Cannabis use is associated with changes in psychological and functional well-being during young adulthood: evidence from self-reports and hair analyses.
Lydia Johnson-Ferguson, Michelle Loher, Laura Bechtiger, Clarissa Janousch, Markus R Baumgartner, Tina M Binz, Denis Ribeaud, Manuel Eisner, Boris B. Quednow, Lilly Shanahan
Psychological Medicine August 26, 2025 DOI: 10.1017/s003329172510144x (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort Peer reviewed |
|---|---|
| Sample size | 863 |
| Population | Community sample of young adults |
| Duration | 4-year follow-up |
| Topics | Cannabis |
| Keywords | Functional well-being Hair Psychopathology Young adulthood |
| Citations | 2 |
| Key findings | Both self-reported frequency of cannabis use and hair THC concentrations at age 20 predicted adverse changes in psychopathology and functional well-being from age 20 to 24. |
Abstract
Cannabis use in young adulthood is common, yet few studies have explored how it predicts changes in psychopathology and functional well-being in community samples. We assessed these links using both self-reported frequency of cannabis use and hair THC concentrations. Data came from a community sample of young adults (N = 863) who reported cannabis use (weekly-to-daily use: n = 150) and provided hair samples at age 20 (cannabis detected: n = 110). Liquid chromatography-tandem mass spectrometry quantified delta-9-tetrahydrocannabinol (THC) and cannabinol (CBN) concentrations in hair. At ages 20 and 24, participants reported psychopathology (psychotic-like experiences, problematic substance use, internalizing symptoms, and aggression) and functional wellbeing (general well-being, delinquency, and not being in employment, education, or training). Multiple linear and logit regression models tested associations between six different continuous and dichotomous operationalizations of self-reported and objective cannabis exposure at age 20 and psychological and functional well-being at age 24, adjusting for sex, sociodemographic characteristics, and the outcomes measured at age 20. Both self-reported frequency of cannabis use and hair THC concentrations predicted increases in psychotic-like experiences and internalizing symptoms, increased aggression, decreased general well-being, higher odds of not being in employment, training, or education, and more problematic substance use from age 20 to 24, with small effect sizes. Composite exposure scores derived from self-reports and hair data were not more informative than either source alone. Frequent cannabis use predicted adverse changes in psychopathological outcomes from ages 20 to 24, regardless of how it was assessed.
Comparable studies
Other observational and cohort studies on cannabis, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| High-potency cannabis and the risk of psychosis People with first episode of psychosis and healthy controls from the local population | 2009 | Case-control study | n = 454 |
| Ayahuasca-Assisted Therapy for Addiction: Results from a Preliminary Observational Study in Canada Rural aboriginal population | 2013 | Observational study | |
| Impaired cognitive performance in drug free users of recreational ecstasy (MDMA) Otherwise healthy young people | 2000 | Observational | |
| Continued cannabis use and risk of incidence and persistence of psychotic symptoms: 10 year follow-up cohort study Individuals from the general population in Germany aged 14-24 at baseline | 2011 | Observational cohort | n = 1,923 |
| Cannabis-induced psychosis and subsequent schizophrenia-spectrum disorders: follow-up study of 535 incident cases Patients treated for cannabis-induced psychotic symptoms in Denmark between 1994 and... | 2005 | Observational cohort | n = 535 |
Citations in the library
Cites 6
- Acute Effects of a Single, Oral dose of d9-tetrahydrocannabinol (THC) and Cannabidiol (CBD) Administration in Healthy Volunteers Current Pharmaceutical Design September 12, 2012
- Which biological and self-report measures of cannabis use predict cannabis dependency and acute psychotic-like effects? Psychological Medicine September 4, 2018
- Anatomy of a Joint: Comparing Self-Reported and Actual Dose of Cannabis and Tobacco in a Joint, and How These Are Influenced by Controlled Acute Administration Cannabis and Cannabinoid Research 2017
- Annual incidence of cannabis-induced psychosis, other substance-induced psychoses and dually diagnosed schizophrenia and cannabis use disorder in Denmark from 1994 to 2016 Psychological Medicine December 16, 2019
- The contribution of cannabis use to variation in the incidence of psychotic disorder across Europe (EU-GEI): a multicentre case-control study The Lancet Psychiatry May 1, 2019
and 1 more in the library