The aim of this study was to examine changes in the distribution of causes of death and mortality rates among psychiatric patients visiting a psychiatric emergency room (PER), to determine clinically useful predictors for avoiding premature mortality among these patients and to discuss possible interventions.

The study was designed as a historical prospective record linkage study of patients with at least one visit to a Danish PER in 1995–2007. Five consecutive 3-year cohorts of individuals aged 20 to <80 years were identified. Data from the Danish Civil Registration System were linked to the Cause of Death Register and the Central Psychiatric Research Register, and logistic predictor analyses for premature death were performed.

The standardised mortality ratio (SMR) of all visitors compared to the general Danish population was approximately 5. Overall, patients with drug and/or alcohol use disorder experienced at least a twofold increase in SMR compared to patients without substance use disorder. In the case of patients with schizophrenia and a concurrent substance use disorder, the SMR increased considerably. During the period, substance use disorder was the strongest predictor of premature death among visitors to a PER (odds ratio (OR) = 1.8; 95% confidence interval (CI) = 1.5, 2.2).

Persons visiting the PER had an increased SMR and substance use disorders were the strongest predictor of premature death within 3 years. However, death caused by substance use disorder is preventable, and PERs are ideal points of early intervention. Systematic screening for substance use disorder at the PER and/or crisis intervention teams may be effective intervention strategies.