Changes in the initiation of heroin use after a reduction in heroin supply

The opioid overdose crisis as a global health challenge

PURPOSE OF REVIEW

To assess the current state of the opioid overdose crisis along three major axes: drug markets and patterns of use, the effectiveness of systems of care, and international developments.

RECENT FINDINGS

Overdose is a major contributor to mortality and disability among people who use drugs. The increasing number of opioid overdoses in North America especially is an indication of changing drug markets and failing regional systems of care. Globally, we see three clusters of overdose prevalence: (1) a group of countries led by the United States with historically high rates of opioid overdose, (2) a group of countries with increasing rates within a concerning range, (3) a group with very low rates. The contamination of street drugs, the quality and accessibility of treatment, and the overall system of care all contribute to the prevalence of overdose.

SUMMARY

Drug markets and pattern of consumption in parts of the world are shifting towards contamination and opioids like fentanyl as the drug of choice, which dismantles insufficient and largely ineffective systems of care. Furthermore, outside of North America, more countries like Estonia, Lithuania, Sweden, Finland, and Norway show very concerning numbers. Without a consistent system response, effects will be devastating.

Opioid use disorder

Opioid use disorder (OUD) is a chronic relapsing disorder that, whilst initially driven by activation of brain reward neurocircuits, increasingly engages anti-reward neurocircuits that drive adverse emotional states and relapse. However, successful recovery is possible with appropriate treatment, although with a persisting propensity to relapse. The individual and public health burdens of OUD are immense; 26.8 million people were estimated to be living with OUD globally in 2016, with >100,000 opioid overdose deaths annually, including >47,000 in the USA in 2017. Well-conducted trials have demonstrated that long-term opioid agonist therapy with methadone and buprenorphine have great efficacy for OUD treatment and can save lives. New forms of the opioid receptor antagonist naltrexone are also being studied. Some frequently used approaches have less scientifically robust evidence but are nevertheless considered important, including community preventive strategies, harm reduction interventions to reduce adverse sequelae from ongoing use and mutual aid groups. Other commonly used approaches, such as detoxification alone, lack scientific evidence. Delivery of effective prevention and treatment responses is often complicated by coexisting comorbidities and inadequate support, as well as by conflicting public and political opinions. Science has a crucial role to play in informing public attitudes and developing fuller evidence to understand OUD and its associated harms, as well as in obtaining the evidence today that will improve the prevention and treatment interventions of tomorrow.

Post-war prevention: Emerging frameworks to prevent drug use after the War on Drugs

The prevention of drug use is one of the primary goals of the War on Drugs. However, despite investment in high-profile interventions such as social marketing campaigns and enforcement-based deterrence, these efforts have generally failed. With the emergence of novel policy frameworks to control and regulate drug use, a window of opportunity exists to test approaches to drug prevention that take into account existing evidence and the rights of individuals who use drugs. Specifically, there is a growing consensus that entry into drug use is a socially-defined event that individuals experience within particular socio-structural contexts. This understanding, coupled with a distinction between the value of preventing problematic drug use rather than all drug use, provides a useful framework within which to develop effective and rights-based approaches to drug prevention.

Anxiety disorders are associated with early onset of heroin use and rapid transition to dependence in methadone maintained patients

Early onset of heroin use is a severity marker of heroin use disorder. We studied the interaction between early onset and rapid transition to heroin dependence recorded with retrospective interviews in 213 patients with severe heroin dependence and history of methadone maintenance treatment. General linear models were used to identify independent factors associated with early onset, factors associated with rapid transition to dependence, and a multivariate model was used to study the interaction of those two dimensions. Lifetime history of anxiety disorders and age at onset of cannabis use are shared common risk factors and are associated with the interaction.

Effect of treatment willingness on specialist assessment and treatment uptake for hepatitis C virus infection among people who use drugs: the ETHOS study

Among people who inject drugs (PWID) with chronic HCV, the association between HCV treatment willingness and intent, and HCV specialist assessment and treatment were evaluated. The Enhancing Treatment for Hepatitis C in Opioid Substitution Settings (ETHOS) is a prospective observational cohort. Recruitment was through six opioid substitution treatment clinics, two community health centres and one Aboriginal community controlled health organisation in Australia. Analyses were performed using logistic regression. Among 415 participants (mean age 41 years, 71% male), 67% were 'definitely willing' to receive HCV treatment and 70% reported plans to initiate therapy 12 months postenrolment. Those definitely willing to receive HCV treatment were more likely to undergo specialist assessment (64% vs 32%, P < 0.001) and initiate therapy (36% vs 9%, P < 0.001), compared to those with lower treatment willingness. Those with early HCV treatment plans were more likely to undergo specialist assessment (65% vs 27%, P < 0.001) and initiate therapy (36% vs 5%, P < 0.001), compared to those without early plans. In adjusted analyses, HCV treatment willingness independently predicted specialist assessment (aOR 3.06, 95% CI 1.90, 4.94) and treatment uptake (aOR 4.33, 95% CI 2.14, 8.76). In adjusted analysis, having early HCV treatment plans independently predicted specialist assessment (aOR 4.38, 95% CI 2.63, 7.29) and treatment uptake (aOR 9.79, 95% CI 3.70, 25.93). HCV treatment willingness was high and predicted specialist assessment and treatment. Strategies for enhanced HCV care should be developed with an initial focus on people willing to receive treatment and to increase treatment willingness among those less willing.

How do drug market changes affect characteristics of injecting initiation and subsequent patterns of drug use? Findings from a cohort of regular heroin and methamphetamine injectors in Melbourne, Australia

BACKGROUND

Changes in drug market characteristics have been shown to affect drug use patterns but few studies have examined their impacts on injecting initiation experiences and subsequent patterns of injecting drug use (IDU).

METHODS

We collected data on self-reported injecting initiation experiences and past-month patterns of IDU from 688 regular heroin and methamphetamine injectors in Melbourne, Australia, who initiated injecting across three different drug market periods (prior to the Australian heroin shortage ('high heroin')/immediately following the shortage ('low heroin')/'contemporary' markets (fluctuating heroin and methamphetamine availability)). We used univariable and multivariable logistic regression to examine the relationship between period of injecting initiation and first drug injected, and multinomial logistic regression for the relationship between period of injecting initiation and current injecting patterns.

RESULTS

425 participants (62%) reported initiating injecting in the high heroin period, 146 (21%) in the low heroin period, and 117 (17%) in the contemporary period. Participants who initiated injecting during the low heroin period were twice as likely to initiate injecting using a drug other than heroin (AOR: 1.94, 95% CI: 1.27-2.95). The most common patterns of drug use among study participants in the month preceding interview were polydrug use (44%) and primary heroin use (41%). Injecting initiation period was either non-significantly or weakly associated with current drug use pattern, which was more strongly associated with other socio-demographic and drug use characteristics, particularly self-reported drug of choice.

CONCLUSION

The drug market period in which injecting initiation occurred influenced the first drug injected and influenced some aspects of subsequent drug use. In the context of highly dynamic drug markets in which polydrug use is common there is a need for broad harm reduction and drug treatment services which are flexible and responsive to changing patterns of drug use.

Polysubstance use: diagnostic challenges, patterns of use and health

PURPOSE OF REVIEW

Polysubstance use is common, particularly amongst some age groups and subcultures. It is also associated with elevated risk of psychiatric and physical health problems. We review the recent research findings, comment on changes to polysubstance diagnoses, report on contemporary clinical and epidemiological polysubstance trends, and examine the efficacy of preventive and treatment approaches.

RECENT FINDINGS

Approaches to describing polysubstance use profiles are becoming more sophisticated. Models over the last 18 months that employ latent class analysis typically report a no use or limited-range cluster (alcohol, tobacco and marijuana), a moderate-range cluster (limited range and amphetamine derivatives), and an extended-range cluster (moderate range, and nonmedical use of prescription drugs and other illicit drugs). Prevalence rates vary as a function of the population surveyed. Wide-ranging polysubstance users carry higher risk of comorbid psychopathology, health problems, and deficits in cognitive functioning.

SUMMARY

Wide-ranging polysubstance use is more prevalent in subcultures such as 'ravers' (dance club attendees) and those already dependent on substances. Health risks are elevated in these groups. Research into the prevention and treatment of polysubstance use is underdeveloped. There may be benefit in targeting specific polysubstance use and risk profiles in prevention and clinical research.

Lower life expectancy among people with an HCV notification: a population-based linkage study

Among people with hepatitis C virus (HCV) infection, liver disease-related deaths have risen over the last 20 years. Life expectancy has not been estimated in this population. HCV notifications (mandatory notification of anti-HCV-positive serology since 1991) reported to the New South Wales Health Department from 1992 to 2006 were linked to cause of death data. Abridged life tables were constructed from age-specific mortality rates. Life expectancy from ages 18-70 years for non-drug-related mortality causes was estimated using competing risk methods and compared to the general population of Australia. The cohort comprised 81 644 individuals with an HCV notification, with median follow-up of 7.6 years. Median age at notification was 34 years [interquartile range (IQR) 28-42] and 63% were male. Between 1992 and 2006, 4607 deaths occurred. Median age at liver- and drug-related death among males was 51 (IQR 45-66) and 36 (IQR 31-42) years, respectively, and among females was 63 (IQR 49-74) and 36 (IQR 30-41) years, respectively. In each year of follow-up before 2000, 15-21% of deaths were liver- and 30-39% were drug-related. After 2000, liver-related deaths increased to 20-26% of deaths in each year and drug-related deaths decreased to 13-19%. Excluding drug-related causes of death, life expectancy was lowered by an average of 4.2 (SD ± 1.0) and 5.4 (SD ± 0.7) years for males and females, respectively. Among people with an HCV notification, an increasing proportion of deaths are liver-related. Following removal of drug-related mortality, life expectancy in this population remained considerably lower, compared with the general population.

Causes of death in a cohort treated for opioid dependence between 1985 and 2005

AIMS

To examine changes in causes of death in a cohort treated for opioid dependence, across time and age; quantify years of potential life lost (YPLL); and identify avoidable causes of death.

DESIGN

People in New South Wales (NSW) who registered for opioid substitution therapy (OST), 1985-2005, were linked to a register of all deaths in Australia.

SETTING

NSW, Australia.

MEASUREMENTS

Crude mortality rates (CMRs), age-sex-standardized mortality rates (ASSRs) and standardized mortality ratios (SMRs) across time, sex and age. Years of potential life lost (YPLL) were calculated with reference to Australian life tables and by calculating years lost before the age of 65 years.

FINDINGS

There were 43 789 people in the cohort, with 412 216 person-years of follow-up. The proportion of the cohort aged 40+ years increased from 1% in 1985 to 39% in 2005. Accidental opioid overdoses, suicides, transport accidents and violent deaths declined with age; deaths from cardiovascular disease, liver disease and cancer increased. Among men, 89% of deaths were potentially avoidable; among women, 86% of deaths were avoidable. There were an estimated 160 555 YPLL in the cohort, an average of 44 YPLL per decedent and an average of 29 YPLL before age 65 years.

CONCLUSIONS

Among a cohort of opioid-dependent people in New South Wales, 1985-2005, almost nine in 10 deaths in the cohort were avoidable. There is huge scope to improve mortality among opioid-dependent people.

Interventions to prevent the initiation of injection drug use: a systematic review

BACKGROUND

Injection drug use has been identified as a key source of morbidity and mortality, primarily from overdose and the transmission of blood-borne diseases such as HIV. Experts have therefore called for the prioritization of resources toward the prevention of injection drug use. However, these strategies have not been systematically assessed.

METHODS

PRISMA guidelines were used to systematically review and extract findings from the peer-reviewed literature evaluating the effectiveness of interventions to prevent injecting initiation. We searched 10 English language electronic databases (PubMed, PsycINFO, EMBASE, Cochrane CENTRAL, CINAHL, Web of Science, TOXNET, AIDSLINE, AMED and ERIC), the Internet (Google, Google Scholar), and article reference lists, from database inception to June 1st, 2012.

RESULTS

Overall, out of 384 studies identified in the initial search, eight met the inclusion criteria. Studies evaluated four different types of interventions: social marketing, peer-based behavior modification, treatment, and drug law enforcement. Four studies observed a significant effect of the intervention on reducing rates of injecting initiation. Peer-based behavior modification and addiction treatment interventions were found to be most effective. Two of three studies assessing the impact of drug law enforcement on patterns of injecting initiation found no impact on injecting initiation, while one study reported inconclusive results.

CONCLUSION

There exists a limited scientific literature on strategies to prevent injecting initiation. Resources should be allocated toward increased research and development of effective interventions to prevent this phenomenon.

The relationship between age and risky injecting behaviours among a sample of Australian people who inject drugs

BACKGROUND

Limited evidence suggests that younger people who inject drugs (PWID) engage in high-risk injecting behaviours. This study aims to better understand the relationships between age and risky injecting behaviours.

METHODS

Data were taken from 11 years of a repeat cross-sectional study of sentinel samples of regular PWID (The Australian Illicit Drug Reporting System, 2001-2011). Multivariable Poisson regression was used to explore the relationship between age and four outcomes of interest: last drug injection occurred in public, receptive needle sharing (past month), experiencing injecting-related problems (e.g. abscess, dirty hit; past month), and non-fatal heroin overdose (past six months).

RESULTS

Data from 6795 first-time study participants were analysed (median age: 33 years, interquartile range [IQR]: 27-40; median duration of injecting: 13 years [IQR: 7-20]). After adjusting for factors including duration of injecting, each five year increase in age was associated with significant reductions in public injecting (adjusted incidence rate ratio [AIRR]: 0.90, 95% confidence interval [CI]: 0.88-0.92), needle sharing (AIRR: 0.84, 95% CI: 0.79-0.89) and injecting-related problems (AIRR: 0.96, 95% CI: 0.95-0.97). Among those who had injected heroin in the six months preceding interview, each five year increase in age was associated with an average 10% reduction in the risk of heroin overdose (AIRR: 0.90, 95% CI: 0.85-0.96).

CONCLUSIONS

Older PWID report significantly lower levels of high-risk injecting practices than younger PWID. Although they make up a small proportion of the current PWID population, younger PWID remain an important group for prevention and harm reduction.

Establishing the Melbourne Injecting Drug User Cohort Study (MIX): rationale, methods, and baseline and twelve-month follow-up results

BACKGROUND

Cohort studies provide an excellent opportunity to monitor changes in behaviour and disease transmission over time. In Australia, cohort studies of people who inject drugs (PWID) have generally focused on older, in-treatment injectors, with only limited outcome measure data collected. In this study we specifically sought to recruit a sample of younger, largely out-of-treatment PWID, in order to study the trajectories of their drug use over time.

METHODS

Respondent driven sampling, traditional snowball sampling and street outreach methods were used to recruit heroin and amphetamine injectors from one outer-urban and two inner-urban regions of Melbourne, Australia. Information was collected on participants' demographic and social characteristics, drug use characteristics, drug market access patterns, health and social functioning, and health service utilisation. Participants are followed-up on an annual basis.

RESULTS

688 PWID were recruited into the study. At baseline, the median age of participants was 27.6 years (IQR: 24.4 years - 29.6 years) and two-thirds (67%) were male. Participants reported injecting for a median of 10.2 years (range: 1.5 months - 21.2 years), with 11% having injected for three years or less. Limited education, unemployment and previous incarceration were common. The majority of participants (82%) reported recent heroin injection, and one third reported being enrolled in Opioid Substitution Therapy (OST) at recruitment. At 12 months follow-up 458 participants (71% of eligible participants) were retained in the study. There were few differences in demographic and drug-use characteristics of those lost to follow-up compared with those retained in the study, with attrition significantly associated with recruitment at an inner-urban location, male gender, and providing incomplete contact information at baseline.

CONCLUSIONS

Our efforts to recruit a sample of largely out-of-treatment PWID were limited by drug market characteristics at the time, where fluctuating heroin availability has led to large numbers of PWID accessing low-threshold OST. Nevertheless, this study of Australian injectors will provide valuable data on the natural history of drug use, along with risk and protective factors for adverse health outcomes associated with injecting drug use. Comprehensive follow-up procedures have led to good participant retention and limited attrition bias.

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.

Drug policy and the public good: evidence for effective interventions

Debates about which policy initiatives can prevent or reduce the damage that illicit drugs cause to the public good are rarely informed by scientific evidence. Fortunately, evidence-based interventions are increasingly being identified that are capable of making drugs less available, reducing violence in drug markets, lessening misuse of legal pharmaceuticals, preventing drug use initiation in young people, and reducing drug use and its consequences in established drug users. We review relevant evidence and outline the likely effects of fuller implementation of existing interventions. The reasoning behind the final decisions for action might be of a non-scientific nature, focused more on what the public and policy-makers deem of value. Nevertheless, important opportunities exist for science to inform these deliberations and guide the selection of policies that maximise the public good.

"Back then" and "nowadays": social transition narratives in accounts of injecting drug use in an East European setting

Whereas most research investigating drug use transitions narrows its analyses around the individual and their decision-making, we explore how personal narratives of drug transition interplay with broader narratives of social and economic change in a 'transition society' of post-Soviet Europe. Informed by narrative theory, we draw upon analyses of 42 audio-recorded qualitative interviews conducted in the city of Balti, Moldova, in late 2009, with people with current and recent experience of injecting drug use. Accounts of drug transition connect with stories of shifting socio-economic conditions, drug markets, drug law enforcement practices, and social relationships across generations. Participants cast themselves as the 'transition generation', juxtaposing 'their' time of drug initiation "back then" with "nowadays". We find that personal stories of drug initiation, transition and career are told in relation to a meta-narrative of social transition. Whereas 'back then', drug use was depicted as 'natural', 'home-produced', embedded in social relations, and symbolically valuable, in the post-transition narrative of 'now', this culture of drug use has become disrupted, through the internationalisation of drug markets, the individualisation of social relations, the weakening of social ties and trust relations, flux in moral boundaries, and shifting social values of drug use. The meta-narrative of social transition serves to bridge biographical adaptation as collective experience. This helps to moderate the social harms linked to the 'becoming other' constituted by drug injecting, and bridge the effects of rationed expectation that can characterise post-Soviet transitions. We suggest that the narrative of transition offers a cultural script that says "transition is to blame".

Fifteen years of HIV surveillance among people who inject drugs: the Australian Needle and Syringe Program Survey 1995-2009

OBJECTIVES

Following bipartisan political support in Australia for the timely introduction of needle and syringe programs (NSPs), HIV prevalence among people who inject drugs (PWID) remains low. This study aimed to determine the correlates of HIV infection among PWID; and to examine these correlates over time.

DESIGN

Annual cross-sectional seroprevalence studies among attendees of sentinel NSP sites.

METHOD

Multiple logistic regressions conducted on aggregated, de-duplicated data from 1995 to 2009 to determine variables independently associated with HIV infection.

RESULTS

Data were available for 22 478 individual NSP attendees, equating to a mean annual response rate of 44% (range 38-60%). Two-thirds of participants were men, with a median age of 30 years, and a median of 10 years since first injection. Eighty-five percent identified as heterosexual, 10% as bisexual and 5% as homosexual. Serology was available for 21 248 participants, of whom 230 (1.1%) tested HIV antibody positive. Variables independently associated with antibody seropositivity were homosexual or bisexual identity; male sex; older age; older age at first injection; and survey participation between 1995 and 1997 rather than later periods.

CONCLUSIONS

Unlike settings in which evidence-based public health approaches to illicit drug policy are yet to be implemented, the epidemiology of HIV among NSP attendees mirrors that of Australia's general population, with the majority of exposures attributed to male-to-male sexual contact. This pattern has remained unchanged over 15 years despite significant variation in drug markets and patterns of drug use. NSPs also play a crucial role in this country's comprehensive HIV surveillance mechanisms.

Modeling initiation into drug injection among street youth

This study aimed at examining the predictors of initiation into drug injection among street youth using social cognitive theory framework. A prospective cohort study based on semi-annual interviews was carried out. Psychosocial determinants referred to avoidance of initiation. Other potential predictors were: sociodemographic characteristics, relationships with injectors, parent's substance misuse, drug use patterns, homelessness, survival sex, sexual abuse. Independent predictors were identified using Cox proportional hazards regression models. Among the 352 participants, high control beliefs about avoidance of initiation was protective while younger age, daily alcohol consumption, heroin use, cocaine use, and survival sex all increased risk of initiation. Preventive strategies targeting street youth should both enhance youth's control beliefs and actual control over their substance use and improve their life conditions.

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.

Opioid agonist pharmacotherapy in New South Wales from 1985 to 2006: patient characteristics and patterns and predictors of treatment retention

AIMS

The aims of this study were to: examine the number and characteristics of patients entering and re-entering opioid replacement treatment between 1985 and 2006, to examine select demographic and treatment correlates of leaving treatment between 1985 and 2000, and to compare retention rates in methadone and buprenorphine maintenance treatment from 2001 to 2006.

DESIGN

A retrospective cohort study using register data from the Pharmaceutical Drugs of Addiction System.

SETTING

Opioid substitution treatment in New South Wales (NSW), Australia.

PARTICIPANTS

A total of n = 42 690 individuals prescribed opioid replacement treatment between 1985 and 2006 in NSW.

MEASUREMENTS

Client characteristics over time, retention in days in first treatment episode, number of episodes of treatment and proportion switching medication.

FINDINGS

Overall, younger individuals were significantly more likely to leave their first treatment episode than older individuals. In 2001-06, after controlling for age, sex and first administration point, the hazard of leaving treatment was 1.9 times for those on buprenorphine relative to those on methadone. Retention in treatment varied somewhat across historical time, with those entering during 1995-2000 more likely to leave at an earlier stage than those who entered before that time.

CONCLUSIONS

Retention in treatment appears to fluctuate in inverse proportion to the availability of heroin. Individuals in contemporary treatment are older users with a lengthy treatment history. This study has provided population-level evidence to suggest that retention in methadone and buprenorphine differ in routine clinical practice. Future work might investigate ways in which patient adherence and retention may be improved.

Comparing the dynamic course of heroin, cocaine, and methamphetamine use over 10 years

To examine dynamic changes in drug-use trajectories over time we analyzed episode types and predictors of quitting use over the 10 years following drug-use initiation for 1797 heroin, cocaine, and methamphetamine (meth) users. Most episodes reflected high use and incarceration, however these events occurred more frequently among heroin and meth users. Quitting was predicted by current treatment and self-help participation among meth (RR 2.57, 1.79-3.70; 2.57, 1.80-3.67) and cocaine (RR 2.00, 1.42-2.81; 2.10, 1.63-2.72) users, and by a history of quitting for meth users (RR 1.11, 1.06-1.17). Quitting was less likely among all users under legal supervision (RR 0.55-0.69) and among heroin (RR 0.66, 0.45-0.97) and meth users (RR 0.73, 0.60-0.89) with an early drug-use onset. Relative to cocaine or meth use, heroin use was characterized by persistent use at a high-level which was often only interrupted by incarceration. While quitting drug use can be facilitated by treatment and/or self-help participation, few people had these experiences in the 10 years following first use.

Implications of Inertia for Assessing Drug Control Policy: Why Upstream Interventions May Not Receive Due Credit

An empirically-derived model of national drug initiation is combined with a compartment model of trends in illicit drug use parameterized for Australia. Numbers of initiates seem to oscillate over time but with fluctuations whose aptitude diminishes over time. Lags and interpersonal variation in drug use careers smooth those oscillations for measures of problem use and total drug-related social cost, so even abrupt changes in initiation barely ripple the trajectory of drug-related social cost. Hence, the benefits of interventions that successfully disrupt initiation may be “hidden in plain sight” by being spread broadly over time so that they leave only the faintest finger-print detectable by before-and-after comparison. Thus, the absence of clear drops in drug-related problems does not imply that an upstream ntervention such as prevention or supply disruption did not produce substantial social benefits. More generally, drug use and related problems are often perceived of as stubborn, even intractable. Some of that perception stems from real limitations in the effectiveness of drug-control interventions. However, inertia inherent in the evolution of drug use can make even cost-effective interventions appear weak (and detrimental interventions appear benign).

Transition to injection drug use among street youth--a qualitative analysis

OBJECTIVES

To examine social contexts and processes influencing transition to drug injection among street youth.

METHODS

42 street youth participated in in-depth interviews. A typology of experiences was built founded on youth's street life and drug use trajectories. The transition to drug injection was examined through these experiences.

RESULTS

We identified five types of mutually exclusive experiences. The "downtowner's" experience is characterised by early street life and drug consumption trajectories, and a strong identification with the downtown milieu. These youth progress from one drug to another and, in a milieu where drug injection is omnipresent, this escalation culminates in transition to injection. The "tripper" street life and substance use trajectories begin later and are less intense. Most "tripper" youth are already chronic hallucinogens users when they arrive in downtown Montréal. Although they judge "junkies" severely, they show some ambivalence towards injection. The "on the go" experience is characterised by trajectories of drug use and street life that are intermingled, leading to a loss of control. These youth, who often have serious delinquent behaviours, come to downtown Montréal to party and consume drugs, mostly stimulants. Their drug use pattern and network make them at high risk of starting cocaine injection. The "hard-luck's" experience is characterised by a lack of identification with the downtown milieu. These youth who use drugs recreationally, end up in the streets accidentally, often because of unemployment. The "alcoholic' experience is related to alcohol misuse. These youth usually end up in the streets due to this dependence. Their street involvement is mostly an experience of solitude. The risk of transitioning to injection for both these types is low.

CONCLUSIONS

Some combinations of street life and drug use trajectories seem to contribute to injection among street youth. Some important factors interact and increase the risk of street youth transitioning to injection: poor personal assets; early rupture with primary social institutions; social integration into subcultures where both street life and "drug trips" are fashionable, drug preferences and the local drug market.

Dynamic compartmental model of trends in Australian drug use

A five-state compartment model of trends in illicit drug use in Australia is parameterized using data from multiple sources. The model reproduces historical prevalence and supports what-if analyses under the assumption that past trajectories of drug escalation and desistance persist. For fixed initiation, the system has a unique stable equilibrium. The chief qualitative finding is that even though some users escalate rapidly, regular injection drug use still adjusts to changes in incidence with considerable inertia and delay. This has important policy implications, e.g., concerning the timing of reductions in drug-related social cost generated by interventions that reduce the social cost per injection user versus those that cut drug initiation.