Under the Swiss Narcotics Act, cannabis is a prohibited narcotic drug. Depending on how often it is used and in what amount, cannabis can put the health of young people in particular at risk. 

Cannabis as a narcotic drug

As a psychoactive substance, cannabis is smoked, with or without tobacco, as marijuana (dried flower heads) or hashish (resin from the flower heads). Rarely, it is consumed dissolved in drinks or food. Depending on its composition and dose, effects range from calming to euphorigenic to mildly hallucinogenic.

Cannabis contains around 400 chemical compounds. The psychoactive (i.e. intoxicating) tetrahydrocannabinol (THC) is the key active substance of the hemp plant. Only THC is controlled under the Narcotics Act. Other active substances (cannabinoids) like cannabidiol (CBD) are not subject to the Narcotics Act as they do not have comparable psychoactive effects.

Health risks of cannabis use

From a public health perspective, frequent use of large amounts of cannabis over a long period is particularly problematic. Although this risk group in Switzerland is relatively small (fewer than 100,000 people), these individuals are at increased risk of mental, social and physical problems as a result of cannabis use.

The health risks of infrequent cannabis use are fairly low compared to other psychoactive substances, but by no means harmless. The risks are greater with long-term use starting at an early age. Long-term high-risk cannabis use increases the likelihood of mental issues such as depression, anxiety and personality disorders. Long-term cannabis use also harbours the risk of developing psychological dependence.

The effect of THC impairs driving, the ability to pay attention, to concentrate and to learn. Continuous high levels of use can negatively impact performance at school or at work. Frequently smoking cannabis mixed with tobacco also increases the risk of respiratory or cardiovascular diseases.

Moreover, since cannabis is illegal, there are no quality controls of the products. Thus, users are generally unaware of the THC content and may expose themselves to unknown risks. Whereas in the 1960s cannabis products contained less than 3% of the psychoactive substance, THC, today THC levels are mainly between 10% and 20%. In addition, cannabis purchased on the black market may also be contaminated with pesticides, adulterants, heavy metals and mould that are dangerous to health and wellbeing (see Documents > Consumer risks).

What is the FOPH doing to address cannabis use?

The Federal Office of Public Health, FOPH supports the cantons, communities and specialist institutions in developing and implementing measures for the prevention, early detection and intervention and treatment of addiction problems.

However, the FOPH’s focus in the area of cannabis is on early detection and early intervention of at-risk adolescents and young adults.

The FOPH uses health promotion and prevention in the school setting to reach out to children and adolescents:

  • Swiss education and health network «bildung + gesundheit Netzwerk Schweiz (b + g)»
  • Swiss Network of Health-Promoting Schools (SNHPS)
  • éducation21

In terms of advice, the FOPH offers the online advisory portal SafeZone.

Through research projects, including monitoring and specific studies on cannabis consumption, the FOPH organizes the scientific research that is essential for planning the necessary measures.

Low-THC cannabis and CBD

Cannabis products with less than 1% THC are not subject to the Narcotics Act and are therefore increasingly exploited commercially. Products containing the non-intoxicating substance CBD in particular are gaining importance.


Prevention and early recognition

Regulation and enforcement

International development

Cannabidiol (CBD)

Further information

Research reports on Cannabis

Here a list of research reports on the topic "Cannabis" that have been funded by the Federal Office of Public Health.

National Strategy on Addiction

The National Strategy on Addiction aims to prevent the development of addiction, provide help to people with an addiction and reduce the negative impact on health and society.

Last modification 04.06.2024

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Federal Office of Public Health FOPH
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