Smoking more than four joints a week involves a health risk, according to a study

This is the conclusion of a group of experts from the Hospital Clínic, who certify that no amount of cannabis is safe, especially among teenagers, young people, and people with mental health problems

That the consumption of cannabis, however small, is not harmless may seem like evidence. But specialists warn that much of the population have false beliefs about the supposed benefits it has.

To this premise, we must add the concern of health professionals about the consumption of high-potency cannabis at an early age. In other words, the “load” of a joint today multiplies by five the effects of one two decades ago.  

The explanation lies in the virulence of THC, the most important active principle of the cannabis plant, which activates the psychoactive effects and has significant addictive potential.

The consumption of leeks by teenagers, young adults, and people with mental health problems is a concern. Especially in this last aspect, as a trigger or aggravator of all kinds of psychiatric illnesses in vulnerable people or those with a family history.

The evidence is concrete in the study of a group of professionals from the Clinical Hospital of Barcelona, ​​experts in addictions, who have agreed that the consumption of five or more leeks a week involves a health risk.

Adolescents, among the population with the highest risk

This a general conclusion, but which, in different segments of the population, falls short, since any consumption of cannabis, however infrequent and intense, involves a significant risk to health.

This is the case for those under 21, pregnant and lactating women, and people suffering from physical illnesses such as cardiorespiratory or mental problems: psychosis, depression, bipolar disorder, anxiety disorders, and addiction, among others.

Therefore, as the authors of the study say, no amount of cannabis is completely safe. As a lesser evil, if you end up consuming it, they recommend that you try not to do it before the age of 21, that it has no more than 10% THC, and that consumption is less than 5 standard leek units per week

The average age of starting cannabis use in Spain is under 15, according to a 2021 survey of high school students.

In the adolescent stage, moreover, the brain is in full development and consumption can be more harmful.

14.2 % of Spaniards aged between 15 and 34 have consumed cannabis at least once in the last month, a figure that rises to 15.9% among those aged between 15 and 24. It is the highest prevalence in the entire European Union (EU).

Regardless of age, it seems clear that if the person has any risk factor, consumption should be avoided. In this sense, people with mental health problems worsen their well-being and pathology if they smoke joints

This is true, experts confirm, even if they may initially feel temporary relief. A case was similar to that of other substances such as alcohol.

Cannabis consumption also has physical health risks, especially when mixed with tobacco, as it causes heart and lung problems.

Spain, the European leader in cannabis consumption

Aside from the high percentages of consumption among young people, Spain is the country in the European Union with the highest consumption of cannabis in the last month, among 9% of the population. Along with Luxembourg and Portugal, it is one of the states with the highest percentage of daily or very frequent users.

3.7% of Spaniards consume cannabis daily or almost every day. This population group, therefore, has a high-risk consumption pattern for health.

In addition, 15% of residents aged between 15 and 64 and 11% of teenagers (14 to 18) think that consuming cannabis has no health consequences.

To this minimization of risks, according to the Clinic’s experts, are added  “unreliable sources of information or directly with commercial interests”,  which makes it difficult for them to have access to messages based on scientific evidence.

Although its usefulness as a treatment for some diseases has been raised, they continue, drugs used outside of prescription and facultative control also pose a health risk, and in this case, moreover, the evidence of its usefulness is scarce.

Worry about overconsumption

These days several addiction professionals have met in Granada as part of the National Conferences and the fifth International Socidrogalcohol Congress.

In this forum, they have expressed concern about the risky consumption of cannabis among the population. Doctor Hugo López calibrates the long-term consequences:

“Substances such as cannabis, even if the person does not suffer from a disorder for consuming it or have consequences on physical or mental health, carry a high probability of presenting these consequences or a disorder in the future.”

Prevention is key for the population to know the real risks of consumption, they say. Mercè Balcells explains :

“Prevention must be universal (for all of society), based on evidence, and away from sensationalist discourses. It must be credible, coherent, and solid.”

The work in specific population groups, young people, or people with mental health problems plays a relevant role, concludes Balcells herself.

Read also: How to deal with an anxiety attack: the symptoms and what to do and what not to do

Consensus conclusions


The experts participating in the study presented by the Hospital Clínic are professionals in mental health, public health, and primary care, and researchers in the field of risky alcohol consumption or the prevention and treatment of problems arising from cannabis consumption

The professionals have reached a consensus when determining the conclusions following the Delphi scientific methodology, in which the participants work anonymously.

The results of this consensus are still preliminary, but they are aligned with other consensuses such as those carried out in Canada.

0 0 votes
Article Rating
Notify of
Inline Feedbacks
View all comments