What rules apply to 18 to 20-year-olds?

Young adults are persons who have reached the age of 18 but not yet 21, under section 1 no. 20 of the Cannabis Act (Konsumcannabisgesetz, KCanG). The KCanG sets some special rules on quantities and THC content for them. From the age of 18, you may possess cannabis and grow it yourself. Within a cannabis association (Anbauvereinigung), stricter limits apply to young adults than to people aged 21 and over.

Who counts as a young adult

The KCanG defines young adults in section 1 no. 20 as persons who have reached the age of 18 but not yet 21. The Juvenile Court Act (JGG) sets the same limits for criminal law: a young adult is anyone who is 18 but not yet 21 at the time of the offence (section 1(2) JGG). The group of young adults ends on the 21st birthday.

In criminal law, the age at the time of the offence is what matters. This matters when a birthday falls close to the date of the offence.

Possession and home cultivation from 18

Persons aged 18 and over may possess up to 25 grams of cannabis under section 3 KCanG. At the place of residence or habitual residence, up to 50 grams in total are permitted, for flowers or other plant material based on weight after drying, plus up to three living plants. These rules apply to young adults in the same way as to adults aged 21 and over.

Home cultivation also begins at 18. Under section 9 KCanG, up to three cannabis plants may be grown at the same time at the place of residence or habitual residence. Passing the harvest on to third parties is prohibited.

The quantities in cannabis associations

Anyone who is a member of a cannabis association and receives cannabis passed on is subject to maximum amounts under section 19(3) KCanG. For young adults, stricter values apply than for people aged 21 and over. The following table shows the difference:

Age group	Maximum per day	Maximum per calendar month
Young adults (18 to under 21 years)	25 grams	30 grams
From 21 years	25 grams	50 grams

For young adults there is also a limit on THC content. The THC content may be at most 10 percent (section 19(3) KCanG). This rule applies only to this age group and is expressly stated in the law.

Why the brain matters especially at this stage

According to the Federal Institute for Public Health (Bundesinstitut für Öffentliche Gesundheit, BIÖG), the human brain is in an important stage of development until the age of 25, which constant exposure to THC can disrupt. For young people, the BIÖG describes as the worst case that a school or vocational qualification is at risk, because memory works much worse.

The risk of psychosis is also an issue. According to the BIÖG, people who use cannabis are more likely to develop psychosis than people who do not. The BIÖG also states that roughly one in eight people who use cannabis becomes dependent. These figures show why caution is worthwhile.

What young adults should watch for in everyday life

Anyone who uses cannabis should know these points:

• Before reaching the age of 21 and during the probationary period, a cannabis ban applies to drivers in road traffic: anyone who takes THC as the driver of a motor vehicle, or begins a journey under its effect, commits a regulatory offence (section 24c StVG). The limit of 3.5 ng/ml in blood serum under section 24a(1a) StVG applies regardless of this.
• Avoid mixing cannabis with alcohol, because under section 24a(2a) StVG this is a separate offence.
• Watch for warning signs such as withdrawal, falling performance or irritability.

Common questions from young adults

Many young adults wonder whether they can use cannabis in their free time without risk. The honest answer is this: anyone who uses regularly during this phase should know the risks and keep an eye on their use. The legal limits and the effects on health and everyday life are two separate questions.

Another point concerns training and studies. School and career goals often depend on concentration and memory. If you notice that performance is falling, raise it early.

What you should know about quantities and limits

The quantities under section 3 KCanG are fixed upper limits. Anyone who exceeds them commits a regulatory offence or a criminal offence, depending on the amount (section 36(1) no. 1 and section 34(1) no. 1 KCanG). The maximum amounts in section 19 KCanG apply to the cannabis association that passes cannabis on. If you are unsure, check beforehand and ask a counselling service.

Especially with membership of a cannabis association, it is worth looking at the maximum amounts before the first collection. The rules for young members differ from those for adults aged 21 and over.

Responsibility in the circle of friends

Anyone over 18 bears responsibility for their surroundings. Younger friends often take their cue from what you do. Passing cannabis on to young people is a criminal offence under section 34 KCanG, regardless of how well people know each other.

A clear approach to cannabis in the circle of friends also protects the younger ones. If you raise the rules openly, you have less to explain later when a situation arises.

If you need support

If you notice that use takes up more room in your life than you intended, you can find confidential help at a local addiction counselling service. The service can help with your questions. General practitioners can also provide information.

If you want to understand your own patterns better, you can start with a self-test. An overview is provided by the guide on self-assessment for dependence.

Individual legal questions

For legal questions about a specific case, such as proceedings or a particular question about quantities, a specialist lawyer should help. Courts decide individual cases. This guide gives an overview, and personal advice remains essential.

For more on which quantities apply to members, see the guide on quantities for young members between 18 and 21. The overview of the KCanG is provided by the guide What does the KCanG regulate on youth protection?.