A large retrospective cohort study from Johns Hopkins suggests that cannabis use disorder is associated with higher psychiatric risks in adolescents than in adults when compared to other substance use disorders. The study uses propensity matching across electronic health records, but it is observational and cannot prove causation. Clinicians should treat these findings as hypothesis-generating, particularly for younger patient populations where the developing brain may be more vulnerable.

Cannabis use among adolescents continues to rise in many jurisdictions, yet most psychiatric risk studies compare cannabis users to non-users rather than to people with other substance use disorders. This comparison gap has left clinicians without a clear framework for contextualizing cannabis-specific risk relative to the broader landscape of substance misuse. Understanding whether cannabis use disorder confers distinct or overlapping psychiatric vulnerabilities across different age groups is essential for risk counseling, screening protocols, and informed policy discussions at a time when legalization is expanding access for younger populations.

Most observational studies examining the association between cannabis and psychiatric outcomes have used non-substance-using populations as the comparator group, making it difficult to disentangle whether observed risks are specific to cannabis or common to substance use disorders in general. Researchers at Johns Hopkins, Brigham and Women’s Hospital, and Tulane University addressed this gap using TriNetX Research Network electronic health record data to construct a propensity-matched retrospective cohort. By comparing patients with cannabis use disorder directly to patients with non-cannabis substance use disorders, the study design more precisely isolates cannabis-attributable psychiatric associations while reducing the healthy-user bias that has plagued earlier literature. The analysis was stratified by age, separating adult from pediatric cohorts, and the propensity matching balanced demographics and clinical characteristics across groups.

The central finding was a striking age-dependent reversal in risk direction. Among adults, cannabis use disorder alone was associated with lower risks of schizophrenia, major depressive disorder, and psychotic disorders compared to other substance use disorders, though slightly higher anxiety risk was observed. Among pediatric patients, this pattern reversed: cannabis use disorder was associated with higher risks of schizophrenia, depression, and anxiety disorders relative to other SUDs. Adults who had cannabis use disorder combined with another SUD also showed lower risks for most outcomes than adults with multiple non-cannabis SUDs. Critically, the study is observational, cannot establish causality, and does not capture cannabis dose, frequency, potency, or product type. The authors themselves note these results do not imply cannabis is safe, and they emphasize the need for longitudinal studies and mechanistic research examining the developing endocannabinoid system.

This study gets something fundamentally right that too many others miss: it compares cannabis use disorder to other substance use disorders rather than to no substance use at all. That active comparator design is a significant methodological step forward, and the age-stratified findings are genuinely thought-provoking. The adolescent signal, in particular, aligns with what we understand about endocannabinoid system development, even though this study does not test that mechanism directly. However, I want to be very clear that we are looking at associations from electronic health records, not causal proof, and the interview format through which these findings were reported lacks the quantitative detail clinicians need to apply them precisely.

In my practice, I already treat adolescent cannabis exposure as a higher-risk scenario, and this study reinforces that posture without fundamentally changing it. When I see younger patients or families considering cannabis, I use the developmental vulnerability argument as a core part of risk counseling, emphasizing that the adolescent brain responds differently than the adult brain. For adult patients with cannabis use disorder, I avoid false reassurance from studies like this, because “lower risk than alcohol use disorder” is not the same as “no risk.” The conversation always returns to individual context: what are you using, how much, how often, and what are we watching for.

This study sits at an important inflection point in the cannabis-psychiatry research arc. Earlier work, such as the Di Forti et al. (2019) study on daily high-potency cannabis use and psychosis risk, established plausible associations but often used non-users as comparators, inflating the apparent cannabis-specific signal. By introducing other substance use disorders as the active comparator, the Nicholson et al. study reframes the question in a way that is more relevant to real-world clinical decision-making, where patients rarely present with cannabis use in a vacuum of other risk behaviors. The age stratification adds a layer of nuance that will be important as screening guidelines evolve.

From a pharmacological perspective, the developmental vulnerability hypothesis is biologically plausible. The endocannabinoid system undergoes substantial maturation through late adolescence, and exogenous cannabinoid exposure during this window may disrupt neurodevelopmental trajectories in ways that are less relevant once the system has matured. Clinicians should note that this study did not assess THC concentration, route of administration, or concurrent medication use, all of which can substantially modify psychiatric risk. Safety considerations around drug interactions remain especially important in adolescent populations where SSRIs, stimulants, and other psychotropic medications are commonly prescribed. The most

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