Comparing characteristics of suicide to non-suicide drug poisoning deaths, by sex, in Ireland

Background: Suicide by drug poisoning is potentially preventable; however, evidence on associated risk factors by sex is limited.

Aim: To assist in understanding how individual and social contextual factors, and specific drugs, influence risk of suicide compared to non-suicide drug poisoning deaths, and how this differs by sex.

Methods: Data were extracted from the National Drug-Related Deaths Index. Analysis included univariable and multivariable logistic regression to estimate unadjusted and adjusted odds ratios (OR) and 95% confidence intervals (CI) for factors associated with suicide drug poisoning deaths (SDPD) (primary outcome) compared with non-suicide drug poisoning deaths (NSDPD) and stratified by sex.

Results: SDPD accounted for 240 (22%) of 1114 poisoning deaths, the majority among men (n = 147, 61%). Increasing age, mental ill health (AOR 7.85, 95% CI: 5.46-11.28), chronic pain (AOR 5.57, 95% CI: 3.28-9.46), and history of previous overdose (AOR 5.06, 95% CI: 3.39-7.56) were associated with increased odds of SDPD, with similar results for both sexes. The main drugs associated with SDPD were non-opioid analgesics (OR 4.06 [95% CI 2.66-6.18]), antipsychotics (OR 2.42 [95% CI 1.63-3.60]) and antidepressants (OR 2.18 [95% CI 1.59-2.97]). Pregabalin was associated with SDPD among women only.

Limitations: Secondary analysis of coronial data on drug poisoning deaths therefore findings may not be relevant to suicide deaths in general.

Conclusions: Ongoing monitoring for signs of suicidal intent in individuals with mental illness, chronic pain, overdose, and/or prescribed mental health medications may identify individuals in need of additional intervention.