# A Longitudinal Qualitative Study of Fentanyl-Stimulant Polysubstance Use Among People Experiencing Homelessness

> **NIH NIH R01** · YALE UNIVERSITY · 2022 · $2,499,566

## Abstract

Project Summary: We propose a five-year prospective, longitudinal qualitative study that will characterize
fentanyl-stimulant (cocaine, crack cocaine, methamphetamine) polysubstance use among people experiencing
homelessness across two cities (New York, NYC; San Francisco, SF). More than 100,000 overdose deaths
occurred in the US in the one-year period ending April 2021. Nearly half involved the co-use of opioids (primarily
fentanyl) and stimulants. People experiencing homelessness report higher prevalence of fentanyl-stimulant
polysubstance use and are more vulnerable to drug-related harms. Fentanyl-stimulant polysubstance use is a
likely contributor to widening racial disparities in overdose mortality, and yet relationships between fentanyl-
stimulant polysubstance use, drug-related harms, and racial health disparities are not well-understood. Similar
to cities in the US, NYC and SF are experiencing rising homelessness and overdoses, especially among Black
and Latinx populations. NYC and SF are implementing comprehensive overdose prevention and SUD treatment
responses, including naloxone and drug-checking programs, MOUD expansion, and, recently in NYC, overdose
prevention centers. Gender differences in engagement with these prevention and treatment services are
understudied. Homelessness crises in both cities have catalyzed novel housing interventions. Yet, we lack the
knowledge about relationships between polysubstance use and housing trajectories, drug-related harms, and
engagement with overdose prevention and SUD treatment services that is needed to inform more effective
responses to the overdose epidemic. Building on our extensive experience studying drug use patterns and their
implications for drug-related harm, we propose the following specific aims: SA1: To characterize fentanyl-
stimulant polysubstance use patterns among people experiencing homelessness and examine how these
patterns evolve over time due to changes to housing status and engagement with overdose prevention and SUD
treatment interventions. SA2: To explore how fentanyl-stimulant polysubstance use patterns shape overdose
vulnerability over time among people experiencing homelessness. SA3: To implement an integrated stakeholder
engagement process to translate qualitative findings to inform overdose prevention, SUD treatment, and
housing strategies and future research targeting fentanyl-stimulant use. Informed by the equity-focused
Intersectional Risk Environment framework, we will: (1) conduct baseline and annual follow-up qualitative
interviews and ethnographic fieldwork (Years 1-4) with a cohort of fentanyl-stimulant-using people experiencing
homelessness (n=120) sampled for racial and gender diversity (SA1&2); (2) conduct targeted qualitative
interviews on emergent fentanyl-stimulant polysubstance use dynamics (Years 3&4); and (3) in collaboration
with our Stakeholder Engagement Board, recruit a stakeholders cohort (n=50; people with lived experience,
substance use and ho...

## Key facts

- **NIH application ID:** 10590218
- **Project number:** 1R01DA057672-01
- **Recipient organization:** YALE UNIVERSITY
- **Principal Investigator:** Kelly Ray Knight
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $2,499,566
- **Award type:** 1
- **Project period:** 2022-09-30 → 2026-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10590218

## Citation

> US National Institutes of Health, RePORTER application 10590218, A Longitudinal Qualitative Study of Fentanyl-Stimulant Polysubstance Use Among People Experiencing Homelessness (1R01DA057672-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10590218. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*