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 2019; 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 2019).

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. Regular injecting drug users and users of ecstasy or other stimulants report that cannabis is ‘easy’ or ‘very easy’ to obtain. This has remained stable over time, as has purity and pricing (Peacock et al. 2019a; Peacock et al. 2019b). Perceived availability was the highest for hydroponic cannabis (88% of IDRS users and 90% of EDRS users rated it ‘easy’ or very easy’ to obtain), followed by bush cannabis (78% of IDRS users and 78% of EDRS users rated it ‘easy or very easy’ to obtain) (Peacock et al. 2019a; Peacock et al. 2019b). The primary source of cannabis reported by recent users aged 14 years or older was friends (65%), followed by dealers (17.9%) in 2019 (AIHW 2020b) (Table S2.5).

In 2017–18, the majority of the number of national illicit drug seizures (52.4%) and arrests (48.8%) were for cannabis (ACIC 2019). However, cannabis only accounted for 28.3% of the weight of illicit drugs seized nationally. There were 72,381 national cannabis arrests in 2017–18, with the number of national cannabis arrests increasing 30% over the last decade (from 55,638 in 2008–09) (ACIC 2019; ACC 2010). The number and weight of national cannabis seizures has also increased over the decade—the number of seizures increased from 46,875 in 2008–09 to 59,139 in 2017–18 and the weight of seizures increased from 5,573 kilograms in 2008–09 to 8,655 kilograms in 2017–18 (ACIC 2019; ACC 2010).

Widespread domestic cultivation generally makes the trafficking of herbal cannabis into Australia unnecessary and unprofitable (ACIC 2018).

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 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).
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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; TableS2.13).

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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 average consumption of cannabis in regional areas exceeded capital city consumption, though consumption increased in capital cities and decreased in regional areas from August to December 2019 (ACIC 2020).

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 2018, there were 264 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 2017–18, the rate of drug-related hospital separations for cannabinoids was similar for people usually residing in Major cities (24.3 per 100,000 population) and Regional and Remote areas (26.9 per 100,000 population). However, the rate was twice as high for people usually residing in Remote and Very remote areas, compared with those in Major cities (54.1 per 100,000 population compared with 24.3 per 100,000 population) (Table S1.8c).

Treatment

The AIHW 2018–19 Alcohol and Other Drug Treatment Services National Minimum Data Set (AODTS NMDS) showed that:

  • Cannabis was a principal drug of concern for a client’s 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.
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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 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.

References

Alcohol and Drug Foundation 2017. Synthetic cannabis. Viewed 30 November 2017.

ABS (Australian Bureau of Statistics) 2017. Causes of Death, Australia, 2016. ABS cat. no. 3303.0. Canberra: ABS. Viewed 4 January 2018.

ABS 2019. National Aboriginal and Torres Strait Islander Health Survey, 2018-19. ABS cat. no. 4715.0. Canberra: ABS. Viewed 8 January 2020.

ACC (Australian Crime Commission) 2010. Illicit Drug Data Report 2008–09. Canberra: ACIC. Viewed 7 August 2019.

ACIC (Australian Criminal Intelligence Commission) 2018. Illicit Drug Data Report 2016–17. Canberra: ACIC. Viewed 21 September 2018.

ACIC 2019. Illicit Drug Data Report 2017–18. Canberra: ACIC. Viewed 7 August 2019.

ACIC 2020. National Wastewater Drug Monitoring Program Report 10, 2020. Canberra: ACIC. Viewed 30 June 2020.

AIHW (Australian Institute of Health and Welfare) 2019a. Alcohol and other drug use in regional and remote Australia: consumption, harms and access to treatment, 2016–17. Cat. no. HSE 212. Canberra: AIHW. Viewed 15 March 2019.

AIHW 2019b. Australian burden of disease study: Impact and causes of illness and death in Australia 2015. Series no.19. BOD 22. Canberra: AIHW. Viewed 13 June 2019.

AIHW 2019c. The health of Australia’s prisoners 2018. Cat. no. PHE 246. Canberra: AIHW. Viewed 30 May 2019.

AIHW 2020a. Alcohol and other drug treatment services in Australia 2018–19. Cat no. HSE 243. Canberra: AIHW Viewed 26 June 2020.

AIHW 2020b. National Drug Strategy Household Survey 2019. Drug statistics series no. 32. Cat. no. PHE 270. Canberra: AIHW. Viewed 16 July 2020.

DoH (Department of Health) 2017. Medicinal cannabis. Canberra: Office of Drug Control. Viewed 4 January 2018.

Hall W & Degenhardt L 2009. Adverse health effects of non-medical cannabis use. Lancet. 374: 1383-1391.

Man N, Chrzanowska A, Dobbins T, Degenhardt L & Peacock A 2019. Trends in drug-induced deaths in Australia, 1997-2018. Drug Trends Bulletin Series. Sydney: National Drug and Alcohol Research Centre, UNSW Sydney. Viewed 8 January 2020.

Nielsen S & Gisev N 2017. Drug pharmacology and pharmacotherapy treatments. In Ritter, King and Lee (eds). Drug use in Australian society. 2nd edn. Oxford University Press.

NSW Ministry of Health 2017. A quick guide to drugs & alcohol, 3rd edn. Sydney: National Drug and Alcohol Research Centre.

Peacock A, Karlsson A, Uporova J, Gibbs D, Swanton R, Kelly G, Price O, Bruno R, Dietze P, Lenton S, Salom C, Degenhardt L, & Farrell, M 2019a. Australian Drug Trends 2019: Key findings from the National Ecstasy and Related Drugs Reporting System (EDRS) Interviews. Sydney, National Drug and Alcohol Research Centre, UNSW.

Peacock A, Uporova J, Karlsson A, Gibbs D, Swanton R, Kelly G, Price O, Bruno R, Dietze P, Lenton S, Salom C,  Degenhardt L & Farrell M 2019b. Australian Drug Trends 2019: Key findings from the National Illicit Drug Reporting System (IDRS) Interviews. Sydney, National Drug and Alcohol Research Centre, UNSW.

UNODC (United Nations Office on Drugs and Crime) 2020. World Drug Report 2020. Vienna: UNODC. Viewed 28 July 2020.

Voce A & Sullivan T 2019. Drug use monitoring in Australia: Drug use among police detainees, 2018. Statistical Reports no. 18. Canberra: Australian Institute of Criminology. Viewed 8 January 2020.