Risk of self-harm and suicide associated with the use of opioid analgesics.

Abstract

Research suggests that there may be an association between prescribed opioid use and suicide-related behaviours. This 15-year retrospective population-based cohort study examines the relationship between opioid use, self-harm and suicide. The study was based on the POPPY II study, a population-based cohort of 3 268 282 adults who initiated a prescription opioid between 1 July 2003 and 31 December 2018, in Australia. Prescription dispensing data were linked to hospitalisation, death and other data collections. Opioid use was defined as current opioid exposure, cumulative duration of exposure and estimated daily dose. Outcomes were self-harm hospitalisation and suicide mortality, categorised as overall and according to the method (opioid poisoning, non-opioid substance poisoning and other methods). Time-varying generalised estimating equations were used to assess the relationship with self-harm hospitalisation, and Cox proportional hazard models were used to assess the relationship with suicide mortality, controlling for known suicide-related risk factors. There were 49 215 self-harm hospitalisations at a crude rate of 262 per 100 000 person-years and 3087 suicide deaths at a crude rate of 16.5 per 100 000 person-years. Intentional opioid poisoning was the least common method for both self-harm hospitalisation and suicide. Following multivariable adjustment, current opioid exposure, longer cumulative duration and higher doses were significantly associated with a greater risk of opioid-related self-harm or suicide. In adjusted models, associations for other methods of self-harm and suicide were not as strong or consistent. Opioid poisoning was the least common method of self-harm and suicide. Despite this, for the minority of people prescribed high doses and/or a long duration of prescription opioids, there is an increased risk for opioid-related self-harm and suicide after controlling for known covariates. Suicide-related behaviours should be screened and monitored in people prescribed opioids, particularly among those on long-term and/or high-dose opioids.