Feasibility of using ecological momentary assessment to examine high-risk drug practices among people who inject drugs.

Objective People who inject drugs (PWID) experience elevated risk for HIV, overdose, and other health harms, yet most research on associated high-risk drug practices has relied on retrospective assessment. This study examined the feasibility and practicality of using ecological momentary assessment (EMA) to assess risk practices among PWID.Method PWID who had injected drugs at least twice in the past week were recruited through street outreach in Honolulu, Hawaii (United States) from June 2022 to April 2024 and completed a 60-min baseline assessment and 14-day smartphone-based self-reported signal-contingent EMA. Risk practices (e.g., syringe reuse) were assessed using items derived from the literature.Results Participants (N = 68) were White (48.6%), Native Hawaiian or Pacific Islander (22.9%), and Asian (20%), and 20% were female. Mean age was 46.5 years (SD = 9.8), and 69.1% (n = 47) were unhoused. Fourteen participants (20.6%) did not respond to any EMA prompts, including seven who had no record of prompts being delivered to their phone's app. Of participants who responded to any EMA (n = 54), 51.9% completed at least one EMA prompt on each study day. On average, participants provided EMA data for 8.6 of the 14 study days (Mdn = 10, SD = 4.9). Variability analyses of individual risk practices suggested meaningful variability both between and within participants across EMA occasions.Conclusions EMA is feasible among PWID, though engagement challenges remain. To allow for improved EMA engagement in vulnerable populations, protocol refinements (e.g., simplified prompts, distribution of portable phone chargers) are necessary. Overall, findings illustrate the utility of EMA for characterizing real-world patterns of risk. (PsycInfo Database Record (c) 2026 APA, all rights reserved).