Veterans with both opioid and cannabis use disorders had fewer opioid prescriptions but more psychiatric hospitalizations

Among veterans with drug use disorders, those with co-occurring opioid and cannabis use disorders received fewer opioid prescriptions than those with opioid use disorder alone, but had higher rates of psychiatric admission and homelessness.

De Aquino, Joao P et al.·The American journal of drug and alcohol abuse·2019·Moderate EvidenceRetrospective Cohort
RTHC-02001Retrospective CohortModerate Evidence2019RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Retrospective Cohort
Evidence
Moderate Evidence
Sample
N=234,181

What This Study Found

Veterans with co-occurring OUD and CUD received fewer opioid prescriptions (mean 3.79 vs 4.8) compared to the OUD-only group, but had a higher likelihood of inpatient psychiatric admission (RR = 1.95) and homelessness (RR = 1.52).

Key Numbers

234,181 veterans studied (94% male). Co-occurring OUD+CUD group: 8.6% of sample. Mean opioid prescriptions: 3.79 (OUD+CUD) vs 4.8 (OUD only). Psychiatric admission risk ratio: 1.95. Homelessness risk ratio: 1.52. No significant difference in ED visits.

How They Did This

Retrospective analysis of 234,181 veterans with drug use disorder diagnoses from the National Veterans Health Administration, comparing outcomes across four groups: co-occurring OUD+CUD, OUD only, CUD only, and other drug use disorders using logistic and linear regression models.

Why This Research Matters

The idea that cannabis might substitute for opioids has gained attention, but this study shows the relationship is complicated. While cannabis co-use was associated with fewer opioid prescriptions, it didn't translate to better overall outcomes.

The Bigger Picture

The opioid-cannabis substitution hypothesis is appealing but oversimplified. These findings suggest that while cannabis co-use correlates with lower opioid prescribing, the people using both substances face compounding challenges that outweigh any prescribing reduction.

What This Study Doesn't Tell Us

Retrospective design cannot establish causation. The veteran population is predominantly male, limiting generalizability. Cannabis use disorder is clinically different from controlled medical cannabis use. Self-reported SC use relied on honesty.

Questions This Raises

  • ?Would supervised medical cannabis programs for OUD patients show different outcomes than the uncontrolled co-use patterns seen here?
  • ?Are the worse psychiatric outcomes driven by the combination of substances or by underlying severity?

Trust & Context

Key Stat:
234,181 veterans: OUD+CUD group had 1.95x higher psychiatric admission risk
Evidence Grade:
Moderate: large national dataset with regression modeling, but retrospective and observational.
Study Age:
Published in 2019, using FY2012 data.
Original Title:
Adverse Consequences of Co-Occurring Opioid Use Disorder and Cannabis Use Disorder Compared to Opioid Use Disorder Only.
Published In:
The American journal of drug and alcohol abuse, 45(5), 527-537 (2019)
Database ID:
RTHC-02001

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-ControlFollows or compares groups over time
This study
Cross-Sectional / Observational
Case Report / Animal Study

Looks back at existing records to find patterns.

What do these levels mean? →

Frequently Asked Questions

Does cannabis help people use fewer opioids?

In this study, veterans with both opioid and cannabis use disorders received fewer opioid prescriptions. However, they also had worse outcomes in other areas like psychiatric hospitalization, so the picture is more complex than simple substitution.

Why were psychiatric admissions higher in the dual-use group?

The study couldn't determine causation. It may reflect greater overall substance use severity, compounding effects of multiple substances, or other unmeasured factors common to people with multiple use disorders.

Read More on RethinkTHC

Cite This Study

RTHC-02001·https://rethinkthc.com/research/RTHC-02001

APA

De Aquino, Joao P; Sofuoglu, Mehmet; Stefanovics, Elina; Rosenheck, Robert. (2019). Adverse Consequences of Co-Occurring Opioid Use Disorder and Cannabis Use Disorder Compared to Opioid Use Disorder Only.. The American journal of drug and alcohol abuse, 45(5), 527-537. https://doi.org/10.1080/00952990.2019.1607363

MLA

De Aquino, Joao P, et al. "Adverse Consequences of Co-Occurring Opioid Use Disorder and Cannabis Use Disorder Compared to Opioid Use Disorder Only.." The American journal of drug and alcohol abuse, 2019. https://doi.org/10.1080/00952990.2019.1607363

RethinkTHC

RethinkTHC Research Database. "Adverse Consequences of Co-Occurring Opioid Use Disorder and..." RTHC-02001. Retrieved from https://rethinkthc.com/research/de-2019-adverse-consequences-of-cooccurring

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.