Technical notes
Alcohol and Other Drug Treatment Services National Minimum Data Set
The Alcohol and Other Drug Treatment National Minimum Data Set (AODTS NMDS) collection covers publicly funded alcohol and other drug (AOD) treatment services but does not capture all treatment episodes provided to clients in Australia. For example, the AODTS NMDS accounted for an estimated 10% of episodes and 20–30% of individual clients who received AOD treatment in Australia in 2013–14 (Ritter et al. 2014).
For the purposes of this report, a range of variables from the AODTS NMDS relating to the cohort receiving treatment for cannabis were examined. These variables have certain limitations and caveats, as outlined in Table 3.
Variable | Description | Analysis criteria |
|---|---|---|
Client type | The status of a person in terms of whether the treatment episode concerns their own drug use or that of another person. | Own drug use. Excludes clients receiving treatment for another person’s drug use. |
Client age | The age of the client, as described by them. | Calculated as age at commencement of first treatment episode within the study period (that is, the first time the client received treatment between 2013–14 and 2021–22). Excludes clients aged <10 years or >100 and records with missing age. |
Client sex | The sex of the client, as described by them. | Excludes ‘Another term’ and records with missing sex. |
Client postcode | The postal code of the client’s last known home address at the start of their treatment episode. | Calculated as postcode at commencement of first treatment episode within the study period (that is, the first time the client received treatment between 2013–14 and 2021–22). Excludes records with an invalid postcode. The postcode data item was first included in the AODTS NMDS for the 2013–14 collection period and has varied greatly in its quality. Postcode data may be of poor quality for certain clients, such as those with no fixed address. Postcodes were not developed for the purpose of geospatial analysis but can be converted to various ASGS ABS and non-ABS structures to produce overall fit for purpose geography. |
Client remoteness area | The remoteness area of the client’s last known address. | Calculated as remoteness area at commencement of first treatment episode within the study period. Remoteness areas were computed by converting client postcodes to the Australian Statistical Geography Standard (ASGS) Remoteness Structure 2021, using the ABS’s Postcode 2022 to Remoteness Area 2021 correspondence file. This correspondence is listed as a ‘good’ conversion, indicating that it is expected to convert data to a high degree of accuracy and that the converted data will reflect the actual characteristics of the geographic areas involved. |
Principal drug of concern | The main substance that the client stated led them to seek treatment. | Coded using the Australian Standard Classification of Drugs of Concern (ASCDC) 2011. For this report, cannabis includes codes 7000–7999. |
Episode main treatment type | The principal activity that is determined at assessment by the treatment provider to treat the client’s alcohol or other drug use for the principal drug of concern. | No exclusions. |
Episode reason for cessation | The reason the client ceased to receive a treatment episode. | Excludes records with missing or invalid reason for cessation. This variable has several limitations; see AODTS NMDS coverage and data quality for more information. |
Episode referral source | The source from which the client was transferred or referred to the treatment service, including diversion. | No exclusions. |
For more information on scope, coverage and data quality, see the AODTS NMDS Data Quality Statement and the AIHW’s Metadata Online Registry (METEOR). For more information on episode and client counts, see Key terminology and glossary.
Australian Secondary Students’ Alcohol and Drug survey
The Australian Secondary Students’ Alcohol and Drug (ASSAD) survey is the largest national survey of alcohol and other drug use among Australian adolescents, aged 12–17. It is conducted every three years and has been running since 1984. The survey includes questions about secondary school students’ use of tobacco, e-cigarettes, alcohol, over-the-counter drugs (used for non-medical reasons) and other drugs (including cannabis). The ASSAD survey is administered without the involvement of parents on school premises. This methodology has been shown to result in higher, and potentially more valid, estimates of health risk behaviours such as drug use, as compared with surveys administered in the home (Brener et al. 2006).
The 2022–2023 iteration of the survey was conducted between March 2022 and July 2023 via an online self-report questionnaire. The data represent 10,314 eligible responses from students in Years 7 to 12 from 83 schools across Australia, with a school response rate of 6%.
For more information, see the full ASSAD report.
Drug Use Monitoring in Australia program
The Drug Use Monitoring in Australia (DUMA) program is an illicit drug monitoring program that contains information on police detainees across 5 locations throughout Australia annually. The DUMA program has two core components:
- A self-report survey of police detainees, including a range of criminal justice, demographic, drug use, drug market participation and offending information.
- Urinalysis, in which participants can choose to provide a urine sample that is tested at an independent laboratory to detect the presence of legal and illegal drugs. Urinalysis provides an objective method to corroborate self-reported drug use. Not all survey participants agree to provide a urine sample when requested, although the compliance rate is high (75% in 2021) (AIC 2022).
Ecstasy and Related Drugs Reporting System
The Ecstasy and Related Drugs Reporting System (EDRS) is a national monitoring system for ecstasy and related drug use, markets and harms in Australia. The EDRS comprises information from interviews with people who regularly use ecstasy and related drugs, and other routinely collected indicator data. The EDRS includes information on the use, price, purity and availability of ‘party’ drugs including ecstasy, methamphetamine, cocaine, LSD, ketamine, new psychoactive substances, and GHB. EDRS interviews have been conducted annually across all Australian capital cities since 2003. The EDRS is not representative of drug use and harms among all groups of people who use drugs.
The 2023 EDRS surveys were conducted between April and July 2023, either face-to-face or via phone or videoconference. The data represent 708 participants in 2023, reflecting predetermined sample size quotas. All interviews conducted prior to 2020 were face-to-face, and this change in methodology should be considered when comparing data across years. Prior to 2020, eligible participants were aged 17 and over (or 16 and over for Perth). In 2020, eligibility criteria were amended to include people aged 18 and over.
For more information, see the Ecstasy and Related Drugs Reporting System project site.
Illicit Drug Data Report
The Illicit Drug Data Report (IDDR) brings together data from a variety of sources to provide an overview of illegal drug markets in Australia. Data are provided annually by law enforcement agencies, forensic services, health departments and academic institutions, including information on arrests, detections, seizures, purity, and price.
For more information, see the Illicit Drug Data Report.
Illicit Drug Reporting System
The Illicit Drug Reporting System (IDRS) is a national monitoring system that aims to identify emerging trends in illegal drug markets in Australia. The IDRS comprises information from interviews with people who regularly inject illegal drugs and other routinely collected indicator data. The IDRS includes information on the use, price, purity and availability of heroin, methamphetamine, cocaine, cannabis, and other illegal drugs. IDRS interviews have been conducted annually across all Australian capital cities since 2000. The IDRS is not representative of drug use and harms among all groups of people
The 2023 IDRS surveys were conducted between June and July 2023, either face-to-face or via phone or videoconference. The data represent 820 participants in 2023, reflecting predetermined sample size quotas. All interviews conducted prior to 2020 were face-to-face, and this change in methodology should be considered when comparing data across years. Prior to 2020, eligible participants were aged 17 and over (or 16 and over for Perth). In 2020, eligibility criteria were amended to include people aged 18 and over.
For more information, see the Illicit Drug Reporting System project site.
National Drug Strategy Household Survey
The National Drug Strategy Household Survey (NDSHS) collects information on consumption of and attitudes towards alcohol, tobacco, and other drugs among people aged 14 and over from all states and territories in Australia. The survey has been conducted every 2 to 3 years since 1985, with the 2022–2023 NDSHS survey being the 14th survey in the series.
The 2022–2023 NDSHS fieldwork was conducted in two stages (20 July to 18 December 2022 and 20 March to 31 May 2023) across all states and territories in Australia. Participants could complete the survey via a paper form, an online form, or a telephone interview. The data represent 21,663 eligible responses.
Medical use and recent use of cannabis
In the NDSHS, marijuana/cannabis is not considered a pharmaceutical and is not grouped with non‑medical use of other drugs such as opioids and steroids. Two new questions were included regarding medical use of cannabis in 2019:
- Have you used Marijuana/Cannabis for medical purposes in the last 12 months?
- Was the medical Marijuana/Cannabis prescribed by a doctor?
People that reported only using marijuana/cannabis for medical purposes in the previous 12 months, and only using it when it was prescribed by a doctor, are not included in recent use results. They are included in lifetime use results, as the questions regarding medical use of cannabis only refer to the previous 12 months. All other respondents that indicated using marijuana/cannabis for any reason in the previous 12 months are included in recent use results.
Key quality issues to consider for the 2022–2023 collection include:
- Reported findings are based on self-reported data and are not empirically verified by blood tests or other screening measures.
- It is known from past studies of alcohol and tobacco consumption that respondents tend to underestimate actual consumption levels. Estimates of illicit drug use and related behaviours are also likely to be underestimates of actual use.
- The exclusion of persons from non-private dwellings, institutional settings, homeless people, and the difficulty in reaching marginalised persons are likely to have affected estimates.
- The response rate for the 2022–2023 survey was 43.9%, lower than previous surveys. Given the nature of the topics in this survey, some non-response bias is expected, but this bias has not been measured.
- Both sampling and non-sampling errors should be considered when interpreting results.
- The 2022–2023 survey used a multi-mode completion methodology—respondents could choose to complete the survey via a paper form, an online form or via a telephone interview. This was the third time an online form has been used in the survey series. Changes in mode may have some impact on responses, and users should exercise some degree of caution when comparing data over time.
- 2022–2023 NDSHS results are disaggregated by the question ‘How do you describe your gender’ rather than the previous question ‘What is your sex’. In tables that disaggregate results by gender, results for 2019 and earlier years are disaggregated by the previous sex question. Caution is advised when considering timeseries comparisons.
- The time-series for methamphetamine and amphetamine was broken in 2022–2023, as the questions used in 2019 and earlier (meth/amphetamine) also included non-medical use of pharmaceutical amphetamines. Data collected in 2022–2023 are not considered comparable to previous years.
For more information, see the full 2022–2023 NDSHS Technical notes.
National Wastewater Drug Monitoring Program
The National Wastewater Drug Monitoring Program (NWDMP) measures the presence of substances in wastewater to create population-weighted average consumption estimates for legal and illegal drugs. Wastewater analysis involves collecting samples from wastewater treatment plants and analysing these for the presence of compounds or metabolites excreted following consumption of specific drugs. A back-calculation factor is applied to determine the amount of each substance used among the population over a given collection period.
The NWDMP has been operating since 2016, with cannabis included for the first time in August 2018. The main psychoactive compound in cannabis (tetrahydrocannabinol or THC) is metabolised and excreted as 11-nor-9-carboxy-tetrahydrocannabinol (THC-COOH). Separate samples are collected at wastewater treatment plants across Australia each day and preserved for THC-COOH analysis. Cannabis results are expressed as daily doses of THC per 1,000 people with a dose amount of 8 mg, representing 210–450mg of dried cannabis containing 15% THC (Sharma et al. 2012).
Wastewater analysis is non-invasive and, because it is carried out on a population-scale level, cannot identify individual people. It also has certain limitations. Firstly, results for a given collection period can be influenced by factors such as factors such as uncertainties in population estimates in an area over a 24-hour period and variation in excretion rates (that is, some people may metabolise a drug faster than others). Sewer design and collection methods may also influence the levels of THC-COOH detected in wastewater, and spatial comparisons should be made with caution. NWDMP data also cannot differentiate between medical and non-medical cannabis use.
Fifty-five wastewater treatment sites participated nationally in the April 2023 collection, covering 55% of the Australian population (approximately 14 million people). This included 20 sites located in capital cities and 35 in regional locations.
For more information, see the National Wastewater Drug Monitoring Program reports.
This section refers to the methodology used to describe the cohort of clients described in Cannabis treatment.
How cannabis clients and treatment episodes were counted
The SLK-581 variable was used to identify unique clients who had received at least one closed treatment episode for cannabis as the principal drug of concern (PDOC) between 2013–14 and 2021–22. Clients were excluded if they:
- Did not receive treatment for their own drug use.
- Did not have a valid SLK-581.
- Had not received at least one treatment episode for cannabis as the principal drug of concern between 1 July 2013 and 30 June 2022. Clients may have received treatment before 1 July 2013, and/or continued to receive treatment beyond 30 June 2022. Services accessed in these periods are outside the scope of this report. Data from 2012–13 was excluded from analysis due to data quality issues with SLK information for this year, which was a pilot year.
This report includes all treatment episodes provided to clients who ever received treatment for cannabis between 2013–14 and 2021–22. As this analysis focuses on the client, this includes those episodes where the client received treatment for a PDOC other than cannabis. For example, if a client received 4 treatment episodes and only one was for cannabis, all 4 episodes were included in the analysis even though 3 were not for cannabis. This differs from the annual AODTS NMDS reporting approach, where cannabis treatment episodes are counted as the number of episodes in which the principal drug of concern was listed as cannabis and the number of clients receiving treatment for cannabis is derived from their first treatment episode.
The total number of clients reported here is lower than the sum of clients in the AODTS NMDS annual report, which counts clients with a unique valid SLK only within each financial year rather than only once across the entire period (2013–14 to 2021–22), as done here. Conversely, the number of treatment episodes reported is higher than in annual AODTS NMDS reporting methodology, as it includes multiple treatment episodes for non-cannabis principal drugs of concern (for example, alcohol) that were provided to clients who also received treatment for cannabis as the PDOC.
Cannabis clients referred via drug diversion programs
The analysis includes a section comparing characteristics of clients within the cannabis cohort based on whether they had ever been referred to treatment via a drug diversion program. To explore these sub-groups, clients were flagged to indicate those who received treatment for cannabis as the PDOC and who received at least one closed treatment episode referred via police or court diversion in at least one collection period between 2013–14 and 2021–22. Clients were classified as those who had:
- only ever been referred to treatment via police or court diversion (‘Diversion only’)
- been referred to treatment via diversion and at least one other treatment episode with a non-diversion referral source (for example, self/family, health service) (‘Diversion and other’)
- never been referred to treatment via diversion (‘Diversion never’).
Sensitivity analysis of diversion referrals by state and territory
States and territories take different approaches to treatment, including varying policies and practices relating to drug diversion programs. Demographic differences between clients who had ever versus never been referred via diversion may therefore be partially explained by other factors, including the state or territory where the client resided. For example, if clients receiving treatment for cannabis use in one state tend to be younger and that state also has a high number of clients referred via diversion, there may appear to be a relationship between age and being referred via diversion that is purely caused by jurisdictional differences. See Table 4 for an overview of the proportion of clients referred via diversion and non-diversion referral sources by state/ territory. See also Table T1.1 to see this information by cannabis cohort.
To overcome this issue, a logistic regression analysis was conducted to examine factors associated with being referred via diversion, within the cohort of clients who had ever received treatment for cannabis between 2013–14 and 2021–22. This allowed us to determine whether differences between the two cohorts (that is, clients referred to diversion ever versus never) were still apparent after controlling for the effects of state/territory. This approach was based on previous logistic regression modelling undertaken by the AIHW using the AODTS NMDS dataset (AIHW 2021; AIHW 2023).
State/territory | Diversion only | Diversion & non-diversion | Diversion never |
|---|---|---|---|
New South Wales | 6.6 | 13.3 | 80.1 |
Victoria | 4.9 | 21.6 | 73.6 |
Queensland | 55.0 | 13.5 | 31.5 |
Western Australia | 41.1 | 15.9 | 43.0 |
South Australia | 35.6 | 12.9 | 51.5 |
Tasmania | 17.9 | 8.7 | 73.4 |
Australian Capital Territory | 13.6 | 22.3 | 64.1 |
Northern Territory | 5.6 | 9.1 | 85.4 |
Total | 32.4 | 15.2 | 52.4 |
Source: AODTS NMDS 2021–22. See table T1.1.
Note: Percentage distributions may not sum to 100 due to rounding.
Results of the logistic regression indicated that, after controlling for state/territory, the differences between clients by diversion referral status generally aligned with the results from our primary analysis (that is, without controlling for state/territory). For example, clients aged 10–29 years were more likely than those aged 30–39 to be referred via diversion, and males were more likely than females to be referred via diversion. Only differences that were statistically significant after controlling for state/territory in the logistic regression model are described in this report, to prevent differences in states or territories from confounding the results.
AIC (Australian Institute of Criminology) (2022) Drug use monitoring in Australia: Drug use among police detainees, 2021, AIC, Australian Government, accessed 05 February 2024.
AIHW (Australian Institute of Health and Welfare) (2011) Review of the Alcohol and Other Drug Treatment Services National Minimum Data Set, AIHW, Australian Government, accessed 12 February 2024.
AIHW (2021) Patterns of intensive alcohol and other drug treatment service use in Australia, 1 July 2014 to 30 June 2019, AIHW, Australian Government, accessed 12 February 2024.
AIHW (2023) Completion of alcohol and drug treatment in Australia, 2011–12 to 2020–21: differences by drugs of concern and treatment characteristics, AIHW, Australian Government, accessed 13 February 2024.
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