Psychotherapeutic benefits of opioid agonist therapy

Prescription opioid dispensing patterns among patients with schizophrenia or bipolar disorder

BACKGROUND

Patients with schizophrenia (SZ) or bipolar disorder (BD) may have increased risk of complications from prescribed opioids, including opioid-induced respiratory depression. We compared prescription opioid pain medication dispensing for patients with SZ or BD versus controls over 5 years to assess dispensing trends.

METHODS

This retrospective, observational study analysed US claims data from the IBM® MarketScan® Commercial and Multi-State Medicaid databases for individuals aged 18-64 years with prevalent SZ or BD for years 2015-2019 compared with age- and sex-matched controls. Baseline characteristics, comorbidities, and medication use were assessed. Proportions of individuals dispensed prescription opioids chronically (ie, ≥70 days over a 90-day period or ≥ 6 prescriptions annually) or nonchronically (≥1 prescription, chronic definition not met) were assessed.

RESULTS

In 2019, the Commercial and Medicaid databases contained records for 4773 and 30,179 patients with SZ and 52,780 and 63,455 patients with BD, respectively. Patients with SZ or BD had a higher prevalence of comorbidities, including pain, versus controls in each analysis year. From 2015 to 2019, among commercially insured patients with SZ, chronic opioid-dispensing proportions decreased from 6.1% (controls: 2.7%) to 2.3% (controls: 1.2%) and, for patients with BD, from 11.4% (controls: 2.7%) to 6.4% (controls: 1.6%). Chronic opioid dispensing declined in Medicaid-covered patients with SZ from 15.0% (controls: 14.7%) to 6.7% (controls: 6.0%) and, for patients with BD, from 27.4% (controls: 12.0%) to 12.4% (controls: 4.7%). Among commercially insured patients with SZ, nonchronic opioid dispensing decreased from 15.5% (controls: 16.4%) to 10.7% (controls: 11.0%) and, for patients with BD, from 26.1% (controls: 17.5%) to 20.0% (controls: 12.2%). In Medicaid-covered patients with SZ, nonchronic opioid dispensing declined from 22.5% (controls: 24.4%) to 15.1% (controls: 12.7%) and, for patients with BD, from 32.3% (controls: 25.9%) to 24.6% (controls: 13.6%).

CONCLUSIONS

The proportions of individuals dispensed chronic or nonchronic opioid medications each year were similar between commercially and Medicaid-insured patients with SZ versus controls and were higher for patients with BD versus controls. From 2015 to 2019, the proportions of individuals who were dispensed prescription opioids chronically or nonchronically decreased for patients with SZ or BD and controls.

Opioid Mechanisms and the Treatment of Depression

Opioid receptors are widely expressed in the brain, and the opioid system has a key role in modulating mood, reward processing and stress responsivity. There is mounting evidence that the endogenous opioid system may be dysregulated in depression and that drug treatments targeting mu, delta and kappa opioid receptors may show antidepressant potential. The mechanisms underlying the therapeutic effects of opioid system engagement are complex and likely multi-factorial. This chapter explores various pathways through which the modulation of the opioid system may influence depression. These include impacts on monoaminergic systems, the regulation of stress and the hypothalamic-pituitary-adrenal axis, the immune system and inflammation, brain-derived neurotrophic factors, neurogenesis and neuroplasticity, social pain and social reward, as well as expectancy and placebo effects. A greater understanding of the diverse mechanisms through which opioid system modulation may improve depressive symptoms could ultimately aid in the development of safe and effective alternative treatments for individuals with difficult-to-treat depression.

Psychiatric comorbidities and concurrent substance use among people who inject drugs: a single-centre hospital-based study

The management of people who inject drugs (PWID) is compounded by the presence of psychiatric comorbidities leading to frequent relapses and poor treatment outcomes. Early identification and treatment of psychiatric comorbidities should be included in the management to enhance treatment outcomes. The objective of this study was to estimate the prevalence of psychiatric comorbidities and concurrent substance use among opioid injectors. This hospital-based, cross-sectional study was conducted from March 2021 to August 2022. This study included opioid injectors of all ages and both sexes. The Mini International Neuropsychiatric Interview-7 (MINI-7) and WHO-ASSIST were used to determine psychiatric comorbidities and concurrent substance use, respectively. Both crude and adjusted odds ratios were calculated to assess associations among demographic variables, concurrent substance use and psychiatric comorbidities. Among the 328 opioid injectors, the overall prevalence of psychiatric comorbidities was 88.1%, with the majority (68.6%) having more than one comorbidity. The most common psychiatric comorbidities were panic disorder (41.2%), social anxiety disorder (40.5%), and antisocial personality disorder (39.3%). Concurrent use of alcoholic beverages doubled the risk of ASPD (odds ratio 2.14 (1.24-3.72)). Cocaine (odds ratio 2.36 (1.10-5.03)) and amphetamines (odds ratio 7.68 (2.21-26.65)) increased the risk of OCD. Daily heroin injections were negatively associated (odds ratio 0.18 (0.03-0.94)) with psychotic disorders. Younger age (adjusted odds ratio 0.20 (0.79-0.53)) and never married status (adjusted odds ratio 2.62 (1.06-6.47)) were the only significant variables in the regression analysis. In conclusion, opioid injectors had a higher prevalence of numerous psychiatric comorbidities. The most common comorbidity was anxiety disorders. Concurrent use of tobacco, cannabis, cocaine, inhalants, etc., greatly increased the risk of psychiatric comorbidities.

Effects of Buprenorphine/Naloxone and Methadone on Depressive Symptoms in People with Prescription Opioid Use Disorder: A Pragmatic Randomised Controlled Trial

OBJECTIVE

This study aimed to evaluate the effectiveness of flexible take-home dosing of buprenorphine/naloxone (BUP/NX) and methadone standard model of care in reducing depressive symptoms in people with prescription-type opioid use disorder (POUD). This trial also evaluated whether improvements in depressive symptoms were mediated by opioid use.

METHODS

Analyzed data came from the OPTIMA study (clinicaltrials.gov identifier: NCT03033732), a pragmatic randomised controlled trial comparing flexible take-home dosing of BUP/NX and methadone standard model of care for reducing opioid use in people with POUD. A total of 272 participants were recruited in four Canadian provinces. Participants were randomised 1:1 to BUP/NX or methadone. After treatment induction, past two-week opioid use was measured using the Timeline Followback every two weeks for a total of 24 weeks. Depressive symptoms were measured with the Beck Depression Inventory at baseline, weeks 12 and 24.

RESULTS

Both BUP/NX and methadone significantly reduced depressive symptoms at week 12 (aβ ± SE = -3.167 ± 1.233; P < 0.001) and week 24 (aβ ± SE = -7.280 ± 1.285; P < 0.001), with no interaction between type of treatment and time (P = 0.284). Improvements in depressive symptoms were only partially mediated by a reduction in opioid use (proportion mediated = 36.8%; 95% confidence interval = -1.158 to -0.070; P = 0.015).

CONCLUSIONS

BUP/NX and methadone showed similar effectiveness in decreasing comorbid depressive symptoms in people with POUD. This effect was partially explained by a reduction in opioid use. As both treatments seem equally effective, clinicians are encouraged to tailor the selection of OAT to patients' needs and characteristics.

Treatment-Resistant Depression (TRD): Is the Opioid System Involved?

About 30% of major depression disorder patients fail to achieve remission, hence being diagnosed with treatment-resistant major depression (TRD). Opium had been largely used effectively to treat depression for centuries, but when other medications were introduced, its use was discounted due to addiction and other hazards. In a series of previous studies, we evaluated the antinociceptive effects of eight antidepressant medications and their interaction with the opioid system. Mice were tested with a hotplate or tail-flick after being injected with different doses of mianserin, mirtazapine, trazodone, venlafaxine, reboxetine, moclobemide, fluoxetine, or fluvoxamine to determine the effect of each drug in eliciting antinociception. When naloxone inhibited the antinociceptive effect, we further examined the effect of the specific opioid antagonists of each antidepressant drug. Mianserin and mirtazapine (separately) induced dose-dependent antinociception, each one yielding a biphasic dose-response curve, and they were antagonized by naloxone. Trazodone and venlafaxine (separately) induced a dose-dependent antinociceptive effect, antagonized by naloxone. Reboxetine induced a weak antinociceptive effect with no significant opioid involvement, while moclobemide, fluoxetine, and fluvoxamine had no opioid-involved antinociceptive effects. Controlled clinical studies are needed to establish the efficacy of the augmentation of opiate antidepressants in persons with treatment-resistant depression and the optimal dosage of drugs prescribed.

EPD1504: a novel μ-opioid receptor partial agonist attenuates obsessive-compulsive disorder (OCD)-like behaviors

Low doses of μ-opioid receptor (MOR) agonists rapidly ameliorate symptoms in treatment-resistant obsessive-compulsive disorder (OCD) patients (10-50% of OCD patients). However, the utility of MOR agonists is limited by their safety liabilities. We developed a novel MOR partial agonist (EPD1540) that has an improved respiratory safety profile when compared to buprenorphine. Buprenorphine is a MOR partial agonist primarily used in the treatment of opiate-use disorder, which in investigator-led trials, has been shown to rapidly ameliorate symptoms in treatment-resistant OCD patients. In this study, we show that doses of EPD1504 and buprenorphine that occupy small fractions of MORs in the CNS (approximately 20%) are as effective as fluoxetine at ameliorating OCD-like behaviors in two different rat models (an operant probabilistic reversal task and marble burying). Importantly, effective doses of EPD1504 did not impair either locomotor activity, or respiration under normoxic or hypercapnic conditions. Additionally, EPD1504 had effects comparable to buprenorphine in the conditioned place preference assay. These results indicate that EPD1504 may provide a safer alternative to buprenorphine for the treatment of OCD patients.

The Differential Influence of PZM21, A Nonrewarding μ-opioid Receptor Agonist With G Protein Bias, on Behavioural Despair and Fear Response in Mice

A growing body of evidence points out the involvement of the µ-opioid receptors in the modulation of stress-related behaviour. It has been suggested that µ-opioid receptor agonists may attenuate behavioural despair following animals' exposure to an acute, inescapable stressor. Moreover, morphine was shown to ameliorate fear memories caused by a traumatic experience. As typical µ-opioid receptor agonists entail a risk of serious side effects and addiction, novel, possibly safer and less addictive agonists of this receptor are currently under investigation. One of them, PZM21, preferentially acting via the G protein signalling pathway, was previously shown to be analgesic, but less addictive than morphine. Here, we aimed to further test this ligand in stress-related behavioural paradigms in mice. The study has shown that, unlike morphine, PZM21 does not decrease immobility in the forced swimming and tail suspension tests. On the other hand, we observed that both mice treated with PZM21 and those receiving morphine presented a slight attenuation of freezing across the consecutive fear memory retrievals in the fear conditioning test. Therefore, our study implies that at the range of tested doses, PZM21, a nonrewarding representative of G protein-biased µ-opioid receptor agonists, may interfere with fear memory consolidation while having no beneficial effects on behavioural despair in mice.

Incidence of suicide and self-harm among people with opioid use disorder and the impact of opioid agonist treatment: A retrospective data linkage study

BACKGROUND

Rates of suicide and self-harm are elevated among people with opioid use disorder (OUD). This study examined incidence of self-harm and suicide among people who have entered OAT and assessed the impact of different OAT exposure periods on these events.

METHOD

We conducted a retrospective population-based cohort study of all OAT recipients (N = 45,664) in New South Wales, Australia (2002-2017), using linked administrative data. Incidence rates of self-harm hospitalisations and suicide deaths were estimated per 1000 person-years (PY). The first 28 days of an OAT episode, ≥ 29 days on OAT, the first 28 days off OAT, and ≥ 29 days off OAT (maximum four years post-OAT) were exposure periods. Poisson regression models with generalised estimating equations estimated the adjusted incidence rate ratios (ARR) of self-harm and suicide by OAT exposure periods, adjusting for covariates.

RESULTS

There were 7482 hospitalisations (4148 individuals) for self-harm and 556 suicides, equating to incidence rates of 19.2 (95% confidence intervals [CI]=18.8-19.7) and 1.0 (95%CI=0.9-1.1) per 1000 PY, respectively. Opioid overdose was implicated in 9.6% of suicides and 28% of self-harm hospitalisations. Compared to ≥ 29 days on OAT, the incidence rate of suicide was elevated in the 28 days following OAT cessation (ARR=17.4 [95%CI=11.7-25.9]), and the rate of self-harm hospitalisations was elevated during the first 28 days of OAT (ARR=2.2 [95%CI=1.9-2.6]) and the 28 days after leaving OAT (ARR=2.7 [95%CI=2.3-3.2]).

CONCLUSIONS

OAT may reduce suicide and self-harm risk among people with OUD; however, OAT initiation and cessation are critical periods for targeting self-harm and suicide prevention interventions.

Role of the mesolimbic dopamine pathway in the antidepressant effects of ketamine

Depression is a complex and highly heterogeneous disorder which diagnosis is based on an exceedingly variable set of clinical symptoms. Current treatments focus almost exclusively on the manipulation of monoamine neurotransmitter systems, but despite considerable efforts, these remain inadequate for a significant proportion of those afflicted by the disorder. The emergence of racemic (R, S)-ketamine as a fast-acting antidepressant has provided an exciting new path for the study of major depressive disorder (MDD) and the search for better therapeutics for its treatment. Previous work suggested that ketamine's mechanism of action is primarily mediated via blockaded of N-methyl-d-aspartate (NMDA) receptors, however, this is an area of active research and clinical and preclinical evidence now indicate that ketamine acts on multiple systems. The last couple of decades have cemented the mesolimbic dopamine reward pathway's involvement in the pathogenesis of MDD and related mood disorders. Exposure to negative stress dysregulates dopamine neuronal activity disrupting reward and motivational processes resulting in anhedonia (lack of pleasure), a hallmark symptom of depression. Although the mechanism(s) underlying ketamine's antidepressant activity continue to be elucidated, current evidence indicate that its therapeutic effects are mediated, at least in part, via long-lasting synaptic changes and subsequent molecular adaptations in brain regions within the mesolimbic dopamine system. Notwithstanding, ketamine is a drug of abuse, and this liability may pose limitations for long term use as an antidepressant. This review outlines the current knowledge of ketamine's actions within the mesolimbic dopamine system and its abuse potential. This article is part of the Special Issue on 'Ketamine and its Metabolites'.

Changes in Psychological Outcomes after Cessation of Full Mu Agonist Long-Term Opioid Therapy for Chronic Pain

Improved understanding of psychological features associated with full mu agonist long-term opioid therapy (LTOT) cessation may offer advantages for clinicians. This preliminary study presents changes in psychological outcomes in patients with chronic, non-cancer pain (CNCP) after LTOT cessation via a 10-week multidisciplinary program which included treatment with buprenorphine. Paired t-tests pre- and post-LTOT cessation were compared in this retrospective cohort review of data from electronic medical records of 98 patients who successfully ceased LTOT between the dates of October 2017 to December 2019. Indicators of quality of life, depression, catastrophizing, and fear avoidance, as measured by the 36-Item Short Form Survey, the Patient Health Questionnaire-9-Item Scale, the Pain Catastrophizing Scale, and the Fear Avoidance Belief Questionnaires revealed significant improvement. Scores did not significantly improve for daytime sleepiness, generalized anxiety, and kinesiophobia, as measured by the Epworth Sleepiness Scale, the Generalized Anxiety Disorder 7-Item Scale, and the Tampa Scale of Kinesiophobia. The results suggest that successful LTOT cessation may be interconnected with improvements in specific psychological states.

A Transdiagnostic group therapy for sleep and anxiety among adults with substance use disorders: Protocol and pilot investigation

Introduction

Treatment of substance use disorders (SUDs) is challenging with high rates of treatment dropout and relapse, particularly among individuals with comorbid psychiatric conditions. Anxiety and insomnia are prevalent among those with SUD and exacerbate poor treatment outcomes. Interventions that concurrently target anxiety and insomnia during the early stages of SUD treatment are lacking. To this end, we investigated the feasibility and preliminary effectiveness in a single-arm pilot trial of an empirically informed group transdiagnostic intervention, Transdiagnostic SUD Therapy, to concurrently reduce anxiety and improve sleep among adults receiving treatment for SUD. Specifically, we hypothesized that participants would evidence declines in anxiety and insomnia and improvements in sleep health, a holistic, multidimensional pattern of sleep-wakefulness that promotes wellbeing. A secondary aim was to describe the protocol for Transdiagnostic SUD Therapy and how it may be implemented into a real-world addiction treatment setting.

Method

Participants were 163 adults (M_age  = 43.23; 95.1% White; 39.93% female) participating in an intensive outpatient program for SUD who attended at least three of four Transdiagnostic SUD Therapy sessions. Participants had diverse SUDs (58.3% alcohol use disorder, 19.0% opioid use disorder) and nearly a third of the sample met criteria for two SUDs and comorbid mental health diagnoses (28.9% anxiety disorder, 24.6% major depressive disorder).

Results

As anticipated, anxiety and insomnia reduced significantly across the 4-week intervention period from clinical to subclinical severity, and sleep health significantly improved (ps < 0.001). These statistically significant improvements following Transdiagnostic SUD Therapy demonstrated medium to large effects (ds > 0.5).

Conclusion

Transdiagnostic SUD Therapy is designed to be flexibly administered in "real-world" clinical settings and, preliminarily, appears to be effective in improving emotional and behavioral factors that increase risk for return to substance use and poor SUD treatment outcomes. Additional work is needed to replicate these findings, determine the feasibility of widespread uptake of Transdiagnostic SUD Therapy, and examine whether the treatment effects translate to improvement in substance use outcomes.

Comparison of Psychopathologic Characteristics between Individuals Undergoing Methadone Maintenance Treatment, Opioid Dependents, and Control Group

BACKGROUND

Methadone maintenance treatment (MMT) can theoretically reduce the psychosocial harms of opioid dependency. The increasing number of MMT clinics in Iran during the last two decades was not accompanied by a reduction in addiction rates. Therefore, this study was conducted to compare the psychopathological characteristics of individuals on MMT, opioid dependents, and a control group in the Iranian population.

METHODS

This cross-sectional study was conducted in Mashhad to evaluate the psychopathological profile of 99 participants (33 opioid-dependent individuals [ODI], 33 MMT clients, and 33 controls) using the Symptom Checklist-90-Revised (SCL-90-R) questionnaire and demographic form. Parametric and non-parametric tests were used to compare the mean score of symptoms between the three groups. The Spearman correlation test was used to test the correlation of psychological features with age and dependency duration.

FINDINGS

There was no significant difference between MMT clients and ODI regarding the Global Severity Index (GSI) and nine items of the SCL-90-R questionnaire. However, a significant difference was found between the controls and two other groups (P<0.001). Paranoid ideation in the ODI was more frequent compared to MMT clients significantly (P=0.015). Psychological characteristics had a direct correlation with dependency duration and an inverse correlation with age (P<0.05).

CONCLUSION

Psychopathologic features observed in the dependent patients and MMT clients were significantly higher than in the control group. It seems that the psychopathology profile in MMT clients was not better than dependent individuals in Iran.

A possible anti-anxiety effect of appetitive aggression and a possible link to the work of Donald Winnicott

Various pleasant sensations that give a particularly intense pleasure are able to improve anxiety. In the present study I consider the possibility that their anti-anxiety action depends on the strong pleasure they provide, and I propose a possible mechanism of this action. According to some studies, also appetitive aggression (an aggression that provokes a strong pleasure and that is performed only for the pleasure it provides) can improve anxiety, and in this article I consider the possibility that the pleasure of appetitive aggression is able to reduce anxiety by the same mechanism I have proposed for other intense pleasurable sensations.

The aggression performed by a child against the mother or against a substitute for the mother in the first period of life (a period in which this aggression is not dangerous) is a recurring theme throughout the work of of Donald Winnicott. Winnicott stresses that this aggression is necessary for the normal development of the child, and that the child must be free to practise it. According to Winnicott, this aggression is highly pleasurable and is not a response to unpleasant or hostile external situations. For these characteristics it seems to correspond to appetitive aggression in the adult that has been found to be able to reduce anxiety. Consequently, aggression performed by the child in the first period of life may also relieve anxiety, in the same way that appetitive aggression helps against anxiety in the adult.

In his writings, Winnicott returns several times to an unthinkable or archaic anxiety that children experience when they feel abandoned by their mother for a period that is too long for them, and all children, according to Winnicott, live on the brink of this anxiety. In this study I propose the hypothesis that aggression in the early period of life may be necessary for children because the intense pleasure it provides may help them against this continuously impending anxiety.

The Opioid System in Depression

Opioid receptors are widely distributed throughout the brain and play an essential role in modulating aspects of human mood, reward, and well-being. Accumulating evidence indicates the endogenous opioid system is dysregulated in depression and that pharmacological modulators of mu, delta, and kappa opioid receptors hold potential for the treatment of depression. Here we review animal and clinical data, highlighting evidence to support: dysregulation of the opioid system in depression, evidence for opioidergic modulation of behavioural processes and brain regions associated with depression, and evidence for opioidergic modulation in antidepressant responses. We evaluate clinical trials that have examined the safety and efficacy of opioidergic agents in depression and consider how the opioid system may be involved in the effects of other treatments, including ketamine, that are currently understood to exert antidepressant effects through non-opioidergic actions. Finally, we explore key neurochemical and molecular mechanisms underlying the potential therapeutic effects of opioid system engagement, that together provides a rationale for further investigation into this relevant target in the treatment of depression.

Mu opioid receptors on hippocampal GABAergic interneurons are critical for the antidepressant effects of tianeptine

Tianeptine is an atypical antidepressant used in Europe to treat patients who respond poorly to selective serotonin reuptake inhibitors (SSRIs). The recent discovery that tianeptine is a mu opioid receptor (MOR) agonist has provided a potential avenue for expanding our understanding of antidepressant treatment beyond the monoamine hypothesis. Thus, our studies aim to understand the neural circuits underlying tianeptine's antidepressant effects. We show that tianeptine induces rapid antidepressant-like effects in mice after as little as one week of treatment. Critically, we also demonstrate that tianeptine's mechanism of action is distinct from fluoxetine in two important aspects: (1) tianeptine requires MORs for its chronic antidepressant-like effect, while fluoxetine does not, and (2) unlike fluoxetine, tianeptine does not promote hippocampal neurogenesis. Using cell-type specific MOR knockouts we further show that MOR expression on GABAergic cells-specifically somatostatin-positive neurons-is necessary for the acute and chronic antidepressant-like responses to tianeptine. Using central infusion of tianeptine, we also implicate the ventral hippocampus as a potential site of antidepressant action. Moreover, we show a dissociation between the antidepressant-like phenotype and other opioid-like phenotypes resulting from acute tianeptine administration such as analgesia, conditioned place preference, and hyperlocomotion. Taken together, these results suggest a novel entry point for understanding what circuit dysregulations may occur in depression, as well as possible targets for the development of new classes of antidepressant drugs.

Mechanisms of ketamine and its metabolites as antidepressants

Treating major depression is a medical need that remains unmet by monoaminergic therapeutic strategies that commonly fail to achieve symptom remission. A breakthrough in the treatment of depression was the discovery that the anesthetic (R,S)-ketamine (ketamine), when administered at sub-anesthetic doses, elicits rapid (sometimes within hours) antidepressant effects in humans that are otherwise resistant to monoaminergic-acting therapies. While this finding was revolutionary and led to the FDA approval of (S)-ketamine (esketamine) for use in adults with treatment-resistant depression and suicidal ideation, the mechanisms underlying how ketamine or esketamine elicit their effects are still under active investigation. An emerging view is that metabolism of ketamine may be a crucial step in its mechanism of action, as several metabolites of ketamine have neuroactive effects of their own and may be leveraged as therapeutics. For example, (2R,6R)-hydroxynorketamine (HNK), is readily observed in humans following ketamine treatment and has shown therapeutic potential in preclinical tests of antidepressant efficacy and synaptic potentiation while being devoid of the negative adverse effects of ketamine, including its dissociative properties and abuse potential. We discuss preclinical and clinical studies pertaining to how ketamine and its metabolites produce antidepressant effects. Specifically, we explore effects on glutamate neurotransmission through N-methyl D-aspartate receptors (NMDARs) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs), synaptic structural changes via brain derived neurotrophic factor (BDNF) signaling, interactions with opioid receptors, and the enhancement of serotonin, norepinephrine, and dopamine signaling. Strategic targeting of these mechanisms may result in novel rapid-acting antidepressants with fewer undesirable side effects compared to ketamine.

Opioid use and social disadvantage in patients with chronic musculoskeletal pain

BACKGROUND

Historically, marginalized patients were prescribed less opioid medication than affluent, white patients. However, because of persistent differential access to nonopioid pain treatments, this direction of disparity in opioid prescribing may have reversed.

OBJECTIVE

To compare social disadvantage and health in patients with chronic pain who were managed with versus without chronic opioid therapy. It was hypothesized that patients routinely prescribed opioids would be more likely to live in socially disadvantaged communities and report worse health.

DESIGN

Cross-sectional analysis of a retrospective cohort defined from medical records from 2000 to 2019.

SETTING

Single tertiary safety net medical center.

PATIENTS

Adult patients with chronic musculoskeletal pain who were managed longitudinally by a physiatric group practice from at least 2011 to 2015 (n = 1173), subgrouped by chronic (≥4 years) adherent opioid usage (n = 356) versus no chronic opioid usage (n = 817).

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

The primary outcome was the unadjusted between-group difference in social disadvantage, defined by living in the worst national quartile of the Area Deprivation Index (ADI). An adjusted effect size was also calculated using logistic regression, with age, sex, race, and Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference and Physical Function scores as covariates. Secondary outcomes included adjusted differences in health by chronic opioid use (measured by PROMIS).

RESULTS

Patients managed with chronic opioid therapy were more likely to live in a zip code within the most socially disadvantaged national quartile (34.9%; 95% confidence interval [CI] 29.9-39.9%; vs. 24.9%; 95% CI 21.9-28.0%; P < .001), and social disadvantage was independently associated with chronic opioid use (odds ratio [OR] 1.01 per ADI percentile [1.01-1.02]). Opioid use was also associated with meaningfully worse PROMIS Depression (3.8 points [2.4-5.1]), Anxiety (3.0 [1.4-4.5]), and Pain Interference (2.6 [1.7-3.5]) scores.

CONCLUSIONS

Patients prescribed chronic opioid treatment were more likely to live in socially disadvantaged neighborhoods, and chronic opioid use was independently associated with worse behavioral health. Improving access to multidisciplinary, nonopioid treatments for chronic pain may be key to successfully overcoming the opioid crisis.

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.

Long-term follow-up assessment of opioid use outcomes among individuals with comorbid mental disorders and opioid use disorder treated with buprenorphine or methadone in a randomized clinical trial

AIMS

To investigate whether reduction in opioid use differs when treated by either buprenorphine-naloxone (BUP) or methadone (MET) among adults with comorbid opioid use disorder (OUD) and mental disorders.

DESIGN, SETTING AND PARTICIPANTS

In a randomized controlled trial, adults with OUD were randomized to 24 weeks of either BUP or MET treatment and were followed up in 3-yearly assessments. The present secondary analyses were based on 597 participants who completed all assessments.

MEASUREMENTS

The outcome measure was the number of days of using opioids per month during the follow-up period. The Mini-International Neuropsychiatric Interview (MINI) was used to classify participants into three groups: life-time mood disorder (n = 302), life-time mental disorder other than mood disorder (n = 114) and no mental disorder (n = 181). Medication treatment (BUP, MET, no treatment) during the follow-up period was a time-varying predictor.

FINDINGS

Based on zero-inflated Poisson (ZIP) mixed regression analysis, it was found that relative to no treatment, opioid use during the follow-up was significantly reduced by BUP [odds ratio (OR) = 0.12, 95% confidence interval (CI) = 0.07-0.21 for any use; risk ratio (RR) = 0.77, 95% CI =0.66-0.89 for days of use] and by MET [OR = 0.33, 95% CI = 0.25-0.45 for any use; RR = 0.78, 95% CI = 0.72-0.84 for days of use]. Relative to MET, BUP was associated with a lower likelihood of any opioid use among participants with mood disorders (OR = 0.52, 95% CI = 0.36-0.74) and for participants without mental disorder (OR = 0.37, 95% CI = 0.21-0.66) and fewer number of days using opioids (RR = 0.37, 95% CI = 0.25-0.56) among participants with other mental disorders.

CONCLUSIONS

Among adults with comorbid opioid use disorder and mental disorders, treatment with buprenorphine-naloxone produced greater reductions in opioid use than treatment with methadone.

The next psychoactive drugs: From imipramine to ketamine

Since the 1950s, the therapeutic arsenal against depression has grown considerably. From the discovery of mono-amine oxidase inhibitors (MAOIs) to the antidepressant effect of ketamine, several pharmacological breakthroughs made the history of psychiatry. These discoveries oriented the research about the pathophysiology of depression, which is one of the most disabling diseases worldwide affecting 10 to 20% of general population. In this article, we offer a short historical review of the various therapeutic options developed over the past century and the consequences of these innovations. We then review the discovery of the antidepressant effects of ketamine (and its S-enantiomer, esketamine), the lastest development in depression treatment. Ketamine's effects are spectacular both in terms of their very short onset time, and because they are observed even in treatment-resistant depression. Just as MAOIs and tricyclic antidepressants allowed the "monoaminergic hypothesis of depression" to emerge, unravelling the mechanisms of ketamine's antidepressant effects should highlight the role of glutamatergic system and neuro-inflammation in the neurobiology of depression. Ketamine might also help to refine our understanding of the cognitive pathophysiology of depression and to deeply transform the clinical representations of depressive disorder.

Daily heroin injection and psychiatric disorders: A cross-sectional survey among People Who Inject Drugs (PWID) in Haiphong, Vietnam

BACKGROUND

Psychiatric comorbidities are frequent among people who inject drugs, they are associated with a poorer prognosis and need to be addressed. Their interaction with daily heroin injection requires clarification.

METHODS

A cross-sectional survey was conducted among PWID recruited in the city of Haiphong, Vietnam, by respondent-driven sampling. The inclusion criteria were age 18 or older and current injection drug use, verified by skin marks and positive urine tests for heroin or methamphetamine. Data on socio-demographic characteristics, drug use, sexual behaviour and access to treatment were collected using face-to-face questionnaires by trained interviewers. PWID were screened by trained psychiatrists for depression, psychotic disorder and suicidality, using the MINI questionnaire.

RESULTS

418 participants were included in the analyses. All were injected heroin users, 21 % were diagnosed with a current major depressive disorder, 15 % with a current psychotic disorder and 12 % presented a suicide risk. In the bivariate analyses, regular meth use, cannabis use and ketamine use were positively associated with presenting at least one psychiatric condition while daily heroin injection and being currently treated with methadone were negatively associated. In the multivariate model, poly-substance use was positively associated with depression (methamphetamine and drinking in addition to heroin) and psychotic disorder (methamphetamine and/or hazardous drinking in addition to heroin) while daily heroin injection and current methadone treatment were negatively and independently associated with depression and psychotic syndrome.

CONCLUSIONS

Our survey confirms the burden of methamphetamine use and the protective effect of methadone but also a possible protective effect of daily heroin injection.

[The next psychoactive drugs: From imipramine to ketamine]

Depuis les années 1950, l’arsenal thérapeutique permettant de lutter contre la dépression s’est considérablement enrichi. De la découverte des inhibiteurs de la monoamine oxydase (IMAO) à celle de la kétamine, ces percées pharmacologiques ont marqué l’histoire de la psychiatrie et guidé la recherche sur la physiopathologie de la dépression, cette pathologie dévastatrice affectant entre 10 et 20 % de la population mondiale. Nous proposons dans cet article une courte revue historique des différentes options thérapeutiques développées au cours du siècle passé et des conséquences qu’ont eu ces innovations. Nous réalisons ensuite un état des lieux de la plus récente de ces découvertes, celle des effets antidépresseurs de la kétamine (et de son énantiomère S, l’eskétamine), spectaculaires de par leur délai d’apparition et leur efficacité même dans les formes les plus résistantes de dépression. De même que la découverte des IMAO et des tricycliques a permis de concevoir une théorie monoaminergique de la dépression, l’étude des mécanismes d’actions de la kétamine pourrait permettre de comprendre le rôle de la transmission glutamatergique ou de la neuro-inflammation dans la neurobiologie de cette pathologie, d’affiner nos connaissances sur sa physiopathologie cognitive ou encore de transformer en profondeur les représentations des cliniciens sur cette maladie.

Depression and Outcomes of Methadone and Buprenorphine Treatment Among People with Opioid Use Disorders: A Literature Review

Objective: Depression is the most common psychiatric comorbidity among people with opioid use disorders (OUDs). However, whether and how comorbid depression is associated with the outcomes of opioid agonist therapy (OAT) remains poorly understood. The objective of this review was to identify and describe the association between depression and main outcomes (opioid use and treatment retention) of methadone and buprenorphine treatment among people with OUDs. Methods: A literature review was conducted by searching five electronic databases (MEDLINE, PubMed, Embase, Evidence-Based Medicine Reviews [EBMR], and Cumulative Index of Nursing and Allied Health Literature [CINAHL] Complete) from January 1970 to April 2019. Two independent reviewers screened titles and abstracts of the identified records by using pre-established eligibility criteria. Next, full texts were reviewed and studies that met inclusion criteria were selected. Finally, a descriptive synthesis of extracted data was performed. Results: In total, 12,296 records were identified and 18 studies that met inclusion criteria were retained. Of these, six studies reported reduced opioid use and seven reported increased opioid use during methadone or buprenorphine treatment. In addition, three studies reported an increased retention rate and four documented a decreased retention rate during methadone or buprenorphine treatment. The remaining studies did not find any significant association between depression and opioid use or treatment retention. Overall, the evidence did not demonstrate a consistent association between depression and outcomes of methadone or buprenorphine treatment. Conclusions: Although the inconsistent nature of the current evidence prohibited us from drawing definitive conclusions, we posit that the presence of depression among OUDs patients may not always predict negative outcomes related to retention and drug use during the course of OAT. Particularly, the hypothesis that adequate treatment of depression can improve treatment retention is promising and is in line with the call for increased efforts to provide integrated care for comorbid mental health disorders and addiction. Future studies with rigorous methodology are essential to better characterize the complex interplay between depression, OAT, and OUDs.

Opioid system is necessary but not sufficient for antidepressive actions of ketamine in rodents

Slow response to the standard treatment for depression increases suffering and risk of suicide. Ketamine, an N-methyl-d-aspartate (NMDA) receptor antagonist, can rapidly alleviate depressive symptoms and reduce suicidality, possibly by decreasing hyperactivity in the lateral habenula (LHb) brain nucleus. Here we find that in a rat model of human depression, opioid antagonists abolish the ability of ketamine to reduce the depression-like behavioral and LHb hyperactive cellular phenotypes. However, activation of opiate receptors alone is not sufficient to produce ketamine-like effects, nor does ketamine mimic the hedonic effects of an opiate, indicating that the opioid system does not mediate the actions of ketamine but rather is permissive. Thus, ketamine does not act as an opiate but its effects require both NMDA and opiate receptor signaling, suggesting that interactions between these two neurotransmitter systems are necessary to achieve an antidepressant effect.

The Role of Opiates in Social Pain and Suicidal Behavior

With more than 800,000 deaths by suicide each year and 20 to 30 times more suicide attempts worldwide, suicide is a major public health problem. Current treatments of SB are mainly based on pharmacological treatments that are not specific of SB (e.g. antidepressants), and new therapeutic targets are urgently needed. Recent data strengthen the ancient conception pain (social, psychic, physical) that is at the core of the suicidal process and should be incorporated in the clinical assessment of suicide risk. Then, the mechanisms involved in the regulation of pain may open new avenues regarding therapeutic perspectives. Opiates appear to be a promising candidate in treatment of SB. Indeed, since the last two decades, growing evidences suggest an implication of the opioid system in the pathophysiology of SB, this conduct to the elaboration of randomized controlled trials (RCTs) using opiates in patients with SB. Results suggesting an anti-suicidal effect of buprenorphine and the potential opioidergic-related anti-suicidal effect of ketamine both contribute to the growing interest in opiates use in SB. In this review, we will summarize a large part of the evidence that leads researchers and clinicians to be interested in the use of opiates for SB treatment and discuss on new opioid pharmacological options for suicidal patients.

A 20-year study of the bidirectional relationship between anxious and depressive symptomology and pain medication usage

Aim: To investigate the 20-year relationship between anxiety, depression and pain medication use. Patients: A total of 521 individuals reporting chronic pain from the National Survey of Midlife Development in the USA (MIDUS) study. Methods: Structural equation modeling of 20-year longitudinal survey data. Results: Over 20 years, a bidirectional relationship between depression and anxiety in individuals with chronic pain was indicated. Pain medication utilization predicted later use at 10 years. Pain medication use was not strongly related to later anxiety; however, heightened anxiety was associated with later use. Conclusion: Depression and anxiety show an extensive long-term bidirectional relationship. While there was little indication of a relationship between pain medication use and later negative mood, anxiety was associated with subsequent pain medication use.

Potential Health Risks Linked to Emerging Contaminants in Major Rivers and Treated Waters

The presence of endocrine-disrupting chemicals (EDCs) in our local waterways is becoming an increasing threat to the surrounding population. These compounds and their degradation products (found in pesticides, herbicides, and plastic waste) are known to interfere with a range of biological functions from reproduction to differentiation. To better understand these effects, we used an in silico ontological pathway analysis to identify the genes affected by the most commonly detected EDCs in large river water supplies, which we grouped together based on four common functions: Organismal injuries, cell death, cancer, and behavior. In addition to EDCs, we included the opioid buprenorphine in our study, as this similar ecological threat has become increasingly detected in river water supplies. Through the identification of the pleiotropic biological effects associated with both the acute and chronic exposure to EDCs and opioids in local water supplies, our results highlight a serious health threat worthy of additional investigations with a potential emphasis on the effects linked to increased DNA damage.

Results from a long-term open-label extension study of adjunctive buprenorphine/samidorphan combination in patients with major depressive disorder

Buprenorphine/samidorphan (BUP/SAM; ALKS 5461) is an investigational opioid system modulator for the adjunctive treatment of patients with major depressive disorder (MDD), who did not respond adequately to prior antidepressant therapy (ADT). FORWARD-2, an open-label extension study, assessed long-term safety and tolerability of adjunctive BUP/SAM treatment in these patients. Patients from four short-term trials and de novo patients were enrolled; all had confirmed MDD and a current major depressive episode lasting 2-24 months. Patients were treated with an established ADT for ≥8 weeks before receiving sublingual, adjunctive BUP/SAM 2 mg/2 mg for up to 52 weeks. Safety (primary objective) was assessed via adverse events (AEs), the Columbia-Suicide Severity Rating Scale, and the Clinical Opiate Withdrawal Scale (COWS). Exploratory evaluation of efficacy was done using the Montgomery-Åsberg Depression Rating Scale (MADRS). Of 1485 patients, 50% completed the study and 11% discontinued due to AEs. AEs of nausea, headache, constipation, dizziness, and somnolence, each occurred in ≥10% of patients. There was no evidence of increased suicidal ideation or behavior. Euphoria-related AEs were uncommon (1.2%). Following abrupt BUP/SAM discontinuation, "drug withdrawal" AEs were infrequent (0.4%), and the incidence of COWS categorical worsening after abrupt drug discontinuation was low (6.5%). Improvements in mean MADRS scores were maintained until study end, suggesting durability of antidepressant effect in patients continuing treatment. BUP/SAM was generally well tolerated, with a low risk of abuse and an AE profile consistent with those seen in placebo-controlled studies. Withdrawal reports were uncommon and of limited clinical impact.

Keeping up with the clinical advances: depression

Major depressive disorder (MDD) is a prevalent and heterogeneous disorder. Although there are many treatment options for MDD, patients with treatment-resistant depression (TRD) remain prevalent, wherein delayed time to response results in inferior chances of achieving remission. Recently, therapeutics have been developed that depart from the traditional monoamine hypothesis of depression and focus instead on the glutamatergic, GABAergic, opioidergic, and inflammatory systems. The literature suggests that the foregoing systems are implicated in the pathophysiology of MDD and preclinical trials have informed the development of pharmaceuticals using these systems as therapeutic targets. Pharmaceuticals that target the glutamatergic system include ketamine, esketamine, and rapastinel; brexanolone and SAGE-217 target the GABAergic system; minocycline targets the inflammatory system; and the combinatory agent buprenorphine + samidorphan targets the opioidergic system. The aforementioned agents have shown efficacy in treating MDD in clinical trials. Of particular clinical relevance are those agents targeting the glutamatergic and GABAergic systems as they exhibit rapid response relative to conventional antidepressants. Rapid response pharmaceuticals have the potential to transform the treatment of MDD, demonstrating reduction in depressive symptoms within 24 hours, as opposed to weeks noted with conventional antidepressants. Novel therapeutics have the potential to improve both patient mood symptomatology and economical productivity, reducing the debased human capital costs associated with MDD. Furthermore, a selection of therapeutic targets provides diverse treatment options which may be beneficial to the patient considering the heterogeneity of MDD.

Blockade of the Sigma-1 Receptor Relieves Cognitive and Emotional Impairments Associated to Chronic Osteoarthritis Pain

Osteoarthritis is the most common musculoskeletal disease worldwide, often characterized by degradation of the articular cartilage, chronic joint pain and disability. Cognitive dysfunction, anxiety and depression are common comorbidities that impact the quality of life of these patients. In this study, we evaluated the involvement of sigma-1 receptor (σ1R) on the nociceptive, cognitive and emotional alterations associated with chronic osteoarthritis pain. Monosodium iodoacetate (MIA) was injected into the knee of Swiss-albino CD1 mice to induce osteoarthritis pain, which then received a repeated treatment with the σ1R antagonist E-52862 or its vehicle. Nociceptive responses and motor performance were assessed with the von Frey and the Catwalk gait tests. Cognitive alterations were evaluated using the novel object recognition task, anxiety-like behavior with the elevated plus maze and the zero-maze tests, whereas depressive-like responses were determined using the forced swimming test. We also studied the local effect of the σ1R antagonist on cartilage degradation, and its central effects on microglial reactivity in the medial prefrontal cortex. MIA induced mechanical allodynia and gait abnormalities that were prevented by the chronic treatment with the σ1R antagonist. E-52862 also reduced the memory impairment and the depressive-like behavior associated to osteoarthritis pain. Interestingly, the effect of E-52862 on depressive-like behavior was not accompanied by a modification of anxiety-like behavior. The pain-relieving effects of the σ1R antagonist were not due to a local effect on the articular cartilage, since E-52862 treatment did not modify the histological alterations of the knee joints. However, E-52862 induced central effects revealed by a reduction of the cortical microgliosis observed in mice with osteoarthritis pain. These findings show that σ1R antagonism inhibits mechanical hypersensitivity, cognitive deficits and depressive-like states associated with osteoarthritis pain in mice. These effects are associated with central modulation of glial activity but are unrelated to changes in cartilage degradation. Therefore, targeting the σ1R with E-52862 represents a promising pharmacological approach with effects on multiple aspects of chronic osteoarthritis pain that may go beyond the strict inhibition of nociception.

Behavioral effects evoked by the beta globin-derived nonapeptide LVV-H6

LVV-hemorphin-6 (LVV-h6) is bioactive peptide and is a product of the degradation of hemoglobin. Since LVV-h6 effects are possibly mediated by opioid or AT4/IRAP receptors, we hypothesized that LVV-h6 would modify behavior. We evaluated whether LVV-h6 affects: i) anxiety-like behavior and locomotion; ii) depression-like behavior; iii) cardiovascular and neuroendocrine reactivity to emotional stress. Male Wistar rats ( ± 300 g) received LVV-h6 (153 nmol/kg i.p.) or vehicle (NaCl 0.9% i.p.). We used: i) open field (OF) test for locomotion; ii) elevated plus maze (EPM) for anxiety-like behavior; iii) forced swimming test (FST) for depression-like behavior and iv) air jet for cardiovascular and neuroendocrine reactivity to stress. Diazepam (2 mg/kg i.p.) and imipramine (15 mg/kg i.p.) were used as positive control for EPM and FST, respectively. To evaluate the LVV-h6 mechanisms, we used: the antagonist of oxytocin (OT) receptors (atosiban - ATS 1 and 0.1 mg/kg i.p.); the inhibitor of tyrosine hydroxylase (Alpha-methyl-p-tyrosine - AMPT 200 mg/kg i.p.) to investigate the involvement of catecholaminergic paths; and the antagonist of opioid receptors (naltrexone - NTX 0.3 mg/kg s.c.). We found that LVV-h6: i) evoked anxiolytic-like effect; ii) evoked antidepressant-like effect in the FST; and iii) did not change the locomotion, neuroendocrine and cardiovascular responses to stress. The LVV-h6 anxiolytic-like effect was not reverted by ATS and AMPT. However, the antidepressant effects were reverted only by NTX. Hence, our findings demonstrate that LVV-h6 modulates anxiety-like behavior by routes that are not oxytocinergic, catecholaminergic or opioid. The antidepressant-like effects of LVV-h6 rely on opioid pathways.

Substance type moderates the longitudinal association between depression and substance use from pre-treatment through a 1-year follow-up

BACKGROUND

Research examining directionality of the relationship between depressive symptoms and substance use following treatment entry is limited. Furthermore, substances differ in their neurobiological effects on mood. The relationship between depression and substance use following treatment entry may be moderated by dependence on specific substances. The study tested (a) lagged effects between depressive symptoms and substance use frequency following substance use treatment entry through a 1-year post-treatment follow-up and (b) if substance dependence type moderates these effects.

METHODS

Participants (N = 263) entering residential treatment were assessed for DSM-IV substance dependence, depressive symptoms (Beck Depression Inventory), and percentage of substance use days at post-treatment, 1-, 3-, 6- and 12-month follow-up assessments (time t₀ to t₄). Linear mixed effects models tested lagged effects between depressive symptoms and substance use frequency and the impact of substance type (i.e., dependence on alcohol, cannabis, opioid, cocaine, hallucinogen/PCP) on this relationship.

RESULTS

After controlling for concurrent effects, substance type moderated each longitudinal relationship. Depressive symptoms significantly predicted substance use frequency at the subsequent follow-up assessment, only among individuals with pre-treatment opioid dependence (B = 5.55, SE = 0.89, z = 6.21, p < 0.01). Substance use frequency significantly predicted depressive symptoms at the subsequent follow-up assessment, but not among individuals with cannabis dependence at pre-treatment (B = 1.01, SE = 0.22, t (524) = 4.49, p < 0.01).

CONCLUSIONS

The directionality of depression-substance use comorbidity may differ based on the substance of dependence at pre-treatment. Opioid users may especially benefit from treating both depression and substance use.

Locomotor and anti-immobility effects of buprenorphine in combination with the opioid receptor modulator samidorphan in rats

Modulation of the opioid system has re-emerged as a potential therapeutic avenue for treating depression, with efficacy of a fixed-dose combination of buprenorphine (BUP), a partial μ-opioid receptor (MOR) agonist and κ-opioid receptor (KOR) antagonist, and samidorphan (SAM), a potent MOR antagonist, as an adjuvant treatment in patients with major depressive disorder (MDD). To advance understanding of the mechanism of action underlying this combination, we examined BUP, SAM and their combination in a series of rat behavioural assays. We examined effects on locomotor activity in Sprague Dawley (SD) rats over an extended period of time in a home-cage tracking system, and behavioural despair (immobility) in the forced swim test (FST), a commonly-used test to study antidepressants, in SD and Wistar-Kyoto (WKY) rats. Strain differences in opioid receptor and prepropeptide mRNA expression in the brain (prefrontal cortex, amygdala, hippocampus and striatum) were examined using qRT-PCR. BUP produced locomotor hyperactivity in SD rats from 2 to 6 h following administration, which was attenuated by SAM. In SD rats, a low, but not a high, dose of SAM in combination with BUP counteracted swim-stress induced immobility. This effect was not seen with BUP alone. In contrast, BUP alone reduced immobility in WKY rats, and this effect was enhanced by a low, but not high, dose of SAM. In WKY rats, MOR mRNA expression was higher in the hippocampus and lower in the striatum vs. SD rats. KOR mRNA expression was higher in the amygdala and nociceptin receptor (NOP) mRNA expression was lower in the hippocampus vs. SD rats. Differences in opioid receptor expression may account for the differential behavioural profile of WKY and SD rats. In summary, administration of BUP, a MOR receptor agonist together with a MOR opioid-receptor antagonist, SAM, reduces behavioural despair in animal models traditionally used to study effects of antidepressants.

Depression as a Neuroendocrine Disorder: Emerging Neuropsychopharmacological Approaches beyond Monoamines

Depression is currently recognized as a crucial problem in everyday clinical practice, in light of ever-increasing rates of prevalence, as well as disability, morbidity, and mortality related to this disorder. Currently available antidepressant drugs are notoriously problematic, with suboptimal remission rates and troubling side-effect profiles. Their mechanisms of action focus on the monoamine hypothesis for depression, which centers on the disruption of serotonergic, noradrenergic, and dopaminergic neurotransmission in the brain. Nevertheless, views on the pathophysiology of depression have evolved notably, and the comprehension of depression as a complex neuroendocrine disorder with important systemic implications has sparked interest in a myriad of novel neuropsychopharmacological approaches. Innovative pharmacological targets beyond monoamines include glutamatergic and GABAergic neurotransmission, brain-derived neurotrophic factor, various endocrine axes, as well as several neurosteroids, neuropeptides, opioids, endocannabinoids and endovanilloids. This review summarizes current knowledge on these pharmacological targets and their potential utility in the clinical management of depression.

Buprenorphine/samidorphan combination for the adjunctive treatment of major depressive disorder: results of a phase III clinical trial (FORWARD-3)

BACKGROUND

The endogenous opioid system is a fundamental regulator of mood in humans. Previously reported clinical trials have demonstrated the efficacy of the investigational agent buprenorphine/samidorphan (BUP/SAM) combination, an opioid-system modulator, for the adjunctive treatment of major depressive disorder. We present here a third phase III study of different design.

METHODS

Adult patients with major depressive disorder and inadequate response to antidepressant therapy were enrolled in this double-blind, placebo-controlled, placebo run-in study to evaluate the efficacy, safety, and tolerability of adjunctive BUP/SAM 2 mg/2 mg. Patients with baseline Hamilton Depression Rating Scale score $20 received double-blind placebo in addition to background antidepressant therapy for 4 weeks. Nonresponders were randomized to receive adjunctive BUP/SAM 2 mg/2 mg or placebo for 6 weeks. The primary end point was change in Montgomery-Åsberg Depression Rating Scale (MADRS)-10 total score from randomization at baseline to the end of the 6-week treatment period.

RESULTS

Least-squares mean change in MADRS-10 score at end of treatment was -4.8 (SE 0.67) in the BUP/SAM 2 mg/2 mg group and -4.6 (SE 0.66) in the placebo group (mean difference -0.3 [SE 0.95], P=0.782). There were no differences in MADRS-based response or remission rates. Overall, 42.9% of the BUP/SAM 2 mg/2 mg group and 34.5% of the placebo group experienced at least one treatment-emergent adverse event during the 6-week treatment period, most of which were mild or moderate in severity. There were no clinically important changes in laboratory parameters, weight, or vital signs and no evidence of abuse potential during treatment or opiate-withdrawal symptoms post treatment.

CONCLUSION

Efficacy results in FORWARD-3 measured by change in MADRS-10 score did not meet the primary end point, but postbaseline improvement in MADRS-10 in the BUP/SAM 2 mg/2 mg group was consistent with that seen in previously reported trials. BUP/SAM 2 mg/2 mg was well tolerated.

Opioidergic Agents as Antidepressants: Rationale and Promise

Research concerning psychiatric issues relating to opioid drugs currently focuses primarily on their role in reinforcing addictive behaviors, given the recent proliferation of lethal abuse of illicit opiates in the United States and around the world. In contrast, this article will review the mechanism of action of opioids in affective disorders and the available evidence and potential for their use, especially in the treatment of resistant major depression. Buprenorphine is the opioid derivative of special interest; we review this and other opioid derivatives, highlighting the growing role of opioids in treating depressive illnesses and other related psychopathologies.

Endogenous opioid system dysregulation in depression: implications for new therapeutic approaches

The United States is in the midst of an opioid addiction and overdose crisis precipitated and exacerbated by use of prescription opioid medicines. The majority of opioid prescriptions are dispensed to patients with comorbid mood disorders including major depressive disorder (MDD). A growing body of research indicates that the endogenous opioid system is directly involved in the regulation of mood and is dysregulated in MDD. This involvement of the endogenous opioid system may underlie the disproportionate use of opioids among patients with mood disorders. Emerging approaches to address endogenous opioid dysregulation in MDD may yield novel therapeutics that have a low or absent risk of abuse and addiction relative to µ-opioid agonists. Moreover, agents targeting the endogenous opioid system would be expected to yield clinical benefits qualitatively different from conventional monaminergic antidepressants. The development of safe and effective agents to treat MDD-associated endogenous opioid dysregulation may represent a distinct and currently underappreciated means of addressing treatment resistant depression with the potential to attenuate the on-going opioid crisis.

The Efficacy of Buprenorphine in Major Depression, Treatment-Resistant Depression and Suicidal Behavior: A Systematic Review

Although several pharmacological options to treat depression are currently available, approximately one third of patients who receive antidepressant medications do not respond adequately or achieve a complete remission. Thus, novel strategies are needed to successfully address those who did not respond, or partially respond, to available antidepressant pharmacotherapy. Research findings revealed that the opioid system is significantly involved in the regulation of mood and incentives salience and may be an appropriate target for novel therapeutic agents. The present study aimed to systematically review the current literature about the use of buprenorphine (BUP) for major depression, treatment-resistant depression (TRD), non-suicidal self-injury (NSSI) behavior, and suicidal behavior. We investigated Pubmed and Scopus databases using the following keywords: "buprenorphine AND depression", "buprenorphine AND treatment resistant depression", "buprenorphine AND suicid*", "buprenorphine AND refractory depression". Several evidence demonstrate that, at low doses, BUP is an efficacious, well-tolerated, and safe option in reducing depressive symptoms, serious suicidal ideation, and NSSI, even in patients with TRD. However, more studies are needed to evaluate the long-term effects, and relative efficacy of specific combinations (e.g., BUP + samidorphan (BUP/SAM), BUP + naloxone (BUP/NAL), BUP + naltrexone) over BUP monotherapy or adjunctive BUP treatment with standard antidepressants, as well as to obtain more uniform guidance about the optimal BUP dosing interval.

Kappa opioid receptor antagonism: Are opioids the answer for treatment resistant depression?

Introduction:

Past trials of buprenorphine (BUP) in the treatment of major depressive disorder (MDD) have displayed favorable results, although its clinical utility was limited by the risk of abuse or physical dependence. By combining BUP with samidorphan (SAM), the euphoric high is negated by an opposing mechanism, which theoretically reduces addictive-like properties while allowing the antidepressant properties to remain. As such, the objective of this article is to analyze the results of BUP/SAM premarketing clinical trials as adjunctive treatment for treatment-resistant MDD.

Methods:

A comprehensive PubMed/MEDLINE search was conducted through November 9, 2017, using the following search terms: depression, samidorphan, buprenorphine, ALKS-5461. Additional data were obtained from Clinicaltrials.gov and resources included in the present study. All English-language clinical trials evaluating the combination of BUP/SAM in the treatment of MDD were included.

Results:

A few premarketing studies have evaluated the efficacy and safety of BUP/SAM combination as adjunctive treatment in patients with treatment-resistant MDD. The FORWARD-1 through FORWARD-5 trials concluded (1) the most effective dosing ratio of BUP/SAM to reduce abuse potential was 1:1; (2) statistically significant changes in scores from baseline on the Montgomery-Asberg Depression Rating Scale were noted for the 2 mg/2 mg dose compared with placebo; and (3) the most commonly reported adverse effects were nausea, dizziness, and fatigue.

Discussion:

Buprenorphine/samidorphan has shown favorable results for efficacy and tolerability in premarketing studies evaluating its use as adjunctive therapy for treatment-resistant MDD. Its novel mechanism targeting the opioid pathway may serve as a promising antidepressant devoid of abuse potential.

Pharmacodynamic and pharmacokinetic evaluation of buprenorphine + samidorphan for the treatment of major depressive disorder

INTRODUCTION

Treatment resistant depression (TRD) represents approximately 20% of all individuals receiving care for major depressive disorder. The opioidergic system is identified as a novel target which hitherto has not been sufficiently investigated in adults with TRD. The combination product buprenorphine + samidorphan is an opioid modulatory agent which has demonstrated replicated evidence of efficacy in TRD without abuse liability. Areas covered: Databases Pubmed, Google Scholar and clinicaltrials.gov were searched from inception through December 2017 for clinical trial information, pharmacokinetics, and pharmacodynamics of buprenorphine + samidorphan. Herein we provide a summary of the available information. Eight clinical trials were identified for inclusion, of the eight trials, five trials had available results and are included in detail in our review. Expert opinion: Buprenorphine + samidorphan has demonstrated efficacy in TRD. Extant evidence surrounding the safety and tolerability profile of buprenorphine + samidorphan does not identify any significant safety concerns. Additional studies are needed in order to assess the long-term safety and efficacy of this product.

Prevalence of Antipsychotic-Treated Patients in a Cohort of Adult Addicted Patients

PURPOSE

The objective of this cross-sectional study was to describe and estimate the prevalence of antipsychotics (AP) in a cohort of addicted patients, and to compare the profiles of addictive patients receiving AP or not.

METHODS

We included all adult patients seen at the addiction care center of Montpellier University Hospital, between January 1, 2015, and March 31, 2015. Demographic, clinical, and therapeutic data were collected from the patients' medical records.

RESULTS

During the study period, 415 patients were included, with a mean age of 38 ± 10 years. They were mostly men (73.3%), French (54.9%), and unemployed (61.8%). Among the study population, 93 patients (patients treated with AP [trAP], 22.4%) were treated by 111 different AP, mainly cyamemazine (29.0% of treated patients), aripiprazole (20.4%), olanzapine (17.2%), and quetiapine (16.1%), mostly in monotherapy (80.6%) and by oral route (93.2% of AP). Psychiatric history was more frequent in trAP than in those without AP (untrAP) (55.9% vs 35.4% respectively; P < 0.001). Professional activity tended to be less frequent in patients with AP (25.3% vs 38.9%, P = 0.08).When compared with untrAP, trAP consumed more amphetamine (10.8% vs 4.4%; P = 0.02) and tended to consume less opiates (7.5% vs 14.9%; P = 0.06); the consumptions of cannabis (43.0% vs 35.7%; P = 0.20) and cocaine (22.6% vs 16.8%; P = 0.20) were not statistically different.Opiate maintenance therapy was reported in 63.7% of trAP and 68.4% of untrAP (P = 0.41): it consisted of methadone (trAP, 60.3% vs untrAP, 56.5%) and buprenorphine (trAP, 39.7% vs untrAP, 43.5%).

CONCLUSIONS

The concomitant management of psychiatric and substance use disorders in the same center may explain the high prevalence of trAP in this study. Cannabis and psychostimulants may have been used in these patients as self-medication for mental disease-related symptoms or adverse effects of APs.