Cannabis Use Disorder Predicted Shorter Treatment Retention in Young People With Opioid Addiction

What the researchers found

Cannabis use disorder predicted shorter treatment retention (p=0.02), while depression (p=0.04), PTSD (p=0.002), and alcohol use disorder (p=0.04) were associated with longer retention. Cannabis use disorder and male sex predicted positive urine tests for THC, while medication for OUD was linked to lower THC positivity. The median retention time was 300 days.

Why it matters

Opioid addiction treatment in young people is already challenging, and this study suggests co-occurring cannabis use disorder adds another barrier to retention. Understanding which comorbidities help versus hinder treatment can guide clinical approaches.

The numbers in context

157 patients, median retention 300 days. CUD predicted shorter retention (p=0.02). Depression (p=0.04) and PTSD (p=0.002) predicted longer retention. Median proportion positive UDTs: 0.9 for MOUD (good adherence), 0.1 for illicit substances, 0.0 for THC. CUD (p=0.02) and male sex (p=0.04) predicted THC-positive urine tests.

How the study worked

Retrospective cohort study of 157 adolescents and young adults enrolled in a Substance Use Treatment and Recovery clinic from 2009 to 2022. Treatment retention and urine drug test results were analyzed using Kruskal-Wallis tests and regression models.

What this study cannot tell us

Retrospective single-center study. Small sample (157). Cannot determine causation. THC positivity may reflect legal medical use in some cases. The study period (2009-2022) spans significant changes in cannabis policy and availability.

How to read the evidence

Preliminary: retrospective single-center study with relatively small sample, limiting causal inference and generalizability.

When this study was published

2025 study using 2009-2022 clinical data.

The bigger picture

As cannabis becomes more available, its intersection with opioid addiction treatment in young people deserves attention. This study suggests that cannabis use disorder may compete with or undermine opioid treatment engagement in ways that depression and trauma do not.

Questions still open

• Would addressing cannabis use disorder directly improve opioid treatment retention? Does the type of cannabis use (medical vs recreational) matter for treatment outcomes? Should opioid treatment programs screen more aggressively for CUD?

Common questions

Read the original research

Impact of Co-Occurring Psychiatric Comorbidities and Substance Use Disorders on Outcomes in Adolescents and Young Adults with Opioid Use Disorder: A Retrospective Cohort Study.

Pharmaceuticals (Basel, Switzerland), 18(5)

Citation

Liu, Ligang; McKnight, Erin R; Bonny, Andrea E; Tao, Heqing; Zhao, Pujing; Nahata, Milap C. (2025). Impact of Co-Occurring Psychiatric Comorbidities and Substance Use Disorders on Outcomes in Adolescents and Young Adults with Opioid Use Disorder: A Retrospective Cohort Study.. Pharmaceuticals (Basel, Switzerland), 18(5). https://doi.org/10.3390/ph18050609

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