Cannabis and Adolescents and Young Adults

This page is for teens, young adults and the adults who care about them. It is education, not medical or legal advice, and it does not judge anyone. Most of the evidence below is observational, which means researchers compared groups of people and saw patterns. A pattern (an "association") does not prove that cannabis caused the outcome. Where a finding is mixed or small, the page says so.

How evidence is labeled here. Evidence of harm (association) means studies repeatedly link use with a worse outcome. Mixed means studies disagree or the effect is small. Insufficient evidence means the question is not settled.

Why the teen years get special attention

NIDA, the US National Institute on Drug Abuse, describes adolescence as an important period of brain development and says cannabis use may influence the brain in ways that could lead to long-term harm. [1] NIDA also notes that regular, heavy use in adolescence is associated with weaker working memory, processing speed, verbal memory and school functioning. [1] Most studies cannot randomly assign teens to use cannabis, so these are associations.

Thinking and memory: small effects, and they may fade

A 2018 meta-analysis pooled 69 studies of young people (average age about 21). It found a small overall reduction in thinking test scores linked with frequent or heavy use (effect size d of about -0.25). [2] In the studies that required more than 72 hours without cannabis before testing, the difference was not statistically different from zero. [2] The authors concluded that the associations were small, may be of questionable clinical importance for most individuals, and may partly reflect recent use or withdrawal rather than lasting change. [2] Label: mixed. NIDA's summary and this meta-analysis point in different directions on how lasting the effect is.

School and work

A 2024 review of 63 studies with 438,329 people found moderate-certainty evidence that cannabis use in adolescence and young adulthood was probably associated with lower grades, less high school completion, fewer people enrolling in university or finishing a degree, and more dropping out and missing school. [3] For school dropout the odds ratio was 2.19, and the authors estimated absolute risk differences of 7% to 14%. [3] The review also reported worse results for frequent users and for students who started earlier. [3] Other things in a young person's life can affect both school and cannabis use, so this is an association. Label: evidence of harm (association).

Mood and suicidal thoughts

A 2019 meta-analysis of 11 studies (23,317 people) followed teens under 18 into young adulthood. Those who used cannabis had higher odds of later depression (odds ratio 1.37) and suicidal ideation (1.50), and a wider, less certain estimate for suicide attempts (3.46, with a confidence range of 1.53 to 7.84). [4] The estimate for anxiety was not statistically significant (1.18). [4] The authors stressed that the risk for any one person remains moderate to low, but that many young people use cannabis. [4] Label: evidence of harm (association) for depression and suicidal thoughts; mixed to insufficient for anxiety. If you or someone you know is thinking about suicide, call or text 988 (US 988 Suicide & Crisis Lifeline). [1]

Psychosis

A 2021 meta-analysis found that adolescent cannabis use was associated with a higher risk of psychosis later (relative risk 1.71) and with earlier onset of psychosis. [5] The link was stronger with earlier first use, frequent use, childhood trauma, use of other substances and genetic factors. [5] NIDA reports the association between heavy use and schizophrenia is especially strong in young males. [1] See psychosis and mania vulnerability. Label: evidence of harm (association), concentrated in people with other risk factors.

Cannabis use disorder

NCCIH reports that adolescents who use cannabis are four to seven times more likely than adults to develop cannabis use disorder. [6] NIDA says using cannabis at a younger age increases the likelihood of developing the disorder later, and that products with higher THC concentrations have been associated with greater likelihood of progressing to it. [1] Behavioral treatments such as cognitive behavioral therapy, motivational enhancement therapy and contingency management can be effective, and there are currently no FDA-approved medications for cannabis use disorder. [1] More in dependence and withdrawal.

Smoking, vaping and edibles in young people

In a national US survey of 14,798 adolescents aged 12 to 17, those who had used cannabis in nicotine vaping devices had about twice the odds of wheezing (adjusted odds ratio 1.81). [7] This is a single survey, described by its authors as preliminary evidence. [7] NIDA notes that edibles take longer to show effects, which can lead people to use more, and that dabbing can rapidly deliver large amounts of THC. [1] For breathing risks see smoking and vaping cannabis risks.

Where to get help

For substance use treatment referrals in the US, NIDA lists the SAMHSA National Helpline at 1-800-662-HELP (4357) and FindTreatment.gov. [1] A pediatrician, school counselor or family doctor can also talk privately about cannabis use. For driving, see cannabis impairment and driving. For general guidance on young people and natural products, see children and teens safety.