Reduction in HCV incidence among injection drug users attending needle and syringe programs in Australia: a linkage study.

OBJECTIVES: We examined trends in HCV incident infection among injection drug users (IDUs) attending needle and syringe programs (NSPs) in Australia in 1995 to 2010. METHODS: We created a passive retrospective cohort of 724 IDUs who tested negative for HCV antibodies by a simple deterministic method linking partial identifiers to find repeat respondents in annual cross-sectional serosurveillance. RESULTS: We identified 180 HCV seroconversions over the study period, for a pooled incidence density of 17.0 per 100 person-years (95% confidence interval [CI] = 14.68, 19.66). Incidence density declined, from a high of 30.8 per 100 person-years (95% CI = 21.3, 44.6) in 2003 to a low of 4.0 (95% CI = 1.3, 12.3) in 2009. CONCLUSIONS: A decline in HCV incidence among Australian IDUs attending NSPs coincided with considerable expansion of harm reduction programs and a likely reduction in the number of IDUs, associated with significant changes in drug markets. Our results demonstrate the capacity of repeat cross-sectional serosurveillance to monitor trends in HCV incidence and provide a platform from which to assess the impact of prevention and treatment interventions.

A randomised controlled trial of financial incentives to increase hepatitis B vaccination completion among people who inject drugs in Australia.

OBJECTIVE: This study aimed to investigate the efficacy of modest financial incentives in increasing completion of an accelerated 3-dose hepatitis B virus (HBV) vaccination schedule (0, 7, 21days) among people who inject drugs (PWID). METHODS: Randomised controlled trial. Participants were randomly allocated to receive $30 Australian Dollars cash following receipt of vaccine doses two and three ('incentive condition'), or standard care ('control condition'). Serologically confirmed HBV-susceptible PWID. Two inner-city health services and a field study site in Sydney, Australia. The primary outcome was completion of the vaccination series. Additional assessments included self-reported demographic, drug use and treatment, and risk-taking histories. RESULTS: Compared to the control condition, significantly more participants in the incentive condition received all three vaccine doses, under intention-to-treat analyses (n=139; 87% versus 66%; p=.004); and within the specified window periods under per protocol analyses (n=107 received three vaccine doses; 92% versus 67%; p=.001). Multivariate analysis indicated that the incentive condition and longer injecting histories significantly increased the likelihood of series completion. Aboriginal/Torres Strait Islanders were significantly less likely to complete the series. CONCLUSIONS: Modest financial incentives, per-dose, increased adherence to the accelerated HBV vaccination schedule among PWID. Results have implications for increasing HBV and, potentially, other vaccine-preventable infections, among PWID.

Housing instability among people who inject drugs: results from the Australian needle and syringe program survey.

High rates of substance dependence are consistently documented among homeless people, and are associated with a broad range of negative outcomes among this population. Investigations of homelessness among drug users are less readily available. This study examined the prevalence and correlates of housing instability among clients of needle syringe programs (NSPs) via the Australian NSP Survey, annual cross-sectional seroprevalence studies among NSP attendees. Following self-completion of a brief, anonymous survey and provision of a capillary blood sample by 2,396 NSP clients, multivariate logistic regressions identified the variables independently associated with housing instability. Nineteen percent of ANSPS participants reported current unstable housing, with primary ('sleeping rough'; 5 %), secondary (staying with friends/relatives or in specialist homelessness services; 8 %), and tertiary (residential arrangements involving neither secure lease nor private facilities; 6 %) homelessness all evident. Extensive histories of housing instability were apparent among the sample: 66 % reported at least one period of sleeping rough, while 77 % had shifted between friends/relatives (73 %) and/or resided in crisis accommodation (52 %). Participants with a history of homelessness had cycled in and out of homelessness over an average of 10 years; and one third reported first being homeless before age 15. Compared to their stably housed counterparts, unstably housed participants were younger, more likely to be male, of Indigenous Australian descent, and to report previous incarceration; they also reported higher rates of key risk behaviors including public injecting and receptive sharing of injecting equipment. The high prevalence of both historical and current housing instability among this group, particularly when considered in the light of other research documenting the many adverse outcomes associated with this particular form of disadvantage, highlights the need for increased supply of secure, affordable public housing in locations removed from established drug markets and serviced by health, social, and welfare support agencies.

Relative efficacy of cash versus vouchers in engaging opioid substitution treatment clients in survey-based research.

Concerns that cash payments to people who inject drugs (PWID) to reimburse research participation will facilitate illicit drug purchases have led some ethical authorities to mandate department store/supermarket vouchers as research reimbursement. To examine the relative efficacy of the two forms of reimbursement in engaging PWID in research, clients of two public opioid substitution therapy clinics were invited to participate in a 20-30 min, anonymous and confidential interview about alcohol consumption on two separate occasions, 4 months apart. Under the crossover design, at Time 1, clients of Clinic 1 were offered $A20 cash as reimbursement, while clients of Clinic 2 were offered an $A20 voucher; at Time 2, the form of reimbursement was reversed. Using clinic records to determine the denominator (number of clients dosed), we found that compared with clients offered a voucher, a significantly higher proportion of clients who were offered cash participated in the survey (58% (139/241) vs 74% (186/252); χ(2)=14.27; p=0.0002). At first participation, respondents most commonly reported planning to purchase food/drinks/groceries (68%), cigarettes (21%) and transport/fuel (11%) with their payments, with those reimbursed in cash more likely to report planning to fund transport/fuel (19% vs 1%; p<.01) and less likely to report planning to purchase food/drinks/groceries (62% vs 76%; p=0.02). Just three out of 155 cash participants reported planning to purchase illicit drugs with their payment. Results demonstrate that modest cash payments enhanced recruitment of this group, an important consideration given the challenges of delineating the parameters of a population defined by illegal activity, seemingly without promoting excessive additional drug use.

The DACRIN data project: A process for harmonising data collection for clinical research in alcohol and other drugs services in New South Wales.

INTRODUCTION: Standardised data collection processes allow for harmonisation and comparison of data across different studies and services. This project aimed to develop a 'core dataset' to serve as the default collection when designing future studies and evaluations, building upon data routinely collected in clinical alcohol and other drugs (AOD) settings in NSW, Australia. METHODS: A working group was established, comprising clinicians, researchers, data managers and consumers from public sector and non-government organisation AOD services in the NSW Drug and Alcohol Clinical Research and Improvement Network. A series of Delphi meetings occurred to reach consensus on the data items to be included in the core dataset for three domains: demographics, treatment activity and substance use variables. RESULTS: There were 20-40 attendees at each meeting. An initial consensus criterion of having received >70% of the vote was established. Given the difficulty in reaching consensus for most items, subsequently, this was changed to eliminate items that received <5 votes, after which the item receiving the most votes would be selected. DISCUSSIONS AND CONCLUSIONS: This important process received considerable interest and buy-in across the NSW AOD sector. Ample opportunity for discussion and voting was provided for the three domains of interest, allowing participants to contribute their expertise and experience to inform decisions. As such, we believe the core dataset includes the best options currently available to collect data for these domains in the NSW AOD context, and potentially more broadly. This foundational study may inform other attempts to harmonise data across AOD services.

The reliability of sensitive information provided by injecting drug users in a clinical setting: clinician-administered versus audio computer-assisted self-interviewing (ACASI).

Research with injecting drug users (IDUs) suggests greater willingness to report sensitive and stigmatised behaviour via audio computer-assisted self-interviewing (ACASI) methods than during face-to-face interviews (FFIs); however, previous studies were limited in verifying this within the same individuals at the same time point. This study examines the relative willingness of IDUs to report sensitive information via ACASI and during a face-to-face clinical assessment administered in health services for IDUs. During recruitment for a randomised controlled trial undertaken at two IDU-targeted health services, assessments were undertaken as per clinical protocols, followed by referral of eligible clients to the trial, in which baseline self-report data were collected via ACASI. Five questions about sensitive injecting and sexual risk behaviours were administered to participants during both clinical interviews and baseline research data collection. "Percentage agreement" determined the magnitude of concordance/discordance in responses across interview methods, while tests appropriate to data format assessed the statistical significance of this variation. Results for all five variables suggest that, relative to ACASI, FFI elicited responses that may be perceived as more socially desirable. Discordance was statistically significant for four of the five variables examined. Participants who reported a history of sex work were more likely to provide discordant responses to at least one socially sensitive item. In health services for IDUs, information collection via ACASI may elicit more reliable and valid responses than FFI. Adoption of a universal precautionary approach to complement individually tailored assessment of and advice regarding health risk behaviours for IDUs may address this issue.

Correlates of susceptibility to hepatitis B among people who inject drugs in Sydney, Australia.

Despite a safe, effective vaccine, hepatitis B virus (HBV) vaccination coverage remains low among people who inject drugs (PWID). Characteristics of participants screened for a trial investigating the efficacy of financial incentives in increasing vaccination completion among PWID were examined to inform targeting of vaccination programs. Recruitment occurred at two health services in inner-city Sydney that target PWID. HBV status was confirmed via serological testing, and questionnaires elicited demographic, drug use, and HBV risk data. Multinomial logistic regression was utilized to determine variables independently associated with HBV status. Of 172 participants, 64% were susceptible, 17% exposed (HBV core antibody-positive), and 19% demonstrated evidence of prior vaccination (HBV surface antibody ≥ 10 mIU/ml). Compared with exposed participants, susceptible participants were significantly more likely to be aged less than 35 years and significantly less likely to be receiving current opioid substitution therapy (OST) and to test hepatitis C antibody-positive. In comparison to vaccinated participants, susceptible participants were significantly more likely to be male and significantly less likely to report daily or more frequent injecting, current OST, and prior awareness of HBV vaccine. HBV vaccination uptake could potentially be increased by targeting younger, less frequent injectors, particularly young men. In addition to expanding vaccination through OST, targeting "at risk" youth who are likely to have missed adolescent catch-up programs may be an important strategy to increase coverage. The lack of an association between incarceration and vaccination also suggests increasing vaccination uptake and completion in adult and juvenile correctional facilities may also be important.

A cross-sectional survey of prevalence and correlates of suicidal ideation and suicide attempts among prisoners in New South Wales, Australia.

BACKGROUND: We aimed to estimate the prevalence of suicidal ideation and suicide attempt among prisoners in New South Wales, Australia; and, among prisoners reporting suicidal ideation, to identify factors associated with suicide attempt. METHODS: A cross-sectional design was used. Participants were a random, stratified sample of 996 inmates who completed a telephone survey. The estimated population prevalence of suicidal ideation and suicide attempt were calculated and differences by sex and Aboriginality were tested using χ2 tests. Correlates of suicidal ideation and suicide attempt were tested using logistic regression. RESULTS: One-third of inmates reported lifetime suicidal ideation and one-fifth had attempted suicide. Women and Aboriginal participants were significantly more likely than men and non-Aboriginal participants, respectively, to report attempting suicide. Correlates of suicidal ideation included violent offending, traumatic brain injury, depression, self-harm, and psychiatric hospitalisation. Univariate correlates of suicide attempt among ideators were childhood out-of-home care, parental incarceration and psychiatric hospitalization; however, none of these remained significant in a multivariate model. CONCLUSIONS: Suicidal ideation and attempts are highly prevalent among prisoners compared to the general community. Assessment of suicide risk is a critical task for mental health clinicians in prisons. Attention should be given to ensuring assessments are gender- and culturally sensitive. Indicators of mental illness may not be accurate predictors of suicide attempt. Indicators of childhood trauma appear to be particularly relevant to risk of suicide attempt among prisoners and should be given attention as part of risk assessments.

Mental health symptoms among street-based psychostimulant injectors in Sydney's Kings Cross.

Urban frontline services have recorded increases in psychostimulant-related presentations. A convenience sample of 183 street-based psychostimulant injectors recruited in April 2006 was administered the Kessler Psychological Distress Scale (K10) to assess psychological distress. Homelessness, unemployment, and recent public injection, along with gender (female) and financial and relationship problems, best predicted clinically significant K10 scores. Drug use measures were not significantly associated with distress once indicators of social marginalization were included. The risk environment of the street-based drug market accounts for much of the distress experienced in this milieu, highlighting the need for broad structural interventions, together with drug-specific responses.

Can the severity of dependence scale be usefully applied to 'ecstasy'?

BACKGROUND/AIMS: Although use of 'ecstasy' (drugs sold as containing 3,4-methylenedioxymethamphetamine) is prevalent, it is typically infrequent, and treatment presentations involving ecstasy as a principal problem drug are relatively rare. Human case reports and animal literature suggest dependence potential, although there may be some unique aspects to this syndrome for ecstasy in comparison to other substances. The Severity of Dependence Scale (SDS) was examined to determine whether this could usefully identify 'dependent' ecstasy consumers. METHODS: We conducted a cross-sectional survey of 1,658 frequent (at least monthly) ecstasy consumers across Australia, assessing drug use, associated harms and risk behaviours. Dependence was evaluated with the SDS, using a cut-off of > or =4 to identify potential 'dependence'. RESULTS: One fifth of the participants were screened as potentially dependent. These individuals used ecstasy more frequently, in greater amounts, engaged more extensively in risk behaviours and reported greater role interference than other participants. These findings were independent of methamphetamine use or dependence. The underlying structure of the ecstasy SDS was bifactorial. CONCLUSIONS: The SDS has demonstrated construct validity as a screening tool to identify ecstasy users at elevated risk of experiencing adverse consequences, including features of dependence. The underlying structure of dependence symptoms differs for ecstasy compared to other drug classes, and some dependent consumers use the drug infrequently. The unique neurotoxic potential and entactogenic effects of ecstasy may require a distinct nosological classification for the experience of dependence associated with the drug.

The epidemiology of ecstasy use and harms in Australia.

AIMS: This paper examines the epidemiology of ecstasy use and harm in Australia using multiple data sources. DESIGN: The data included (1) Australian Customs Service 3,4-methylenedioxymethamphetamine (MDMA) detections; (2) the National Drug Strategy Household and Australian Secondary Student Alcohol and Drug Surveys; (3) data from Australia's ecstasy and Related Drugs Reporting System; (4) the number of recorded police incidents for ecstasy possession and distribution collated by the N.S.W. Bureau of Crime Statistics and Research; (5) the number of calls to the Alcohol and Drug Information Service and Family Drug Support relating to ecstasy; (6) the Alcohol and Other Drug Treatment Services National Minimum Dataset on number of treatment episodes for ecstasy, and (7) N.S.W. Division of Analytical Laboratories toxicology data on number of deaths where MDMA was detected. FINDINGS: Recent ecstasy use among adults in the general population has increased, whereas among secondary students it has remained low and stable. The patterns of ecstasy consumption among regular ecstasy users have changed over time. Polydrug use and use for extended periods of time (>48 h) remain common among this group. Frequent ecstasy use is associated with a range of risk behaviours and other problems, which tend to be attributed to a number of drugs along with ecstasy. Few ecstasy users present for treatment for problems related to their ecstasy consumption. CONCLUSIONS: Messages and interventions to reduce the risks associated with polydrug use and patterns of extended periods of use are clearly warranted. These messages should be delivered outside of traditional health care settings, as few of these users are engaged with such services.

The epidemiology of hepatitis C in Australia: notifications, treatment uptake and liver transplantations, 1997-2006.

BACKGROUND AND AIM: Regular monitoring of hepatitis C (HCV)-related surveillance data is essential to inform and evaluate strategies to reduce the expanding HCV burden. The aim of this study was to examine trends in the epidemiology and treatment of HCV in Australia. METHODS: We reviewed data about HCV notifications, treatment of HCV infection through the Highly Specialised Drugs (s100) Program, and liver transplants (Australia and New Zealand Liver Transplant Registry) for the period 1997-2006. RESULTS: HCV case notification rates declined by almost 50% between 1999 and 2006, with the greatest reductions between 2001 and 2002 and amongst young adults. For newly acquired HCV cases, 89% were Australian-born and 90% reported injecting drug use as a risk factor for infection. Overall, 30% of liver transplant recipients had HCV-related cirrhosis, but the number and proportion of HCV diagnoses increased between 1997 and 2006. HCV treatment also increased over the review period. However, only 1.4% of the 202,400 people estimated to be living with chronic HCV at the end of 2006 received treatment that year. CONCLUSION: The decline in HCV notifications is consistent with a decline in HCV incidence in Australia. However, the burden of advanced HCV disease continues to expand. To reduce this burden, treatment uptake needs to increase. Consistent and sensitive surveillance mechanisms are required to detect newly acquired cases together with an expansion of surveillance for chronic HCV infections.

Prevalence and predictors of injecting-related injury and disease among clients of Australia's needle and syringe programs.

OBJECTIVE: To identify lifetime prevalence and predictors of self-reported injecting-related injuries and diseases (IRID) and/or injecting-related problems (IRP) among a national cross-sectional sample of injecting drug users. METHODS: 1,961 clients of 45 needle and syringe programs (NSPs) who participated in the 2006 Australian NSP Survey self-completed an item regarding lifetime experience of eight separate IRIDs and IRPs. RESULTS: Sixty-nine per cent of participants reported a history of IRID/IRP, with a mean of 1.9 injuries/problems (range 0-8). Lifetime prevalence of specific injuries/problems ranged from problems finding a vein (43%) to endocarditis (4%). Factors independently associated with IRID/IRP included bisexual identity; daily or more frequent injecting; injection of pharmaceutical preparations; female gender; longer injecting history; and hepatitis C antibody-positive serostatus. CONCLUSIONS: Consistent with existing literature, results suggest that vascular injury and localised infections are common among IDUs; and that treatment-seeking is often delayed until serious complications arise. IMPLICATIONS: Findings support the imperative for co-ordinated and timely treatment and prevention activities to reduce the severity and burden of these prevalent injecting outcomes.

Development of immunity following financial incentives for hepatitis B vaccination among people who inject drugs: A randomized controlled trial.

BACKGROUND: People who inject drugs (PWID) are at risk of hepatitis B virus (HBV) but have low rates of vaccination completion. The provision of modest financial incentives increases vaccination schedule completion, but their association with serological protection has yet to be determined. OBJECTIVE: To investigate factors associated with vaccine-induced immunity among a sample of PWID randomly allocated to receive AUD$30 cash following receipt of doses two and three ('incentive condition') or standard care ('control condition') using an accelerated 3-dose (0,7,21 days) HBV vaccination schedule. STUDY DESIGN: A randomised controlled trial among PWID attending two inner-city health services and a field site in Sydney, Australia, assessing vaccine-induced immunity measured by hepatitis B surface antibodies (HBsAb ≥ 10 mIU/ml) at 12 weeks. The cost of the financial incentives and the provision of the vaccine program are also reported. RESULTS: Just over three-quarters of participants - 107/139 (77%)--completed the vaccination schedule and 79/139 (57%) were HBsAb ≥ 10 mIU/ml at 12 weeks. Vaccine series completion was the only variable significantly associated with vaccine-induced immunity in univariate analysis (62% vs 41%, p<0.035) but was not significant in multivariate analysis. There was no statistically discernible association between group allocation and series completion (62% vs 53%). The mean costs were AUD$150.5, (95% confidence interval [CI]: 142.7-158.3) and AUD$76.9 (95% CI: 72.6-81.3) for the intervention and control groups respectively. CONCLUSION: Despite increasing HBV vaccination completion, provision of financial incentives was not associated with enhanced serological protection. Further research into factors which affect response rates and the optimal vaccination regimen and incentive schemes for this population are needed.

Patterns of ecstasy use in Australia: findings from a national household survey.

AIM: To examine the patterns, correlates and context of 'recent' (preceding 12 months) ecstasy use using data from a nationally representative sample of Australians interviewed in 2001. DESIGN: Data were analysed from the 2001 National Drug Strategy Household Survey, a multi-stage probability sample of Australians aged 14 years or older. The focus was on ecstasy use among 14-19-year-olds and 20-29-year-olds, as the prevalence of recent use is highest among these groups. Recent ecstasy users were compared to those who had not used in the preceding 12 months and those who had never tried ecstasy ('others') on a range of demographic and drug use variables. Comparisons were also drawn between the patterns and context of ecstasy use of the two groups of recent ecstasy users (users aged between 14-19 and 20-29 years). FINDINGS: In 2001, 6.1% of Australians aged 14 years or older reported life-time ecstasy use, and 2.9% reported recent use. One in 10 (10.4%) of 20-29-year-olds and 5.0% of 14-19-year-olds had used ecstasy recently. Although there were few demographic differences between recent users and others, compared to those who had not recently used ecstasy, recent ecstasy users were more likely to have used a range of other drugs. Although recent ecstasy users of both age groups could be characterized as polydrug users, 20-29-year-old users were more likely to use other drugs concurrently with ecstasy. CONCLUSIONS: Following cannabis and amphetamines, ecstasy is the third most widely used illicit drug in Australia. Other than a greater likelihood of having used other drugs, few demographic variables appear to distinguish recent ecstasy users from others. Australian users in their 20s use ecstasy within a context of greater polydrug use than those in their teens. Although most ecstasy users described a pattern of occasional use, minorities reported weekly use, and difficulties in reducing their use despite wishing to do so. There is a need to develop interventions to assist problematic ecstasy users to reduce their use should they wish to do so and to increase education about the potential risks of combining ecstasy with other drugs.

Decreased heroin availability in Sydney in early 2001.

AIM: To examine the veracity of reports of a substantial decrease in the availability of heroin in Sydney in January 2001. DESIGN: Cross-sectional survey. SETTING: Sydney, Australia. PARTICIPANTS: Forty-one injecting drug users (IDUs) and 10 key informants (KIs). FINDINGS: Almost all IDUs (93%) reported that heroin was harder to obtain at the time of interview (mid-February 2001) than it was before Christmas 2000 and KIs concurred. IDUs (83%) and KIs (70%) also reported that the price of heroin had increased since Christmas, and that the purity of heroin had decreased (IDUs 73%; KIs 80%). Almost all IDUs reported a reduction in their heroin use and a subsequent increase in other drug use, particularly cocaine, benzodiazepines and cannabis. Similar reports about IDUs came from nine of the 10 KIs. Over half the KIs reported an increase in both property and violent crime as a result of the heroin shortage. This crime was reportedly occurring mainly between heroin suppliers and/or IDUs. Reports from other Australian jurisdictions suggest that the shortage was not specific to Sydney. CONCLUSIONS: The reduction in the availability of heroin provides a unique opportunity to investigate the impact of supply reduction.

The external validity of results derived from ecstasy users recruited using purposive sampling strategies.

This study sought to compare the patterns and correlates of 'recent' and 'regular' ecstasy use estimated on the basis of two datasets generated in 2001 in New South Wales, Australia, from a probability and a non-probability sample. The first was the National Drug Strategy Household Survey (NDSHS), a multistage probability sample of the general population; and the second was the Illicit Drug Reporting System (IDRS) Party Drugs Module, for which regular ecstasy users were recruited using purposive sampling strategies. NDSHS recent ecstasy users (any use in the preceding 12 months) were compared on a range of demographic and drug use variables to NDSHS regular ecstasy users (at least monthly use in the preceding 12 months) and purposively sampled regular ecstasy users (at least monthly use in the preceding 6 months). The demographic characteristics of the three samples were consistent. Among all three, the mean age was approximately 25 years, and a majority (60%) of subjects were male, relatively well-educated, and currently employed or studying. Patterns of ecstasy use were similar among the three samples, although compared to recent users, regular users were likely to report more frequent use of ecstasy. All samples were characterised by extensive polydrug use, although the two samples of regular ecstasy users reported higher rates of other illicit drug use than the sample of recent users. The similarities between the demographic and drug use characteristics of the samples are striking, and suggest that, at least in NSW, purposive sampling that seeks to draw from a wide cross-section of users and to sample a relatively large number of individuals, can give rise to samples of ecstasy users that may be considered sufficiently representative to reasonably warrant the drawing of inferences relating to the entire population. These findings may partially offset concerns that purposive samples of ecstasy users are likely to remain a primary source of ecstasy-related information.

Cocaine use in New South Wales, Australia, 1996-2000: 5 year monitoring of trends in price, purity, availability and use from the illicit drug reporting system.

This paper describes trends in the price, purity, availability and use of cocaine in Sydney, Australia monitored by the Illicit Drug Reporting System (IDRS) between 1996 and 2000. The IDRS monitors illicit drug trends by means of triangulation of data from interviews with injecting drug users (IDU), reports of key informants, and analysis of indicator data. The price of a 'cap' of cocaine fell from 80 Australian dollars in 1997 to 50 Australian dollars in 1998, and remained at the lower price in subsequent years. Cocaine purity was high in all years (range 50-64%), and was highest in the 1997-1998 period. The availability of cocaine and its use by IDU increased substantially, 1997 and 1998, and remained high in subsequent years. The median number of cocaine use days also increased substantially between 1997 (4 days) and 1998 (25 days), and remained at higher levels than prior to 1998 in subsequent years. Cocaine use was primarily of powder, by injection, and strongly associated with existing heroin injectors. The availability and use of crack remained rare in Sydney. Use of cocaine among IDU was associated with more frequent injections, more injection-related health problems, higher levels of needle sharing, and higher levels of criminality. It is concluded that the use and availability of cocaine in Sydney increased substantially between 1997 and 1998, and has remained entrenched in the Sydney illicit drug market. The regular and formal monitoring of illicit drug trends enabled substantial changes in the cocaine market in Sydney to be detected, and the information to be fed back to the health and law enforcement sectors.

Changes in patterns of drug injection concurrent with a sustained reduction in the availability of heroin in Australia.

Between 1996 and 2000, heroin was the drug most frequently injected in Australia, and viable heroin markets existed in six of Australia's eight jurisdictions. In 2001, there was a dramatic and sustained reduction in the availability of heroin that was accompanied by a substantial increase in its price, and a 14% decline in the average purity of seizures analysed by forensic laboratories. The shortage of heroin constitutes a unique natural experiment within which to examine the impact of supply reduction. This paper reviews one important correlate of the shortage, namely changes in patterns of illicit drug injection. A number of studies have consistently suggested that between 2000 and 2001, there was a sizeable decrease in both prevalence and frequency of heroin injection among injecting drug users. These changes were accompanied by increased prevalence and frequency of stimulant injection. Cocaine was favoured in NSW, the sole jurisdiction in which a cocaine market was established prior to the heroin shortage; whereas methamphetamine predominated in other jurisdictions. Some data suggest that, at least in the short-term, some drug injectors left the market altogether subsequent to the reduced heroin availability. However, the findings that (1) some former heroin users switched their drug preference to a stimulant; and (2) subsequently attributed this change to the reduced availability of heroin, suggests that reducing the supply of one drug may serve to increase the use of others. Given the differential harms associated with the use of stimulants and opiates, this possibility has grave implications for Australia, where the intervention and treatment system is designed primarily to accommodate opiate use and dependence.