The majority of evidence came from primary research and the most common data sources included drug treatment databases, national death indexes, coronial and medical records. They identified 11 potential factors associated with death by suicide among people who use drugs: sex; mental health conditions; periods of heightened vulnerability; age profile; use of stimulants, cannabis, or new psychoactive substances; specific medical conditions; lack of dual diagnosis service provision; homelessness; incarceration; intravenous drug use; and race or ethnicity. 

Key findings include: 

  • Drug type: Opioids, followed by cannabis and stimulant drugs were the most prevalent drugs used by those who died by suicide, with violent methods of suicide more prevalent in cannabis and stimulant users. Polydrug use was linked to increased risk, especially among people who injected drugs. These findings suggest that it is important to consider risk factors and type of drug use, and to tailor policies and practices accordingly. 
  • Sex: While overall men were more likely than women to die by suicide if they had a drug use disorder, some studies showed a higher proportion of suicide among women who used drugs. Risk factors for women were mental health problems, high prevalence of opioid and other central nervous depressant drug use, and poor retention in treatment for drug use disorder. 
  • Mental health: The research revealed a high prevalence of mental health problems among people who used drugs and died by suicide, with depressive disorders the most common type of condition reported.

Commenting on the findings, Senior Researcher at the HRB and co-author of the paper Dr Ena Lynn said: “The role played by mental health issues is striking, with our research also highlighting the particular challenges faced by people with a dual diagnosis – the combined presence of a mental health problem and a substance use problem – which can be a barrier to accessing treatment. These findings underline the importance of the HSE’s new dual diagnosis model of care with a focus on integrated care pathways, as a potential way to decrease the risk of suicide in this group.”

Read the paper: ‘Factors associated with suicide in people who use drugs: a scoping review’