Shared characteristics among those who co-ingest cocaine and alcohol prior to death by suicide: An examination of trends within the National Programme on Substance Use Mortality data

Background Whilst substance dependence is well-documented as a risk factor for suicide, less is understood about individuals who die by suicide following recreational polydrug use. Cocaethylene, a psychoactive metabolite produced by the co-ingestion of alcohol and cocaine, may be a cumulative risk factor for suicidality. This study examines the sociocultural, psychiatric and toxicological complexity of individuals whose deaths by suicide involved both alcohol and cocaine use. Methods Data were sourced from the National Programme on Substance Use Mortality (2007–2023), including coronial reports for 147 individuals where both cocaine and alcohol were present at post-mortem. Descriptive analyses examined sociodemographics, psychiatric diagnoses, prescribed medications, substance use, and method of suicide. Results The cohort was predominantly male (72.4%), aged 25–45, and overrepresented in the most deprived socio-economic deciles. Psychiatric morbidity was high: over half had documented mental health conditions, and 32.6% were in receipt of psychotropic medication at the time of death. Nearly one-third of medicated cases showed markers of pharmacological complexity, including treatment-resistant prescriptions and high-risk polypharmacy. Hanging was the most frequent method of suicide (72.1%), consistent with national trends in suicide. Conclusion Individuals who die by suicide following the co-use of alcohol and cocaine appear to represent a highly vulnerable and clinically complex group. Cocaethylene may serve as a marker for heightened psychiatric and behavioural risk. These findings underscore the need for integrated, cross-sector care models and routine suicide risk screening in substance use settings. Structural deprivation, psychiatric complexity and impulsivity are prominent factors in this population.