Längsschnittstudie findet Zusammenhang zwischen Cannabiskonsum bei Teenagern und späterer Psychose | Cannabiskonsum bei Jugendlichen und Risiko für psychotische, bipolare, depressive und Angststörungen

Some highlights from the news article:

>Researchers analyzed health data on 460,000 teenagers in the Kaiser Permanente Health System in Northern California. The teens were followed until they were 25 years old. The data included annual screenings for substance use and any mental health diagnoses from the health records. Researchers excluded the adolescents who had symptoms of mental illnesses before using cannabis.
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>“We looked at kids using cannabis before they had any evidence of these psychiatric conditions and then followed them to understand if they were more likely or less likely to develop them,“ says Dr. Lynn Silver, a pediatrician and researcher at the Public Health Institute, and an author of the new study.
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>They found that the teens who reported using cannabis in the past year were at a higher risk of being diagnosed with several mental health conditions a few years later, compared to teens who didn’t use cannabis.
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>Teens who reported using cannabis had twice the risk of developing two serious mental illnesses: bipolar, which manifests as alternating episodes of depression and mania, and psychotic disorders, such as schizophrenia which involve a break with reality.
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>Now, only a small fraction — nearly 4,000 — of all teens in the study were diagnosed with each of these two disorders. Both bipolar and psychotic disorders are among the most serious and disabling of mental illnesses.
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>“Those are the scarier conditions that we worry about,“ says Sultan.
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>…
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>The new study also found that the risk for more common conditions like depression and anxiety was also higher among cannabis users.
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>“Depression alone went up by about a third,“ says Silver, „and anxiety went up by about a quarter.“
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>But the link between cannabis use and depression and anxiety got weaker for teens who were older when they used cannabis. „Which really shows the sensitivity of the younger child’s brain to the effects of cannabis,“ says Silver. „The brain is still developing. The effects of cannabis on the receptors in the brain seem to have a significant impact on their neurological development and the risk for these mental health disorders.“
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>Silver hopes these findings will make teens more cautious about using the drug, which is not as safe as people perceive it to be.
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>“With legalization, we’ve had a tremendous wave of this perception of cannabis as a safe, natural product to treat your stress with,“ she says. „That is simply not true.“
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>The new study is well designed and gets at „the chicken or the egg, order-of-operations question,“ says Sultan. There have been other past studies that have also found a link between cannabis use and mental health conditions, especially psychosis. But, those studies couldn’t tell whether cannabis affected the likelihood of developing mental health symptoms or whether people with existing problems were more likely to use cannabis — perhaps to treat their symptoms.
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>But by excluding teens who were already showing mental health symptoms, the new study points to a potential causal link between cannabis use and later mental health diagnoses. Additional research is needed to understand the link fully.

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Link to the research: [Adolescent Cannabis Use and Risk of Psychotic, Bipolar, Depressive, and Anxiety Disorders](https://jamanetwork.com/journals/jama-health-forum/fullarticle/2845356)

Abstract:

>**Importance** As cannabis becomes more accessible and socially accepted, concerns have grown about its potential implications for adolescent mental health. While prior research has linked adolescent cannabis use to psychiatric symptoms, few large, population-based, longitudinal studies have examined associations with clinically diagnosed psychiatric disorders.
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>**Objective** To evaluate whether adolescent cannabis use is associated with an increased risk of incident psychotic, bipolar, depressive, and anxiety disorders during adolescence and young adulthood.
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>**Design, Setting, and Participants** This cohort study included adolescents aged 13 to 17 years who were screened for past-year cannabis use at Kaiser Permanente Northern California from 2016 to 2023. Adolescents were followed up through age 25 years or until December 31, 2023. Data were analyzed from February 21, 2024, to August 27, 2025.
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>**Exposure** Time-varying self-reported past-year cannabis use based on universal, confidential screening during standard pediatric care.
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>**Main Outcomes and Measures** Incident clinician-diagnosed psychotic, bipolar, depressive, and anxiety disorders, which were identified through electronic health records using International Classification of Disease codes. Cox proportional hazards regression models were used to measure the strength of associations between adolescent cannabis use and incident psychiatric diagnoses, with adjustments for sex, race and ethnicity, neighborhood deprivation index, insurance type, and time-varying alcohol and other substance use.
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>**Results** Of 463 396 adolescents (234 114 males [50.5%]; mean [SD] age, 14.5 [1.3] years) included in the sample, 136 708 were Hispanic individuals (29.5%), 93 737 were non-Hispanic Asian individuals (20.2%), 35 346 were non-Hispanic Black individuals (7.6%), 153 102 were non-Hispanic White individuals (33.0%), and 18 795 individuals were multiracial or of other races or ethnicities (4.1%). At baseline, 26 345 adolescents (5.7%) self-reported past-year cannabis use. Past-year cannabis use was associated with an increased risk of incident psychotic (adjusted hazard ratio [AHR], 2.19; 95% CI, 1.97-2.42), bipolar (AHR, 2.01; 95% CI, 1.82-2.22), depressive (AHR, 1.34; 95% CI, 1.30-1.39), and anxiety disorders (AHR, 1.24; 95% CI, 1.21-1.28). The strength of the associations between cannabis use and incident depressive and anxiety disorders decreased as adolescents aged. This pattern was similar but slightly attenuated after additional adjustment for past psychiatric conditions (psychotic disorder: AHR, 1.92; 95% CI, 1.73-2.13; bipolar disorder: AHR, 1.73; 95% CI, 1.57-1.90; depressive disorder: AHR, 1.33; 95% CI, 1.29-1.38; anxiety disorder: AHR, 1.19; 95% CI, 1.16-1.23).
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>**Conclusions and Relevance** This cohort study found that adolescent cannabis use was associated with increased risk of incident psychiatric disorders, particularly psychotic and bipolar disorders. These results could inform the development of clinical and educational interventions for parents, adolescents, and clinicians, as well as protective policies to prevent or delay adolescent cannabis use in the context of expanding cannabis legalization.

did they screen for the genetic propensity for psychotic disorders?