Q&A: Medicine restrictions for suicide prevention

My research is about identifying poisons that are the most common and/or lethal in the population and recommending them as priorities for means restriction. Means restriction refers to removing access to a suicide method, but even partial restrictions are effective, such as reducing the number of tablets sold in a standard medicine pack. A recent 2024 paper, Restriction of access to means used for suicide explains more about means reduction.

There is also good research throughout Australia focused on understanding the toxicology and risk factors related to suicide by specific drugs and substances of concern using data on drug and alcohol use collected by the National Coronial Information System. Research can also evaluate changes in intentional self-poisoning after legislative changes such as medicines being made prescription only instead of being available over-the-counter, or changes in medicine listings on the Pharmaceutical Benefit Scheme (PBS).

Our research team at the University of Sydney investigated around 14,000 suicides that occurred from 2013-2019 in the national Australian Suicide Prevention using Health Linked data (ASHLi) study. We used coroners’ toxicology reports to identify all substances and medicines present at the time of death, as well as data linkage of PBS and Medicare Benefits Schedule (MBS) records to understand what medicines and health services were accessed before death.

Our research, Substances Detected During Coroner Postmortem Toxicology, found that there are a few leading medicines of concern in suicide deaths in Australia, with combinations of medicines often detected together. Alcohol was very common in both poisoning and non-poisoning suicides.

Australia is similar to other high-income Western countries where poisoning suicides often involve psychotropic medicines for mental health, and drugs with a potential for misuse.

However, the majority of suicides worldwide occur in low-income countries, with pesticide poisoning being a significant cause of death of those suicides. Research shows that when the most toxic pesticides are banned or restricted, the population suicide rate decreases overall. This is because the highly toxic pesticides are less accessible during a crisis and there is a greater chance of recovering from poisoning from a less toxic pesticide.

We need more research and programs that understand and address the needs of populations with higher suicide rates - especially remote areas in Australia, in Aboriginal and Torres Strait Islander populations and those in lower socioeconomic groups.

The current surveillance of suicide by intentional poisoning in Australia is limited in ability to classify mixed drug toxicity and drug combinations as a cause of death. Even if the main drug responsible for self-poisoning is identified, most suicides by self-poisoning will include a combination of medicines or substances that contribute to the cause of death. There is no ICD-10 code (International Classification of Diseases, Tenth Revision) to classify drug combinations, which is a system commonly used by hospitals and government reports. There should be more focus on identifying medicines as part of means restrictions especially when new technology like real-time prescription monitoring provides good opportunities for healthcare professionals to intervene.