# Cannabis use and health outcomes among opioid-using people who inject drugs in the context of cannabis legalization

> **NIH NIH R01** · UNIVERSITY OF SOUTHERN CALIFORNIA · 2020 · $592,802

## Abstract

Project Summary
 We propose a longitudinal, prospective cohort study to determine if changes in cannabis use frequency
are associated with changes in frequency of opioid use and drug-use related health outcomes among opioid-
using (both heroin and prescription opiates) people who inject drugs (PWID) in two states with legal adult
cannabis sales and use. State-level legalization of adult cannabis sales and use is likely to lead to greater
cannabis use and cannabis-related health problems among vulnerable populations. However, increases in
cannabis sales and use might have unanticipated consequences for PWID. Preliminary studies suggest
substitution of cannabis for opioids among medicinal cannabis patients and community recruited PWID.
Ecological studies have found that medical marijuana legalization is associated with lower rates of opioid-
related overdose and hospitalization, outcomes that might be observable for legal adult use cannabis. Based
on these findings, we theorize that cannabis use may reduce opioid use and thereby lower the risk for opioid-
related drug harms such as nonfatal overdose events. Therefore, we propose the following aims:
AIM 1: To determine whether changes in cannabis use are associated with changes in frequency of opioid use
among opioid-using PWID while adjusting for confounders. Hypothesis 1 (H1): The rate of change in cannabis
use over time will be inversely associated with the rate of change in opioid use during the same period.
AIM 2: To determine whether changes in cannabis use among opioid-using PWID is associated with changes
in non-fatal overdose events while adjusting for confounders. H2: The rate of change in cannabis use will be
inversely associated with the rate of change in the number of non-fatal overdose events.
 To achieve these aims, we propose to recruit, interview, and follow at baseline, 6 and 12 months a
prospective, longitudinal cohort of 1,000 opioid-using PWID in Denver, CO (N=500) and Los Angeles, CA
(N=500). Opioid-using PWID will be recruited using targeted sampling methods. Multiple observation periods
and large sample size will permit the use of cutting edge statistical techniques such as latent growth modelling
and finite mixture modelling to rigorously test our hypotheses. Our two sites allow us to observe drug use
patterns and health outcomes among racially/ethnically diverse PWID. The prevalence of non-fatal overdoses
has increased in recent years. In our 2016/17 sample of Los Angeles PWID (n=472), 21% reported a non-fatal
overdose in the last 6 months, meaning the proposed sample should have sufficient non-fatal overdoses
events to permit statistical analyses of changes over time as proposed here. Findings will advance drug use
epidemiology and may inform new prevention programs for the reduction of drug-related harms. Our study
team is multidisciplinary (economics [Pacula], epidemiology [Corsi, Kral], psychology [Booth & Huh], and
sociology [Bluthenthal]) and well-prepared to conduct ...

## Key facts

- **NIH application ID:** 9856430
- **Project number:** 5R01DA046049-02
- **Recipient organization:** UNIVERSITY OF SOUTHERN CALIFORNIA
- **Principal Investigator:** Ricky N Bluthenthal
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $592,802
- **Award type:** 5
- **Project period:** 2019-02-01 → 2022-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9856430

## Citation

> US National Institutes of Health, RePORTER application 9856430, Cannabis use and health outcomes among opioid-using people who inject drugs in the context of cannabis legalization (5R01DA046049-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9856430. Licensed CC0.

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