Many mentally distressed individuals seek emergency department (ED) care in the US, but the extent and correlates of significant mental health problems in such patients is unknown.

All patients aged 18-60 presenting to an inner-city midwestern US ED April 2006-March 2007 were approached to participate in brief health screening. Exclusions were serious trauma preventing interview, unable to provide informed consent, pregnancy, acute suicidality, or presenting for psychiatric evaluation. Consenting patients completed a short web-tablet screen, including SF-12 for mental and physical health status, recent substance use and DSM-IV diagnoses of substance use disorders.

The lowest 25% on the SF-12 Mental Health Component were assigned to “poor mental health functioning” (PMHF). 5641 patients participated (58% female, 57% African-American). In bivariate analysis, the PMHF group was significantly more likely to be unmarried, female, use cocaine and marijuana, and binge drink in the past year, and have DSM-IV substance use disorders. Multiple logistic regression found that being female (OR=1.8), older (OR=1.01), not being married (OR=1.2) and DSM-IV alcohol abuse and dependence (OR=1.7, 2.4), cocaine abuse and dependence (OR=1.9, 2.0), and marijuana dependence (OR=1.7) were all independent predictors of PMHF. In a separate model, use of cocaine (OR=2.7) and marijuana (OR=1.7) but not use of alcohol, were independent predictors of PMHF as well as gender, age, and marital status.

Therefore PMHF in ED patients is strongly associated with recent substance use. ED clinicians should regularly ascertain both mental health status and substance use and refer for additional services where appropriate.