ability, attention and concentration. «In studies, young people who binge drink even show lower IQ scores later in life, poorer school grades, less educational success and therefore less life satisfaction,» says Quednow.

Long-term cannabis abuse is also associated with the so-called amotivational syndrome. «In addiction counselling, I often notice a significantly reduced drive and little structure in heavy cannabis users, instead often sluggishness, listlessness or even confusion,» says Sebastian Züst. «As a result, heavy stoners often fall through the social net.»

After a longer period of abstinence, however, the lost cognitive abilities usually return in adult users. «Unfortunately, this is not necessarily the case with adolescents,» says pharmacopsychologist Quednow. «In the vulnerable phase of brain development during puberty up to around the age of 25, long-term high cannabis consumption can have an impact on brain development and thus cause permanent damage to the brain - and the earlier consumption begins, the more severe the damage.»

Cannabis and psychosis

Scientists have long observed a connection between cannabis use and the occurrence of psychoses. However, there is still no evidence of a direct cause-and-effect principle. «Rather, it is assumed that people who are genetically predisposed because they have relatives with mental illness in their close family environment have an increased risk of developing psychosis through cannabis use,» explains Quednow.

Addiction counsellor Züst has also observed that many sufferers use cannabis to self-medicate existing mental illnesses such as depression, ADHD, sleep disorders or schizophrenia, which may bring short-term relief, but noticeably intensifies the symptoms in the medium and long term.

«What is now also well known is that people who have already experienced psychotic symptoms, i.e. horror trips in the form of temporary delusions of persecution and threatening hallucinations, have a greatly increased risk of reacting psychotically again if they continue to use cannabis,» emphasises addiction scientist Quednow. «The risk of psychosis also increases with the frequency of use and the THC content.»

It is therefore also important to know in this context that cannabis has become increasingly potent over the years thanks to targeted breeding. «While the average THC content of cannabis plants in the mid-1990s was still around 4 to 5 per cent, today's varieties contain 14 to 15 per cent and more,» says Quednow.

Prudent action is required

But how should parents react if they have a concrete suspicion that their child is smoking pot? «It doesn't help to keep quiet and worry in silence, nor to bluster around and play the moraliser,» says the expert from Uri. Instead, Sebastian Züst advises always addressing the issue directly and without accusations or taboos in a quiet moment in order to get a real picture of the situation. «You should also show the child that you love them, that they are important to you and that you are simply worried.»

If everyday life and school or education suffer as a result, parents should seek professional advice.

Sebastian Züst, social worker

The conversation itself is then primarily about clarifying exactly what cannabis use looks like. Parents should ask their child why they smoke pot, when and where, with whom and also how much. In this way, parents can find out whether it is an occasional use with friends in a protected environment, where everyone looks out for each other and can react quickly if one of the group is not feeling well.

«If this is the case, you don't always have to react with a strict ban,» says Züst. «Parents can also decide that this is a phase in which young people are trying out something that experience has shown loses its appeal after a while.»

Critically scrutinise your own substance use

It is different if parents get the impression that cannabis use is frequent, questionable people are involved, everyday life can no longer be mastered and school or education suffer, says Züst. Even in such cases, parents should convey that they are there for their child - and at the same time seek professional counselling. «In Switzerland, there is a dense network of regional addiction counselling centres that offer non-binding advice and help with all questions relating to addiction and drug use,» says Züst.

Last but not least, it is also important for parents to critically scrutinise their own substance use. «Because children learn by example,» Boris Quednow reminds us. «Only those who set an example of responsible behaviour with tobacco, beer or wine are credible and can serve as a good role model for their child.»