The association between cocaine use and short-term outcomes for the treatment of heroin dependence: findings from the Australian Treatment Outcome Study (ATOS)

Changes in substance use in relation to opioid agonist therapy among people who use drugs in a Canadian setting

BACKGROUND

Although previous studies have shown that opioid agonist therapy (OAT) is linked to reductions in illicit opioid use, less is known about how OAT impacts the use of other psychoactive substances. We aimed to examine the changes in use of different substances by comparing patterns before and after initiating OAT.

METHODS

Data for this study was derived from three ongoing prospective cohorts involving people who use drugs in Vancouver, Canada from 1996 to 2018. We assessed use patterns for heroin, illicit prescription opioid, cocaine, crack cocaine, crystal methamphetamine, cannabis, daily alcohol use, and benzodiazepines. Segmented regression was conducted to compare the trends of substance use between pre-treatment and post-treatment periods.

RESULTS

The study included 1107 participants. After OAT engagement, we observed an immediate decline in the proportion as well as a decreasing trend for heroin (Adjusted Odds Ratio (AOR): 0.80, 95% confidence interval (CI): 0.77, 0.83), illicit prescription opioid (AOR: 0.87, 95% CI: 0.83, 0.90), and benzodiazepines (AOR: 0.73, 95 % CI: 0.67, 0.80). There was no significant difference comparing the pre-treatment and post-treatment trends for cocaine, crack cocaine, crystal methamphetamine, and cannabis. However, higher growth slope was noted during the post-treatment period for daily alcohol use (P = 0.016).

CONCLUSIONS

We observed significant reduction in illicit opioids use following OAT initiation, but not for stimulant and cannabis. The increasing problematic use of alcohol may pose challenges to the safety and effectiveness of OAT. Development of comprehensive and tailored treatment strategies is needed for poly-substance users accessing OAT.

Polydrug Use and Heterogeneity in HIV Risk Among People Who Inject Drugs in Estonia and Russia: A Latent Class Analysis

Non-medical drug injection is a major risk factor for HIV infection in Russia and Estonia. Multiple drug use (polydrug) has further been associated with increased harms. We compared HIV, injecting and sexual risk associated with polydrug use among people who injected drugs (PWID) in 2012–2013 in Kohtla-Järve (Estonia, n = 591) and St Petersburg (Russia, n = 811). Using latent class analysis, we identified five (poly)drug classes, the largest consisting of single-drug injectors among whom an opioid was the sole drug injected (56% of PWID). The four remaining polydrug classes included polydrug-polyroute injectors who injected and used opiates and stimulants (9%), opiate-stimulant poly-injectors who injected amphetamine-type-stimulants with a primary opiate (7%) and opiate-opioid poly-injectors who injected opioids and opiates (16%). Non-injection stimulant co-users were injectors who also used non-injection stimulants (12%). In multivariable multinomial regressions, all four polydrug classes were associated with greater injection risks than single-drug injection, while opiate-stimulant and opiate-opioid poly-injection were also associated with having multiple sex partners. Riskier behaviours among polydrug-injectors suggest increased potential for transmission of blood-borne and sexually-transmitted infections. In addition to needles/syringes provision, services tailored to PWID drug and risk profiles, could consider drug-appropriate treatment and sexual risk reduction strategies to curb HIV transmission.

Polydrug use and its association with drug treatment outcomes among primary heroin, methamphetamine, and cocaine users

BACKGROUND

Polydrug use may challenge effective treatment for substance use disorders. We evaluate whether secondary substance use modifies the association between treatment and primary drug use among primary heroin, cocaine and methamphetamine (MA) users.

METHODS

Data were obtained from prospective cohort studies on people who use illicit drugs (PWUD) in California, USA. Using repeated monthly data on self-reported secondary substance use (heroin, cocaine, MA, alcohol or marijuana; ≥1day in a month), primary drug use (≥1day in a month), and treatment participation, collected via timeline follow-back, we fitted generalized linear mixed multiple regression models controlling for potential confounders to examine the interactions between treatment and secondary substance use on the odds of primary heroin, cocaine and MA use, respectively.

RESULTS

Included in our study were 587 primary heroin, 444 primary MA, and 501 primary cocaine users, with a median of 32.4, 13.3 and 18.9 years of follow-up, respectively. In the absence of secondary substance use, treatment was strongly associated with decreased odds of primary drug use (adjusted odds ratios (aORs): 0.25, 95% CI: 0.24, 0.27, 0.07 (0.06, 0.08), and 0.07 (0.07, 0.09)) for primary heroin, MA, and cocaine users, respectively. Secondary substance use of any kind moderated these associations (0.82 (0.78, 0.87), 0.25 (0.21, 0.30) and 0.53 (0.45, 0.61), respectively), and these findings were consistent for each type of secondary substance considered. Moreover, we observed different associations in terms of direction and magnitude between secondary substance use and primary drug use during off-treatment periods across substance types.

CONCLUSION

This study demonstrates secondary substance use moderates the temporal associations between treatment and primary drug use among primary heroin, MA and cocaine users. Disparate patterns of polydrug use require careful measurement and analysis to inform targeted treatment for polydrug users.

Patterns of use of other drugs among those with alcohol dependence: Associations with drinking behavior and psychopathology

INTRODUCTION

Alcohol dependence (AD) presents with substantial clinical heterogeneity, including concurrent use of non-alcohol drugs. Here, we examine specific patterns of concurrent non-alcohol substance use during the previous year among a nationally representative sample of adults with DSM-IV AD, and estimate their population prevalence in the U.S. We then evaluate alcohol use behavior and comorbid psychopathology among respondents with AD according to their patterns of concurrent non-alcohol substance use.

METHODS

These analyses utilized data from Waves 1 and 2 of the National Epidemiologic Survey on Alcohol and Related Conditions. Latent class analyses classified respondents with AD into four clinically meaningful patterns of concurrent substance use: (1) use of alcohol only; (2) use of alcohol and tobacco only; (3) use of alcohol, tobacco and cannabis; and (4) use of alcohol, tobacco, cannabis, cocaine, and other illicit drug(s).

RESULTS

Among AD respondents, the most prevalent pattern was the use of alcohol and tobacco only (weighted percentage, 32.4%), followed by the use of alcohol only (weighted percentage, 27.5%). AD respondents who used alcohol, tobacco, cannabis, cocaine, and other illicit drug(s) (weighted percentage, 25.3%) manifested the most severe pattern of alcohol consumption, and had significant overrepresentations of major depression, panic, and other anxiety disorders as well as paranoid, schizotypal, borderline, antisocial, and histrionic personality disorders compared with those who used alcohol alone.

CONCLUSIONS

Specific patterns of concurrent substance use convey important information regarding the clinical presentation and prognosis for AD. In particular, concurrent use of illicit drugs over the past year by AD individuals was associated with greater severity and comorbid psychopathology. These data suggest the need for pragmatic trials of AD interventions that take into account patterns of substance use behavior in addition to an AD diagnosis.

The impact of recent cocaine use on plasma levels of methadone and buprenorphine in patients with and without HIV-infection

Cocaine decreases methadone and buprenorphine plasma concentrations. HIV infection and/or antiretroviral medication use may impact these relationships. We sought to determine the association between recent cocaine use and methadone and buprenorphine concentrations in HIV-infected and uninfected subjects in clinical care. R- and S-methadone or buprenorphine and norbuprenorphine concentrations were assessed at 0.5, 1, 2, and 24 hours after dosing in subjects with confirmed cocaine use and abstinence. We compared methadone and buprenorphine concentrations for cocaine use vs. abstinence, by HIV status in 16 subjects receiving methadone (6 HIV-infected) and 17 receiving buprenorphine (8 HIV-infected). With recent cocaine use, peak R-methadone (244 vs. 297 ng/mL, p = 0.03) and peak S-methadone (285 vs. 339 ng/mL); p = 0.03 concentrations were lower in HIV-uninfected subjects only. Peak buprenorphine and norbuprenorphine concentrations were unchanged regardless of cocaine use or HIV status. Cocaine may decrease methadone concentrations in HIV-uninfected subjects. HIV infection or its treatment may attenuate cocaine's effect on methadone.

Predictors of non-prescribed opioid use after one year of methadone treatment: an attributable-risk approach (ANRS-Methaville trial)

BACKGROUND

The effectiveness of methadone as an opioid maintenance treatment (OMT) for opioid dependence has been widely demonstrated. However many patients continue to use other opioids while on methadone treatment. Studies assessing avoidable cases of continued non-prescribed opioid use during methadone treatment are sparse.

METHODS

At 12 months of treatment (M12), 158 subjects had available data on opioid use, measured using the Opiate Treatment Index. We identified variables associated with non-prescribed opioid use at M12, using a univariate logistic regression and two multivariate models, one incorporating only pre-treatment variables, the second adding the in-treatment variables. We also calculated attributable fractions for risk factors.

RESULTS

At M12, 32.3% of the patients had used non-prescribed opioids during the previous month. A good patient-physician relationship was the most influential factor associated with not using non-prescribed opioids after one year. Living with a heroin user after one year of treatment, using cocaine during treatment and hazardous alcohol consumption at enrolment were all associated with an increased risk of non-prescribed opioid use at M12. Analysis of attributable fractions indicated that living with a heroin user at M12 accounted for 21% of patients reporting non-prescribed opioid use at M12, while the lack of a good relationship with the physician accounted for 26%.

CONCLUSIONS

The attributable risk approach suggests that continued non-prescribed opioid use by a considerable proportion of individuals could potentially be reduced by improving patient-physician relationships, enhancing care for co-dependent patients and encouraging patients to modify their social network.

How do researchers categorize drugs, and how do drug users categorize them?

This paper considers drug classifications and terms widely used in US survey research, and compares these to classifications and terms used by drug users. We begin with a critical review of drug classification systems, including those oriented to public policy and health services as well as survey research. We then consider the results of a pile sort exercise we conducted with 76 respondents within a mixed method study of Southeast Asian American adolescent and young adult drug users in urban Northern California, USA. We included the pile sort to clarify how respondents handled specific terms which we understood to be related to Ecstasy and methamphetamines. Results of the pile sort were analyzed using graphic layout algorithms as well as content analysis of pile labels. Similar to the national surveys, our respondents consistently differentiated Ecstasy terms from methamphetamine terms. We found high agreement between some specific local terms (thizz, crystal) and popular drug terms, while other terms thought to be mainstream (crank, speed) were reported as unknown by many respondents. In labeling piles, respondents created taxonomies based on consumption method (in particular, pill) as well as the social contexts of use. We conclude by proposing that divergences between drug terms utilized in survey research and those used by drug users may reflect two opposing tendencies: the tendency of survey researchers to utilize standardized language that constructs persons and experiences as relatively homogeneous, varying only within measurable degrees, and the tendency of drug users to utilize specialized language (argot) that reflects their understandings of their experiences as hybrid and diverse. The findings problematize the validity of drug terms and categories used in survey research.

Impact of an 18-month, NHS-based, treatment exposure for heroin dependence: results from the London Area Treat 2000 Study

We set out to examine the impact of treatment for heroin dependence on drug use, injecting behavior, health problems, criminality, and physical and mental health over 18 months among heroin-dependent Londoners. A total of 100 heroin users were recruited for this longitudinal prospective cohort study with repeated measures (T0 as baseline, T1 after 9 months, and T2 after 18 months). The psychiatric evaluation and assessment of drug abuse levels were determined by the CIDI and the EuropASI. Additional evaluations included the WHO-DAS II for disability assessment and the UCLA-SSI for social support. The number of days of heroin use in the 30 days previous to each single assessment significantly reduced over time (p < .001). Similar reduction levels were observed for cocaine (p < .05), benzodiazepines (p < .001), and polydrug abuse (p < .001), but not for cannabis and alcohol. The number of injecting occasions reduced in parallel, with increase in days in work and reduction of money spent for drug acquisition activities and money obtained from criminal/illegal activities. The number of subjects experiencing suicidal ideation reduced over time (p < .05). In line with previous suggestions, significant reductions in drug use, criminality, psychopathology, and injecting behavior following treatment exposure for heroin dependence were observed. It is, however, of concern that alcohol and cannabis misuse levels remained unchanged.

Does concurrent cocaine use compromise 1-year treatment outcomes for opiate users?

The current study aimed to determine whether cocaine use compromises treatment outcomes for opiate users. Data were collected from 404 opiate users at treatment intake and 1-year follow-up as part of a national treatment outcome study. Because of higher intake measures, cocaine users improved in more outcomes than nonusers, but comparisons between groups found that cocaine users had more coexisting problems. Regression analysis revealed that those who used cocaine at intake were more likely to use cocaine at 1-year follow-up, to commit crime, and to be homeless. It is concluded that treatment for opiate use "works" even in the presence of concurrent cocaine use.

Acculturation and polysubstance abuse in Arab-American treatment clients

Acculturation to U.S. culture by Latinos and Asian Americans has been associated with increased prevalence of substance abuse. However, little is known about the association between acculturation and substance use among Arab Americans, or more specifically, among Arab-American treatment clients. In 156 Arab-American male treatment clients, we found that higher levels of U.S. acculturation were positively associated with increased prevalence of polysubstance abuse. This first report on a large series of Arab-American clients also found considerable within-group variability. These results can be used to develop treatment plans and work-force training on the importance of U.S. acculturation and variability within Arab Americans.

Comparison of characteristics of opioid-using pregnant women in rural and urban settings

Historically, research on opioid use during pregnancy has occurred in urban settings and it is unclear how urban and rural populations compare. We examined socio-demographic and other variables in opioid-using pregnant women seeking treatment and screened for participation in a multi-site randomized controlled trial. Women screened in rural Burlington, Vermont (n = 54), were compared to those screened in urban Baltimore, Maryland (n = 305). Rural opioid-using pregnant women appear to have some characteristics associated with better treatment outcomes (e.g., less severe drug use, greater employment). However, they may face additional barriers in accessing treatment (e.g., greater distance from treatment clinic).

Efficacy of central nervous system stimulant treatment for cocaine dependence: a systematic review and meta-analysis of randomized controlled clinical trials

AIMS

To evaluate the efficacy of central nervous system (CNS) stimulants compared with placebo for the treatment of cocaine dependence.

METHODS

A systematic review and meta-analysis was carried out. Bibliographic databases were searched, reference lists of retrieved studies were hand-searched and the first authors of each study were contacted. All randomized controlled clinical trials (RCCT) comparing the efficacy of any CNS stimulant with placebo in cocaine-dependent patients were included. Quantitative data synthesis was performed for each single CNS stimulant and for all CNS stimulants.

RESULTS

Nine RCCT met the inclusion criteria. These RCCT included 640 patients and compared five CNS stimulants: mazindol, dextroamphetamine, methylphenidate, modafinil and bupropion with placebo. No CNS stimulant improved study retention [RR = 0.94 (0.81-1.09)] or cocaine use [RR = 0.90 (0.79-1.02)]. An exploratory analysis using indirect estimations of cocaine use showed that the proportion of cocaine-positive urine screens was lower with dexamphetamine than with placebo [RR = 0.73 (0.60-0.90)] and that all CNS stimulants pooled together also suggested a significant decrease of cocaine use [RR = 0.87 (0.77-0.99)]. Data on craving could not be meta-analysed due to heterogeneity, but no RCCT found differences in cocaine craving between active drug and placebo except one, whose outcome favoured dexamphetamine. No serious adverse event (AE) was reported. Average of AE-induced dropouts was low and was greater for CNS stimulants than placebo: 4.4% versus 1.3% (P = 0.03).

CONCLUSION

The main outcomes of this study do not support the use of CNS stimulants for cocaine dependence. Nevertheless, secondary analyses provide some hopeful results that encourage further research with these drugs, mainly with dexamphetamine and modafinil.

The effect of baseline cocaine use on treatment outcomes for heroin dependence over 24 months: Findings from the Australian Treatment Outcome Study

AIMS

The aim of this study was to determine the effects of baseline cocaine use on treatment outcomes for heroin dependence over a 24-month period.

DESIGN

A longitudinal cohort (24 months) study was carried out. Interviews were conducted at baseline, 3, 12, and 24 months.

SETTING

The study setting was Sydney, Australia.

PARTICIPANTS

Six hundred fifteen heroin users were recruited for the Australian Treatment Outcome Study.

FINDINGS

Cocaine use was common at baseline (40%) but decreased significantly over the study period. Even after taking into account age, sex, treatment variables, current heroin use, and baseline polydrug use, baseline cocaine use remained a significant predictor of poorer outcomes across a range of areas. Baseline cocaine users were more likely to report heroin use, unemployment, needle sharing, criminal activity, and incarceration over the 24-month study period.

CONCLUSIONS

Cocaine consumption among heroin users has repercussions across a range of areas that persist far beyond the actual period of use. Consequently, treatment providers should regard cocaine use among clients as an important marker for individuals who are at risk of poorer treatment outcome.

The Australian Treatment Outcome Study (ATOS): what have we learnt about treatment for heroin dependence?

Opioids make the single largest contribution to illicit drug-related mortality and morbidity worldwide In this paper we reflect upon what has been learnt regarding treatment outcome and the natural history of heroin use from the Australian Treatment Outcome Study (ATOS). We focus on what we knew prior to ATOS, what ATOS revealed that is novel, and the implications for research, practice and policy. ATOS provided strong evidence for sustained improvement attributable to treatment across the three years of the study. It is argued that treatment for heroin dependence is money well spent, and leads to clear and sustained benefits to both heroin users and society.

Psychosocial approaches to psychostimulant dependence: A systematic review

This review examines the nature and evidence for the effectiveness of psychosocial interventions for psychostimulant dependence. Psychostimulant dependence and related harms continue to increase in many parts of the world, while treatment responses are predominantly limited to psychosocial interventions. The effectiveness of psychosocial interventions is compromised by poor rates of treatment induction and retention. As with other substance use disorders, increasing the diversity of treatment options is likely to improve treatment coverage and outcomes across a broader range of users. Identifying medications that might enhance treatment induction and retention would also enhance the effectiveness of psychosocial programs. It is concluded that psychosocial interventions are moderately effective in reducing psychostimulant use and related harms among psychostimulant-dependent persons.