Cannabis

The 2 most common subspecies within the cannabis genus from which cannabis is harvested are Cannabis sativa and Cannabis indica. Cannabis comes in 3 main forms:

  • Herbal cannabis (also referred to as marijuana) – the dried leaves and flowers of the cannabis plant (the weakest form);
  • Cannabis resin (hashish) – the dried resin from the cannabis plant;
  • Cannabis oil (hashish oil) – the oil extracted from the resin (the strongest form) (ACIC 2020; NSW Ministry of Health 2017).

Cannabis is most commonly smoked in a rolled cigarette (joint) or water pipe, often in combination with tobacco, but it may also be added to food and eaten. Cannabis oil is generally applied to cannabis herb or tobacco and smoked, or heated and the vapours inhaled (ACIC 2020).

The main psychoactive component of the cannabis plant is delta-9-tetrahydrocannabinol (THC). THC is highest in the flowering tops and leaves of the plant. Other than THC, cannabis has more than 70 unique chemicals that are collectively referred to as cannabinoids (ACIC 2018). Cannabis is a central nervous system depressant, but also alters sensory perceptions and may produce hallucinogenic effects when large quantities are used (ACIC 2018; NSW Ministry of Health 2017). The use of cannabis for medicinal purposes was legislated by the Australian parliament in 2016.

Synthetic cannabis is a new psychoactive substance that was originally designed to mimic or produce similar effects to cannabis (Alcohol & Drug Foundation 2017). The availability, consumption and harms associated with synthetic cannabis are discussed further in the section on new (and emerging) psychoactive substances (NPS).

Availability

Cannabis is relatively easy to obtain in Australia. Most participants in the Illicit Drug Reporting System (IDRS) and the Ecstasy and Related Drugs Reporting System (EDRS) report that cannabis is perceived as ‘easy’ or ‘very easy’ to obtain. This has remained relatively stable over time, as has perceived purity and pricing (Peacock et al. 2020; Peacock et al. 2021).

Perceived availability was the highest for hydroponic cannabis (81% of 2020 IDRS participants and 89% of 2020 EDRS participants rated it ‘easy’ or ‘very easy’ to obtain), followed by bush cannabis (68% of 2020 IDRS participants and 81% of 2020 EDRS users participants it ‘easy’ or ‘very easy’ to obtain) (Peacock et al. 2020; Peacock et al. 2021).

The collection of cannabis availability data for 2020 took place from April–July 2020 for the EDRS and from June–September for the IDRS, after COVID-19 restrictions were introduced (Peacock et al. 2020; Peacock et al. 2021). This should be taken into account when comparing data between 2020 and previous years.

The primary source of cannabis reported by people aged 14 years and over who had recently used cannabis was friends (65%), followed by dealers (17.9%) in 2019 (AIHW 2020) (Table S2.5).

In 2018–19, the majority of national illicit drug seizures (50%) were for cannabis (ACIC 2020). However, cannabis only accounted for 29% of the weight of illicit drugs seized nationally. The number and weight of national cannabis seizures has increased over the last decade—the number of seizures increased from 44,736 in 2009–10 to 56,491 in 2018–19 and the weight seized increased from 5,989.8 kilograms in 2009–10 to 7,740.8 kilograms in 2018–19 (ACIC 2020; tables S1.21 and S1.22).

The number of detections of cannabis at the Australian border decreased between 2017–18 and 2018–19 by 36% (17,383 and 11,133 respectively). However, the number of detections have increased by 666% since 2009–10 (1,454).

The weight of cannabis detected at the Australian border increased from 19.6 kilograms in 2009-10 to 580.2 kilograms in 2017–18 and increased again in 2018–19 to 1,811.7 kilograms.

Consumption

Cannabis continues to be the world’s most widely used illicit drug, with an estimated annual prevalence of 3.9% of the adult population aged 15–64 years, or the equivalent of 192 million people having used cannabis at least once in 2018. The reported consumption of cannabis in Australia and New Zealand in 2018 (10.6%) was substantially higher than the global average (UNODC 2020).

The 2019 National Drug Strategy Household Survey (NDSHS) showed that cannabis continues to have the highest reported prevalence of lifetime and recent consumption among the general population, compared with other illicit drugs (tables S2.31 and S2.32). Note: for the first time in 2019, people who had used cannabis only for medicinal purposes and always had it prescribed by a doctor were identified and excluded from data relating to the recent use of cannabis, which focuses on illicit use (AIHW 2020b). Data relating to the medicinal use of cannabis are reported separately (see Medicinal cannabis).

  • For people aged 14 and over in Australia in 2019, 36% had used cannabis in their lifetime and 11.6% had used cannabis in the prior 12 months (Figure CANNABIS1).
  • The lifetime use of cannabis has increased from 33% in 2001 while recent use of cannabis has decreased from 12.9%.
  • Lifetime and recent use of cannabis increased significantly between 2016 and 2019 (up from 35% and 10.4% in 2016, respectively) (tables S2.38 and S2.39).

Figure CANNABIS1: Lifetime and recent use of cannabis, people aged 14 and older, by age and sex, 2001 to 2019 (per cent)

The figure shows the proportion of people who recently used cannabis by age group between 2001 and 2019. Between 2001 and 2019, there were decreases in the proportion of people aged 14–19 (from 24.6% to 13.3%) and 20–29 (from 29.3% to 23.8%) who used recently used cannabis. Over the same period, there were increases in the proportion of people aged 50–59 who recently used cannabis (from 3.3% to 9.2%). In 2019, people aged 20–29 (23.8%) and 30–39 (13.7%) were most likely to have recently used cannabis.

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Cannabis use by age and sex

Since 2001, recent cannabis use has generally declined among the younger age groups (those aged 14–39), but has increased for the older age groups (40 or over).

  • Compared with those in other age groups, people aged 20–29 continue to be the most likely to use cannabis but this declined from 29% in 2001 to 24% in 2019.
  • Males aged 14 and over were more likely to have recently used cannabis (14.7%) than females (8.6%) (Table S2.39).

Between 2016 and 2019 there were significant increases in the use of cannabis among people aged 50–59 (from 7.2% to 9.2%) and 60 and over (from 1.9% to 2.9%) (Figure CANNABIS1; Table S2.39).

In 2001, the average age of cannabis users was 29 and this increased to 35 in 2019 (AIHW 2020b). These results suggest there may be an ageing cohort of cannabis users.

Cannabis is used more frequently than other drugs such as ecstasy and cocaine. Specifically, 37% of people who used cannabis did so as often as weekly or more, compared with only 6.7% and 4.5% of ecstasy and cocaine users respectively. Males were more likely than females to use cannabis weekly (41% compared with 31%) (AIHW 2020b).

Cannabis is the most commonly used illicit substance among adolescents aged 12–17. For further information, see also Younger people: Cannabis.

Geographic trends

There was little change in the proportion of recent cannabis use between 2016 and 2019 for all states and territories, except New South Wales where it increased significantly from 9.3% to 11.0% (Table S2.33).

Explore state and territory data on the use of cannabis in Australia

There was a significant increase in recent use of cannabis for people living in Major cities (from 10.4% in 2016 to 11.7% in 2019) (Table S2.12). However, after adjusting for differences in age, Australians living in Inner regional, Outer regional and Remote and very remote areas were more likely than those living in Major cities to have used cannabis in the previous 12 months (AIHW 2020b).

For people living in areas of highest socioeconomic advantage, there was a significant increase in recent use of cannabis (from 9.4% in 2016 to 12.4% in 2019). Across other socioeconomic areas, at least 1 in 10 people had recently used cannabis (Figure CANNABIS2; Table S2.13).

Figure CANNABIS2: Recent use of cannabis, by remoteness and socioeconomic area, people aged 14 and over, 2010 to 2019 (per cent)

The figure shows the proportion of recent cannabis use for people aged 14 and over by socioeconomic area for 2010, 2013, 2016 and 2019. Recent cannabis use trends were fairly stable across all 5 socioeconomic areas between 2010 and 2019. In 2019, regardless of what socioeconomic area a person came from, about 1 in 10 had recently used cannabis (12.6% of most disadvantaged socioeconomic areas and 12.4% of most advantaged socioeconomic areas).

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Where the most common drug of concern was cannabis, the proportion of people living in Regional and remote areas who travelled 1 hour or longer to treatment services was higher than in Major cities (25% compared with 7%) (AIHW 2019a). 

The National Wastewater Drug Monitoring Program (NWDMP) measures the presence of substances in sewerage treatment plants across Australia. Measurement of cannabis consumption was included for the first time in the August 2018 collection. It is important to note that an average dose was not defined for cannabis because reliable dose figures are not available. As such, cannabis was not included in the comparison of the highest consumed drugs monitored by the program. For further information, see Box HARM2 and Data quality for the National Wastewater Drug Monitoring Program.

The most recent data indicate that the population-weighted average consumption of cannabis in regional areas continues to exceed capital city consumption. Average cannabis consumption increased in regional areas from April 2020 to a record high level in August (ACIC 2020). Cannabis consumption in capital cities increased from April to August 2020, before declining in October 2020. In June 2020, capital city consumption reached the highest levels recorded by the program (ACIC 2021).

Harms

The effects of cannabis (like all drugs) vary from one person to another including, but not limited to, the amount consumed, the mode of administration, the user’s previous experience, mood and body weight (NSW Ministry of Health 2017). The active drug in cannabis makes its way into the bloodstream more quickly when cannabis is smoked, compared to when it is orally ingested. Ongoing and regular use of cannabis is associated with a number of negative long-term effects. Regular users of cannabis can become dependent and commonly reported symptoms of withdrawal include anxiety, sleep difficulties, appetite disturbance and depression (Hall & Degenhardt 2009; Nielsen & Gisev 2017).

An overview of some of the short and long-term effects of cannabis are provided in Table CANNABIS1.

Table CANNABIS1: Effects of cannabis

Short-term effects

Long-term effects

  • Mild euphoria, relaxation and reduced inhibitions
  • Perceptual alterations, including time distortion and intensification of ordinary experiences
  • Feelings of hunger
  • Panic reactions, confusion and feelings of paranoia – mainly reported by naïve users
  • Nausea, headache and reddened eyes
  • Increased heart rate for up to 3 hours after smoking
  • Dizziness, with impaired balance and coordination
  • Physical dependence
  • Upper respiratory tract cancers, chronic bronchitis and permanent damage to the airways when smoked
  • Cardiovascular system damage
  • Mental health conditions including depression
  • Poor adolescent psychosocial development

Source: Adapted from (Hall & Degenhardt 2009; Nielsen & Gisev 2017; NSW Ministry of Health 2017).

Burden of disease and injury

Cannabis use contributed to 0.2% of the total burden of disease and injuries in 2015 and 8.3% of the total burden due to illicit drugs (AIHW 2019b; Table S2.69). Drug use disorders (excluding alcohol) (13%) contributed most to the burden due to cannabis use. Only a small proportion (3% or less) of the burden of schizophrenia, poisoning, anxiety disorders, road traffic injuries and depressive disorders was attributable to cannabis use (AIHW 2019b).

Poly drug use

Cannabis use is also highly correlated with the use of tobacco, alcohol and other drugs. This makes measuring the effects of cannabis alone difficult and potentially increases risks for users.

The 2019 NDSHS showed that alcohol was the most common substance used concurrently with cannabis. Of those recent cannabis users who also consumed alcohol, 62% exceeded the single occasion risk guidelines at least monthly and 39% exceeded the lifetime risk guidelines (Table S2.68).

The most common other drugs concurrently used by recent cannabis users were:

  • tobacco (29%)
  • cocaine (25%)
  • ecstasy (19.7%),
  • the non-medical use of pharmaceuticals (14.1%) (Table S2.68).

Deaths

In 2019, there were 206 drug-induced deaths where cannabinoids were present (Table S1.1). Compared with other licit and illicit drugs, cannabinoids are less frequently present in drug-induced deaths (Table S1.1). However, cannabis was the second most common drug identified at toxicology for transport accident deaths (ABS 2017). The short-term effects of cannabis can increase the risk of road traffic crashes, largely due to diminished driving performance in response to emergencies (Hall & Degenhardt 2009).

Hospitalisations

The National Hospital Morbidity Database showed that in 2018–19, the rate of drug-related hospital separations for cannabinoids was similar for people usually residing in Major cities (22.8 per 100,000 population) and Regional and remote areas (26.5 per 100,000 population). However, the rate was highest for people usually residing in Remote and very remote areas (56.3 per 100,000 population (Table S1.8c).

Ambulance attendances

Data on alcohol and other drug-related ambulance attendances are sourced from the National Surveillance System for Alcohol and Other Drug Misuse and Overdose report. Data for 2019 are available for New South Wales, Victoria, Tasmania and the Australian Capital Territory. Data are presented for 4 snapshot months per year, specifically March, June, September and December. Please see the data quality statement for further information.

The rate of cannabis-related ambulance attendances ranged from 20.2 per 100,000 population in New South Wales to 28.1 per 100,000 population in Tasmania.

The majority of cannabis-related attendances were for males, ranging from 58% of attendances in the Australian Capital Territory to 66% of attendances in New South Wales. The median age for cannabis-related attendances was similar across jurisdictions, ranging from 28 years in New South Wales to 31 years in the Australian Capital Territory.

Higher rates for cannabis-related ambulance attendances were reported in regional areas for New South Wales (22.4 per 100,000 population compared with 19.2 for metropolitan areas) and Victoria (25.6 per 100,000 population compared with 20.7 for metropolitan areas). However, in Tasmania the rate for these attendances was higher for Greater Hobart (31.9 per 100,000) than for Regional Tasmania (25.1 per 100,000). Similar proportions of cannabis-related attendances were transported to hospital in metropolitan and regional areas for New South Wales (84% and 81%, respectively), Victoria (80% and 83%, respectively) and Tasmania (77% and 74%, respectively) (Table S2.81) (Moayeri et al. 2020).

Treatment

Data collected for the AODTS NMDS are released twice each year—a key findings report in April and a detailed report in June. Detailed information about closed treatment episodes for cannabis will be updated in June 2021.

The 2018–19 AODTS NMDS showed that cannabis was the principal drug of concern for clients’ own drug use in 19.8% of closed treatment episodes, and was the third most common principal drug overall (Table S2.76; Figure CANNABIS3).

  • Client demographics where cannabis was the principal drug of concern:
    • Almost 7 out of 10 clients were males (68%) (Table S2.77), and around 1 in 6 were Indigenous (18.8%) (Table S2.78).
    • Indigenous Australians (927 per 100,000 population) were more likely to have received treatment than non-Indigenous Australians (116 per 100,000 population) (AIHW 2020a).
  • Source of referral for treatment:
    • The most common source of referral for treatment where cannabis was the principal drug of concern was diversion (that is, referred from the criminal justice system into AOD treatment for drug or drug-related offences) and self/family (both 28% of treatment episodes) (Table S2.79).
  • Treatment type:
    • Where cannabis was the principal drug of concern, counselling was the most common treatment type (38% of treatment episodes), followed by information and education only (20%) (Table S2.80).
    • The median treatment length for closed treatment episodes where cannabis was the principal drug of concern was 17 days.

Figure CANNABIS3: Snapshot of closed treatment episodes for own cannabis use, 2018-19 (per cent)

The visualisation shows that cannabis was a principal drug of concern for clients’ own drug use in 19.8% of closed treatment episodes in 2018–19. The most common main treatment type provided to clients for their own cannabis use was counselling (38%). Around 1 in 6 clients (18.8%) who sort treatment for their own cannabis use were Indigenous Australians.

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At-risk groups

The use of cannabis can be disproportionately higher for specific population groups.

Marijuana, hashish or cannabis resin is the most commonly reported illicit drug used by Aboriginal and Torres Strait Islander people. See also: Illicit drugs in the Aboriginal and Torres Strait Islander people section.

The highest recorded number of arrests were those relating to cannabis and high proportions of police detainees and prison entrants recently used cannabis. See also: Illicit drugs in the People in contact with the criminal justice system section.

Cannabis is the most frequently used illicit drug for people who inject drugs. See also: Illicit drugs in the People who inject drugs section.

Policy context

Public perceptions and policy support

There have been changes over time in public perceptions of cannabis use in Australia. Data from the 2019 NDSHS showed:

  • There was a significant decrease in the proportion of Australians reporting cannabis as the first drug they thought of when asked about a drug problem—12.4% in 2019 compared with 14.6% in 2013.
  • Only 2.2% thought that cannabis caused the most concern to the general community.
  • Personal approval of cannabis use by an adult increased significantly from 14.5% in 2016 to 19.6% in 2019 (AIHW 2020b).

There have also been some associated changes in public perceptions about cannabis-related policies. For example:

  • the majority of Australians aged 14 years and over (78%) do not support the possession of cannabis being a criminal offence, which is significantly higher than the 74% reported in 2016
  • 2 in 5 (41%) support the legalisation of cannabis for personal use (Table S2.42; AIHW 2020b).

Medicinal cannabis

Box CANNABIS1: What is medicinal cannabis?

Prior to 2016, cannabis was classified as an illegal narcotic under Australian law. This changed in February 2016, when the National Drugs Amendment Act 2016 established a national licensing and permit scheme to enable the cultivation, production, and manufacture of cannabis for medicinal and related research purposes. Under this scheme, specific patient groups can now access medicinal cannabis products under strict medical supervision. Cannabis cultivated for other purposes remains illegal.

Medicinal cannabis typically refers to use of cannabis that is prescribed by a healthcare professional. However, in the 2019 National Drug Strategy Household Survey, this included any use of cannabis for medical purposes, regardless of whether a doctor prescribed it.

In 2019, the National Drug Strategy Household Survey (NDSHS) included 2 new questions regarding medical use of cannabis—if respondents had recently used cannabis for medical purposes, and whether the cannabis was prescribed by a doctor (AIHW 2020b).

  • Of people aged 14 and over who had used cannabis in the previous 12 months in 2019, 6.8% always used it for medical purposes and 16.3% used it for both medical and non-medical reasons.
  • Of those who had recently used cannabis for medical purposes, 1.8% always obtained cannabis with a prescription and 2.1% sometimes did.
  • When asked about their usual source, around half (51%) of people who had recently used cannabis medically said they normally obtained it from a friend, and 22% purchased it from a dealer (AIHW 2020b).

Compared with people who did not use cannabis for medical purposes, people who had recently used cannabis for medical purposes only were:

  • typically older (43% aged 50 and over) than people who used cannabis non-medically (16%)
  • more likely to live in the lowest socioeconomic areas (32% compared with 20%) and Inner regional areas (28% compared with 17.0%).
  • more likely to experience chronic pain (53% compared with 6.9%), very high levels of psychological distress (27% compared with 9.7%) and poor or fair health (33% compared with 10.4%)
  • less likely to have recently used another illicit substance (20% compared with 44%) but more likely to smoke tobacco (51% compared with 39%)
  • more likely to use cannabis daily or weekly (56% compared with 29%)
  • more likely to use cannabis oil (23% compared with 4.5%), and less likely to use leaf (27% compared with 51%) (AIHW 2020b).

Resources and further information

Information about the medicinal use of cannabis in Australia can be found at the Office of Drug Control.