Buprenorphine-naloxone treatment responses differ between young adults with heroin and prescription opioid use disorders

(2R,6R)-hydroxynorketamine prevents opioid abstinence-related negative affect and stress-induced reinstatement in mice

BACKGROUND AND PURPOSE

Opioid use disorder (OUD) is a pressing public health concern marked by frequent relapse during periods of abstinence, perpetuated by negative affective states. Classical antidepressants or the currently prescribed opioid pharmacotherapies have limited efficacy to reverse the negative affect or prevent relapse.

EXPERIMENTAL APPROACH

Using mouse models, we investigated the effects of ketamine's metabolite (2R,6R)-hydroxynorketamine (HNK) on reversing conditioning to sub-effective doses of morphine in stress-susceptible mice, preventing conditioned-place aversion and alleviating acute somatic abstinence symptoms in opioid-dependent mice. Additionally, we evaluated its effects on anhedonia, anxiety-like behaviours and cognitive impairment during protracted opioid abstinence, while mechanistic studies examined cortical EEG oscillations and synaptic plasticity markers.

KEY RESULTS

(2R,6R)-HNK reversed conditioning to sub-effective doses of morphine in stress-susceptible mice and prevented conditioned-place aversion and acute somatic abstinence symptoms in opioid-dependent mice. In addition, (2R,6R)-HNK reversed anhedonia, anxiety-like behaviours and cognitive impairment emerging during protracted opioid abstinence plausibly via a restoration of impaired cortical high-frequency EEG oscillations, through a GluN2A-NMDA receptor-dependent mechanism. Notably, (2R,6R)-HNK facilitated the extinction of opioid conditioning, prevented stress-induced reinstatement of opioid-seeking behaviours and reduced the propensity for enhanced morphine self-consumption in mice previously exposed to opioids.

CONCLUSIONS AND IMPLICATIONS

These findings emphasize the therapeutic potential of (2R,6R)-HNK, which is currently in Phase II clinical trials, in addressing stress-related opioid responses. Reducing the time and cost required for development of new medications for the treatment of OUDs via drug repurposing is critical due to the opioid crisis we currently face.

Ketamine and Hydroxynorketamine as Novel Pharmacotherapies for the Treatment of Opioid Use Disorders

Opioid use disorder (OUD) has reached epidemic proportions, with many countries facing high levels of opioid use and related fatalities. Although currently prescribed medications for OUD are considered lifesaving, they inadequately address negative affect and cognitive impairment, resulting in high relapse rates to nonmedical opioid use even years after drug cessation (protracted abstinence). Evidence supports the notion that ketamine, an anesthetic and rapid-acting antidepressant drug, holds promise as a candidate for OUD treatment, including the management of acute withdrawal somatic symptoms, negative affect during protracted opioid abstinence, and prevention of retaking nonmedical opioids. In this review, we comprehensively discuss preclinical and clinical research that has evaluated ketamine and its metabolites as potential novel therapeutic strategies for treating OUD. Furthermore, we examine evidence that supports the relevance of the molecular targets of ketamine and its metabolites in relation to their potential effects and therapeutic outcomes in OUD. Overall, existing evidence demonstrates that ketamine and its metabolites can effectively modulate pathophysiological processes affected in OUD, suggesting a promising therapeutic role in the treatment of OUD and the prevention of return to opioid use during abstinence.

Benzodiazepine use, quality of life and psychiatric symptom burden in oral and injectable opioid agonist treatment: a cross-sectional study

BACKGROUND

Use of benzodiazepines (BZD) in patients receiving opioid agonist treatment (OAT) is common and associated with a variety of negative health and social outcomes. This cross-sectional study investigates the impact of BZD use in OAT patients on their quality of life (QoL).

METHODS

A convenience sample of patients receiving oral OAT or heroin-assisted treatment in two outpatient centres in Basel, Switzerland was investigated. Participants (n = 141) completed self-report questionnaires on psychiatric symptoms and psychological distress (The Symptom Checklist 27, SCL-27), depressive state (German version of the Center for Epidemiological Studies Depression Scale), quality of life (Lancashire Quality of Life Profile, LQOLP) and use of BZD and other drugs (self-report questionnaire). Substance use was assessed by urine toxicology testing.

RESULTS

In bivariate analysis, total QoL scores were significantly lower for lifetime, current, and prolonged BZD users compared to participants without the respective use patterns. There was no significant relationship between BZD dose and QoL. In multivariable linear regression models controlling for psychiatric symptom load and depressive state, only lifetime use predicted lower QoL, whereas other BZD use patterns were not significantly associated.

CONCLUSIONS

The association of lower QoL and BZD use in OAT patients is strongly confounded by co-occurring depressive state and psychiatric symptoms. Careful diagnosis and treatment of co-occurring mental disorders in OAT is paramount to improve QoL in this patient population and may also help reduce BZD use.

Interventions to Reduce Opioid Use in Youth At-Risk and in Treatment for Substance Use Disorders: A Scoping Review

BACKGROUND

Youth and young adults have been significantly impacted by the opioid overdose and health crisis in North America. There is evidence of increasing morbidity and mortality due to opioids among those aged 15-29. Our review of key international reports indicates there are few youth-focused interventions and treatments for opioid use. Our scoping review sought to identify, characterize, and qualitatively evaluate the youth-specific clinical and pre-clinical interventions for opioid use among youth.

METHOD

We searched MedLine and PsycInfo for articles that were published between 2013 and 2021. Previous reports published in 2015 and 2016 did not identify opioid-specific interventions for youth and we thus focused on the time period following the periods covered by these prior reports. We input three groups of relevant keywords in the aforementioned search engines. Specifically, articles were included if they targeted a youth population (ages 15-25), studied an intervention, and measured impacts on opioid use.

RESULTS

We identified 21 studies that examined the impacts of heterogeneous interventions on youth opioid consumption. The studies were classified inductively as psycho-social-educational, pharmacological, or combined pharmacological-psycho-social-educational. Most studies focused on treatment of opioid use disorder among youth, with few studies focused on early or experimental stages of opioid use. A larger proportion of studies focused heavily on male participants (i.e., male gender and/or sex). Very few studies involved and/or included youth in treatment/program development, with one study premised on previous research about sexual minority youth.

CONCLUSIONS

Research on treatments and interventions for youth using or at-risk of opioids appears to be sparse. More youth involvement in research and program development is vital. The intersectional and multi-factorial nature of youth opioid use and the youth opioid crisis necessitates the development and evaluation of novel treatments that address youth-specific contexts and needs (i.e., those that address socio-economic, neurobiological, psychological, and environmental factors that promote opioid use among youth).

Treatment approaches and outcome trajectories for youth with high-risk opioid use: A narrative review

AIM

First use of opioids often happens in adolescence and an increasing number of opioid overdoses are being reported among youth. The purpose of this narrative review was to present the treatment approaches for youth with high-risk opioid use, determine whether the literature supports the use of opioid agonist treatment among youth and identify evidence for better treatment outcomes in the younger population.

METHODS

A search of the literature on PubMed using MeSH terms specific to youth, opioid use and treatment approaches generated 1436 references. Following a screening process, 137 papers were found to be relevant to the treatment of high-risk opioid use among youth. After full-text review, 19 eligible studies were included: four randomized controlled trials, nine observational studies and six reviews.

RESULTS

Research for the different treatment options among youth is limited. The available evidence shows better outcomes in terms of retention in care and cost-effectiveness for opioid agonist treatment than abstinence-based comparisons. Integrating psychosocial interventions into the continuum of care for youth can be an effective way of addressing comorbid psychiatric conditions and emotional drivers of substance use, leading to improved treatment trajectories.

CONCLUSIONS

From the limited findings, there is no evidence to deny youth with high-risk opioid use the same treatment options available to adults. A combination of pharmacological and youth-specific psychosocial interventions is required to maximize retention and survival. There is an urgent need for more research to inform clinical strategies toward appropriate treatment goals for such vulnerable individuals.

Buprenorphine as a Treatment for Major Depression and Opioid Use Disorder

Rates of major depressive disorder (MDD) are disproportionally high in subjects with opioid use disorder (OUD) relative to the general population. MDD is often more severe in OUD patients, leading to compliance issues with maintenance therapies and poor outcomes. A growing body of literature suggests that endogenous opioid system dysregulation may play a role in the emergence of MDD. Buprenorphine, a mixed opioid receptor agonist/antagonist approved for the treatment of OUD and chronic pain, may have potential as a novel therapeutic for MDD, especially for patients with a dual diagnosis of MDD and OUD. This paper presents a comprehensive review of papers relevant to the assessment of buprenorphine as a treatment for MDD, OUD, and/or suicide compiled using electronic databases per Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The principal goal of this literature review was to compile the clinical studies that have interrogated the antidepressant activity of buprenorphine in opioid naïve MDD patients and OUD patients with comorbid MDD. Evidence supporting buprenorphine's superiority over methadone for treating comorbid OUD and MDD was also considered. Finally, recent evidence for the ability of buprenorphine to alleviate suicidal ideation in both opioid-naïve patients and opioid-experienced patients was evaluated. Synthesizing all of this information, buprenorphine emerges as a potentially effective therapeutic for the dual purposes of treating MDD and OUD.

Patient Characteristics Associated with Opioid Abstinence after Participation in a Trial of Buprenorphine versus Injectable Naltrexone

Background and Objectives: Better understanding of predictors of opioid abstinence among patients with opioid use disorder (OUD) may help to inform interventions and personalize treatment plans. This analysis examined patient characteristics associated with opioid abstinence in the X:BOT (Extended-Release Naltrexone versus Buprenorphine for Opioid Treatment) trial. Methods: This post-hoc analysis examined factors associated with past-month opioid abstinence at the 36-week follow-up visit among participants in the X:BOT study. 428 participants (75% of original sample) attended the visit at 36 weeks. Logistic regression models were used to estimate the probability of opioid abstinence across various baseline sociodemographics, clinical characteristics, and treatment variables. Results: Of the 428 participants, 143 (33%) reported abstinence from non-prescribed opioids at the 36-week follow-up. Participants were more likely to be opioid abstinent if randomized to XR-NTX (compared to BUP-NX), were on XR-NTX at week 36 (compared to those off OUD pharmacotherapy), successfully inducted onto either study medication, had longer time on study medication, reported a greater number of abstinent weeks, or had longer time to relapse during the 24-week treatment trial. Participants were less likely to be abstinent if Hispanic, had a severe baseline Hamilton Depression Rating (HAM-D) score, or had baseline sedative use. Conclusions: A substantial proportion of participants was available at follow-up (75%), was on OUD pharmacotherapy (53%), and reported past-month opioid abstinence (33%) at 36 weeks. A minority of patients off medication for OUD reported abstinence and additional research is needed exploring patient characteristics that may be associated with successful treatment outcomes.

Investigating interventions that lead to the highest treatment retention for emerging adults with substance use disorder: A systematic review

BACKGROUND AND AIMS

Emerging adults (age 18-25) have the highest rate of substance use disorders (SUD) and often drop out of treatment earlier than those age twenty six or older. In order to increase treatment retention in emerging adults, there needs to be a better understanding of which SUD treatment interventions work best for this population. The purpose of this systematic review was to evaluate treatment interventions for emerging adults with SUD and identify which interventions show promise for retention in treatment.

METHODS

Following the PRISMA guidelines, Medline, PsycInfo, CINAHL (all via EBSCO), and Embase were systematically searched for articles that evaluated treatment interventions for emerging adults with SUD. From here, the authors identified treatment interventions that showed promise for retention in treatment.

RESULTS

Nine studies were included. The main findings indicate (1) behavioral therapy such as cognitive behavioral therapy and contingency management for cannabis and alcohol use disorders, or (2) cognitive behavioral therapy paired with opioid-agonist-therapy for opioid use disorder demonstrate the most promise for retention in treatment.

CONCLUSION

The interventions identified that show promise for emerging adults was similar to studies evaluating interventions for all ages. Given that retention rates are often lower in emerging adults despite the application of the full range of effective adult treatments, this review suggests they may require something different. While further studies are warranted to determine with more certainty what works best to keep emerging adults in treatment, some tentative suggestions are included.

Depression history as a predictor of outcomes during buprenorphine-naloxone treatment of prescription opioid use disorder

BACKGROUND

In the multi-site Prescription Opioid Addiction Treatment Study (POATS), the best predictor of successful opioid use outcome was lifetime diagnosis of major depressive disorder. The primary aim of this secondary analysis of data from POATS was to empirically assess two explanations for this counterintuitive finding.

METHODS

The POATS study was a national, 10-site randomized controlled trial (N = 360 enrolled in the 12-week buprenorphine-naloxone maintenance treatment phase) sponsored by the NIDA Clinical Trials Network. We evaluated how the presence of a history of depression influences opioid use outcome (negative urine drug assays). Using adjusted logistic regression models, we tested the hypotheses that 1) a reduction in depressive symptoms and 2) greater motivation and engagement in treatment account for the association between depression history and good treatment outcome.

RESULTS

Although depressive symptoms decreased significantly throughout treatment (p <.001), this improvement was not associated with opioid outcomes (aOR = 0.98, ns). Reporting a goal of opioid abstinence at treatment entry was also not associated with outcomes (aOR = 1.39, ns); however, mutual-help group participation was associated with good treatment outcomes (aOR = 1.67, p <.05). In each of these models, lifetime major depressive disorder remained associated with good outcomes (aORs = 1.63-1.82, ps = .01-.055).

CONCLUSIONS

Findings are consistent with the premise that greater engagement in treatment is associated with good opioid outcomes. Nevertheless, depression history continues to be associated with good opioid outcomes in adjusted models. More research is needed to understand how these factors could improve treatment outcomes for those with opioid use disorder.

Endogenous opiates and behavior: 2017

This paper is the fortieth consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2017 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

Adherence to and Retention in Medications for Opioid Use Disorder Among Adolescents and Young Adults

The volatile opioid epidemic is associated with higher levels of opioid use disorder (OUD) and negative health outcomes in adolescents and young adults. Medications for opioid use disorder (MOUD) demonstrate the best evidence for treating OUD. Adherence to and retention in MOUD, defined as continuous engagement in treatment, among adolescents and young adults, however, is incompletely understood. We examined the state of the literature regarding the association of age with adherence to and retention in MOUD using methadone, buprenorphine, or naltrexone among persons aged 10-24 years, along with related facilitators and barriers. All studies of MOUD were searched for that examined adherence, retention, or related concepts as an outcome variable and included adolescents or young adults. Search criteria generated 10,229 records; after removing duplicates and screening titles and abstracts, 587 studies were identified for full-text review. Ultimately, 52 articles met inclusion criteria for abstraction and 17 were selected for qualitative coding and analysis. Younger age was consistently associated with shorter retention, although the overall quality of included studies was low. Several factors at the individual, interpersonal, and institutional levels, such as concurrent substance use, MOUD adherence, family conflict, and MOUD dosage and flexibility, appeared to have roles in MOUD retention among adolescents and young adults. Ways MOUD providers can tailor treatment to increase retention of adolescents and young adults are highlighted, as is the need for more research explaining MOUD adherence and retention disparities in this age group.

Zebrafish models relevant to studying central opioid and endocannabinoid systems

The endocannabinoid and opioid systems are two interplaying neurotransmitter systems that modulate drug abuse, anxiety, pain, cognition, neurogenesis and immune activity. Although they are involved in such critical functions, our understanding of endocannabinoid and opioid physiology remains limited, necessitating further studies, novel models and new model organisms in this field. Zebrafish (Danio rerio) is rapidly emerging as one of the most effective translational models in neuroscience and biological psychiatry. Due to their high physiological and genetic homology to humans, zebrafish may be effectively used to study the endocannabinoid and opioid systems. Here, we discuss current models used to target the endocannabinoid and opioid systems in zebrafish, and their potential use in future translational research and high-throughput drug screening. Emphasizing the high degree of conservation of the endocannabinoid and opioid systems in zebrafish and mammals, we suggest zebrafish as an excellent model organism to study these systems and to search for the new drugs and therapies targeting their evolutionarily conserved mechanisms.