Cannabis use in youth linked to depression, psychosis, and suicide in Australia and US | Research

The takeaway

A scoping review of 24 studies found youth cannabis use associated with depression, psychosis, suicide, cognitive decline, and ADHD-related behaviors, with effects worse at higher frequency and earlier onset, though the anxiety link remained unclear.

Parents, school health programs, youth mental health providers, cannabis prevention researchers

Depression, psychosis, suicide linked; anxiety unclear

What the researchers found

Cannabis use in youth was associated with depression, psychosis, suicide, cannabis use disorder, cognitive decline, and externalizing behaviors (particularly ADHD). The cannabis-anxiety relationship was equivocal. Vulnerable groups included females, minorities, LGBTQI youth, African Americans, and Aboriginal/Torres Strait Islander populations.

Why it matters

With 2.8% of youth currently smoking cannabis and growing perception of harmlessness, documenting the mental health associations across two major English-speaking countries provides evidence for school and community prevention programs.

The numbers in context

24 articles analyzed. 2.8% of youth currently smoke cannabis. Mental health issues more prevalent with increased frequency, duration, intensity, and type of use.

How the study worked

Scoping review following JBI protocol, analyzing 24 articles from ProQuest Central and EBSCO databases, including systematic reviews, meta-analyses, cohort, longitudinal, and cross-sectional studies from Australia and the US.

What this study cannot tell us

Scoping review includes heterogeneous study designs with varying quality. Limited to Australia and US. Cannot establish causation. The equivocal anxiety finding may reflect measurement differences or bidirectional relationships.

How to read the evidence

Scoping review of 24 studies provides broad evidence synthesis, but heterogeneous study designs limit the strength of specific conclusions.

When this study was published

2024 scoping review of Australian and US studies

The bigger picture

The consistency of findings across Australia and the US, two countries with different cannabis policy landscapes, strengthens the evidence that these associations are not artifacts of a particular legal or cultural context.

Questions still open

Why is the cannabis-anxiety relationship unclear when depression and psychosis links are more consistent? Do prevention programs that address cannabis risk perceptions actually reduce use?

Common questions

Which mental health issues are most clearly linked to youth cannabis use?

Depression, psychosis, suicide, and cognitive decline showed the most consistent associations. Cannabis use disorder and ADHD-related behaviors were also linked. The relationship with anxiety was less clear.

Who is most at risk?

Earlier age of onset and higher frequency of use increased risk. Females, minority groups, LGBTQI youth, and Indigenous populations were identified as particularly vulnerable.

Read the original research

Cannabis Use and Its Impact on Mental Health in Youth in Australia and the United States: A Scoping Review.

Epidemiologia (Basel, Switzerland), 5(1), 106-121

View on PubMed ↗Publisher’s paper ↗

Citation

Baral, Aayush; Hanna, Fahad; Chimoriya, Ritesh; Rana, Kritika. (2024). Cannabis Use and Its Impact on Mental Health in Youth in Australia and the United States: A Scoping Review.. Epidemiologia (Basel, Switzerland), 5(1), 106-121. https://doi.org/10.3390/epidemiologia5010007