In Ireland, data on dual diagnosis (DD) is limited. This study aims to describe the characteristics of deaths among people who both used drugs and had a mental health (MH) condition to better understand DD and to help improve the provision of DD services in Ireland.

Data from the National Drug-Related Deaths Index (NDRDI) was used to identify deaths among people who used drugs and had history of at least one MH condition. Sociodemographic characteristics, risk factors, substance use, MH conditions, and type and cause of death, stratified by sex, were analysed descriptively. Variance by MH condition was examined using cross tabulation.

Between 2019 and 2021, 567 deaths met the inclusion criteria. The majority (67.9%) were men. The mean age was 42 years. The most common drugs used were cocaine (47.6%), heroin (37.4%) and cannabis (36.3%). The most common MH conditions were depressive disorders (52.7%), anxiety disorders (36.7%) and specific personality disorders (16.6%). Misadventure (46.6%) and suicide (27.2%) were the most frequent verdicts recorded. Almost equal proportions of deaths were poisonings (48.9%) and non-poisonings (51.1%). Most poisoning deaths involved an opioid-type drug and/or polysubstances (83.8%).

The NDRDI data enables in-depth description of those who died with DD in Ireland. While it does not provide comparisons with those who survived, given the limited amount of research in this area in Ireland, the data contributes valuable insights into the issue.