What topics does this cannabis study cover?

This study covers research on: THC, Addiction.

Where was this research published?

Published in Addictive behaviors on July 29, 2026.

Cannabis use linked to cocaine use during addiction treatment

Q: What did this research study find?

Participants with a *THC*-positive urine test had **1.47 times higher odds** of a cocaine-positive urine test during treatment than participants with a *THC*-negative test.

Relationships between cannabis and cocaine use in a randomized trial of combined buprenorphine and naltrexone for DSM-IV cocaine dependence.

Addictive behaviors • July 29, 2026 • Highly Relevant

🤖

AI Summary

This secondary analysis examined whether THC-positive urine tests were associated with cocaine-positive tests during an 8-week treatment trial for cocaine and opioid use disorders. The analysis included 301 participants and tracked urine samples across 25 time points while participants received extended-release naltrexone with different doses of buprenorphine or placebo.

Participants with a THC-positive urine test had 1.47 times higher odds of also having a cocaine-positive test than those with a THC-negative test. The researchers emphasize that this is an association, not proof that cannabis use causes cocaine use. They suggest that clinicians may want to discuss cannabis reduction or cessation with patients receiving treatment for cocaine use, while noting that further research is needed to determine whether changing cannabis use improves cocaine-related outcomes.

💡 Key Findings

Participants with a THC-positive urine test had 1.47 times higher odds of a cocaine-positive urine test during treatment than participants with a THC-negative test.

Good

75%

The study found an association, but it did not establish that cannabis use causes increased cocaine use or poorer treatment outcomes.

High

85%

The authors suggest that discussing cannabis reduction or cessation may be useful during treatment for cocaine use, while calling for further research.

Good

65%

Cocaine-positive tests showed a very small decrease over time across the treatment period, and females had 77% higher odds of a cocaine-positive test in the model.

Good

70%

📄 Original Abstract

Cannabis is the most commonly used drug in the United States, and among people who use cannabis, polysubstance use is common and understudied. We aimed to examine the association of tetrahydrocannabinol (THC) positive urine drug screen (+UDS) with the odds of submitting a cocaine + UDS during cocaine use disorder treatment. We conducted a secondary data analysis of a previously reported double-blind, placebo-controlled clinical trial, CTN0048. Participants meeting criteria for opioid abuse/dependence were assigned to receive extended-release naltrexone and one of three conditions of buprenorphine (placebo, 4 mg/day, 16 mg/day) for 8 weeks. Generalized estimating equations (GEE) were used to analyze urine samples (Liu et al., 2018) collected over time, examining the association between THC + UDS and cocaine + UDS during treatment. Participants (n = 301) averaged 46 (SD = 8.64) years of age, were majority male (78.41 %), non-Hispanic (89.70 %), and African American (66.45 %). GEE results indicated that patients who submitted THC + UDS had significantly higher odds of submitting cocaine + UDS compared to participants who submitted THC-negative UDS across the 25 time points examined (OR = 1.47, 95 % CI = 1.21-1.79, p = 0.00). Time (OR = 0.9998, 95 % CI: 0.9997, 0.9999, p = 0.018) and the covariate of sex assigned at birth (OR = 1.77, 95 % CI = 1.13-2.77, p = 0.013) were also significant in the model, indicating very small decreases in the odds of submitting a cocaine + UDS over time for all patients and 77 % higher odds of submitting cocaine + UDS for females. THC + UDS was associated with increased odds of submitting a cocaine + UDS during treatment. Further investigation is needed to discern whether decreasing THC use will result in reduced cocaine use; however, these results suggest that it may be beneficial to counsel patients on cannabis use cessation both before and during treatment for cocaine use, as it is related to cocaine use treatment outcomes. Secondary data analysis of ClinicalTrials.gov, TRN: NCT01402492 ("A randomized study to test the safety and effectiveness of buprenorphine in the presence of naltrexone for the treatment of cocaine dependence"; National Drug Abuse Treatment Clinical Trials Network (CTN) clinical trial: CTN0048), Registration date: 27 July 2011.

Paper Type

📄 Research

Publication

Journal: Addictive behaviors
Published: July 29, 2026
PMID: 42561565
DOI: 10.1016/j.addbeh.2026.108817

Authors (9)

Crystal L Smith Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA; Analytics and PsychoPharmacology Laboratory (APPL), Washington State University, Spokane, WA, USA; Laboratory for Innovations in Therapeutics (LIT), Washington State University, Spokane, WA, USA. Electronic address: Crystal.lederhos@wsu.edu.
Amaya Pelagio Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA; Analytics and PsychoPharmacology Laboratory (APPL), Washington State University, Spokane, WA, USA.
Alex Schmidt Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA; Analytics and PsychoPharmacology Laboratory (APPL), Washington State University, Spokane, WA, USA; Laboratory for Innovations in Therapeutics (LIT), Washington State University, Spokane, WA, USA.
Sterling McPherson Elson S. Floyd College of Medicine, Washington State University, Spokane, WA, USA; Analytics and PsychoPharmacology Laboratory (APPL), Washington State University, Spokane, WA, USA; Laboratory for Innovations in Therapeutics (LIT), Washington State University, Spokane, WA, USA; Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, USA.
Nicole Rodin Analytics and PsychoPharmacology Laboratory (APPL), Washington State University, Spokane, WA, USA; Laboratory for Innovations in Therapeutics (LIT), Washington State University, Spokane, WA, USA; College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA.
+4 more authors