Association of loneliness and substance use among emergency department patients

Loneliness is associated with numerous adverse health outcomes. However, little is known about its relationship with substance use among emergency department (ED) patients, a population at elevated risk for substance use and related harms. We examined associations between loneliness and past 90-day substance use among ED patients.

A convenience sample of patients aged 18-75 years was recruited from an urban academic ED between March 2025 and January 2026 (N = 300). Loneliness was assessed using the UCLA Loneliness Scale (UCLA-20; range = 20 to 80). The Tobacco, Alcohol, Prescription Medication, and Other Substance Use (TAPS) tool assessed binge alcohol use, cannabis use, and illicit drug use, including crack/cocaine, sedatives/hypnotics, opioids, and polydrug use. Multivariable logistic regression models examined associations between loneliness and substance use outcomes, adjusting for demographic characteristics, cigarette use and anxiety and depression symptoms.

Each one-point increase in loneliness was associated with greater odds of illicit drug use (adjusted odds ratio [aOR] = 1.07, 95% confidence interval [CI]:1.03-1.11), including use of opioids (aOR = 1.10, 95% CI:1.03-1.19), crack/cocaine (aOR = 1.06, 95% CI:1.01-1.13), and polydrug use (aOR = 1.04, 95% CI:1.01-1.08).

Loneliness was independently associated with recent illicit drug use. These findings suggest that loneliness may be an important and underrecognized correlate of high-risk substance use in ED populations. Incorporating loneliness assessment into ED screening workflows may help identify patients at elevated risk for substance-related harms and inform interventions aimed at improving engagement with substance use treatment and supportive services.