The effect of persistence of cocaine use on 12-month outcomes for the treatment of heroin dependence

Integrative Pharmacology in the Treatment of Substance Use Disorders

The detrimental physical, mental, and socioeconomic effects of substance use disorders (SUDs) have been apparent to the medical community for decades. However, it has become increasingly urgent in recent years to develop novel pharmacotherapies to treat SUDs. Currently, practitioners typically rely on monotherapy. Monotherapy has been shown to be superior to no treatment at all for most substance classes. However, many randomized controlled trials (RCTs) have revealed that monotherapy leads to poorer outcomes when compared with combination treatment in all specialties of medicine. The results of RCTs suggest that monotherapy frequently fails since multiple dysregulated pathways, enzymes, neurotransmitters, and receptors are involved in the pathophysiology of SUDs. As such, research is urgently needed to determine how various neurobiological mechanisms can be targeted by novel combination treatments to create increasingly specific yet exceedingly comprehensive approaches to SUD treatment. This article aims to review the neurobiology that integrates many pathophysiologic mechanisms and discuss integrative pharmacology developments that may ultimately improve clinical outcomes for patients with SUDs. Many neurobiological mechanisms are known to be involved in SUDs including dopaminergic, nicotinic, N-methyl-D-aspartate (NMDA), and kynurenic acid (KYNA) mechanisms. Emerging evidence indicates that KYNA, a tryptophan metabolite, modulates all these major pathophysiologic mechanisms. Therefore, achieving KYNA homeostasis by harmonizing integrative pathophysiology and pharmacology could prove to be a better therapeutic approach for SUDs. We propose KYNA-NMDA-α7nAChRcentric pathophysiology, the "conductor of the orchestra," as a novel approach to treat many SUDs concurrently. KYNA-NMDA-α7nAChR pathophysiology may be the "command center" of neuropsychiatry. To date, extant RCTs have shown equivocal findings across comparison conditions, possibly because investigators targeted single pathophysiologic mechanisms, hit wrong targets in underlying pathophysiologic mechanisms, and tested inadequate monotherapy treatment. We provide examples of potential combination treatments that simultaneously target multiple pathophysiologic mechanisms in addition to KYNA. Kynurenine pathway metabolism demonstrates the greatest potential as a target for neuropsychiatric diseases. The investigational medications with the most evidence include memantine, galantamine, and N-acetylcysteine. Future RCTs are warranted with novel combination treatments for SUDs. Multicenter RCTs with integrative pharmacology offer a promising, potentially fruitful avenue to develop novel therapeutics for the treatment of SUDs.

Associations Between Buprenorphine\Naloxone and Methadone Treatment and non-Opioid Substance Use in Prescription-Type Opioid Use Disorder: Secondary Analyses From the OPTIMA Study: Associations entre le traitement avec la buprénorphine/naloxone et avec la méthadone et l'utilisation de substances non opioïdes dans le trouble lié à l'usage d'opioïdes de type sur ordonnance : analyses secondaires de l'étude OPTIMA

OBJECTIVES

There is limited evidence on how opioid agonist treatment (OAT) may affect psychoactive non-opioid substance use in prescription-type opioid use disorder (POUD) and whether this effect might explain OAT outcomes. We aimed to assess the effect of methadone on non-opioid substance use compared to buprenorphine/naloxone (BUP/NX), to explore whether non-opioid substance use is associated with opioid use and retention in treatment, and to test non-opioid use as a moderator of associations between methadone with retention in OAT and opioid use compared to BUP/NX.

METHODS

This is a secondary analysis of data from the OPTIMA trial, an open-label, pragmatic, parallel, two-arm, pan-Canadian, multicentre, randomized-controlled trial to compare standard methadone model of care and flexible take-home dosing BUP/NX for POUD treatment. We studied the effect of methadone and BUP/NX on non-opioid substance use evaluated by urine drug screen (UDS) and by classes of non-opioid substances (i.e., tetrahydrocannabinol [THC], benzodiazepines, stimulants) (weeks 2-24) using adjusted generalized estimation equation (GEE). We studied the association between non-opioid substance-positive UDS and opioid-positive UDS and retention in treatment, using adjusted GEE and logistic regressions.

RESULTS

Overall, methadone was not associated with non-opioid substance-positive UDS compared to BUP/NX (OR: 0.78; 95%CI, 0.41 to 1.48). When non-opioid substances were studied separately, methadone was associated with lower odds of benzodiazepine-positive UDS (OR: 0.63; 95% CI: 0.40 to 0.98) and THC-positive UDS (OR: 0.47; 95% CI: 0.28 to 0.77), but not with different odds of stimulant-positive UDS (OR: 1.29; 95% CI: 0.78 to 2.16) compared to BUP/NX. Substance-positive UDS, overall and separate classes, were not associated with opioid-positive UDS or retention in treatment.

CONCLUSION

Methadone did not show a significant effect on overall non-opioid substance use in POUD compared to BUP/NX treatment but was associated with lower odds of benzodiazepine and THC use in particular. Non-opioid substance use did not predict OAT outcomes. Further research is needed to ascertain whether specific patterns of polysubstance use (quantity and frequency) may affect treatment outcomes.

Effects of a Two-Month Exercise Training Program on Concurrent Non-Opiate Substance Use in Opioid-Dependent Patients during Substitution Treatment

BACKGROUND

This randomized controlled trial aimed to evaluate the effects of a two-month exercise intervention on the concurrent non-opiate substance use (alcohol, cocaine, cannabis, and benzodiazepines) in opioid users during their medication treatment.

METHODS

Ninety opioid users (41 females) in methadone and buprenorphine medication treatment were randomly divided into four groups: (a) buprenorphine experimental (BEX; n = 26, aged 41.9 ± 6.1 yrs); (b) buprenorphine control (BCON; n = 25, aged 41.9 ± 5.6 yrs); (c) methadone experimental (MEX; n = 20, aged 46.7 ± 6.6 yrs); and (d) methadone control (MCON; n = 19, aged 46.1 ± 7.5 yrs). The experimental groups (BEX and MEX) followed an aerobic exercise training program on a treadmill for 20 min at 70% HRmax, 3 days/week for 8 weeks. Socio-demographic, anthropometric, and clinical characteristics, as well as non-opioid drug use in days and quantity per week, were assessed before and after the intervention period.

RESULTS

Following the exercise training, the weekly non-opioid substance consumption (days) decreased (p < 0.05) in both exercise groups and was lower in BEX compared to MEX, while no differences were observed (p > 0.05) between the control groups (BCON vs. MCON) or compared to their baseline levels. Similarly, the daily amount of non-opiate substance intake was reduced (p < 0.05) post-training in BEX and MEX, whereas it did not differ (p > 0.05) in BCON and MCON compared to the baseline.

CONCLUSIONS

The two-month exercise intervention reduced the non-opioid drug use in both the methadone and buprenorphine substitution groups compared to the controls, suggesting that aerobic exercise training may be an effective strategy for treating patients with OUDs.

The four-factor personality model and its qualitative correlates among opioid agonist therapy clients

Background

The Four Factor Personality Vulnerability model identifies four specific personality traits (e.g., sensation seeking [SS], impulsivity [IMP], anxiety sensitivity [AS], and hopelessness [HOP]) as implicated in substance use behaviors, motives for substance use, and co-occurring psychiatric conditions. Although the relationship between these traits and polysubstance use in opioid agonist therapy (OAT) clients has been investigated quantitatively, no study has examined the qualitative expression of each trait using clients' voice.

Method

Nineteen Methadone Maintenance Therapy (MMT) clients (68.4% male, 84.2% white, mean age[SD] = 42.71 [10.18]) scoring high on one of the four personality traits measured by the Substance Use Risk Profile Scale [SURPS] completed a semi-structured qualitative interview designed to explore their lived experience of their respective trait. Thematic analysis was used to derive themes, which were further quantified using content analysis.

Results

Themes emerging from interviews reflected (1) internalizing and externalizing symptoms, (2) adversity experiences, and (3) polysubstance use. Internalizing symptoms subthemes included symptoms of anxiety, fear, stress, depression, and avoidance coping. Externalizing subthemes included anger, disinhibited cognitions, and anti-social and risk-taking behaviors. Adverse experiences subthemes included poor health, poverty, homelessness, unemployment, trauma, and conflict. Finally, polysubstance use subthemes include substance types, methods of use, and motives. Differences emerged between personality profiles in the relative endorsement of various subthemes, including those pertaining to polysubstance use, that were largely as theoretically expected.

Conclusion

Personality is associated with unique cognitive, affective, and behavioral lived experiences, suggesting that personality may be a novel intervention target in adjunctive psychosocial treatment for those undergoing OAT.

Polysubstance use in South Asia

PURPOSE OF REVIEW

Polysubstance use is very common in the world, but there has been limited research in this area. South Asia is sandwiched between two of the world's largest heroin producing areas: the Golden Crescent and the Golden Triangle. The burden and prevalence of polysubstance use have not been estimated in this region of the world. We review the research findings on polysubstance use in different South Asian countries. The review also comments on the gaps in knowledge regarding polysubstance use in this region of the world.

RECENT FINDINGS

The available literature on polysubstance use from South Asia suggests its widespread presence in the region, ranging from 20 to 90%, more commonly among illicit opioid drug users and injection drug users. Most of the available data is from epidemiological studies. There are few studies on the adverse effects of polysubstance use, but the limited data clearly suggests an elevated risk of comorbid psychopathology and health problems.

SUMMARY

Polysubstance use still lacks a consensus definition. There is a need of more research on its prevalence, effects on health, and prevention and treatment.

Current Perspectives on Selective Dopamine D3 Receptor Antagonists/Partial Agonists as Pharmacotherapeutics for Opioid and Psychostimulant Use Disorders

Over three decades of evidence indicate that dopamine (DA) D3 receptors (D3R) are involved in the control of drug-seeking behavior and may play an important role in the pathophysiology of substance use disorders (SUD). The expectation that a selective D3R antagonist/partial agonist would be efficacious for the treatment of SUD is based on the following key observations. First, D3R are distributed in strategic areas belonging to the mesolimbic DA system such as the ventral striatum, midbrain, and ventral pallidum, which have been associated with behaviors controlled by the presentation of drug-associated cues. Second, repeated exposure to drugs of abuse produces neuroadaptations in the D3R system. Third, the synthesis and characterization of highly potent and selective D3R antagonists/partial agonists have further strengthened the role of the D3R in SUD. Based on extensive preclinical and preliminary clinical evidence, the D3R shows promise as a target for the development of pharmacotherapies for SUD as reflected by their potential to (1) regulate the motivation to self-administer drugs and (2) disrupt the responsiveness to drug-associated stimuli that play a key role in reinstatement of drug-seeking behavior triggered by re-exposure to the drug itself, drug-associated environmental cues, or stress. The availability of PET ligands to assess clinically relevant receptor occupancy by selective D3R antagonists/partial agonists, the definition of reliable dosing, and the prospect of using human laboratory models may further guide the design of clinical proof of concept studies. Pivotal clinical trials for more rapid progression of this target toward regulatory approval are urgently required. Finally, the discovery that highly selective D3R antagonists, such as R-VK4-116 and R-VK4-40, do not adversely affect peripheral biometrics or cardiovascular effects alone or in the presence of oxycodone or cocaine suggests that this class of drugs has great potential in safely treating psychostimulant and/or opioid use disorders.

Tramadol misuse in treatment-seeking adolescents and young adults with problematic substance use - Prediction of treatment retention

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Misuse of tramadol is increasingly highlighted as a problem in adolescents and adults.

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In treatment for substance use in the young, tramadol use increased the risk of treatment drop-out.

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Tramadol misuse, hitherto little examined, requires further clinical research.

Non-medical prescription use of opioids (NMPUO) is a public health concern worldwide. Recently, tramadol misuse is increasing, but the systematic research of misuse of this specific opioid is limited. This study set out to assess the relationship between tramadol use and completion of treatment for substance use among adolescents and adults ≤ 25 years in an outpatient clinical setting. A retrospective cohort study of treatment outcome, expressed as “completion” or “non-completion” of treatment, was conducted in treatment-seeking adolescents with problematic substance use (n = 335). Data was extracted from Ung-DOK interviews, a semi-structured assessment instrument designed for adolescents with substance abuse. The study included all treatment-seeking patients at an out-patient facility in 2014–2017. A total of 26% (n = 88) were tramadol users (life-time prevalence). Twenty percent (n = 66) of all treatments were non-completed. Tramadol users were significantly more likely than non-users to drop out of treatment (35% vs 15%, p < 0.001). In multivariate logistic regression, tramadol use and age 18 and above were factors significantly associated with non-completion. Tramadol use was statistically significantly associated with non-completion of treatment. Further research addressing treatment needs and treatment completion among tramadol users is needed.

Effect of Combined Methamphetamine and Oxycodone Use on the Synaptic Proteome in an In Vitro Model of Polysubstance Use

Polysubstance use (PSU) generally involves the simultaneous use of an opioid along with a stimulant. In recent years, this problem has escalated into a nationwide epidemic. Understanding the mechanisms and effects underlying the interaction between these drugs is essential for the development of treatments for those suffering from addiction. Currently, the effect of PSU on synapses-critical points of contact between neurons-remains poorly understood. Using an in vitro model of primary neurons, we examined the combined effects of the psychostimulant methamphetamine (METH) and the prescription opioid oxycodone (oxy) on the synaptic proteome using quantitative mass-spectrometry-based proteomics. A further ClueGO analysis and Ingenuity Pathway Analysis (IPA) indicated the dysregulation of several molecular functions, biological processes, and pathways associated with neural plasticity and structural development. We identified one key synaptic protein, Striatin-1, which plays a vital role in many of these processes and functions, to be downregulated following METH+oxy treatment. This downregulation of Striatin-1 was further validated by Western blot. Overall, the present study indicates several damaging effects of the combined use of METH and oxy on neural function and warrants further detailed investigation into mechanisms contributing to synaptic dysfunction.

The effect of concurrent access to alcohol and oxycodone on self-administration and reinstatement in rats

RATIONALE

Although polysubstance use is highly prevalent, preclinical studies that assess voluntary consumption of multiple substances at the same time are rather uncommon. Overlooking drug taking patterns commonly observed in humans may limit the translational value of preclinical models.

OBJECTIVES

Here, we aimed to develop a model of polysubstance use that could be used to assess oral operant self-administration patterns under concurrent access to alcohol and the prescription opioid oxycodone.

METHODS

After a training period where animals associated specific cues and levers with each drug, rats self-administered alcohol and oxycodone solutions concurrently in daily sessions. Oxycodone was then removed to assess potential changes in alcohol consumption. The role of cues and stress on alcohol consumption and oxycodone seeking was also examined under reinstatement conditions.

RESULTS

We found that females consumed more alcohol and oxycodone than males when given access to both drugs, and this effect on alcohol intake persisted when oxycodone was removed. Additionally, re-exposure to oxycodone cues in combination with the administration of the pharmacological stressor yohimbine drove reinstatement of oxycodone seeking in females but did not have a strong effect in males, possibly due to low levels of oxycodone intake during active self-administration in male rats. Additionally, yohimbine drove increased alcohol consumption, in line with prior findings from our group and others.

CONCLUSIONS

Taken together, this study demonstrates that rats will concurrently self-administer both oxycodone and alcohol in operant chambers, and this procedure can serve as a platform for future investigations in polysubstance use and relapse-like behavior.

Optimizing Substance Use Treatment Selection Using Reinforcement Learning

Substance use disorder (SUD) exacts a substantial economic and social cost in the United States, and it is crucial for SUD treatment providers to match patients with feasible, effective, and affordable treatment plans. The availability of large SUD patient datasets allows for machine learning techniques to predict patient-level SUD outcomes, yet there has been almost no research on whether machine learning can be used to optimize or personalize which treatment plans SUD patients receive. We use contextual bandits (a reinforcement learning technique) to optimally map patients to SUD treatment plans, based on dozens of patient-level and geographic covariates. We also use near-optimal policies to incorporate treatments’ time-intensiveness and cost into our recommendations, to aid treatment providers and policymakers in allocating treatment resources. Our personalized treatment recommendation policies are estimated to yield higher remission rates than observed in our original dataset, and they suggest clinical insights to inform future research on data-driven SUD treatment matching.

Role of preexisting inhibitory control deficits vs. drug use history in mediating insensitivity to aversive consequences in a rat model of polysubstance use

RATIONALE

The nature and predictors of insensitivity to aversive consequences of heroin + cocaine polysubstance use are not well characterized.

OBJECTIVES

Translational methods incorporating a tightly controlled animal model of drug self-administration and measures of inhibitory control and avoidance behavior might be helpful for clarifying this issue.

METHODS

The key approach for distinguishing potential contributions of pre-existing inhibitory control deficits vs. drug use history in meditating insensitivity to aversive consequences was comparison of two rat strains: Wistar (WIS/Crl), an outbred strain, and the spontaneously hypertensive rat (SHR/NCrl), an inbred strain shown previously to exhibit heightened cocaine and heroin self-administration and poor inhibitory control relative to WIS/Crl.

RESULTS

In separate tasks, SHR/NCrl displayed greater impulsive action and compulsive-like behavior than WIS/Crl prior to drug exposure. Under two different schedules of drug delivery, SHR/NCrl self-administered more cocaine than WIS/Crl, but self-administered a similar amount of heroin + cocaine as WIS/Crl. When half the session cycles were punished by random foot shock, SHR/NCrl initially were less sensitive to punishment than WIS/Crl when self-administering cocaine, but were similarly insensitive to punishment when self-administering heroin + cocaine. Based on correlation analyses, only trait impulsivity predicted avoidance capacity in rats self-administering cocaine and receiving yoked-saline. In contrast, only amount of drug use predicted avoidance capacity in rats self-administering heroin + cocaine. Additionally, baseline drug seeking and taking predicted punishment insensitivity in rats self-administering cocaine or heroin + cocaine.

CONCLUSIONS

Based on the findings revealed in this animal model, human laboratory research concerning the nature and predictors of insensitivity to aversive consequences in heroin and cocaine polysubstance vs. monosubstance users is warranted.

Epidemiological trends in opioid-only and opioid/polysubstance-related death rates among American Indian/Alaska Native populations from 1999 to 2019: a retrospective longitudinal ecological study

OBJECTIVES

The rate of drug overdose deaths in the USA has more than tripled since the turn of the century, and rates are disproportionately high among the American Indian/Alaska Native (AI/AN) population. Little is known about the overall historical trends in AI/AN opioid-only and opioid/polysubstance-related mortality. This study will address this gap.

DESIGN

This is a retrospective longitudinal ecological study.

SETTING

US death records from 1999 to 2019 using the Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research.

PARTICIPANTS

US non-Hispanic AI/AN people age 12 years and older.

MEASURES

The primary outcomes, identified via the 10th revision of the International Statistical Classification of Diseases and Related Health Problems codes, included overdose deaths due to (1) opioids only, opioids in combination with any other substance, all-opioid related overdoses; (2) combinations of opioids and alcohol, opioids and methamphetamine, opioids and cocaine, opioids and benzodiazepines; and (3) specific types of opioids.

RESULTS

From 1999 to 2019, opioid-only mortality rates increased from 2.8 to 15.8 per 100 000 (p<0.001) for AI/AN women and 4.6 to 25.6 per 100 000 (p<0.001) for AI/AN men. All opioid-related mortality rates increased significantly (p<0.001) from 5.2 to 33.9 per 100 000 AI/AN persons, 3.9 to 26.1 for women and 6.5 to 42.1 for men. AI/AN also exhibited significant increases in mortality rates due to opioids and alcohol, opioids and benzodiazepines, opioids and methamphetamine, and AI/AN men experienced substantial increases in mortality due to opioids and cocaine. Mortality rates by individual opioid types increased significantly over time for heroin, natural and semi-synthetic (prescription), and synthetic opioids (fentanyl/fentanyl analogues) other than methadone.

CONCLUSIONS

These findings highlight magnification over time in opioid-related deaths and may point to broader systemic factors that may disproportionately affect members of AI/AN communities and drive inequities.

Addressing injecting related risks among people who inject both opioids and stimulants: Findings from an Australian survey of people who inject drugs

Background

Opioids and stimulants are the most commonly injected illicit drugs worldwide and in Australia. While some people who inject drugs (PWID) prefer either opioids or stimulants, others regularly use both opioids and stimulants. Limited available research indicates that those who use opioids and stimulants together, either in combination or alternating between the two, may engage in injection-related practices which potentially place them at greater health risk and could lead to poorer health outcomes.

Methods

Participants were recruited nationally through member organizations of the Australian Injecting and Illicit Drug Users League (AIVL); these organizations represent PWID in each Australian state and territory. This study compared a sample of PWID (N = 535) who reported past-month injection of opioids only (N = 173), stimulants only (N = 208), or both (N = 154) on a range of health and wellbeing outcomes. PWID completed a survey assessing drugs injected, frequency of injecting, receptive equipment sharing, psychological distress, self-reported hepatitis C (HCV) status, experienced and internalized stigma, drug use salience, and community attachment.

Results

People who injected both opioids and stimulants reported more frequent injecting, more experiences of stigma, and greater reported HCV diagnosis than people who injected stimulants or opioids alone. They also showed greater attachment to a community of PWID and greater salience of drug use to their identity.

Conclusions

The findings of increased injecting and broader harms associated with injecting both stimulants and opioids are important for tailoring harm reduction and intervention designs for people who use both opioid and stimulant drugs, including prioritizing peer-based approaches.

Modeling Stimulant and Opioid Co-use in Rats Provided Concurrent Access to Methamphetamine and Fentanyl

Concurrent use of stimulants (e.g., methamphetamine) and opioids (e.g., fentanyl) has become increasingly common in recent years and continues to pose an enormous health burden, worldwide. Despite the prevalence, relatively little is known about interactions between the reinforcing effects of stimulants and opioids in this pattern of polysubstance use. The goals of the current study were to evaluate the relative reinforcing and relapse-related effects of methamphetamine and fentanyl using a concurrent access, drug-vs.-drug choice procedure. Male Sprague-Dawley rats were first allowed to acquire self-administration for either 0.1 mg/kg/infusion methamphetamine or 0.0032 mg/kg/infusion fentanyl, independently, after which concurrent access to both drugs was provided. When training doses of methamphetamine and fentanyl were concurrently available, a subset of rats self-administered both drugs, either within a session or alternating across sessions, whereas the remaining rats responded exclusively for one drug. When the cost of the preferred drug was increased (i.e., unit dose reduced), or the cost of the non-preferred drug was decreased (i.e., unit dose increased), choice was largely allocated toward the cheaper alternative. Following extinction of responding, methamphetamine- and fentanyl-paired cues reinstated responding on both levers. Responding reinstated by a priming injection of methamphetamine or fentanyl allocated more responding to the lever previously reinforced by the priming drug. The current studies suggest that choice of methamphetamine and fentanyl is largely allocated to the cheaper alternative, although more co-use was observed than would be expected for economic substitutes. Moreover, they lay the groundwork for more fully evaluating interactions between commonly co-abused drugs (e.g., stimulants and opioids) in order to better understand the determinants of polysubstance use and develop effective treatment strategies for individuals suffering from a polysubstance use disorder.

Naturalistic follow-up after a trial of medications for opioid use disorder: Medication status, opioid use, and relapse

AIM

This report examined naturalistic opioid use outcomes and utilization of medications for opioid use disorder (MOUD) 36 weeks post-randomization in the National Drug Abuse Treatment Clinical Trials Network (CTN) Extended-Release Naltrexone (XR-NTX) versus Buprenorphine-Naloxone (BUP-NX) for Opioid Treatment trial (CTN-0051, X:BOT).

DESIGN

X:BOT was a multisite, randomized, 24-week comparative effectiveness trial of BUP-NX (N = 287) and XR-NTX (N = 283). Study medications were discontinued following treatment completion, relapse, or dropout. Participants were encouraged to continue MOUD. This report examined opioid use outcomes in 428 (75%) of the 570 participants who attended the 36-week follow-up visit.

SETTING AND PARTICIPANTS

Adults with opioid use disorder recruited from 8 community treatment programs across the United States.

MEASUREMENTS

Outcomes included medication status (on/off MOUD), type of MOUD (BUP-NX, XR-NTX, or methadone), abstinence from non-prescribed opioids, opioid use days, relapse, and other substance use 30 days prior to the 36-week visit. Relapse was defined as opioid use for 4 consecutive weeks or 7 consecutive days in the past month. Baseline and clinical variables included opioid use severity, intravenous drug use, study medication assignment, and induction status.

FINDINGS

Of the 428 participants who completed the 36-week visit, 225 (53%) of participants were receiving MOUD and 203 (47%) were not. Compared to those off medication, participants on medication had fewer opioid use days (4.4 days (SD 9.0) versus 9.8 days (SD 12.1)), fewer met relapse criteria (37 (16.4%) versus 79 (38.9%)), and reported less stimulant use (34 (15.2%) versus 56 (27.7%)) and sedative use (14 (6.3%) versus 31 (15.3%)). There was no difference in abstinence rates between those on or off MOUD. A greater proportion of participants on XR-NTX (47 (53.4%) of 88 participants) were abstinent from non-prescribed opioids compared to those on buprenorphine (28 (23.3%) of 120 participants).

CONCLUSIONS

Naturalistic outcomes data showed that despite potential barriers to continuing treatment in the community, about half of individuals were on opioid use disorder pharmacotherapy at follow-up and those on medication generally had better outcomes. Future research should explore barriers and facilitators to treatment retention in community settings; and developing interventions tailored to improve treatment engagement and adherence.

Age of Onset and Its Related Factors in Cocaine or Methamphetamine Use in Adults from the United States: Results from NHANES 2005-2018

Cocaine and methamphetamine are widely used illicit psychostimulants worldwide, with steadily increasing global markets that may impact on the frequency of use. Importantly, their use typically begins in youth. This is a particular concern because there is a link between the early age of first substance use and severity of substance use disorder later in life. The aim of the present study was therefore to investigate trends in prevalence, frequency, and age of onset of cocaine or methamphetamine use between 2005 and 2018 in the United States, using the nationally representative NHANES datasets. Factors associated with the ages of cocaine or methamphetamine use onset were also identified. From 2005 to 2018, prevalence and frequencies of cocaine or methamphetamine use increased, while age of onset remained relatively stable (~20 years of age). Annual household income, use of other substances, and intravenous drug use were identified as factors associated with early onset cocaine or methamphetamine use. These factors have important implications toward developing new prevention programs to reduce psychostimulant use.

Prevalence and Characteristics of Borderline Intellectual Functioning in a Cohort of Patients With Polysubstance Use Disorder

Objective: To determine the prevalence and associated demographic and clinical features of borderline intellectual functioning (BIF) among individuals with polysubstance use disorder (pSUD). Methods: We applied a cross-sectional analytical design to data from the Norwegian STAYER study (n = 162), a cohort study of patients with a pSUD from the Stavanger University hospital catchment area. We used Wechsler Abbreviated Scale of Intelligence Full Scale IQ (FSIQ) to define BIF (FSIQ = 70-85) and non-BIF (FSIQ = >85) and collected demographic and clinical data using semi-structured interviews and self-reports on the Symptom Checklist 90-Revised (SCL-90-R) and the Satisfaction With Life Scale (SWLS). Results: The prevalence of BIF was 18% in the present study. The presence of BIF was associated with higher SCL-90-R GSI scores than in the non-BIF group. There were no significant differences between the BIF and non-BIF groups regarding age, gender, participation in meaningful daily activity, years of work experience, years of education, satisfaction with life, level of care, treatment attempts, age at substance-use onset, years of substance use, history of injecting drugs, or age of onset of injecting drugs. Conclusion: The present study confirmed a higher prevalence of BIF among patients with pSUD than expected from the distribution of IQ scores in a general population. Elevated SCL-90-R GSI scores suggested that BIF is associated with increased psychological distress in patients receiving treatment for pSUD. Further studies on this association, and its effect on treatment procedure and outcomes are strongly warranted.

Long term pre-treatment opioid use trajectories in relation to opioid agonist therapy outcomes among people who use drugs in a Canadian setting

BACKGROUND

Opioid agonist therapy (OAT) models are generally provided without consideration of how pre-treatment characteristics may be associated with outcome. Therefore, we aimed to first characterize longitudinal trajectories of opioid use before initiating OAT. Then we explored the impact of OAT on opioid use across these pre-treatment trajectories.

METHODS

Data were derived from three prospective cohort studies involving people who use drugs in Vancouver, Canada. Latent class growth analysis was applied to identify opioid use trajectories based on individual-level observations three years before starting OAT. Multivariable generalized linear mixed model was used to examine whether engaging in OAT was associated with lower risk of illicit opioid use among participants with different pre-treatment opioid use trajectories.

RESULTS

464 participants were included in the study between September 2005 and November 2018. Two pre-treatment opioid use trajectories were identified: high frequency users (246, 53.0%) and gradually increasing frequency users (218, 47.0%). We observed different strengths of association between OAT engagement and illicit opioid use among high frequency users (adjusted odds ratio [AOR] = 0.36, 95% Confidence Interval [CI]: 0.20 - 0.63) and gradually increasing frequency users (AOR = 0.91, 95% CI: 0.53 - 1.56). Unstable housing, any stimulant use, experiencing violence, drug dealing, sex work involvement, and incarceration were independently and positively associated with ongoing illicit opioid use.

CONCLUSIONS

Distinct pre-treatment opioid use trajectories are likely to influence treatment outcomes. Research is required to determine if tailored strategies specific to people with different pre-treatment opioid use patterns have potential to improve outcomes of OAT.

The switch from one substance-of-abuse to another: illicit drug substitution behaviors in a sample of high-risk drug users

Background

Substitution can be defined as the consciously motivated choice to use one drug, either licit or illicit, instead of another, due to perceptions of cost, availability, safety, legality, substance characteristics, and substance attributions. Substitution represents a potential risk to drug users, mainly when substitutes are of higher potency and toxicity. This study offers a basic conceptualization of illicit substitution behavior and describes substitution patterns among users of two highly prevalent drugs of abuse-heroin and cannabis.

Methods

Here, 592 high-risk drug users undergoing pharmacological and psycho-social treatment were interviewed. Patients were asked questions about current drug use, lifetime substitution, and substitution patterns. Descriptive statistics, chi-square tests of independence, and multinomial logistic regressions were used to identify and test correlates of substitution patterns for heroin and cannabis.

Results

Of the 592 drug users interviewed, 448 subjects (75.7%) reported having substituted their preferred drug for another illicit substance. Interviews yielded a total of 275 substitution events reported by users of cannabis, and 351 substitution events reported by users of heroin. The most frequently reported substitution substances for responders who preferred heroin were illicit non-prescribed "street" methadone (35.9%), followed by oral and transdermal prescription opioids (17.7%). For responders who preferred cannabis, substitution for synthetic cannabinoid receptor agonists (33.5%) followed by alcohol (16.0%) were the most commonly reported. Age at onset-of-use (p < 0.005), population group (p = 0.008), and attending treatment for the first time (p = 0.026) were significantly associated with reported lifetime substitution. Past-year use of stimulants, heroin, hallucinogens, methylenedioxymethamphetamine (MDMA), and novel psychoactive substances were-at the 95% confidence level-also significantly associated with reported lifetime substitution. In multivariate analysis, the odds for methadone substitution among heroin users were significantly affected by age at onset-of-use, type of treatment center, and education. Odds for substitution for synthetic cannabinoid receptor agonists among cannabis users were significantly affected by age, population group, type of treatment center, and education.

Conclusion

Self-substitution behavior should be considered by clinicians and policymakers as a common practice among most drugusers. Substitution for street methadone provides evidence for the ongoing diversion of this substance from Opioid Maintenance Treatment Centers, while the prominence of substitution of synthetic cannabinoids among dual-diagnosis patients should be regarded as an ongoing risk to patients that needs to be addressed by clinicians. Analysis of additional substitution patterns should provide further valuable insights into the behavior of drugusers.

One Is Not Enough: Understanding and Modeling Polysubstance Use

Substance use disorder (SUD) is a chronic, relapsing disease with a highly multifaceted pathology that includes (but is not limited to) sensitivity to drug-associated cues, negative affect, and motivation to maintain drug consumption. SUDs are highly prevalent, with 35 million people meeting criteria for SUD. While drug use and addiction are highly studied, most investigations of SUDs examine drug use in isolation, rather than in the more prevalent context of comorbid substance histories. Indeed, 11.3% of individuals diagnosed with a SUD have concurrent alcohol and illicit drug use disorders. Furthermore, having a SUD with one substance increases susceptibility to developing dependence on additional substances. For example, the increased risk of developing heroin dependence is twofold for alcohol misusers, threefold for cannabis users, 15-fold for cocaine users, and 40-fold for prescription misusers. Given the prevalence and risk associated with polysubstance use and current public health crises, examining these disorders through the lens of co-use is essential for translatability and improved treatment efficacy. The escalating economic and social costs and continued rise in drug use has spurred interest in developing preclinical models that effectively model this phenomenon. Here, we review the current state of the field in understanding the behavioral and neural circuitry in the context of co-use with common pairings of alcohol, nicotine, cannabis, and other addictive substances. Moreover, we outline key considerations when developing polysubstance models, including challenges to developing preclinical models to provide insights and improve treatment outcomes.

Increased neural activity in the right dorsolateral prefrontal cortex during a risky decision-making task is associated with cocaine use in methadone-maintained patients

BACKGROUND

Methadone maintenance is an effective treatment for opioid use disorder (OUD), yet many methadone-maintained patients (MMPs) struggle with cocaine use during OUD recovery. The current study aimed to identify whether prefrontal cortex (PFC) activity during a risky decision-making task was associated with cocaine use during a 90-day follow-up in MMPs.

METHODS

MMPs (N = 28) attended a single neuroimaging session wherein PFC activity was measured using functional near-infrared spectroscopy (fNIRS) during the Balloon Analogue Risk Task (BART). Trait impulsivity was assessed via the Barratt Impulsiveness Scale version 11 (BIS-11). Following the neuroimaging session, MMPs were tracked via electronic health records for 90 days to determine treatment outcomes including cocaine use verified by urine drug screens.

RESULTS

During the BART, MMPs who used cocaine displayed increased neural activity in the right PFC during active decision-making (F1, 22 = 14.75, p = 0.001) and the right dorsolateral PFC during active minus passive decision-making (F1, 22 = 5.56, p = 0.028) compared to participants who did not use cocaine. Receiver operating characteristic curves confirmed that neural activity in the right PFC during active decision-making (AUC = 0.841, 95% CI, 0.697-0.985, p = 002), and in the right dorsolateral PFC during active minus passive decision-making (AUC = 0.805, 95% CI, 0.643-0.968, p = 0.006) was associated with continued cocaine use. MMPs who used cocaine versus those who did not reported increased trait impulsivity on the BIS-11 Total Score (t=-2.28, p = 0.031).

CONCLUSIONS

The fNIRS device is portable, relatively easy to use, and potentially feasible for use in methadone outpatient programs to assess propensity for negative treatment outcomes such as continued cocaine use.

Measurement-based care using DSM-5 for opioid use disorder: can we make opioid medication treatment more effective?

CONTEXT AND PURPOSE

Measurement-based care (MBC) is an evidence-based health-care practice in which indicators of disease are tracked to inform clinical actions, provide feedback to patients and improve outcomes. The current opioid crisis in multiple countries provides a pressing rationale for adopting a basic MBC approach for opioid use disorder (OUD) using DSM-5 to increase treatment retention and effectiveness.

PROPOSAL

To stimulate debate, we propose a basic MBC approach using the 11 symptoms of OUD (DSM-5) to inform the delivery of medications for opioid use disorder (MOUD; including methadone, buprenorphine and naltrexone) and their evaluation in office-based primary care and specialist clinics. Key features of a basic MBC approach for OUD using DSM-5 are described, with an illustration of how clinical actions are guided and outcomes communicated. For core treatment tasks, we propose that craving and drug use response to MOUD should be assessed after 2 weeks, and OUD remission status should be evaluated at 3, 6 and 12 months (and exit from MOUD treatment) and beyond. Each of the 11 DSM-5 symptoms of OUD should be discussed with the patient to develop a case formulation and guide selection of adjunctive psychological interventions, supplemented with information on substance use, and optionally extended with information from other clinical instruments. A patient-reported outcome measure should be recorded and discussed at each remission assessment.

CONCLUSIONS

MBC can be used to tailor and adapt MOUD treatment to increase engagement, retention and effectiveness. MBC practice principles can help promote patient-centred care in OUD, personalized addiction therapeutics and facilitate communication of outcomes.

Polydrug use patterns and their impact on relapse among heroin-dependent patients in Shanghai, China

AIMS

To describe the polysubstance use patterns of heroin-dependent patients and to understand the impact of polysubstance use patterns on relapse during the 5 years after completing compulsory rehabilitation programmes.

DESIGN

In this secondary analysis, the baseline data of 503 heroin-dependent patients were linked with their 5-year follow-up data from official records.

SETTING

Four compulsory rehabilitation centres in Shanghai, China.

PARTICIPANTS

A total of 564 heroin-dependent patients who were discharged from Shanghai compulsory rehabilitation facilities in 2007 and 2008 were recruited. Among these, 503 patients with available follow-up records were included in this analysis.

MEASUREMENTS

The baseline measurements included the Addiction Severity Index, the Temperament and Character Inventory and the Medical Outcomes Study Social Support Scale. Relapses after discharge from the compulsory rehabilitation centres were extracted monthly from the official electronic record system. Latent class analysis was used to identify different polysubstance use patterns. Associations between the identified latent classes and heroin use and the factors related to relapse during the 5-year follow-up were analysed with the Cox regression model.

FINDINGS

Three latent classes were identified in this cohort: (1) alcohol polydrug users (APU; 13.7%), (2) low polydrug users (LPU; 76.5%) and (3) amphetamine-type stimulant polydrug users (ASPU; 9.7%). During the 5-year follow-up, 298 heroin patients relapsed, and the three groups showed different relapse rates (ASPU 69.4 versus LPU 60.5 versus APU 44.9%, P = 0.02). The average durations of abstinence for the three groups differed (ASPU 31.27 ± 3.41 months versus LPU 36.77 ± 1.19 months versus APU 42.46 ± 2.81 months, P = 0.02). Multivariate Cox regression analyses found that the LPU [hazard ratio (HR) = 1.63, 1.06-2.51] and ASPU (HR = 2.10, 1.24-3.56) classes were positively associated with the risk of heroin relapse.

CONCLUSION

Polydrug use patterns differ among heroin-dependent patients in compulsory rehabilitation programmes in China. A history of polydrug use may predict heroin relapse risk among patients in those compulsory rehabilitation programmes.

Expectations about alcohol, cocaine, and benzodiazepine abstinence following inpatient heroin withdrawal management

BACKGROUND AND OBJECTIVES

Polysubstance use is associated with relapse and poor treatment outcomes among people dependent on heroin. Despite the high prevalence of polysubstance use among patients detoxifying from heroin, little is known about patients' expectations to abstain or use non-opiate substances. The current study examined factors associated with expectations about abstaining from alcohol, cocaine, and benzodiazepines (BZDs) following heroin withdrawal management.

METHODS

Between May and December of 2015, we surveyed 417 patients (71.9% male, 31.7 [±8.39] mean years old) initiating short-term inpatient heroin withdrawal management who reported alcohol, cocaine, or BZD use in the past 30 days. We used logistic regression to evaluate the adjusted associations of background characteristics with expectations about using each substance following discharge.

RESULTS

Approximately half of respondents reported past month alcohol (52%), cocaine (47.0%), or BZD (47.0%) use, and 25.9% reported using all three substances. Approximately half of those reporting drinking, 6.6% reporting cocaine use, and 27% of reporting BZD use expected to abstain from using that substance following heroin withdrawal. Prior opioid withdrawal was associated with a lower likelihood of expecting to stop using alcohol and BZDs, and more days of BZD use was associated with a greater likelihood of expecting to abstain from BZDs following discharge.

CONCLUSION

Persons with opioid use disorder often do not expect to stop using other substances following withdrawal management, with very few planning cocaine cessation.

SCIENTIFIC SIGNIFICANCE

Inpatient heroin withdrawal programs need to address and educate patients about how polysubstance use complicates recovery from heroin use. (Am J Addict 2019;28:36-42).

Psychiatric and Substance Use Comorbidity in Treatment-Seeking Injection Opioid Users Referred From Syringe Exchange

OBJECTIVE

The present study evaluated rates of co-occurring current psychiatric and substance use disorders in a sample of opioid-dependent treatment-seeking injection drug users referred from syringe exchange.

METHODS

Participants (N = 208) completed the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders (DSM) IV-R to assess current (within the past year) psychiatric and substance use disorders and the two most commonly diagnosed personality disorders (antisocial and borderline personality disorders).

RESULTS

Forty-eight percent of the sample had a current Axis I psychiatric disorder, and 67% had a co-occurring current substance use disorder. Posttraumatic stress disorder (21%), major depression (17%), and bipolar I (12%) were the most prevalent Axis I psychiatric disorders, and cocaine use disorder (53%) was the most commonly co-occurring substance use disorder. Women were more likely to have diagnoses of most anxiety disorders and less likely to have diagnoses of alcohol use disorder or antisocial personality disorder. The presence of a personality disorder was associated with higher rates of cocaine and sedative use disorder.

CONCLUSIONS

Findings suggest the importance of evaluating and treating co-occurring psychiatric and substance use disorders in the treatment of injection drug users with opioid dependence.

Opioid substitution treatment and heroin dependent adolescents: reductions in heroin use and treatment retention over twelve months

BACKGROUND

Opioid dependence is a major health concern across the world and does also occur in adolescents. While opioid substitution treatment (OST) has been thoroughly evaluated in adult populations, very few studies have examined its use in adolescents. There are concerns that OST is underutilised in adolescents with heroin dependence. We sought to measure changes in drug use among adolescents receiving OST and also to examine treatment attrition during the first 12 months of this treatment.

METHODS

We included all heroin dependent patients aged under 18.5 years commencing OST at one outpatient multidisciplinary adolescent addiction treatment service in Dublin, Ireland. Psycho-social needs were also addressed during treatment. Drug use was monitored by twice weekly urine drugs screens (UDS). Change in the proportion of UDS negative for heroin was examined using the Wilcoxon signed rank test. Attrition was explored via a Cox Regression multivariate analysis.

RESULTS

OST was commenced by 120 patients (51% female and mean age 17.3 years). Among the 39 patients who persisted with OST until month 12, heroin abstinence was 21% (95% confidence interval [CI] = 9-36%) at month three and it was 46% (95% CI = 30-63%) at month 12. Heroin use declined significantly from baseline to month three (p < 0.001) and from month three to month 12 (p = 0.01). Use of other drugs did not change significantly. People using cocaine during month 12 were more likely to be also using heroin (p = 0.02). Unplanned exit occurred in 25% patients by 120 days. The independent predictors of attrition were having children, single parent family of origin, not being in an intimate relationship with another heroin user and evidence of cocaine use just before treatment entry.

CONCLUSIONS

We found that heroin dependent adolescent patients achieved significant reductions in heroin use within three months of starting OST and this improved further after a year of treatment, about half being heroin abstinent at that stage. Patient drop out from treatment remains a challenge, as it is in adults. Cocaine use before and during treatment may be a negative prognostic factor.

Predictors of heroin abstinence in opiate substitution therapy in heroin-only users and dual users of heroin and crack

AIMS

To analyse predictors of heroin abstinence in opiate substitution therapy (OST) based on frequency of crack use and its interactions with other predictors in a clinical non-experimental setting.

DESIGN

Retrospective study.

SETTING

A community drug service in London, UK.

PARTICIPANTS

325 clients starting OST between 2010 and 2014 (197 methadone and 128 buprenorphine).

MEASUREMENTS

Logistic regression models (a general model and separate models for methadone and buprenorphine) assessed demographic and clinical data as predictors of heroin abstinence at one year after treatment start (or at the date of transfer to another service).

FINDINGS

For the general model participants choosing methadone were more likely to use heroin at follow up (OR=2.36, 95% CI: 1.40-3.17) as were daily crack users on methadone (OR=2.62, 95% CI: 0.96-7.16). For the methadone model only daily crack use predicted heroin use at follow up (OR=2.62, 95% CI: 0.96-7.16). For buprenorphine, higher amounts of baseline heroin use, lower buprenorphine dose and daily drinking predicted heroin use at follow up (OR=0.85, 95% CI: 0.75-0.95; OR=1.31, 95% CI: 1.06-1.60 and OR=6.04, 95% CI: 1.26-28.92). Both use of cannabis and depression increased likelihood of heroin abstinence for clients not using crack compared to occasional (OR=6.68, 95% CI: 0.37-119.59; OR=106.31, 95% CI: 3.41-3313.30) and daily (OR=57.49 (95% CI: 2.37-1396.46; OR=170.99 (95% CI: 4.61-6339.47) users.

CONCLUSIONS

Most of the predictors in the general model were found significant only in the buprenorphine but not in the methadone model, suggesting that a general model has little predictive value. Crack use was a significant predictor of heroin abstinence at follow up in all models, however for buprenorphine only when depression or cannabis use was present. Further research is needed to assess effective treatment approaches for the growing population of dual users.

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.

Effectiveness of treatment for opioid use disorder: A national, five-year, prospective, observational study in England

BACKGROUND

This the first 5-year effectiveness study of publicly funded treatment for opioid use disorder (OUD) in England.

METHODS

All adults initiating treatment in 2008/09 in all 149 local treatment systems reporting to the National Drug Treatment Monitoring System (n=54,347). Admission polydrug use sub-populations were identified by Latent Class Analysis. The treatment outcome measure was 'successful completion and no re-presentation within six months' (SCNR) analysed by multilevel, multivariable logistic regression and funnel plots to contrast outcome by treatment system.

RESULTS

SCNR was achieved by 21.9%. Heroin and crack cocaine users were significantly less likely to achieve this outcome than patients who used heroin only (adjusted odds ratio [AOR] 0.90; 95% confidence interval [CI] 0.85-0.95). Older patients (AOR 1.09; CI 1.07-1.11), those employed (AOR 1.27; CI 1.18-1.37) and those enrolled for longer treatment were more likely to achieve the outcome measure. After risk adjustment, the local treatment systems that achieved substantially better outcome performance (14/149) had a lower rate of opiate prevalence in the local population at time of study initiation (incidence rate difference [IRD] 4.1; CI 4.0-4.2), fewer criminal offences per thousand (IRD 28.5; CI 28.1-28.8) and lower drug-related deaths per million (IRD 5.9; CI 5.9-5.9).

CONCLUSIONS

In an English national study, one fifth of patients successful completed treatment for OUD and did not present for further treatment within six months. Longer time in treatment increases the probability of achieving and maintaining clinical benefit from treatment. After risk-adjustment, an important minority of treatment systems achieve substantially better outcome performance.

Effects of daily delta-9-tetrahydrocannabinol treatment on heroin self-administration in rhesus monkeys

Opioid abuse remains a significant public health problem; together with the greater availability of marijuana in some regions there is an increasing likelihood that opioids and marijuana will be used together. Polydrug abuse is associated with increased toxicity and poorer treatment outcome; thus, a better understanding of the consequences of repeated coadministration of these drugs will facilitate the development of better prevention and treatment strategies. This study examined the effects of daily treatment with the cannabinoid receptor agonist delta-9-tetrahydrocannabinol (Δ-THC) and its discontinuation on self-administration of heroin in rhesus monkeys (n=4) lever-pressing under a fixed-ratio 30 schedule. Heroin self-administration (0.32-32 μg/kg/infusion, intravenously) generated an inverted U-shaped dose-effect curve. Administered acutely, Δ-THC (0.01-0.32 mg/kg, subcutaneously) dose dependently decreased responding for heroin and flattened the self-administration dose-effect curve. Daily treatment with Δ-THC (0.01-0.1 mg/kg/12 h, subcutaneously) either had no effect on or decreased responding for heroin. In addition, daily treatment did not significantly impact extinction of heroin self-administration or resumption of responding for heroin after extinction. Discontinuation of daily Δ-THC treatment did not systematically impact rates of heroin self-administration. These data suggest that repeated administration of a cannabinoid receptor agonist likely does not increase, and possibly decreases, the positive reinforcing effects of a mu opioid receptor agonist.

Effectiveness of adjunctive, personalised psychosocial intervention for non-response to opioid agonist treatment: Study protocol for a pragmatic randomised controlled trial

INTRODUCTION

Opioid use disorder (OUD) is a debilitating and relapsing psychiatric disorder; opioid agonist therapy (OAT) is the front-line, evidence-supported treatment. A substantial number of patients relapse or continue to use heroin or other illicit drugs during OAT. There is considerable heterogeneity in the OAT-resistant sub-population, with many behavioural moderators of treatment response. We have developed a personalised psychosocial intervention (PSI) targeting these individuals. A formulation-guided assessment is linked to a toolkit of motivational, cognitive/behavioural and social support techniques. Change methods have been adapted from evidence-supported psychological therapies and are idiosyncratically tailored to the need and response.

METHODS

In this single-centre, 18-week, parallel group, pragmatic randomised clinical trial, we will determine the clinical and cost-effectiveness of the PSI as an adjunctive intervention during OAT, in comparison to opioid agonist treatment-as-usual. We plan to recruit 368 adults. The primary outcome measure is the proportion of participants categorised as 'responders' at the end of the intervention (defined as self-reported abstinence from heroin and cocaine with no positive biological drug tests during the 28days prior to the endpoint). Secondary outcomes include: percentage of days abstinent from heroin and cocaine in the 28days before follow-up; treatment retention; therapy compliance; health and social functioning; exploratory genetic biomarkers; and analyses of treatment moderation and mediation.

CONCLUSIONS

This pragmatic controlled trial determines the effectiveness and cost-effectiveness of a personalised PSI for non-responding patients during OAT. Our intervention applies motivational, cognitive/behavioural and social support techniques adapted from evidence-based therapies. Findings will inform stratified delivery of OAT.

Methadone maintenance therapy and viral suppression among HIV-infected opioid users: The impacts of crack and injection cocaine use

BACKGROUND

Methadone maintenance therapy (MMT) is associated with improved HIV treatment outcomes among people who use drugs (PWUD). The extent to which these benefits are sustained in the context of ongoing cocaine use is unclear. We assessed differential impacts of MMT on HIV viral load (VL) suppression in relation to discrete patterns of cocaine use.

METHODS

Data was drawn from ACCESS, a prospective cohort of HIV-positive PWUD in Vancouver, Canada. Generalized linear mixed-effects were used to model the independent effect of MMT on VL suppression across strata of frequency of cocaine injection and crack smoking (≥daily versus <daily), after adjustment for confounders.

RESULTS

The analysis included 397 HIV-positive opioid users who completed ≥1 study interview between 2005 and 2014. At baseline, 304 (77%) reported participation in MMT, 37 (9%) ≥daily cocaine injection, and 158 (40%) ≥daily crack smoking. In adjusted analyses, MMT remained independently associated with increased odds of VL suppression in both strata of crack smokers (AOR=3.11, 95% CI: 1.86-5.21 and AOR=1.48, 95%CI: 1.04-2.09, for ≥daily and <daily smokers, respectively), and among <daily cocaine injectors (AOR=1.88, 95%CI 1.38-2.56), but not among ≥daily cocaine injectors (AOR=1.37, 95%CI 0.53-3.49). Longer retention on MMT was positively associated with VL suppression in all strata of cocaine injection and crack smoke.

CONCLUSIONS

Exposure to MMT was associated with increased odds of VL suppression among HIV- positive opioid users regardless of crack use. However, this beneficial effect of MMT was lost among frequent cocaine injectors with shorter retention on MMT.

Anticipatory reward processing among cocaine-dependent individuals with and without concurrent methadone-maintenance treatment: Relationship to treatment response

BACKGROUND

Cocaine dependence among opioid-dependent methadone-maintained individuals is a significant public health problem and is particularly challenging to treat. The neurobiology of this clinically complex population has not been previously assessed using fMRI.

METHODS

fMRI data from cocaine-dependent, methadone-maintained (CD-MM) patients (n=24), cocaine-dependent (CD) patients (n=20) and healthy comparison (HC) participants (n=21) were acquired during monetary incentive delay task performance. All patients were scanned prior to treatment for cocaine dependence. Between-group differences in anticipatory reward and loss processing were assessed using whole-brain ANOVAs in SPM12 (pFWE<0.05). Correlations between durations of abstinence during treatment and BOLD responses within the insula and caudate were also explored.

RESULTS

Main effects of diagnostic group, primarily involving decreased BOLD responses among CD-MM patients in comparison to HCs, were observed during anticipatory reward and loss processing within regions of posterior cingulate cortex, precuneus, inferior frontal gyrus and dorsolateral prefrontal cortex. BOLD responses within the right caudate were negatively associated with percentage of cocaine-negative urines during treatment among CD-MM patients, but not among non-methadone-maintained CD patients.

CONCLUSIONS

These data suggest neurofunctional differences that may be related to treatment outcomes for behavioral therapies between cocaine-dependent individuals with and without methadone-maintenance treatment. These findings may relate to differences in treatment efficacies and to the elevated relapse rates observed in methadone-maintained populations.

Long-term outcomes after randomization to buprenorphine/naloxone versus methadone in a multi-site trial

AIMS

To compare long-term outcomes among participants randomized to buprenorphine or methadone.

DESIGN, SETTING AND PARTICIPANTS

Follow-up was conducted in 2011-14 of 1080 opioid-dependent participants entering seven opioid treatment programs in the United States between 2006 and 2009 and randomized (within each program) to receive open-label buprenorphine/naloxone or methadone for up to 24 weeks; 795 participants completed in-person interviews (~74% follow-up interview rate) covering on average 4.5 years.

MEASUREMENTS

Outcomes were indicated by mortality and opioid use. Covariates included demographics, site, cocaine use and treatment experiences.

FINDINGS

Mortality was not different between the two randomized conditions, with 23 (3.6%) of 630 participants randomized to buprenorphine having died versus 26 (5.8%) of 450 participants randomized to methadone. Opioid use at follow-up was higher among participants randomized to buprenorphine relative to methadone [42.8 versus 31.7% positive opioid urine specimens, P < 0.01, effect size (h) = 0.23 (0.09, 0.38); 5.8 days versus 4.4 days of past 30-day heroin use, P < 0.05, effect size (d) = 0.14 (0.00, 0.28)]. Opioid use during the follow-up period by randomization condition was also significant (F(7,39,600) = 3.16; P < 0.001) due mainly to less treatment participation among participants randomized to buprenorphine than methadone. Less opioid use was associated with both buprenorphine and methadone treatment (relative to no treatment); no difference was found between the two treatments. Individuals who are white or used cocaine at baseline responded better to methadone than to buprenorphine.

CONCLUSIONS

There are few differences in long-term outcomes between buprenorphine and methadone treatment for opioid dependence, and treatment with each medication is associated with a strong reduction in opioid use.

Profiles of substance use disorders in patients of therapeutic communities: link to social, medical and psychiatric characteristics

BACKGROUND

Therapeutic community (TC) clients frequently display a pattern of multiple substance use disorders (SUDs) which is associated with poorer treatment outcomes. This study aimed to characterize multiple SUD profiles in patients enrolled in TCs, and examine the association of these profiles with social, medical and psychiatric outcomes.

METHODS

Observational study. We acquired substance use diagnoses and sociodemographic, medical and psychiatric comorbidity data for 4102 patients who had been admitted to six public TCs in Andalusia (Spain) from 2004 to 2012. Latent class analysis was applied to participants' substance use diagnoses, and the resulting classes were associated with social (i.e., education, employment, criminality), medical (i.e., infectious diseases) and psychiatric comorbidity.

RESULTS

We found four differentiated profiles of substance use diagnoses among TC patients: cocaine/opiates (Class 1: 37% of participants); cocaine/opiates/benzodiazepines (Class 2: 25.3%); alcohol (Class 3: 24.7%); and cocaine/cannabis/alcohol (Class 4: 12.9%). Classes 1 and 2 were associated with poorer social and medical characteristics. Class 2 was also associated with greater prevalence of impulsive spectrum mental disorders. Class 3 was associated with greater prevalence of mood and anxiety disorders and cognitive dysfunction, and Class 4 was associated with higher prevalence of psychotic illness.

CONCLUSIONS

Patients admitted to TCs have heterogeneous substance use diagnostic profiles. Profiles involving multiple use of heroin, cocaine, alcohol and benzodiazepines are associated with poorer social and medical function and impulse control disorders. Profiles involving alcohol use and cannabis/cocaine use are associated with cognitive dysfunction and psychotic illness respectively.

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.

Older methadone patients achieve greater durations of cocaine abstinence with contingency management than younger patients

BACKGROUND AND OBJECTIVES

Contingency management (CM) interventions are efficacious in treating cocaine abusing methadone patients, but few studies have examined the effect of age on treatment outcomes in this population. This study evaluated the impact of age on treatment outcomes in cocaine abusing methadone patients.

METHODS

Data were analyzed from 189 patients enrolled in one of three randomized studies that evaluated the efficacy of CM versus standard care (SC) treatment.

RESULTS

Age was associated with some demographics and drug use characteristics including racial composition, education, and methadone dose. Primary drug abuse treatment outcomes did not vary across age groups, but CM had a greater benefit for engendering longer durations of abstinence in the middle/older and older age groups compared to the younger age groups. At the 6-month follow-up, submission of a cocaine positive urine sample was predicted by submission of a cocaine positive sample at intake, higher methadone doses, and assignment to SC rather than CM treatment.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

As substance abusers are living longer, examination of the efficacy of pharmacological and psychosocial treatments specifically within older age groups may lead to a better understanding of subpopulations for whom enhanced treatments such as CM are warranted.

The Recovery Line: A pilot trial of automated, telephone-based treatment for continued drug use in methadone maintenance

The current pilot study evaluated feasibility, acceptability, and initial efficacy of a therapeutic Interactive Voice Response (IVR) system ("the Recovery Line") for patients receiving methadone maintenance who continue to use illicit drugs. Patients were randomized (N=36) to 4weeks of treatment-as-usual (TAU) or Recovery Line plus TAU. Ratings of the Recovery Line were high and remained stable throughout the study. However, despite instructions and reminders, patients used substantially less than the recommended daily use (<10days of 28). Patients were more likely to report abstinence from opioids and cocaine on days they used the Recovery Line (p=.01) than those they did not. Conditions did not differ significantly on patient satisfaction, urine screen outcomes, or coping efficacy. As with other computer-based treatments, findings suggest the Recovery Line is acceptable and feasible. However, additional methods to increase patient utilization of automated systems and larger clinical trials are needed.

Alcohol, tobacco, and prescription drugs: the relationship with illicit drugs in the treatment of substance users

Alcohol, tobacco, prescription drug, and illicit drug use frequently co-occur. This paper reviews the extent of this co-occurrence in both general population samples and clinical samples, and its impact on treatment outcome. We argue that the research base for understanding comorbidity among tobacco, alcohol, prescription, and illicit drugs needs to be broadened. We specifically advocate for: (1) more epidemiological studies of relationships among alcohol, tobacco, and other illicit drug use; and (2) increased research on treatment options that address the problematic use of all of these drugs.

Non-medical use of opioids among HIV-infected opioid dependent individuals on opioid maintenance treatment: the need for a more comprehensive approach

BACKGROUND

Opioid maintenance treatment (OMT) has a positive impact on substance use and health outcomes among HIV-infected opioid dependent patients. The present study investigates non-medical use of opioids by HIV-infected opioid-dependent individuals treated with buprenorphine or methadone.

METHODS

The MANIF 2000 study is a longitudinal study that enrolled a cohort of 476 HIV-infected opioid-dependent individuals. Data were collected in outpatient hospital services delivering HIV care in France. The sample comprised all patients receiving OMT (either methadone or buprenorphine) who attended at least one follow-up visit with data on adherence to OMT (N = 235 patients, 1056 visits). Non-medical use of opioids during OMT was defined as having reported use of opioids in a non-medical context, and/or the misuse of the prescribed oral OMT by an inappropriate route of administration (injection or sniffing). After adjusting for the non-random assignment of OMT type, a model based on GEE was then used to identify predictors of non-medical use of opioids.

RESULTS

Among the 235 patients, 144 (61.3%) and 91 (38.9%) patients were receiving buprenorphine and methadone, respectively, at baseline. Non-medical use of opioids was found in 41.6% of visits for 83% of individual patients. In the multivariate analysis, predictors of non-medical use of opioids were: cocaine, daily cannabis, and benzodiazepine use, experience of opioid withdrawal symptoms, and less time since OMT initiation.

CONCLUSIONS

Non-medical use of opioids was found to be comparable in OMT patients receiving methadone or buprenorphine. The presence of opioid withdrawal symptoms was a determinant of non-medical use of opioids and may serve as a clinical indicator of inadequate dosage, medication, or type of follow-up. Sustainability and continuity of care with adequate monitoring of withdrawal symptoms and polydrug use may contribute to reduced harms from ongoing non-medical use of opioids.

Understanding subtypes of inner-city drug users with a latent class approach

AIMS

We empirically identified subtypes of inner-city users of heroin and cocaine based on type of drug used and route of administration.

METHOD

The sample was recruited from the communities in Baltimore, MD (SHIELD study) and consisted of 1061 participants who used heroin and or cocaine in the past 6 months on a weekly basis or more. Latent class analysis (LCA) was used to identify subtypes of drug users based on type of drug and route of administration. Logistic regression was used to compare the subtypes on depressive symptoms, injection risk and drug network compositions.

FINDINGS

Inner-city drug users were classified into five subtypes: three subtypes of injection drug users (IDUs) [heroin injecting (n=134; 13%), polydrug and polyroute (n=88, 8%), and heroin and cocaine injecting (n=404, 38%)], and two subtypes with low proportions of IDUs (LIDUs) [heroin snorting (n=275, 26%) and crack smoking (n=160; 14%)]. The polydrug and polyroute subtype had the highest depressive symptoms risk among all subtypes. Injection risk was lowest in the heroin injecting subtype and significantly differed from heroin and cocaine injecting subtype. The IDU subtypes also varied in the drug network compositions. The LIDU subtypes had similar depressive symptoms risk but vastly differed in the drug network compositions.

CONCLUSIONS

Subgroups of inner-city cocaine and heroin users based on type and route of administration differed in their depressive symptoms, injection risk and drug network compositions. Future studies should longitudinally examine factors associated with transitioning across these subtypes to better inform prevention and treatment efforts.

Associations between polysubstance use and psychiatric problems in a criminal justice population in Sweden

BACKGROUND

Polysubstance use is common in substance users, and may complicate their clinical course. This study, in a criminal justice setting in Sweden, examines the association between the number of concurrently used substance types and psychiatric symptoms during 30 days before incarceration, while controlling for background variables such as family history (drug and alcohol problems, psychiatric problems, criminality), demographic data and history of emotional, physical or sexual abuse.

METHODS

The data material comprised 5659 criminal justice clients reporting a substance use problem, examined with the Addiction Severity Index. Variables were compared in a multinomial regression analysis, comparing clients reporting one (n=1877), two (n=1408), three (n=956), four (n=443) and five or more (n=167) substance types.

RESULTS

The 30-day prevalence of most psychiatric symptoms included in the study (depression, anxiety, cognitive problems, hallucinations, difficulty controlling violent behaviour, suicidal ideation, suicide attempts) was higher in individuals with a higher number of concurrent substance types used. In multinomial regression analysis, while controlling for background variables, these associations remained for concurrent suicidal ideation, cognitive problems, hallucinations and violent behaviour, with the latter two being associated with the higher numbers of substance types. Binge alcohol drinking, tranquilizers, opioids and the number of substance types reported were associated with several of the psychiatric symptoms.

CONCLUSIONS

In the present criminal justice setting in Sweden, the use of multiple substance types and concurrent psychiatric symptoms appear to be associated, and a sub-group reporting particularly high numbers of concurrent substance types are particularly likely to report potentially severe psychiatric problems.

Self-administration of cocaine and remifentanil by monkeys: choice between single drugs and mixtures

RATIONALE

Cocaine and opioids are often co-abused. As yet, however, there is no clear evidence that the drugs interact to make the mixture a more effective reinforcer.

OBJECTIVE

The present study examined the relative reinforcing potency and maximum effectiveness of the cocaine-opioid combination in monkeys given a choice between cocaine-opioid mixtures and the single-component drugs.

METHOD

Rhesus monkeys were allowed to choose between injections of cocaine (100 μg/kg/inj) and other doses of cocaine (10-560 μg/kg/inj) or remifentanil (0.03-3.0 μg/kg/inj). A dose-addition model was used to select dose combinations for mixtures of cocaine and remifentanil predicted to be equivalent to 100 μg/kg/inj of cocaine in reinforcing effect if the drugs were additive. The monkeys were then allowed to choose between (a) cocaine and mixtures predicted to be equivalent to 100 μg/kg/inj of cocaine, (b) increasing doses of the mixtures and the single-component drugs, and (c) cocaine or remifentanil at doses that were in the highest safe range.

RESULTS

Generally, monkeys preferred the mixtures over 100 μg/kg/inj of cocaine, evidence for superadditivity. However, preferences for the mixture ceased when relatively high doses of single-component drugs were offered as alternatives. When doses within the mixture were raised and offered with relatively high doses of the single drugs, there was no clear preference for either option. The highest dose of remifentanil was chosen over the highest dose of cocaine by all monkeys.

CONCLUSION

The current results indicate that cocaine-opioid combinations can be super-additive in terms of potency, but are not, at maximum, more effective than the single-component drugs.