Cannabis and other substance use was linked to worse COVID-19 outcomes but not higher death rates | Research

The takeaway

Among 17,423 COVID-19 patients, cannabis, cocaine, sedative, and opioid use were each associated with more ICU admissions, ventilator use, and longer hospitalizations, but not increased mortality.

Hospital physicians, addiction medicine specialists, public health planners

Substance use increased ICU and ventilator needs but not COVID-19 mortality

What the researchers found

Cannabis, cocaine, sedative, and opioid use were each associated with increased ICU care, ventilatory support, more hospitalizations, and longer stays; substance use was not associated with increased mortality; no differences between methadone, buprenorphine, and other opioids.

Why it matters

Understanding how substance use affects COVID-19 severity can inform clinical management and resource allocation during future outbreaks.

The numbers in context

n=17,423 COVID-19 patients; cannabis, cocaine, sedative, and opioid use each significantly associated with ICU admission, ventilation, and longer hospitalization; no mortality increase; no difference between MOUD types.

How the study worked

Retrospective cohort using EHR data from a large urban hospital system; 17,423 COVID-19 positive patients (2020-2021); substance use identified from urine toxicology within 90 days; multivariable logistic regression controlling for age, sex, comorbidity, tobacco, and social disadvantage.

What this study cannot tell us

Retrospective design; substance use identified by urine toxicology (may miss some users); single hospital system; cannot separate individual substance effects in polysubstance users.

How to read the evidence

Large cohort with objective substance detection (urine toxicology) and adjusted analyses, though retrospective design and single-system data limit generalizability.

When this study was published

Published 2025, data from 2020-2021

The bigger picture

Substance use may increase COVID-19 morbidity through immune, pulmonary, and cardiovascular mechanisms, but the lack of mortality association suggests these patients can recover with appropriate care.

Questions still open

Which specific mechanisms link cannabis to worse COVID-19 morbidity? Does smoking route drive pulmonary complications? Would vaccination modify the substance-COVID interaction?

Common questions

Did cannabis use make COVID-19 worse?

Cannabis use was associated with more ICU admissions, ventilator needs, and longer hospitalizations, but not with higher death rates from COVID-19.

Did addiction medications affect COVID outcomes?

No. There were no significant differences between methadone, buprenorphine, and other opioids on COVID-19 outcomes.

Read the original research

Effects of Buprenorphine, Methadone, and Substance Use on COVID-19 Morbidity and Mortality.

Journal of addiction medicine, 19(2), 223-226

View on PubMed ↗Publisher’s paper ↗

Citation

Christian, Nicholaus J; Zhou, Xin; Radhakrishnan, Rajiv. (2025). Effects of Buprenorphine, Methadone, and Substance Use on COVID-19 Morbidity and Mortality.. Journal of addiction medicine, 19(2), 223-226. https://doi.org/10.1097/ADM.0000000000001386