Non-medical use of pharmaceutical drugs

In Australia, pharmaceutical drugs are available via a prescription from a registered healthcare professional or over-the-counter (OTC) from a pharmacy, and are widely used to prevent, treat and cure injury and illness. When used appropriately, pharmaceutical drugs are associated with considerable reductions in morbidity and mortality and are an important pillar of public health. However, pharmaceutical drugs are subject to misuse (see Box PHARMS1 for more information).

Pharmaceutical non-medical use refers to the consumption of a prescription or over-the-counter drug for non-therapeutic purposes or other than directed by a registered healthcare professional (Larance et al. 2011). People may misuse pharmaceutical drugs for a range of reasons including to induce euphoria, to enhance the effects of alcohol and other drugs, to self-medicate illness or injury, to mitigate the symptoms of withdrawal from alcohol and other drugs, or to improve performance.

Box PHARMS1: Common pharmaceuticals used for non-medical purposes in Australia

In Australia, pharmaceutical drugs that are most often subject to non-medical use are opioids (painkillers/analgesics) and sedatives (sleeping/anti-anxiety medications).

Pharmaceutical opioids are used to treat pain and opioid (including heroin) dependence and examples include oxycodone, buprenorphine and codeine.

Sedatives are a group of drugs that cause calming and sedative effects due to their depressive activity on the central nervous system. Benzodiazepines comprise the largest group of drugs in this class and examples include diazepam, alprazolam and temazepam.

The non-medical use of pharmaceutical drugs is a growing problem internationally, with different pharmaceutical opioids being misused in different regions (UNODC 2019). The use of opioids in Australia and New Zealand also remains much higher than the global average (3.3 per cent of the adult population), with the non-medical use of pharmaceutical opioids also being the main opioids of concern (UNODC 2019). In 2016 in the US an estimated 6.2 million people aged 12 and older misused a pharmaceutical drug at least once in the past month, with pharmaceutical opioids (painkillers) the most commonly misused (SAMHSA 2017). Dramatic increases in opioid-related deaths associated with rising use in the US have led to the problem being declared an 'epidemic' (CDC 2017; U.S. Department of Health & Human Services 2017).

Availability

Data from the Pharmaceutical Benefits Scheme (PBS) indicates that there has been an increase in the prescribing of pharmaceutical opioids in Australia (AIHW 2018).

  • The number of prescriptions dispensed for opioids rose between 2012–13 and 2016–17 from 13.08 million, a rate of 57,522 per 100,000 population, to 15.42 million, a rate of 63,429 per 100,000 population (Figure PHARMS1). This represents an 11% rise in the rate of opioid prescriptions dispensed over this period.
  • Oxycodone was the most commonly dispensed opioid, with 5.7 million prescriptions dispensed (a rate of 23,515 prescriptions dispensed per 100,000 population), followed by codeine (3.7 million prescriptions, or a rate of 15,216 prescriptions dispensed per 100,000 population) and tramadol (2.7 million prescriptions, or a rate of 11,147 prescriptions dispensed per 100,000 population) (tables S2.7 and S2.8).

Analysis of 2010–11 to 2014–15 PBS data indicates that there had been a decrease in the prescribing on benzodiazepines:

  • In 2014–15, about 4.86 million prescriptions were dispensed for benzodiazepines, a rate of 19,911 per 100,000 population. Between 2010–11 and 2014–15, the number of prescriptions dispensed for benzodiazepines remained relatively stable, but the rate fell from 21,800 per 100,000 population.
  • In 2014–15, more than one-third (37%) of dispensed benzodiazepine prescriptions were for diazepam (1.81 million prescriptions). Since 2010–11, diazepam has been the only form of benzodiazepine for which the number (up 14%) and rate of prescriptions dispensed rose substantially (from 6,950 to 7,440 per 100,000 population) (AIHW 2017b) (tables S2.9 and S2.10).

PBS data from 2016–17 show that the most commonly prescribed benzodiazepine continues to be diazepam with just under 1.7 million prescriptions in 2016–17 (DoH 2017).

The ACIC’s Illicit Drug Data Report includes data on prescription pharmaceuticals detections at the Australian border (ACIC 2019). The importation of prescription pharmaceuticals is primarily undertaken by individuals for personal use and without criminal intent (ACIC 2019).

The number of pharmaceutical detections reported at the Australian border only reflect detections of benzodiazepines and opioids (including morphine, buprenorphine, methadone and oxycodone) (ACIC 2019). In 2017–18 there were a total of 1,425 pharmaceutical detections, an increase of 592% since 2008–09 (206 detections) (ACIC 2019; ACC 2010). The vast majority (88.4%) of these detections were for benzodiazepines (1,260 in 2017–18). However, though they remain the minority of overall pharmaceutical detections, there has been a 725% increase in the number of pharmaceutical opioid detections over the past decade (165 in 2017-18, up from 20 in 2008–09) (ACIC 2019; ACC 2010).

Consumption

Data from the 2016 NDSHS showed that:

  • 1 in 20 (4.8%) Australians aged 14 and over had used a pharmaceutical for non-medical purposes in the previous 12 months (Table S2.32).
  • 1 in 8 (12.8%) Australians aged 14 and over had used a pharmaceutical for non-medical purposes in their lifetime (Table S2.31).
  • 1 in 4 (28%) used pharmaceutical drugs daily or weekly for non-medical purposes (AIHW 2017a).
  • Pharmaceutical opioids/painkillers (excluding over-the-counter) are the most common pharmaceuticals used for non-medical purposes (3.6%), followed by tranquilisers/sleeping pills (1.6%) (tables S2.31 and S2.32).

In 2013, before the break in time series (see Box PHARMS2), the recent use of a pharmaceutical for non-medical purposes was 4.7%, having steadily increased from 3.7% in 2007 (AIHW 2017a).

The National Wastewater Drug Monitoring Program (NWDMP) data indicates the average consumption of fentanyl decreased in both capital city and regional sites when comparing April 2019 and August 2019 data. Over this period, the average consumption of oxycodone increased in both capital city and regional sites. Average fentanyl and oxycodone consumption was higher in regional sites than capital city sites (ACIC 2020). It is important to note that wastewater analysis cannot differentiate between prescribed and illicit use.

The 2016 NDSHS showed that people who use pharmaceutical drugs for non-medical purposes were older than illicit drug users; in 2016, their mean age was 45 compared with 34 for users of illicit drugs (AIHW 2017a). Non-medical use of pharmaceutical opioids was most common among those in their 40s (4.5%) and least common among those aged 14–19 (2.7%). Those aged 20–29 were most likely to use sedatives (2.1%) for non-medical purposes with those aged 14–19 least likely (1.1%) to use this category of pharmaceuticals for non-medical purposes (Figure PHARMS2).

Box PHARMS2: Changes to pharmaceutical questions in the 2016 NDSHS

In 2016, the way the NDSHS captured non-medical use of painkillers/analgesics and opioids changed to better reflect how these substances are used and understood in the community.

Specifically:

  • over-the-counter non-opioid analgesics, such as paracetamol and aspirin, were removed from the section, because they are not known to be misused for cosmetic purposes, to induce or increase a drug experience, or to increase performance
  • the previously separate ‘painkillers/analgesics’ and ‘other opiates/opioids’ sections of the survey were combined, to avoid capturing users of prescription pain-killer/opiates such as oxycodone in 2 sections
  • categories of analgesics are now defined by their most psychoactive ingredient, rather than their brand name, and brand names are only presented as examples, bringing the section in line with other pharmaceuticals captured in the survey.

There were no changes to the tranquillisers/sleeping pills, steroids, or methadone/buprenorphine sections of the questionnaire.

These changes to the 2016 survey has resulted in a break in the time-series for painkillers and opiates and for the overall misuse of pharmaceuticals.

Data from the 2016 NDSHS showed that more than one-quarter (28%) of Australians aged 14 and over perceive the non-medical use of pharmaceuticals to be acceptable, an increase from 23% in 2013. To put this in perspective, nearly twice the number of people approved the use of pharmaceutical drugs compared with the use of tobacco (15.7%) and cannabis (14.5%) (AIHW 2017a).

Geographic trends

In 2016, among people aged 14 and over (AIHW 2017a):

  • South Australians were more likely to have recently used pain-killers/opiates (4.3%) for non-medical purposes than people in any other state or territory.
  • People living in Tasmania were more than 1.5 times more likely to have recently used tranquillisers/sleeping pills (2.9%) for non-medical purposes than people in other jurisdictions
  • Tasmania (5.6%) and South Australia (5.5%) had the highest rates of non-medical pharmaceutical use.

People living in Remote and very remote areas were twice as likely as those from Major Cities to have recently used pain-killers/opiates for non-medical purposes (6.6% compared with 3.3%). Overall, they were 1.7 times more likely than those from Major Cities to have used pharmaceuticals for non-medical purposes (8.0% compared with 4.6%) (Figure PHARMS3).

Similarly, people living in the most disadvantaged socioeconomic areas were 1.8 times more likely than those from the most advantaged socioeconomic areas to have the highest level of non-medical pain-killers/opiates use (4.8% compared with 2.6%). They were also more likely to have used pharmaceuticals for non-medical use in the past 12 months than people living in the most advantaged socioeconomic areas (6.0% compared with 4.2%) (Table S2.13).

Harms

There are a range of short and long-term health, social and economic harms associated with the misuse of pharmaceutical drugs (Table PHARMS1).

Table PHARMS1: Short and long term effects associated with pharmaceutical misuse

Drug type

Short-term effects

Longer-term effects

Pharmaceutical opioids

  • Constipation
  • Nausea
  • Sedation
  • Vomiting
  • Dizziness
  • Itching
  • Dry mouth
  • Overdose (fatal and non-fatal)
  • Dependence
  • Decreased cognitive function
  • Psychiatric co-morbidity
  • Occlusion of blood vessels
  • Gastro-intestinal bleeding
  • Mental health conditions including depression

Benzodiazepines

  • Relaxation, sleepiness and lack of energy
  • Dizziness
  • Euphoria
  • Confusion
  • Visual distortions
  • Moodiness
  • Short-term memory loss
  • Anxiety, irritability, paranoia, aggression and depression
    Muscle weakness, rashes, nausea and weight gain
  • Sexual problems
  • Menstrual irregularities
  • Memory loss, cognitive impairment, dementia and falls
  • Confusion, lethargy and sleep problems

Source: Adapted from Currow, Phillips & Clark 2016; DCPC 2007; Nicholas, Lee & Roche 2011; NSW Ministry of Health 2017.

Mental health

In the 2016 NDSHS, adults aged 18 and over who had recently misused a pharmaceutical were more likely than those who had not to:

  • Assess their health status as good, fair or poor (53%) compared with 44% who had not recently misused a pharmaceutical.
  • Self-report higher rates of health conditions, particularly for the conditions of mental illness (29% compared with 15.2%) and chronic pain (15.9% compared with 10.3%).
  • Have experienced ‘high or very high’ levels of psychological distress (24% compared with 11%) (Table S2.75).

There were also differences in mental health status depending on the type of pharmaceutical drug used. Specifically:

  • Adults misusing benzodiazepines were more likely to report a mental illness, including anxiety disorders and depression, than people misusing opioid analgesics (35% compared with 29%).
  • Adults who misused benzodiazepines were slightly more likely than those who misused opioid analgesics to experience ‘high or very high’ levels of psychological distress (28% compared with 24%) (Figure PHARMS4).

Hospitalisations

A hospital separation is a completed episode of admitted hospital care ending with discharge, death, transfer, or a portion of a hospital stay. The AIHW’s National Hospital Morbidity Database (NHMD) showed that in 2017–18 of all separations with a drug-related principal diagnosis:

  • benzodiazepines and other sedatives and hypnotics (including barbiturates; excluding ethanol) accounted for 7.3% of all drug-related separations.
  • 12% were for analgesics, with opioids (heroin, opium, morphine and methadone) accounting for half of this group (6.4% of all drug-related separations) (Table S1.8a).

Between 2013–14 and 2017–18, benzodiazepines and other sedatives and hypnotics (excluding alcohol) continued to result in more drug-related hospital separations than opioids (Table S1.8b).

In 2017–18, hospital separation rates (per 100,000 population) for benzodiazepines and other sedatives and hypnotics were 1.4 and 1.5 times, respectively higher for people living in Major cities compared with Remote and very remote areas.

Hospital separation rates (per 100,000 population) for opioids were 1.8 times higher for people residing in Major cities compared with Remote and very remote areas in 2017–18.

The rate of drug-related hospital separations for non-opioid analgesics was 1.2 times higher for people usually residing in Remote and very remote areas compared with those in Major cities (36.8 per 100,000 population compared with 28.5 per 100,000 population) (Table S1.8c).

Deaths

Of the 1,740 drug induced deaths in 2018, the most common substance present was a benzodiazepine (51%)—this is consistent with findings from previous years (Figure PHARMS5). Between 2009 and 2018, the number of deaths where benzodiazepines were present rose by 70% (from 518 to 883 deaths) (Table S1.1).

It is important to note that benzodiazepines may not have been recorded as the underlying cause of death, as they often occur in the context of polysubstance use. Analysis by the National Drug and Alcohol Research Centre (NDARC) found that in 693 deaths in which opioids were deemed to be the underlying cause of death, benzodiazepines were recorded as contributing to the death (Man et al. 2019). In 2018, in over 97% of drug-induced deaths where benzodiazepines were present, they were taken in conjunction with other drugs, including alcohol (AIHW unpublished).

Over the past decade, drug-induced deaths were more likely to be due to prescription drugs than illegal drugs, and there has been a substantial rise in the number of deaths with a prescription drug present. For synthetic opioids (including fentanyl and tramadol) in particular, the rate has increased from 0.1 per 100,000 (32 deaths) in 2009 to 1.0 per 100,000 (241 deaths) in 2018 (Table S1.1).

NDARC reported that in 2018,  there were 655 (60%) deaths attributed to pharmaceutical opioids only, 322 (30%) to illicit opioids only (such as heroin and opium) and 108 (10%) deaths to both pharmaceutical opioids and illicit opioids (Man et al. 2019). This is consistent with the findings from the ABS that indicated that pharmaceutical opioids and prescription opioids were present in over 70% of opioid-induced deaths in 2018 (ABS 2019a). Pharmaceutical opioids were also the most common opioid present in suicide overdose (ABS 2019a).

The rate of drug-induced deaths involving benzodiazepines was similar in Major cities and Regional and remote areas in 2018 (Table S2.71). However, the rate of drug-induced deaths involving prescription opioids was higher in Regional and remote areas than in Major cities for natural and semi-synthetic opioids (2.3 deaths per 100,000 population compared with 1.8 per 100,000 population) and synthetic opioids (1.3 deaths per 100,0000 population in Regional and remote areas, compared with 0.9 deaths per 100,0000 population in Major cities) (Table S2.71).

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Treatment

Data collected as part of the AIHW’s 2018–19 Alcohol and Other Drug Treatment Services National Minimum Data Set (AODTS NMDS) showed that:

  • Pharmaceuticals were the principal drug of concern for a client’s own drug use in 4.7% of closed treatment episodes (Table S2.76; Figure PHARMS6).
  • Client demographics where pharmaceuticals were the principal drug of concern:
    • Almost two-thirds (61%) of clients were male (Table S2.77) and around 1 in 10 were Indigenous (12.6% ) (Table S2.78).
  • In 2018–19, a higher proportion of female clients (55%) reported codeine as their principal drug of concern, males were more likely than females to report other sedatives and hypnotics as their principal drug of concern (59%) (Table S2.77).
  • Source of referral for treatment:
    • Almost half of the referrals for treatment where pharmaceuticals were the principal drug of concern were for self/family (44% of treatment episodes), followed by a health service (41%) (Table S2.79).
  • Treatment type:
    • The most common main treatment type where pharmaceuticals were the principal drug of concern was counselling (27% of episodes) followed by assessment only (21%) (AIHW 2020) (Table S2.80).
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At-risk groups

The available evidence indicates that the misuse of pharmaceuticals among vulnerable populations is at substantially higher levels than in the general population.

Aboriginal and Torres Strait Islander people

Data from the 2016 NDSHS showed that about 1 in 10 (10.6%) Aboriginal and Torres Strait Islander people had used a pharmaceutical for non-medical purposes. This was about 2.3 times higher than the rate for non-Indigenous Australians (4.6%) (AIHW 2017a).

The ABS 2014–15 National Aboriginal and Torres Strait Islander Social Survey (NATSISS) found that the non-medical use of pharmaceuticals among Indigenous Australians was higher than reported in the NDSHS, with 12.6% of Indigenous Australians aged 15 and over having recently used a pharmaceutical for non-medical purposes (ABS 2016). However, the 2018-19 National Aboriginal and Torres Strait Islander Health Survey (NATSIHS) reported a lower proportion (3.8%) of Indigenous Australians aged 15 and over had used analgesics and sedatives for non-medical use in the last 12 months (ABS 2019b).

People engaged in the criminal justice system

Data from the Drug Use Monitoring in Australia (DUMA) program are unable to specify the proportions of non-medical use of pharmaceuticals, yet showed a stable proportion of detainees tested positive to benzodiazepines in 2017 (22%) (Patterson et al. 2019) and 2018 (23%) (Voce & Sullivan 2019). In 2018, 14% of police detainees tested positive to opioids, including heroin, methadone, buprenorphine, prescription and other opioids (Voce & Sullivan 2019), a decrease from 17% in 2017 (Patterson et al. 2019).

People in remote and disadvantaged socioeconomic areas

Data from the 2016 NDSHS showed that people living in Remote and very remote areas were 1.7 times as likely as those living in Major cities to have recently misused a pharmaceutical (8.0% compared with 4.6%). In particular, use of opioid analgesics in these areas was twice as high as in Remote and very remote areas compared with Major cities (6.6% compared with 3.3%) (AIHW 2018). Whereas the levels of recent benzodiazepine misuse in these areas was similar, 1.7% compared with 1.8% (AIHW 2017a).

This is consistent with data from the National Wastewater Drug Monitoring Program that found the pharmaceutical opioids oxycodone and fentanyl, were detected at higher levels in regional areas than capital city areas (ACIC 2020).

People living with chronic pain

People who use opioids for chronic pain are more likely than the general population to misuse pharmaceutical drugs (Currow, Phillips & Clark 2016; Vowels et al. 2015). Iatrogenic dependence occurs when patients become dependent on medications that they were medically prescribed for legitimate purposes. Iatrogenic dependence is an increasing concern among people living with chronic non-cancer pain.

People who inject drugs

People who inject drugs may substitute illicit drugs, such as heroin, for pharmaceutical drugs depending on availability. It is well known that people who inject drugs consume pharmaceutical drugs, particularly prescription opioids, at far higher rates than the general population (Peacock et al. 2019).

Data from the 2019 IDRS showed that respondents commonly reported the non-prescribed use of the following drugs in the preceding 6 months (Peacock et al. 2019):

  • Morphine (18%)
  • Oxycodone (15%)
  • Buprenorphine (5%) and buprenorphine-naloxone film (12%)
  • Fentanyl (9%).

Policy context

Real-time prescription monitoring

In July 2017, the Australian Government announced $16 million in funding to implement a national real-time monitoring system of prescription drugs. The system will provide an instant alert to pharmacists and doctors if patients are receiving multiple supplies of prescription only medicines (also referred to as ‘doctor or pharmacy shopping’). The program will initially include the monitoring of controlled medicines that are particularly susceptible to misuse including morphine, oxycodone, dexamphetamine and alprazolam. The system aims to assist doctors and pharmacists to identify patients who are at risk of harm due to dependency, misuse or abuse of pharmaceutical drugs and patients that are diverting these medicines.

Restricting access to codeine

As of 1 February 2018, medicines containing codeine were no longer sold over-the-counter in pharmacies and were available by prescription only. This decision was made by the Therapeutic Goods Administration (TGA) following substantial evidence of harm from the abuse and misuse of low dose codeine-containing medicines including analgesic preparations combined with other pain relief medicines such as aspirin, paracetamol and ibuprofen (TGA 2018).

Resources and further information

References

ABS (Australian Bureau of Statistics) 2016. National Aboriginal and Torres Strait Islander Social Survey, 2014–15. ABS cat. no. 4714.0. Canberra: ABS. Viewed 14 December 2017.

ABS 2017. Causes of Death, Australia, 2016. ABS cat no. 3303.0. Canberra: ABS.

ABS 2019a. Causes of Death, Australia, 2018. ABS cat no. 3303.0. Canberra: ABS.

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

ACIC 2020. National Wastewater Drug Monitoring Program Report 9, 2020 . Canberra: ACIC. Viewed 3 April 2020.

AIHW (Australian Institute of Health and Welfare) 2017a. National Drug Strategy Household Survey 2016: detailed findings. Drug statistics series no. 31. Cat. no. PHE 214. Canberra: AIHW. Viewed 14 December 2017.

AIHW 2017b. Non-medical use of pharmaceuticals: trends, harms and treatment 2006–07 and 2015–16. Cat. no. HSE 195. Canberra: AIHW. Viewed 19 January 2018.

AIHW 2018. Opioid harm in Australia and comparisons between Australia and Canada. Cat. no. HSE 210. Canberra: AIHW.

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

CDC (Centres for Disease Control and Prevention) 2017. Prescription opioid overdose data. Viewed 30 November 2017.

Currow DC, Phillips J & Clark K 2016. Using opioids in general practice for chronic non-cancer pain: an overview of current evidence. The Medical Journal of Australia. 204(8):305–209.

Degenhardt L, Gilmour S, Shand F, Bruno R, Campbell G, Mattick RP et al. 2013. Estimating the proportion of prescription opioids that is consumed by people who inject drugs in Australia. Drug and Alcohol Review 32(5):468–74.

DoH (Department of Health) 2017. PDF DownloadPDF DownloadExpenditure and prescriptions twelve months to June 2017. Canberra: DoH. Viewed 5 June 2018.

DCPC (Drugs and Crime Prevention Committee) 2007. Inquiry into the misuse/abuse of benzodiazepines and other forms of pharmaceutical drugs in Victoria: final report. Melbourne: Drugs and Crime Prevention Committee. Viewed 5 October 2017.

Larance B, Degenhardt L, Lintzeris N, Winstock A & Mattick R 2011. Definitions related to the use of pharmaceutical opioids: extramedical use, diversion, non-adherence and aberrant medication-related behaviours. Drug and Alcohol Review 30(3):236–245.

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.

Nicholas R, Lee N & Roche A 2011. Pharmaceutical drug misuse in Australia: complex problems, balanced responses. Adelaide: National Centre for Education and Training on Addiction.

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

Patterson E, Sullivan T & Bricknell S 2019. Drug use monitoring in Australia: Drug use among police detainees, 2017, Statistical Reports Number 14. Canberra: Australian Institute of Criminology. Viewed 8 January 2020.

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

SAMHSA (Substance Abuse and Mental Health Services Administration) 2017. Key substance use and mental health indicators in the United States: results from the 2016 national survey on drug use and health. Publication no. SMA 17-5044, NSDUH Series H-52. Rockville: Center for Behavioral Health Statistics and Quality, Substance Abuse and Mental Health Services Administration. Viewed 30 November 2017.

TGA (Therapeutic Goods Administration) 2018. Regulation basics. Viewed 2 February 2018.

UNODC (United Nations Office on Drugs and Crime) 2019. World Drug Report 2019Vienna: UNODC. Viewed 16 July 2019.

U.S. Department of Health & Human Services 2017. Opioids: the prescription drug and heroin overdose epidemic. Washington, D.C: DHHS. Viewed 7 December 2017.

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.

Vowels KE, McEntee ML, Julnes PS, Frohe T, Ney JP & van der Goes, DN 2015. Rates of opioid misuse, abuse and addiction in chronic pain: a systematic review and data synthesis. PAIN (156):569–576.