Aims: To estimate both self-reported and corrected prevalences of substance use in a population-based study of general hospital emergency department (ED) patients and predict undeclared use.
Design: A state-wide cross-sectional, two-stage probability sample survey that incorporates toxicological screening.
Setting: Seven Tennessee EDs in acute care, adult, civilian, non-psychiatric hospitals.
Participants: A total of 1502 Tennessee residents, 18 years of age and older, possessing intact cognition, able to give informed consent and not in police custody. Measurements Prevalence of self-reported current substance use by age, sex and type with correction for under-reporting based on toxicological screening. Covariates in the multivariate analysis of undeclared use were socio-demographics, ED visit circumstances, health-care coverage, prior health status and treatment history and tobacco addiction.
Findings: Declared current use was highest for alcohol (females 26%, males 47%), marijuana (males 11%, females 6%) and benzodiazepines (females 10%, males 7%). After correction for under-reporting, overall use for any of the eight targeted substances rose from 44% to 56% for females and 61% to 69% for males. Largest absolute changes involved opioids, benzodiazepines, marijuana, amphetamines and/or methamphetamine, with little change for alcohol. Patients aged 65 years and older manifested excess undeclared use relative to patients aged 18-24 years, as did patients not reporting tobacco addiction or receiving substance abuse treatment.
Conclusion: Adjustment for under-reporting produced minimal change in the estimated prevalence of alcohol use. However, toxicological screening markedly increased estimates of other drug use, especially for the elderly, who may under-report medication use. Screening tests are useful tools for detecting undeclared substance use.