Objective This study describes the profile of people with mental disorders attending emergency departments (EDs) in two countries and to identify specific mental disorders associated with repeat emergency visits.

Methods Retrospective analyses of 1 year of EDs data from two hospitals with psychiatric departments, one in Amadora/Sintra (Lisbon, Portugal, 2008) and the other in Malaga (Spain, 2009), were carried out. To determine which mental disorders were associated with repeat visits in each setting, negative binomial models were calculated.

Results There were 5141 visits for a mental disorder made by 3667 patients. Patients with affective disorder were the most frequent (32.2%). Among all mental health patients, 19.9% had at least one repeat visit during the year. For the two EDs setting combined, patients with personality disorders (incidence rate ratio (IRR)=3.79, 95% CI: 2.39 to 6.02) and psychotic disorders (IRR=1.46, 95% CI: 1.13 to 1.89) were more likely to have repeat visits compared with patients with affective disorders, whereas mental disorders due to psychoactive substance use (IRR=0.52, 95% CI: 0.37 to 0.73) was associated with lower likelihood of repeat visits. Nearly all significant differences were attributable to the Malaga sample, where patients with personality disorders were four times more likely to have repeat EDs visits compared with patients with affective disorders. However, at both sites, patients with mental disorders due to psychoactive substance use were less likely to have repeat visits.

Conclusions Certain mental disorders may be predictive of more frequent ED visits. The different results for each country suggest that further studies might focus not only on the characteristics of patients, but also on local healthcare organisation.