People who received specialist Alcohol and Other Drug Treatment Services in their last year of life

Alcohol and other drug (AOD) use is associated with a higher risk of dying (by any cause) and premature death compared with the general population (Abdul-Rahman et al. 2018; Havard et al. 2023).

Among clients of Alcohol and Other Drug Treatment Services (AODTS), studies have found an increased risk of dying following treatment (Lloyd et al. 2017; Havard et al. 2023). Increased risk of death following the end of an AOD treatment service (specialist or otherwise) may be due to a reduction in drug tolerance following a period of abstinence and returning to pre-treatment drug use habits, underlying health problems or insufficient post-treatment support (Lloyd et al. 2017; Havard et al. 2023; Ledberg & Reitan 2022).

The National Framework for Alcohol, Tobacco and other Drug Treatment notes that the AOD treatment service should be a ‘learning system’ of reflective practice and ongoing interrogation of data to identify areas for improvements (Australian Government 2019). As mainstream health services do not capture all people with substance dependence, the following analysis of deaths among clients accessing specialist AODTS can improve our understanding of those with substance dependence, highlight areas for further research, and inform targeted prevention activities.

Specialist Alcohol and Other Drug Treatment Services and clients in Australia

Publicly funded specialist Alcohol and Other Drug Treatment Services (AODTS) provide clinical care and support to people receiving treatment for their own drug use, as well as for their family and friends. Entry to a specialist AODTS involves an initial formal assessment by an alcohol and drug clinician. Services are available in all states and territories in Australia and across several setting types including residential, non-residential, outreach and home-based settings (Department of Health and Aged Care 2019). Treatment services can include detoxification, rehabilitation, counselling and pharmacotherapy. Since 2014–15, counselling has been the most common treatment type provided to AODTS clients (AIHW 2025a).

In 2023–24 more than half of all specialist AODTS clients were male (60%) and the median age of all clients was 36 years. Of all treatment episodes provided to clients who received treatment for their own AOD use, alcohol was the most common principal drug of concern (PDOC) reported, followed by amphetamines, cannabis, and heroin. Of the clients who entered treatment for their own AOD use (93%), around 1 in 5 (22%) ended treatment due to an unplanned event (the technical term is ‘unplanned completion’) in 2023–24 (for example, due to the client ceasing treatment without notice; see the Alcohol and other drug treatment services in Australia annual report 'Key terminology and glossary'). More than half of all clients who received treatment in 2023–24 (56%) had previously received an AOD treatment from a specialist service at some point since 2013–14 (AIHW 2025b).

People receiving specialist Alcohol and Other Drug Treatment Services who died

Over the study period, around 15,400 people received publicly funded, specialist Alcohol and Other Drug Treatment Services (AODTS) in their last year of life, for their own (99%) or somebody else’s drug use (1%) – around 11,000 male clients and around 4,400 female clients (Figure 1 and Table S1).

In each year of the 11-year study period, the death rate of people who received AODTS in their last year of life was higher than people who didn’t receive any AODTS.

In 2022–23:

• the age-standardised mortality rate of AODTS clients was 3.3 times higher than the non-AODTS population (Figure 1 and Table S1).
• The age-standardised mortality rate among male clients who received AODTS in their last year of life was 3.6 times higher than males with no AODTS – 2,348 per 100,000 clients compared with 655 per 100,000 people.
• The age-standardised mortality rate among female clients who received AODTS in their last year of life was 2.9 times higher than females with no AODTS – 1,435 per 100,000 clients compared with 503 per 100,000 people.

The mortality rate of males receiving AODTS in their last year of life was consistently higher than females. The age-standardised mortality rate for males was between 1.5 and 2.1 times higher than the rate for females in each year. In general, the rate of death for both males and females who received AODTS in their last year of life increased across the study period, with some variability year-to-year.

Age at death

Age at death – Specialist AODTS clients

Over the study period, among the nearly 15,400 people who received AODTS in their last year of life:

• Around 1 in 9 deaths (11% or around 1,600) were people aged 10–29 years.
• Almost 1 in 2 deaths (44% or around 6,700) were people aged 30–49 years. 
• More than 1 in 3 deaths (37% or around 5,800) were people aged 50–69 years.

Over the study period age at death profiles were similar among males and females who received AODTS in their last year of life with nearly half aged 30–49 years at death – 43% of males and 44% of females (Figure 2 and Table S2). The age profile of people who died and received AODTS in the last year of life in part reflects the age profile of people receiving specialist AODTS, that is, AODTS clients tend to be younger than the general Australian population (AIHW 2025a).

The age at death profile of AODTS clients who received treatment in their last year of life shifted towards older age groups across the years from 2013–14 to 2022–23. 

Among clients who received AODTS support in their last year of life across all age groups and in all years, male clients consistently had higher death rates than females.

In all age groups, people who received AODTS treatment in their last year of life had higher mortality rates compared with the non-AODTS population of the same age, except those in the older age groups (50–69 and 70 and above at death). This pattern was the same for both males and females (Figure 2 and Table S2).

Specialist AODTS clients among all deaths in Australia

Over the study period, people who received AODTS in their last year of life accounted for:

• around 1 in 13 (7.9%) of all males aged 10–29 at death
• around 1 in 11 (9.5%) of all males aged 30–49 at death
• around 1 in 15 (6.6%) of all females aged 30–49 at death.

Each year between 2013–14 and 2022–23, 6.6–9.6% of all deaths in Australia among both the 10–29 and 30–49 age groups were people who received AODTS in their last year of life. 

The median age at death for both male and female AODTS clients across the study period (1 July 2012 to 30 June 2023) was 48 years and 49 years, respectively. This is 32 years and 36 years lower than the median age at death for non-AODTS males and females – 80 years for males and 85 years for females (Figure 2 and Table S2). 

Underlying cause of death

Between 1 July 2012 and 30 June 2023, Injury and poisoning was the most common broad cause of death among people who received specialist AODTS treatment in their last year of life (44%) (Table S4).

For more information see Technical notes – classifying causes of death.

Underlying causes of death among people receiving Specialist Alcohol and Other Drug Treatment Services

Among clients who received specialist AODTS in their last year of life:

• Accidental poisoning (20%) was the most common underlying cause of death over the study period (1 July 2012 to 30 June 2023) followed by suicide (15%) and liver disease (15%).

  • These underlying causes of death consistently remained the top 3 in each year between 2012–13 to 2022–2023 (albeit with differing rankings between years).

• Among male clients, accidental poisoning (20%), suicide (16%) and liver disease (13%) were also the most common underlying causes of death over the study period.

  • Accidental poisoning was the top ranked underlying cause of death most years between 2012–13 to 2022–23 for males, with suicide replacing accidental poisoning in 3 of the 11 years (2012–13, 2020–21 and 2022–23).

• Among female clients, accidental poisoning was the most common underlying cause of death followed by liver disease and then suicide (19%, 18%, 13%, respectively) over the study period.

  • Accidental poisoning was the top ranked underlying cause of death each year between 2012–13 to 2022–23 for females, except in 2014–15 and between 2020–21 to 2022–23, when liver disease became the top ranked underlying cause.

• The most common underlying cause of death among the older, non-AODTS population over the study period was coronary heart disease (12%), followed by dementia (including Alzheimer’s disease) (8.8%) and cerebrovascular disease (6.4%) (Figure 3 and Table S3).

Specialist Alcohol and Other Drug Treatment Services clients among all deaths in Australia, by underlying cause

As a proportion of all deaths in Australia by underlying cause where age at death was 10 years or older, over the study period, people who received AODTS in their last year of life accounted for:

• around 1 in every 5 deaths due to accidental poisoning (20%)
• around 1 in every 7 deaths due to mental and behavioural disorders due to psychoactive substance use (14%)
• around 1 in every 10 deaths due to liver disease (10%)
• around 1 in every 14 deaths due to suicide (7%).

Male AODTS clients accounted for 21% of all males in Australia who died by accidental poisoning, 14% who died by mental and behavioural disorders due to psychoactive substance use deaths, and 12% of all males who died by assault. Female AODTS clients accounted for 18% of all females in Australia who died by accidental poisoning, 14% by mental and behavioural disorders due to psychoactive substance use, and 10% by liver disease (Figure S3 and Table S3).

Principal drug of concern

A principal drug of concern (PDOC) refers to the main substance which an AODTS client stated led them to receive treatment (AIHW 2025b). A person may have multiple treatment episodes over their lifetime and may receive treatment for different PDOCs in each treatment episode. For example, a person may receive treatment for alcohol use in one treatment episode, followed by another treatment episode for heroin use. Some people may receive treatment for the same PDOC each time they receive treatment (that is, each episode). These episodes could occur in the same year, or in different years. This means for certain results below of clients treated for two different PDOCs, some clients will be counted more than once. For example, a client treated for Alcohol and Heroin will be included in results for 'Alcohol and another drug' and 'Heroin and another drug'. See the AODTS NMDS Annual Reporting Technical notes for more information on how drugs of concern are classified.

While other information presented on clients who received AODTS in their last year of life is taken from the treatment episode prior to their death, the information presented below on PDOC, includes all treatment episodes the client received over the study period. That is, it presents a combination of all PDOCs a person has received treatment for, at any point between 1 July 2012 and 30 June 2023. This is because some drug use and drug combinations may indicate a greater rate of death. To only include the PDOC a client received in their last treatment episode prior to death would mask any differences the combination of PDOCs may have on a person’s outcomes. Due to the nature of this study, the service and PDOC history will not be as complete for those clients who died earlier in the reporting period, as those clients who died later in the reporting period. Similarly, the analysis here only presents a client’s PDOC history over the entire study period, which may mask changes over time for specific PDOC combinations. Detailed information on the approach used to derive PDOC combinations is provided in the footnotes of Figure 4 and Supplementary tables S5 and S6.

This section also only includes people who have had at least one treatment episode for their own drug use over the study period (that is, it also includes the small proportion of clients who have received treatment for both their own and someone else’s drug use). People who only received treatment for someone else’s use in the study period are not included in the analyses below.

Over the study period, the majority of people who received AODTS in their last year of life received treatment for their own substance use – 99% or just over 15,200 of the 15,400 who received AODTS in their last year of life.

Over the study period among just over 15,200 people who received AODTS for their own AOD use and who died within 12 months of their last treatment:

• almost 1 in 2 deaths were people treated for alcohol only throughout their treatment history (49% or about 7,400 people).
• Around 1 in 10 deaths were people treated for alcohol and another drug (9.7% or almost 1,500 people).
• Around 1 in 13 deaths were people treated for 3 or more PDOCs (7.8% or about 1,200 people).

Among males who died and received AODTS in their last year of life, those treated for alcohol only throughout their treatment history accounted for the largest proportion of deaths (48%), followed by alcohol and another drug (10%), and 3 or more PDOCs (8.3%).

The profile for females was different to males. While alcohol only accounted for 51% of deaths, this was followed by alcohol and another drug (9.0%) and pharmaceuticals only (8.4%) (Figure 4 and Table S5).

People who received AODTS in their last year of life among all AODTS clients, by PDOC

Of all people who received specialist AODTS over the study period for their own AOD use (nearly 790,000 clients), most people had a history of only receiving treatment for alcohol (31% or nearly 250,000 people), followed by cannabis only (23% or around 180,000), and meth/amphetamines only (14% or around 110,000). However, as a proportion of all clients treated for a particular PDOC(s) over the study period, people whose treatment history included either heroin or pharmaceuticals (with, or without another drug) experienced higher mortality rates.

Among all people who received specialist AODTS for their own drug use over the study period, people who died and received treatment in their last year of life accounted for:

• around 1 in 20 (4.9%) of all clients who were treated for heroin and another drug throughout their treatment history
• around 1 in 22 of all clients treated for pharmaceuticals and another drug (4.6%)
• around 1 in 26 of all clients treated for either pharmaceuticals only (3.8%) or heroin only (3.8%).

This PDOC treatment history pattern was the same among male clients – around 1 in 19 of all males with a treatment history of heroin and another drug (5.3%), followed by pharmaceuticals and another drug (4.8%), pharmaceuticals only (4.4%), heroin only (4.1%) and 3 or more PDOCs (3.6%). For female clients, those with a treatment history of pharmaceuticals and another drug and heroin and another drug accounted for the highest proportion of deaths (both 4.1%), followed by heroin only (3.5%), and pharmaceuticals only (3.2%).

Despite a treatment history for cannabis only being the second largest group of clients in the study period (around 180,000 clients), it accounted for the lowest proportion of people receiving AODTS in their last year of life (0.4%) (Figure 4 and Table S5).

Underlying cause of death, by PDOC

Over the study period, among all PDOC combinations that people received AODTS for the most common underlying causes of death were either accidental poisoning or suicide, except where there was a treatment history of alcohol only. Liver disease was the most common underlying cause of death for these clients.

The highest rates of accidental poisoning were for AODTS clients who had a PDOC treatment history for:

• heroin and another drug (50% or around 320 deaths), followed by
• 3 or more PDOCs (45% or around 540 deaths), and
• heroin only (43% or around 300 deaths) (Table S6).

The highest rates of suicide were for AODTS clients who had a treatment history for:

• Meth/amphetamines only or cannabis only (both 31%, or around 300 and 230 deaths, respectively) (Table S6).

For people who only received treatment for alcohol over the study period and who received treatment in their last year of life, accidental poisoning and suicide were still in the top 3 most common leading causes of death. However, the most common leading cause of death for this group was liver disease:

• 25% (around 1,900 deaths) where liver disease was their leading cause of death
• 11% (around 840 deaths) where suicide was the leading cause of death
• 9.0% (around 670 deaths) where accidental poisoning was their leading cause of death (Table S6).

Future work

This descriptive study is the third in a series of articles examining health and specialist homelessness service or AODTS use prior to death, with a specific focus on people with drug and/or alcohol issues, housing insecurity, and risk factors associated with specific causes of death, particularly suicide, and acute and chronic AOD use. It is the first in a series of analysis of mortality outcomes examining specialist Alcohol and Other Drug Treatment service use prior to death.

Future analysis of AODTS clients may include:

• analysis of time between treatment and death, including demographic and service use risk factors associated with all-cause mortality
• specialist AODTS service use prior to death by suicide.

Future research will expand to include other AIHW-funded NACS analysis including those focused on people who also received specialist homelessness services, as well as analysis of mortality outcomes examining a broader range of risk factors and patterns of health service use.