Review: Sex-Based Differences in Treatment Outcomes for Persons With Opioid Use Disorder

Epigenetic and sex differences in opioid use disorder in chronic pain: A real-world study linked with OPRM1 DNA methylation

Opioid use disorder (OUD) is a multifaceted condition influenced by sex, genetic and environmental factors that could be linked with epigenetic changes. Understanding how these factors interact is crucial to understand and address the development and progression of this disorder. Our aim was to elucidate different potential epigenetic and genetic mechanisms between women and men that correlate with OUD under real-world pain unit conditions. Associations between analgesic response and the DNA methylation level of the opioid mu receptor (OPRM1) gene (CpG sites 1-5 selected in the promoter region) were evaluated in 345 long opioid-treated chronic non cancer pain: cases with OUD (n = 67) and controls (without OUD, n = 278). Cases showed younger ages, low employment status and quality of life, but higher morphine equivalent daily dose and psychotropic use, compared to the controls. The patients with OUD showed a significant decrease in OPRM1 DNA methylation, which correlated with clinical outcomes like pain relief, depression and different adverse events. Significant differences were found at the five CpG sites studied for men, and exclusively in women for CpG site 3, in relation to OUD diagnosis. These findings support the importance of epigenetics and sex as biological variables to be considered toward efficient OUD understanding and therapy development.

Neuronal biomarkers as potential therapeutic targets for drug addiction related to sex differences in the brain: Opportunities for personalized treatment approaches

Biological sex disparities manifest at various stages of drug addiction, including craving, substance abuse, abstinence, and relapse. These discrepancies are underpinned by notable distinctions in neurobiological substrates, encompassing brain structures, functions, and neurotransmitter systems implicated in drug addiction. Neuronal biomarkers, such as neurotransmitters, signaling proteins, and genes may be associated with the diagnosis, prognosis, and treatment outcomes in both biological sexes afflicted by drug abuse. Sex differences in the neural reward system, mainly through dopaminergic transmission during drug abuse, can be attributed to modifications in neurotransmitter systems and signaling pathways. This results in distinct patterns of neural activation and responsiveness to addictive substances in males and females. Sex hormones, the estrus/menstrual cycle, and cerebral neurochemistry contribute to the progression of psychological and physiological dependence in both male and female individuals grappling with addiction. Moreover, the alteration of sex hormone balance and neurotransmitter release plays a pivotal role in substance use disorders, subsequently modulating cognitive functions pertinent to reward, including memory formation, decision-making, and locomotor activity. Comparative investigations reveal distinctions in brain region volume, gene expression, neuronal firing, and circuitry in substance use disorders affecting individuals of both biological sexes. This review examines prevalent substance use disorders to elucidate the impact of sex hormones as therapeutic biomarkers on the mesocorticolimbic neurotransmitter systems via diverse mechanisms within the addicted brain. We underscore the imperative necessity of considering these variations to gain a deeper comprehension of addiction mechanisms and potentially discern sex-specific neuronal biomarkers for tailored therapeutic interventions.

The lived experiences and treatment needs of women with opioid use disorder and posttraumatic stress symptoms: A mixed methods study

INTRODUCTION

Women show a gender-specific risk for co-occurring opioid use disorder (OUD) and posttraumatic stress disorder (PTSD). Expert groups have called for the development of integrated treatments for women with OUD/PTSD, but there remains limited information on such interventions.

METHODS

This mixed-methods study interviewed and surveyed 10 women with current or past OUD and co-occurring posttraumatic stress symptoms (PTSS) and 16 providers who work with these women. Interviews and surveys queried patient participants' and providers' experiences of OUD/PTSS and how to best design an integrated, trauma-focused treatment for OUD/PTSD.

RESULTS

Patient participants (90 % white, 90 % mothers, Mage = 45.70) met criteria for severe, lifetime OUD and 40 % met a provisional diagnosis for PTSD. Four themes emerged for participants' experiences of OUD/PTSS: 1) numerous stressors; 2) shame; 3) multiple motivations to use opioids; and 4) a cycle of trauma and opioid use. Four themes emerged regarding patient participants' perceptions on the development of an OUD/PTSD treatment: 1) mixed attitudes towards medications for OUD; 2) barriers to treatment (e.g., insufficient treatments and contextual factors); 3) treatment facilitators (e.g., social support); and 4) preferences in treatment (e.g., trauma-focused, gender-focused, family content, ambivalence around group therapy). Providers (Mage = 38.94) were primarily white women (76.5 %). Two themes emerged from their experiences working with women with OUD/PTSS: 1) perceiving women to use opioids to regulate emotions and 2) gender differences in trauma types. Three themes emerged for providers' perceptions on the development of an OUD/PTSD treatment: 1) barriers to treatment (e.g., chaotic lives, contextual factors, family); 2) treatment facilitators (e.g., trust and external motivations); and 3) desired treatment modifications (e.g., stabilization, early skills in therapy, flexibility in therapy, social supports, safety guidelines, and assistance in identifying an index trauma). Most participants (90.0 %) and providers (93.5 %) preferred working on OUD/PTSD symptoms simultaneously rather than separately.

CONCLUSIONS

Findings demonstrate the need to modify integrated treatments to meet the preferences of providers and women with OUD/PTSS and OUD/PTSD. Treatments should consider therapeutic content, structure, contextual factors, social support, and PTSD severity to enhance uptake and reach.

Intersectional Risk and the Significant Gap in Care for Persons With Co-occurring Chronic Pain and Opioid Withdrawal

OBJECTIVES

Persons with chronic pain and women tend to enter treatment for opioid use disorder with greater opioid withdrawal severity than persons without chronic pain and men, respectively. This study examined characteristics of facilities with opioid withdrawal treatment, including gender-based services, as a function of whether they reported having a tailored pain management program.

METHODS

The National Survey of Substance Abuse Treatment Services 2020 was used to examine 3942 facilities with opioid withdrawal treatment in the United States. Using a multivariable binary logistic regression model, facilities were examined for the presence of a tailored program for individuals with co-occurring pain. Regional location of the facility, ownership status, and availability of tailored gender programs, nonhospital residential services, and outpatient services served as independent variables in the analysis.

RESULTS

A slight majority of the sample had a program for both adult men and adult women ( n = 2010, 51.0%). Most facilities had outpatient services ( n = 3289, 83.4%) and did not have a tailored program for addressing co-occurring pain ( n = 2756, 69.9%). Binary logistic regression analysis showed that among opioid withdrawal facilities, programs with nonhospital residential services, government or private nonprofit funding, or tailored gender programming had higher odds of reporting having a tailored program for pain and substance use disorder. Facilities in the Western United States were most likely to have tailored programs for pain and substance use disorder.

CONCLUSIONS

Future research should investigate what support patients may receive and how to better scale access to pain management during opioid withdrawal treatment.

Lipophilic analogues of D-cysteine prevent and reverse physical dependence to fentanyl in male rats

We examined whether co-injections of the cell-permeant D-cysteine analogues, D-cysteine ethyl ester (D-CYSee) and D-cysteine ethyl amide (D-CYSea), prevent acquisition of physical dependence induced by twice-daily injections of fentanyl, and reverse acquired dependence to these injections in freely-moving male Sprague Dawley rats. Injection of the opioid receptor antagonist, naloxone HCl (NLX, 1.5 mg/kg, IV), elicited a series of withdrawal phenomena that included cardiorespiratory and behavioral responses, and falls in body weight and body temperature, in rats that received 5 or 10 injections of fentanyl (125 μg/kg, IV), and the same number of vehicle co-injections. Regarding the development of physical dependence, the NLX-precipitated withdrawal phenomena were markedly reduced in fentanyl-injected rats that had received co-injections of D-CYSee (250 μmol/kg, IV) or D-CYSea (100 μmol/kg, IV), but not D-cysteine (250 μmol/kg, IV). Regarding reversal of established dependence to fentanyl, the NLX-precipitated withdrawal phenomena in rats that had received 10 injections of fentanyl (125 μg/kg, IV) was markedly reduced in rats that received co-injections of D-CYSee (250 μmol/kg, IV) or D-CYSea (100 μmol/kg, IV), but not D-cysteine (250 μmol/kg, IV), starting with injection 6 of fentanyl. This study provides evidence that co-injections of D-CYSee and D-CYSea prevent the acquisition of physical dependence, and reverse acquired dependence to fentanyl in male rats. The lack of effect of D-cysteine suggests that the enhanced cell-penetrability of D-CYSee and D-CYSea into cells, particularly within the brain, is key to their ability to interact with intracellular signaling events involved in acquisition to physical dependence to fentanyl.

Intersectional inequities and longitudinal prevalence estimates of opioid use disorder in Massachusetts 2014-2020: a multi-sample capture-recapture analysis

Background

As overdoses continue to increase worldwide, accurate estimates are needed to understand the size of the population at risk and address health disparities. Capture-recapture methods may be used in place of direct estimation at nearly any geographic level (e.g., city, state, country) to estimate the size of the population with opioid use disorder (OUD). We performed a multi-sample capture-recapture analysis with persons aged 18-64 years to estimate the prevalence of OUD in Massachusetts from 2014 to 2020, stratified by sex and race/ethnicity.

Methods

We used seven statewide administrative data sources linked at the individual level. We developed log-linear models to estimate the unknown OUD-affected population. Uncertainty was characterized using 95% confidence intervals (95% CI) on the total counts and prevalence estimates.

Findings

The estimated OUD prevalence increased from 5.47% (95% CI = 4.89%, 5.98%) in 2014 to 5.79% (95% CI = 5.34%, 6.19%) in 2020. Prevalence among Hispanic females doubled (2.46% in 2014 to 4.23% in 2020) and prevalence rose to nearly 10% among Black non-Hispanic males and Hispanic males from 2014 through 2019. Estimates for Black non-Hispanic females more than doubled from 2014 through 2019 (3.39% to 7.09%), and then decreased to 5.69% in 2020.

Interpretation

This study is the first to provide OUD prevalence trend estimates by binary sex and race/ethnicity at a state level using capture-recapture methods. Using these methods as the international overdose crisis worsens can allow jurisdictions to appropriately allocate resources and targeted interventions to marginalised populations.

Funding

NIDA.

Sex differences in neonatal outcomes following prenatal opioid exposure

The impact of the opioid epidemic on pregnant people and children is a growing public health crisis. Understanding how opioids affect the developing brain during pregnancy and postnatally remains a critical area of investigation. Biological sex plays a crucial role in all physiologic processes, with the potential for a significant impact on neonatal outcomes, including those infants with opioid exposure. Here, we aim to explore current literature on the effect of sex on neonatal outcomes following prenatal opioid exposure. Sex differences in adults with opioid use disorder have been well studied, including increased mortality among males and higher rates of psychiatric comorbidities and likelihood of relapse in females. However, such differences are not yet well understood in neonates. Emerging clinical data suggest sex-specific effects in infants with prenatal opioid exposure on the expression of genes related to feeding regulation and reward signaling pathways. Increased susceptibility to white matter injury has also been noted in female infants following prenatal opioid exposure. Understanding the impact of sex as a biological variable on neonatal outcomes following prenatal opioid exposure is paramount to improving the health and well-being of infants, children, and adults impacted by the opioid epidemic.

Modeling the Therapeutic Process of Patients with Cocaine Use Disorders: A Guide for Predicting Readmission

INTRODUCTION

Patients with cocaine use disorders have very high readmission rates. Our aim was to model the relationships between attributes of patients with cocaine use disorder at the beginning of treatment, therapeutic process indicators of time in treatment or proportion of appointments attended, and treatment outcomes, including outcomes at discharge and non-readmissions posttreatment as indicators of therapeutic success.

METHOD

A retrospective observational design was used with 10,298 cocaine use disorder patients. Electronic health records were used for statistical analysis of the data. Randomized subsample 1 (n = 5,150) was used for exploratory analysis and subsample 2 (n = 5,148) for modeling relationships between the variables.

RESULTS

Patients attributes at intake (e.g., legal services as the source of referral) were of limited significance in explaining time in treatment, proportion of appointments attended, and treatment outcomes. Time in treatment and proportion of appointments attended emerged as significant factors in explaining outcomes at discharge. However, readmissions were primarily explained by time in treatment and outcomes at discharge, although referrals to addiction centers by health services also appeared to be relevant for explaining readmission.

DISCUSSION/CONCLUSION

Our study has shown that maintaining a sufficient appointment attendance rate and remaining in treatment for a longer duration are critical therapeutic process indicators for explaining outcomes at the point of discharge and therapeutic success, as indicated by a reduced likelihood of readmissions. Patients who remained in treatment for an extended period were found to have a reduced risk of future readmissions. In addition, our study highlights the importance of maintaining a satisfactory appointment attendance rate to attain successful short- and medium-term therapeutic discharge outcomes. These guidelines could help to increase the efficiency of patient treatment and alleviate the suffering of both patients and their families.

Single nuclei transcriptomics in human and non-human primate striatum in opioid use disorder

In brain, the striatum is a heterogenous region involved in reward and goal-directed behaviors. Striatal dysfunction is linked to psychiatric disorders, including opioid use disorder (OUD). Striatal subregions are divided based on neuroanatomy, each with unique roles in OUD. In OUD, the dorsal striatum is involved in altered reward processing, formation of habits, and development of negative affect during withdrawal. Using single nuclei RNA-sequencing, we identified both canonical (e.g., dopamine receptor subtype) and less abundant cell populations (e.g., interneurons) in human dorsal striatum. Pathways related to neurodegeneration, interferon response, and DNA damage were significantly enriched in striatal neurons of individuals with OUD. DNA damage markers were also elevated in striatal neurons of opioid-exposed rhesus macaques. Sex-specific molecular differences in glial cell subtypes associated with chronic stress were found in OUD, particularly female individuals. Together, we describe different cell types in human dorsal striatum and identify cell type-specific alterations in OUD.

Repeated measures analysis of opioid use disorder treatment on clinical opiate withdrawal scale in a randomized clinical trial: sex differences

PURPOSE

Sex differences may exist in opioid use disorder (OUD) treatment. This study examined the treatment effects of buprenorphine/naloxone (BUP/NX) and methadone (MET) on the Clinical Opiate Withdrawal Scale (COWS) score in individuals with OUD and tested whether the associations differ by sex.

METHOD

We performed a secondary analysis of the data from the National Drug Abuse Treatment Clinical Trials Network (CTN) protocol-0027. A total of 1269 participants (861 males and 408 females) being aged 18 or older with OUD were randomly assigned to receive BUP/NX (n = 740) or MET (n = 529). The paired t test was initially used to compare the COWS scores between pre-dose and post-dose for BUP/NX and MET treatments, separately. The linear mixed model was used to examine the changes in COWS score adjusted for baseline demographic, substance use, and mental health disorders. The interaction of sex and treatment was detected and stratified analysis by sex was conducted.

RESULTS

The paired t test showed that both BUP/NX and MET treatments significantly reduced the COWS scores (p values <0.0001). BUP/NX revealed higher COWS scores than MET (p = 0.0008) and females demonstrated significantly higher COWS scores than males (p = 0.0169). Stratified by sex, BUP/NX compared with MET revealed higher COWS scores only in males (p = 0.0043), whereas baseline amphetamines use disorder and major depressive disorder were significantly associated with COWS scores in females (p = 0.0158 and 0.0422, respectively).

CONCLUSIONS

Both BUP/NX and MET are effective in decreasing opioid withdrawal symptoms via COWS scores, however, treatment plans for OUD by clinical providers should consider sex differences.

A genome-wide association, polygenic risk score and sex study on opioid use disorder treatment outcomes

Opioid use disorder continues to be a health concern with a high rate of opioid related deaths occurring worldwide. Medication Assisted Treatments (MAT) have been shown to reduce opioid withdrawal, cravings and opioid use, however variability exists in individual's treatment outcomes. Sex-specific differences have been reported in opioid use patterns, polysubstance use and health and social functioning. Candidate gene studies investigating methadone dose as an outcome have identified several candidate genes and only five genome-wide associations studies have been conducted for MAT outcomes. This study aimed to identify genetic variants associated with MAT outcomes through genome-wide association study (GWAS) and test the association between genetic variants previously associated with methadone dose through a polygenic risk score (PRS). Study outcomes include: continued opioid use, relapse, methadone dose and opioid overdose. No genome-wide significance SNPs or sex-specific results were identified. The PRS identified statistically significant results (p < 0.05) for the outcome of methadone dose (R2 = 3.45 × 10-3). No other PRS was statistically significant. This study provides evidence for association between a PRS and methadone dose. More research on the PRS to increase the variance explained is needed before it can be used as a tool to help identify a suitable methadone dose within this population.

L-cysteine ethyl ester prevents and reverses acquired physical dependence on morphine in male Sprague Dawley rats

The molecular mechanisms underlying the acquisition of addiction/dependence on morphine may result from the ability of the opioid to diminish the transport of L-cysteine into neurons via inhibition of excitatory amino acid transporter 3 (EAA3). The objective of this study was to determine whether the co-administration of the cell-penetrant L-thiol ester, L-cysteine ethyl ester (L-CYSee), would reduce physical dependence on morphine in male Sprague Dawley rats. Injection of the opioid-receptor antagonist, naloxone HCl (NLX; 1.5 mg/kg, IP), elicited pronounced withdrawal phenomena in rats which received a subcutaneous depot of morphine (150 mg/kg) for 36 h and were receiving a continuous infusion of saline (20 μL/h, IV) via osmotic minipumps for the same 36 h period. The withdrawal phenomena included wet-dog shakes, jumping, rearing, fore-paw licking, 360° circling, writhing, apneas, cardiovascular (pressor and tachycardia) responses, hypothermia, and body weight loss. NLX elicited substantially reduced withdrawal syndrome in rats that received an infusion of L-CYSee (20.8 μmol/kg/h, IV) for 36 h. NLX precipitated a marked withdrawal syndrome in rats that had received subcutaneous depots of morphine (150 mg/kg) for 48 h) and a co-infusion of vehicle. However, the NLX-precipitated withdrawal signs were markedly reduced in morphine (150 mg/kg for 48 h)-treated rats that began receiving an infusion of L-CYSee (20.8 μmol/kg/h, IV) at 36 h. In similar studies to those described previously, neither L-cysteine nor L-serine ethyl ester (both at 20.8 μmol/kg/h, IV) mimicked the effects of L-CYSee. This study demonstrates that 1) L-CYSee attenuates the development of physical dependence on morphine in male rats and 2) prior administration of L-CYSee reverses morphine dependence, most likely by intracellular actions within the brain. The lack of the effect of L-serine ethyl ester (oxygen atom instead of sulfur atom) strongly implicates thiol biochemistry in the efficacy of L-CYSee. Accordingly, L-CYSee and analogs may be a novel class of therapeutics that ameliorate the development of physical dependence on opioids in humans.

Endogenous opioid system modulates conditioned cocaine reward in a sex-dependent manner

Cocaine predictive cues and contexts exert powerful control over behaviour and can incite cocaine seeking and taking. This type of conditioned behaviour is encoded within striatal circuits, and these circuits and behaviours are, in part, regulated by opioid peptides and receptors expressed in striatal medium spiny neurons. We previously showed that augmenting levels of the opioid peptide enkephalin in the striatum facilitates acquisition of cocaine conditioned place preference (CPP), while opioid receptor antagonists attenuate expression of cocaine CPP. However, whether striatal enkephalin is necessary for acquisition of cocaine CPP and maintenance during extinction remains unknown. To address this, we generated mice with a targeted deletion of enkephalin from dopamine D2-receptor expressing medium spiny neurons and tested them in a cocaine CPP paradigm. Low striatal enkephalin levels did not attenuate acquisition of CPP. However, expression of preference, assessed after acute administration of the opioid receptor antagonist naloxone, was blocked in females, regardless of genotype. When saline was paired with the cocaine context during extinction sessions, females, regardless of genotype, extinguished preference faster than males, and this was prevented by naloxone when paired with the cocaine context. We conclude that while striatal enkephalin is not necessary for acquisition, expression, or extinction of cocaine CPP, expression and extinction of cocaine preference in females is mediated by an opioid peptide other than striatal enkephalin. The unique sensitivity of females to opioid antagonists suggests sex should be a consideration when using these compounds in the treatment of cocaine use disorder.

Focus on fentanyl in females: Sex and gender differences in the physiological and behavioral effects of fentanyl

The prevalence of opioid use disorder and overdose continues to harm the U.S. population and is further exacerbated by the use of the synthetic opioid, fentanyl, and its analogs. Gender differences in the effects of fentanyl are not well understood. The present article reviews evidence for gender and sex differences in the physiological and behavioral effects of fentanyl in humans and animals. Biological sex seems to be a foundational driver in addiction vulnerability and affects mechanisms related to opioid use including fentanyl. Fentanyl has distinct pharmacodynamics and enhanced efficacy relative to other opioids that highlights the need to investigate how females may be uniquely altered by its use. Behavioral and physiological responses to fentanyl are found to differ by sex and gender in many cases, including outputs like affective symptoms, analgesia, tolerance, and withdrawal emphasizing the need for further research about the role of biological sex on fentanyl use.

Fentanyl-induced reward seeking is sex and dose dependent and is prevented by D-cysteine ethylester

Introduction: Despite their inclination to induce tolerance, addictive states, and respiratory depression, synthetic opioids are among the most effective clinically administered drugs to treat severe acute/chronic pain and induce surgical anesthesia. Current medical interventions for opioid-induced respiratory depression (OIRD), wooden chest syndrome, and opioid use disorder (OUD) show limited efficacy and are marked by low success in the face of highly potent synthetic opioids such as fentanyl. D-Cysteine ethylester (D-CYSee) prevents OIRD and post-treatment withdrawal in male/female rats and mice with minimal effect on analgesic status. However, the potential aversive or rewarding effects of D-CYSee have yet to be fully characterized and its efficacy could be compromised by interactions with opioid-reward pathology. Methods: Using a model of fentanyl-induced conditioned place preference (CPP), this study evaluated 1) the dose and sex dependent effects of fentanyl to induce rewarding states, and 2) the extent to which D-CYSee alters affective state and the acquisition of fentanyl-induced seeking behaviors. Results: Fentanyl reward-related effects were found to be dose and sex dependent. Male rats exhibited a range-bound dose response centered at 5 µg/kg. Female rats exhibited a CPP only at 50 µg/kg. This dose was effective in 25% of females with the remaining 75% showing no significant CPP at any dose. Pretreatment with 100 mg/kg, but not 10 mg/kg, D-CYSee prevented acquisition of fentanyl seeking in males while both doses were effective at preventing acquisition in females. Discussion: These findings suggest that D-CYSee is an effective co-treatment with prescribed opioids to reduce the development of OUD.

Transgender individuals are at higher risk for suicidal ideation and preparation than cisgender individuals in substance use treatment

Introduction

This study describes the differences and similarities in mental health, substance use, and substance use treatment outcomes between people presenting for SUD treatment who identified as transgender and those who identified as cisgender men or women.

Methods

We compared 64 individuals who self-identified as transgender and presented for SUD treatment to samples of cisgender men and women (separately) matched based on propensity scores which were created based on sociodemographic factors known to influence both the nature of substance use and patterns of treatment engagement including age, education, race, stable housing, and employment status. Comparisons were made using χ2 tests and t-tests in over 150 variables collected at treatment intake regarding physical and mental health, substance use patterns, events that led to treatment, reasons for seeking treatment, and treatment outcomes.

Results

The transgender sample endorsed six of the seven suicide-related items more often than at least one of the cisgender-matched samples. Furthermore, the transgender sample remained in treatment significantly longer (M = 32.3, SD = 22.2) than the cisgender male sample (M = 19.5, SD = 26.1, t = 2.17, p = 0.03).

Discussion

This study is a first step into understanding gender minority population experiences during SUD treatment. While there was no significant difference between the cisgender and transgender samples on most variables, there was an elevated prevalence of suicidal ideation and behaviors in the transgender sample, which warrants further investigation.

Gender-Specific Interactions in a Visual Object Recognition Task in Persons with Opioid Use Disorder

Opioid use disorder (OUD)-associated overdose deaths have reached epidemic proportions worldwide over the past two decades, with death rates for men reported at twice the rate for women. Using a controlled, cross-sectional, age-matched (18-56 y) design to better understand the cognitive neuroscience of OUD, we evaluated the electroencephalographic (EEG) responses of male and female participants with OUD vs. age- and gender-matched non-OUD controls during a simple visual object recognition Go/No-Go task. Overall, women had significantly slower reaction times (RTs) than men. In addition, EEG N200 and P300 event-related potential (ERP) amplitudes for non-OUD controls were significantly larger for men, while their latencies were significantly shorter than for women. However, while N200 and P300 amplitudes were not significantly affected by OUD for either men or women in this task, latencies were also affected differentially in men vs. women with OUD. Accordingly, for both N200 and P300, male OUD participants exhibited longer latencies while female OUD participants exhibited shorter ones than in non-OUD controls. Additionally, robust oscillations were found in all participants during a feedback message associated with performance in the task. Although alpha and beta power during the feedback message were significantly greater for men than women overall, both alpha and beta oscillations exhibited significantly lower power in all participants with OUD. Taken together, these findings suggest important gender by OUD differences in cognitive processing and reflection of performance in this simple visual task.

Weight change among patients engaged in medication treatment for opioid use disorder: a scoping review

Background: Medication treatment for opioid use disorder (MOUD) is an instrumental tool in combatting opioid use and overdose. Excess weight gain associated with MOUD initiation is a potential barrier that is not well understood.Objectives: Conduct a scoping review of available studies investigating the effect of MOUD on weight.Methods: Included studies consisted of adults taking any type of MOUD (e.g. methadone, buprenorphine/naloxone, naltrexone) with data on weight or body mass index for at least two time points. Evidence was synthesized using qualitative and descriptive approaches, and predictors of weight gain including demographics, comorbid substance use, and medication dose were examined.Results: Twenty-one unique studies were identified. Most studies were uncontrolled cohort studies or retrospective chart reviews testing the association between methadone and weight gain (n = 16). Studies examining 6 months of methadone treatment reported weight gain ranging from 4.2 to 23.4 pounds. Women appear to gain more weight from methadone than men, while patients using cocaine may gain less. Racial and ethnic disparities were largely unexamined. Only three case reports and two nonrandomized studies examined the effects of either buprenorphine/naloxone or naltrexone, and potential associations with weight gain were not clear.Conclusion: The use of methadone as an MOUD appears to be associated with mild to moderate weight gain. In contrast, there is little data supporting or refuting weight gain with buprenorphine/naloxone or naltrexone. Providers should discuss the potential risk for weight gain with patients as well as prevention and intervention methods for excess weight gain.

Development and clinical feasibility study of a brief version of an addiction-focused phenotyping battery in females receiving buprenorphine for opioid use disorder

INTRODUCTION

We aimed to streamline the NIDA Phenotyping Assessment Battery (PhAB), a package of self-report scales and neurobehavioral tasks used in substance use disorder (SUD) clinical trials, for clinical administration ease. Tailoring the PhAB to shorten administration time for a treatment setting is critical to expanding its acceptability in SUD clinical trials. This study's primary objectives were to develop a brief version of PhAB (PhAB-B) and assess its operational feasibility and acceptability in a female clinical treatment sample.

METHODS

Assessments of the original PhAB were evaluated along several criteria to identify a subset for the PhAB-B. Non-pregnant females (N=55) between ages 18-65, stabilized on buprenorphine for opioid use disorder (OUD) at an outpatient addiction clinic, completed this abbreviated battery remotely or after a provider visit in clinic. Participant satisfaction questions were administered. REDCap recorded the time to complete PhAB-B measures.

RESULTS

The PhAB-B included 11 measures that probed reward, cognition, negative emotionality, interoception, metacognition, and sleep. Participants who completed the PhAB-B (N =55) were 36.1 ± 8.9 years of age, White (54.5%), Black (34.5%), and non-Latinx (96.0%). Most participants completed the PhAB-B remotely (n = 42, 76.4%). Some participants completed it in-person (n = 13, 23.6%). PhAB-B mean completion time was 23.0 ± 12.0 min. Participant experiences were positive, and 96% of whom reported that they would participate in the study again.

CONCLUSION

Our findings support the clinical feasibility and acceptability of the PhAB-B among a female opioid use disorder outpatient addiction treatment sample. Future studies should assess the PhAB-B psychometric properties among broader treatment samples.

Association of Urine Fentanyl Concentration With Severity of Opioid Withdrawal Among Patients Presenting to the Emergency Department

BACKGROUND AND AIMS

Fentanyl is involved in most US drug overdose deaths and its use can complicate opioid withdrawal management. Clinical applications of quantitative urine fentanyl testing have not been demonstrated previously. The aim of this study was to determine whether urine fentanyl concentration is associated with severity of opioid withdrawal.

DESIGN

This is a retrospective cross-sectional study.

SETTING

This study was conducted in 3 emergency departments in an urban, academic health system from January 1, 2020, to December 31, 2021.

PARTICIPANTS

This study included patients with opioid use disorder, detectable urine fentanyl or norfentanyl, and Clinical Opiate Withdrawal Scale (COWS) recorded within 6 hours of urine drug testing.

MEASUREMENTS

The primary exposure was urine fentanyl concentration stratified as high (>400 ng/mL), medium (40-399 ng/mL), or low (<40 ng/mL). The primary outcome was opioid withdrawal severity measured with COWS within 6 hours before or after urine specimen collection. We used a generalized linear model with γ distribution and log-link function to estimate the adjusted association between COWS and the exposures.

FINDINGS

For the 1127 patients in our sample, the mean age (SD) was 40.0 (10.7), 384 (34.1%) identified as female, 332 (29.5%) reported their race/ethnicity as non-Hispanic Black, and 658 (58.4%) reported their race/ethnicity as non-Hispanic White. For patients with high urine fentanyl concentrations, the adjusted mean COWS (95% confidence interval) was 4.4 (3.9-4.8) compared with 5.5 (5.1-6.0) among those with medium and 7.7 (6.8-8.7) among those with low fentanyl concentrations.

CONCLUSIONS

Lower urine fentanyl concentration was associated with more severe opioid withdrawal, suggesting potential clinical applications for quantitative urine measurements in evolving approaches to fentanyl withdrawal management.

Pain-related cortico-limbic plasticity and opioid signaling

Neuroplasticity in cortico-limbic circuits has been implicated in pain persistence and pain modulation in clinical and preclinical studies. The amygdala has emerged as a key player in the emotional-affective dimension of pain and pain modulation. Reciprocal interactions with medial prefrontal cortical regions undergo changes in pain conditions. Other limbic and paralimbic regions have been implicated in pain modulation as well. The cortico-limbic system is rich in opioids and opioid receptors. Preclinical evidence for their pain modulatory effects in different regions of this highly interactive system, potentially opposing functions of different opioid receptors, and knowledge gaps will be described here. There is little information about cell type- and circuit-specific functions of opioid receptor subtypes related to pain processing and pain-related plasticity in the cortico-limbic system. The important role of anterior cingulate cortex (ACC) and amygdala in MOR-dependent analgesia is most well-established, and MOR actions in the mesolimbic system appear to be similar but remain to be determined in mPFC regions other than ACC. Evidence also suggests that KOR signaling generally serves opposing functions whereas DOR signaling in the ACC has similar, if not synergistic effects, to MOR. A unifying picture of pain-related neuronal mechanisms of opioid signaling in different elements of the cortico-limbic circuitry has yet to emerge. This article is part of the Special Issue on "Opioid-induced changes in addiction and pain circuits".

Ketogenic diet enhances the effects of oxycodone in mice

Opioids have been used to manage pain for thousands of years, but they have significant potential for abuse. Prescription opioids, like oxycodone, are associated with 32% of overdoses, that have reached a total of 75,673 deaths in 2021. A major challenge is maximizing their therapeutic potential while minimizing the negative side effects including opioid use disorder (OUD). The Ketogenic Diet (KD) has been reported to reduce pain and decrease the severity of alcohol use disorder, yet its effects on oxycodone responses remain unknown. KD mice displayed increased oxycodone-induced locomotor activity and enhanced antinociceptive effects of oxycodone, suggesting a dietary effect on opiate sensitivity. Male KD mice exposed to chronic oxycodone exhibited increased naloxone-induced jumps, suggesting a sex-specific effect of diet on opioid withdrawal. Consistent with this, male KD mice self-administered less oxycodone while female KD mice did not differ from controls. Finally, no effect of KD on motivation to obtain oxycodone was observed during a progressive ratio schedule. These data suggest sex-biased effects of KD on responses to opioids that should be considered and potentially leveraged in both clinical pain management and treatment of OUD.

Exploring potential moderators of depressive symptoms and treatment outcomes among patients with opioid use disorder

BACKGROUND

Depressive symptoms are common in patients seeking medication treatment for opioid use disorder (MOUD treatment) and decrease quality of life but have been inconsistently related to opioid treatment outcomes. Here, we explore whether depressive symptoms may only be related to adverse treatment outcomes among individuals reporting high opioid use-related coping motives (i.e., use of opioids to change affective states) and high trait impulsivity, two common treatment targets.

METHODS

Patients seeking MOUD treatment (N = 118) completed several questionnaires within two weeks of their treatment intake. Treatment outcomes (opioid-positive urine screens and days retained in treatment) were extracted from treatment records. Moderation analyses controlling for demographic characteristics and main effects were conducted to explore interaction effects between depressive symptoms and two distinct moderators.

RESULTS

Depressive symptoms were only related to opioid use during early treatment among patients reporting high opioid use-related coping motives (B = 2.67, p =.004) and patients reporting high trait impulsivity (B = 2.01, p =.039). Further, depressive symptoms were only inversely related to days retained among individuals with high opioid use-related coping motives (B = -10.12, p =.003).

CONCLUSIONS

Individuals presenting to treatment with opioid-related coping motives and/or impulsivity in the context of depressive symptoms may confer unique risk for adverse treatment outcomes. Clinicians may wish to consider these additive risk factors when developing their treatment plan.

The importance of translationally evaluating steroid hormone contributions to substance use

Clinically, women appear to be more susceptible to certain aspects of substance use disorders (SUDs). The steroid hormones 17β-estradiol (E2) and progesterone (Pg) have been linked to women-specific drug behaviors. Here, we review clinical and preclinical studies investigating how cycling ovarian hormones affect nicotine-, cocaine-, and opioid-related behaviors. We also highlight gaps in the literature regarding how synthetic steroid hormone use may influence drug-related behaviors. In addition, we explore how E2 and Pg are known to interact in brain reward pathways and provide evidence of how these interactions may influence drug-related behaviors. The synthesis of this review demonstrates the critical need to study women-specific factors that may influence aspects of SUDs, which may play important roles in addiction processes in a sex-specific fashion. It is important to understand factors that impact women's health and may be key to moving the field forward toward more efficacious and individualized treatment strategies.

Insights into the mechanisms underlying opioid use disorder and potential treatment strategies

Opioid use disorder is a worldwide societal problem and public health burden. Strategies for treating opioid use disorder can be divided into those that target the opioid receptor system and those that target non-opioid receptor systems, including the dopamine and glutamate receptor systems. Currently, the clinical drugs used to treat opioid use disorder include the opioid receptor agonists methadone and buprenorphine, which are limited by their abuse liability, and the opioid receptor antagonist naltrexone, which is limited by poor compliance. Therefore, the development of effective medications with lower abuse liability and better potential for compliance is urgently needed. Based on recent advances in the understanding of the neurobiological mechanisms underlying opioid use disorder, potential treatment strategies and targets have emerged. This review focuses on the progress made in identifying potential targets and developing medications to treat opioid use disorder, including progress made by our laboratory, and provides insights for future medication development. LINKED ARTICLES: This article is part of a themed issue on Advances in Opioid Pharmacology at the Time of the Opioid Epidemic. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v180.7/issuetoc.

Estradiol Enhances the Development of Addiction-Like Features in a Female Rat Model of Opioid Use Disorder

INTRODUCTION

Women are more vulnerable than men in many aspects of opioid use disorder (OUD); a major theory of sex differences in substance use disorders is that these differences are due to ovarian hormones with estradiol enhancing vulnerability in females. However, most of this evidence is for psychostimulants and alcohol; evidence with opioids is sparse. Thus, the goal of this study was to determine the impact of estradiol on vulnerability in females in a rat model of OUD.

METHOD

Following self-administration training, ovariectomized (OVX) females with (E) or without (V) estradiol replacement were given extended (24 h/day), intermittent access (2, 5-min trials/h) to fentanyl for 10 days. Then, the development of three key features of OUD were assessed, including physical dependence, defined by the magnitude and time course of weight loss during withdrawal; an enhanced motivation for fentanyl, assessed using a progressive-ratio schedule; and relapse vulnerability, assessed using an extinction/cue-induced reinstatement procedure. These later two characteristics were examined following 14 days of withdrawal when the phenotypes are known to be highly expressed.

RESULTS

OVX+E females self-administered markedly higher levels of fentanyl under extended, intermittent-access conditions and showed a longer time course of physical dependence, a greater increase in motivation for fentanyl, and an enhanced sensitivity to the reinstating effects of fentanyl-associated cues compared to OVX+V rats. Severe health complications were also observed in OVX+E, but not OVX+V females, during withdrawal.

CONCLUSION

These results indicate that, as with findings with psychostimulants and alcohol, estradiol enhances vulnerability in females to developing opioid addiction-like features and serious opioid-related health complications.

Childhood Adversity, Addiction Severity, and Comorbidity Among Patients Receiving Opioid Use Disorder Treatment: The Role of Emotion Regulation

Patients in opioid use disorder (OUD) treatment report high rates of childhood adversity, and women experience greater exposure to certain types of childhood adversity ( e.g. , sexual abuse). Childhood adversity is associated with clinical severity, but the mechanisms explaining this association are not well understood. Participants ( N = 171) in opioid agonist treatment completed measures of childhood adversity, emotion regulation, and clinical severity ( i.e. , addictive behaviors, depression, and anxiety). Women endorsed greater childhood adversity and higher current psychopathology than men. The association between childhood adversity and clinical severity varied as a function of symptom type, although emotion regulation was a strong predictor in all models. Women reported higher levels of anxiety after controlling for covariates, childhood adversity, and emotion dysregulation. Future research should investigate treatment strategies to address emotion dysregulation among patients in OUD treatment, particularly women who may present with greater childhood adversity exposure and anxiety.

Current and emerging pharmacotherapies for opioid dependence treatments in adults: a comprehensive update

INTRODUCTION

Opioid use disorder (OUD) is characterized by compulsive opioid seeking and taking, intense drug craving, and intake of opioids despite negative consequences. The prevalence of OUDs has now reached an all-time high, in parallel with peak rates of fatal opioid-related overdoses, where 15 million individuals worldwide meet the criteria for OUD. Further, in 2020, 120,000 opioid-related deaths were reported worldwide with over 75,000 of those deaths occurring within the United States.

AREAS COVERED

In this review, we highlight pharmacotherapies utilized in patients with OUDs, including opioid replacement therapies, and opioid antagonists utilized for opioid overdoses and deterrent of opioid use. We also highlight newer treatments, such as those targeting the neuroimmune system, which are potential new directions for research given the recently established role of opioids in activating neuroinflammatory pathways, as well as over the counter remedies, including kratom, that may mitigate withdrawal.

EXPERT OPINION

To effectively treat OUDs, a deeper understanding of the current therapeutics being utilized, their additive effects, and the added involvement of the neuroimmune system are essential. Additionally, a complete understanding of opioid-induced neuronal alterations and therapeutics that target these abnormalities - including the neuroimmune system - is required to develop effective treatments for OUDs.

The association of chronic pain and opioid withdrawal in men and women with opioid use disorder

BACKGROUND

Approximately 2.7 million individuals in the United States had an opioid use disorder (OUD) in 2020. Chronic pain may exacerbate opioid withdrawal severity, yet most research on opioid withdrawal has not collected data on chronic pain status. Moreover, there is limited evidence that women tend to experience greater opioid withdrawal severity than men, but large, confirmatory studies on this topic have not been published. The goal of this study was to examine the roles of chronic pain and gender on opioid withdrawal severity using a large, multi-site database.

METHODS

Data were collected from N = 1252 individuals with OUD entering eight residential addiction treatment facilities. Demographic, drug use behaviors, and chronic pain status were collected at treatment intake, and self-reported opioid withdrawal and craving were measured at intake and 1-3 days, 4-6 days, and 7-9 days after intake. Regression analyses were used to predict withdrawal and craving severity at intake and across the four timepoints.

RESULTS

At intake, withdrawal was higher in persons who were older, had greater SUD severity, women, had chronic pain, and used > 1 substance (p-values ≤.007) and craving was higher in persons with greater SUD severity (p < .001) and women (p = .033). Withdrawal remained higher in women and persons with chronic pain across timepoints but decreased at a similar rate relative to comparators.

CONCLUSIONS

Women and persons with chronic pain would benefit from earlier engagement in treatment and may require a more intensive strategy to mitigate opioid withdrawal in early treatment.

A role for the circadian transcription factor NPAS2 in the progressive loss of non-rapid eye movement sleep and increased arousal during fentanyl withdrawal in male mice

RATIONALE

Synthetic opioids like fentanyl are contributing to the rise in rates of opioid use disorder and drug overdose deaths. Sleep dysfunction and circadian rhythm disruption may worsen during opioid withdrawal and persist during abstinence. Severe and persistent sleep and circadian alterations are putative factors in opioid craving and relapse. However, very little is known about the impact of fentanyl on sleep architecture and sleep-wake cycles, particularly opioid withdrawal. Further, circadian rhythms regulate sleep-wake cycles, and the circadian transcription factor, neuronal PAS domain 2 (NPAS2) is involved in the modulation of sleep architecture and drug reward. Here, we investigate the role of NPAS2 in fentanyl-induced sleep alterations.

OBJECTIVES

To determine the effect of fentanyl administration and withdrawal on sleep architecture, and the role of NPAS2 as a factor in fentanyl-induced sleep changes.

METHODS

Electroencephalography (EEG) and electromyography (EMG) was used to measure non-rapid eye movement sleep (NREMS) and rapid eye movement sleep (REMS) at baseline and following acute and chronic fentanyl administration in wild-type and NPAS2-deficient male mice.

RESULTS

Acute and chronic administration of fentanyl led to increased wake and arousal in both wild-type and NPAS2-deficient mice, an effect that was more pronounced in NPAS2-deficient mice. Chronic fentanyl administration led to decreased NREMS, which persisted during withdrawal, progressively decreasing from day 1 to 4 of withdrawal. The impact of fentanyl on NREMS and arousal was more pronounced in NPAS2-deficient mice.

CONCLUSIONS

Chronic fentanyl disrupts NREMS, leading to a progressive loss of NREMS during subsequent days of withdrawal. Loss of NPAS2 exacerbates the impact of fentanyl on sleep and wake, revealing a potential role for the circadian transcription factor in opioid-induced sleep changes.

The Impact of Individual Counseling on Treatment for Opioid Use

ABSTRACT

In 2018, more than 67,000 people died because of drug overdoses, and of that number, approximately 69.5% involved an opioid, making it a leading cause of death in the United States. Additionally concerning is that 40 states have reported increased overdose deaths and opioid-related deaths since the start of the COVID-19 global pandemic. Presently, many insurance companies and healthcare providers require patients to receive counseling during medication treatment for opioid use disorder (OUD), despite the lack of evidence that it is necessary for all patients. To inform policy and improve quality of treatment, this nonexperimental, correlational study examined the relationship between individual counseling status and treatment outcomes in patients receiving medication treatment for OUD. Treatment outcome variables (treatment utilization, medication use, and opioid use) were extracted from the electronic health records of 669 adults who received treatment between January 2016 and January 2018. Study findings suggest women in our sample were more likely to test positive for benzodiazepines (t = -4.3, p < .001) and amphetamines (t = -4.4, p < .001), whereas men used alcohol at higher rates than women (t = 2.2, p = .026). In addition, women were more likely to report having experienced Post-Traumatic Stress Disorder/trauma (χ2 = 16.5, p < .001) and anxiety (χ2 = 9.4, p = .002). Regression analyses revealed concurrent counseling was unrelated to medication utilization and ongoing opioid use. Patients who had prior counseling utilized buprenorphine more frequently (β = 0.13, p < .001) and used opioids less often (β = -0.14, p < .001); however, both relationships were weak. These data do not provide evidence that counseling during OUD outpatient has a significant impact on treatment outcomes. These findings provide further evidence that barriers to medication treatment such as mandatory counseling can and should be removed.

Sex differences in weight gain during medication-based treatment for opioid use disorder: A meta-analysis and retrospective analysis of clinical trial data

BACKGROUND

Side effects of medications for opioid use disorder (MOUD) such as weight gain contribute to their stigma. Substantial evidence suggests that women have a more severe side effect profile to MOUD than men, and concerns about weight gain during treatment are prevalent. However, the few studies reporting sex differences in weight gain during treatment show conflicting results and are restricted to methadone. In addition, little is known about possible sex differences in weight gain to buprenorphine, which is the most commonly prescribed MOUD in the United States.

METHODS

To address these issues, we performed a systematic review and meta-analysis on the few studies reporting longitudinal data on sex differences in body mass index (BMI) gain during methadone treatment (Study 1). In a separate study, we also re-analyzed data from trial CTN-0030 of the National Institute on Drug Abuse Clinical Trial Network (NIDA CTN), which involved a 12-week buprenorphine treatment regimen (Study 2; n = 360; 209 Male, 151 Female).

RESULTS

For Study 1, across all papers reporting longitudinal data (k = 4, n = 362 OUD patients), there were BMI increases that ranged from 2.2 to 5.4 BMI after at least one year of methadone treatment, but there were no significant sex differences in BMI increases (Standardized Mean Difference, Female > Male = 0.352, SE =0.270; 95 % CI = [-0.18 0.88]; p = .193). Study 2 showed no significant differences in weight before and after 12 weeks of buprenorphine treatment nor did it show sex differences in weight change with treatment (β = 2.34, p = .511).

CONCLUSION

These analyses corroborate evidence of weight gain with methadone treatment but did not observe a sex-based disparity in weight gain with methadone or buprenorphine treatment for OUD.

Prevalence of mental disorders among people with opioid use disorder: A systematic review and meta-analysis

BACKGROUND

Opioid use disorder (OUD) and mental disorders are major public health issues and comorbidity is common. Among people with OUD, comorbid mental disorders are associated with poorer health outcomes. To our knowledge, this is the first systematic review and meta-analysis to estimate prevalence of specific mental disorders among people with OUD.

METHODS

We searched Embase, MEDLINE, and PsycInfo from 1990 to 2021 for observational studies of depression, anxiety, post-traumatic stress disorder (PTSD), bipolar, personality, and other pre-specified mental disorders among people with OUD. We pooled current and lifetime estimates of each disorder using random-effects meta-analyses with 95% Confidence Intervals (CIs). Meta-regressions and stratified analyses were used to assess heterogeneity of prevalence estimates by methodological factors and sample characteristics.

FINDINGS

Of the 36,971 publications identified, we included data from 345 studies and 104,135 people with OUD in at least one pooled estimate. Among people with OUD, the prevalence of current depression was 36.1% (95%CI 32.4-39.7%), anxiety was 29.1% (95%CI 24.0-33.3%), attention-deficit/hyperactivity disorder was 20.9% (95%CI 15.7-26.2%), PTSD was 18.1% (95%CI 15.4-20.9%), and bipolar disorder was 8.7% (95%CI 6.7-10.7%). Lifetime prevalence of anti-social personality disorder was 33.6% (95%CI 29.1-38.0%) and borderline personality disorder was 18.2% (95% CI 13.4-23.1%). Sample characteristics and methodological factors, including sex, were associated with variance of multiple prevalence estimates.

INTERPRETATION

Our findings emphasise the need for access to mental disorder treatment among people with OUD. Specific mental disorder estimates may inform clinical guidelines, treatment services, and future research for people with OUD, including subpopulations with distinct treatment needs.

Using crowdsourcing to study the differential effects of cross-drug withdrawal for cigarettes and opioids in a behavioral economic demand framework

Smoking rates among those who use prescribed or recreational opioids are significantly higher than the general population. Hypothesized neuropharmacological interactions between opioids and nicotine may contribute to this pattern of polysubstance use, especially during withdrawal. However, little research has examined how the withdrawal of one substance may affect the consumption of the other (i.e., cross-drug withdrawal effects). Behavioral economic demand tasks (e.g., hypothetical purchase tasks) can be used to quickly assess the value of a drug. Crowdsourcing can be a convenient tool to gain preliminary insight into different processes in substance valuation that may otherwise be impossible or prohibitively difficult to study. The purpose of the present study was to provide a preliminary examination of the effects of hypothetical withdrawal of cigarettes and opioids on the consumption of those drugs among polysubstance users. Amazon Mechanical Turk workers who reported daily smoking and at least monthly opioid use completed a series of hypothetical purchase tasks for doses of opioids and cigarettes under various withdrawal conditions. Sensitivity to the price of both drugs decreased when under withdrawal for either, indicating a higher drug value of cigarettes and opioids due to effects of cross-drug withdrawal. Nicotine and opioid dependence severity, impulsive choice, and riskiness were also positively related to drug purchasing. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Consideration of sex and gender differences in addiction medication response

Substance use continues to contribute to significant morbidity and mortality in the United States, for both women and men, more so than another other preventable health condition. To reduce the public health burden attributable to substances, the National Institute on Drug Abuse and the National Institute on Alcohol Abuse and Alcoholism have identified that medication development for substance use disorder is a high priority research area. Furthermore, both Institutes have stated that research on sex and gender differences in substance use medication development is a critical area. The purpose of the current narrative review is to highlight how sex and gender have been considered (or not) in medication trials for substance use disorders to clarify and summarize what is known regarding sex and gender differences in efficacy and to provide direction to the field to advance medication development that is consistent with current NIH 'sex as a biological variable' (SABV) policy. To that end, we reviewed major classes of abused substances (nicotine, alcohol, cocaine, cannabis, opioids) demonstrating that, sex and gender have not been well-considered in addiction medication development research. However, when adequate data on sex and gender differences have been evaluated (i.e., in tobacco cessation), clinically significant differences in response have been identified between women and men. Across the other drugs of abuse reviewed, data also suggest sex and gender may be predictive of outcome for some agents, although the relatively low representation of women in clinical research samples limits making definitive conclusions. We recommend the incorporation of sex and gender into clinical care guidelines and improved access to publicly available sex-stratified data from medication development investigations.

Is Illicit Substance Use Gender-Specific? The Basic Points of Mental and Health Disorders

Among the groups of users of illicit substances, a high percentage are persons deprived of their liberty; at the same time, each social and age group is also affected, to one degree or another. The purpose of this study is to provide general data on the relationship between different psychostimulants, clinical and socio-demographic studies, and gender, both among the general population and in one of the most at-risk groups. This review identifies the use of illicit substances as gender-specific in the general population. A detailed study of the causal relationship between the use of illicit substances and gender was carried out. Electronic databases Academic Search Complete, PubMed, HealthCare, Web of Science, and Google Scholar were searched for relevant studies up to 2022 associated with drug abuse and mental and health disorders. The analysis indicated that the human population showed significant differences between the sex of the consumer as to the type of drug consumers, development of addiction, and relapse. We focus on the pathological changes caused by drug use, the personal and physiological individual traits that influence drug choice, and the extent of use in one of the most affected groups of individuals. The study may provide some guidance in developing gender-specific treatment and prevention, including response to some pharmacological and behavioral therapies. The review is intended for a wide audience of social workers, toxicologists, and pharmacologists.

Systematic review and meta-analysis of changes in quality of life following initiation of buprenorphine for opioid use disorder

BACKGROUND

People with opioid use disorder (OUD) experience lower quality of life (QoL) than the general population, but buprenorphine treatment for OUD could help improve QoL of individuals with OUD. Thus, we conducted a systematic review and meta-analysis of the impact of buprenorphine on QoL among people with OUD.

METHODS

Seven databases were searched through August 2020. We included English-language studies with pre- and post- QoL assessments internationally. Standardized mean differences were calculated for five domains of QoL measures using a random effects model for correlated effect sizes with robust variance estimation. Meta-regression was used to assess variation in effect sizes based on QoL domain, treatment, and patient factors.

RESULTS

Twenty-one peer-reviewed studies from twelve countries were included. Only three studies included a no-treatment control group and five studies assigned groups using randomization. Improvements between baseline and follow-up were observed across all five domains of QoL measures (overall, physical, psychological, social, and environmental). The certainty of evidence was low for all domains of QoL, and very low for environmental QoL. We did not observe differences in the effect of buprenorphine on QoL by QoL domain, duration, dose, participant characteristics, or adjunctive counseling services.

CONCLUSIONS

Buprenorphine treatment likely improves overall, physical, psychological, and social QoL, and may improve environmental QoL, for individuals with OUD. Findings are limited by study quality, including lack of control groups and incomplete reporting. Future studies with more rigorous methods and comprehensive reporting are needed.

Sex, gender, and the opioid epidemic: Crucial implications for acute care

INTRODUCTION

The opioid epidemic continues to escalate in the United States, exacerbated significantly by the COVID-19 pandemic. Necessary steps in acute care medicine to expand efforts to combat this epidemic involve increased emergency department engagement of patients with opioid use disorder (OUD) and an incorporation of evolving sex- and gender-based factors that affect this disease presentation and management course.

METHODS & AIMS

An ever-increasing amount of peer-reviewed, evidence-based literature has shed light on the important biologic and sociocultural variables, specifically sex and gender, which impact OUD trajectory and outcomes. As a collaborative effort of the Sex and Gender in Emergency Medicine (SGEM) Interest Group, a community within the Society for Academic Emergency Medicine (SAEM), we sought to consider, review, and summarize clinically pertinent information as a comprehensive introduction to this topic for the emergency medicine (EM) clinician and educator.

RESULTS

A selected overview of current evidence-based data and publications, to include current epidemiologic trends, opioid-based physiology and pathophysiology, as well as opioid use disorder management and outcomes, through a sex- and gender-based lens, was reviewed and included in this summary. Also discussed are implications and recommendations for EM educators seeking insight and resources for continuing, graduate, and/or undergraduate education on this topic.

CONCLUSION

Incorporation of emerging sex- and gender-specific scientific knowledge into clinical context represents a critical link to effective management of the OUD patient in the ED. Similarly, integration of this information into EM education represents an essential step for both sex- and gender-based medicine and opioid-specific training.

Positive associations between cannabis and alcohol use polygenic risk scores and phenotypic opioid misuse among African-Americans

BACKGROUND

This study examined whether polygenic risk scores (PRS) for lifetime cannabis and alcohol use were associated with misusing opioids, and whether sex differences existed in these relations in an urban, African-American sample.

METHODS

Data were drawn from three cohorts of participants (N = 1,103; 45% male) who were recruited in first grade as part of a series of elementary school-based, universal preventive intervention trials conducted in a Mid-Atlantic region of the U.S. In young adulthood, participants provided a DNA sample and reported on whether they had used heroin or misused prescription opioids in their lifetime. Three substance use PRS were computed based on prior GWAS: lifetime cannabis use from Pasman et al. (2018), heavy drinking indexed via maximum number of drinks from Gelernter et al. (2019), and alcohol consumption from Kranzler et al. (2019).

RESULTS

Higher PRS for lifetime cannabis use, greater heavy drinking, and greater alcohol consumption were associated with heightened risk for misusing opioids among the whole sample. Significant sex by PRS interactions were also observed such that higher PRS for heavy drinking and alcohol consumption were associated with a greater likelihood of opioid misuse among males, but not females.

CONCLUSION

Our findings further elucidate the genetic contributions to misusing opioids by showing that the genetics of cannabis and alcohol consumption are associated with lifetime opioid misuse among young adults, though replication of our findings is needed.

Sex differences in opioid receptor mediated effects: Role of androgens

An abundance of data indicates there are sex differences in endogenous opioid peptides and opioid receptors, leading to functional differences in sensitivity to opioid receptor mediated behaviors between males and females. Many of these sex differences are mediated by the effects of gonadal hormones on the endogenous opioid system. Whereas much research has examined the role of ovarian hormones on opioid receptor mediated endpoints, comparatively less research has examined the role of androgens. This review describes what is currently known regarding the influence of androgens on opioid receptor mediated endpoints and how androgens may contribute to sex differences in these effects. The review also addresses the clinical implications of androgenic modulation of opioid receptor mediated behaviors and suggests future lines of research for preclinical and clinical investigators. We conclude that further investigation into androgenic modulation of opioid receptor mediated effects may lead to new options for addressing conditions such as chronic pain and substance use disorders.

Latent trajectories of anxiety and depressive symptoms among adults in early treatment for nonmedical opioid use

BACKGROUND

Understanding the course of anxiety and depressive symptoms in early opioid use disorder (OUD) treatment may inform efforts to promote positive early treatment response and reduce treatment attrition.

METHODS

Persons in treatment for nonmedical opioid use were identified from 86 addiction treatment facilities. Growth mixture modeling was used to identify trajectories of anxiety and depression symptoms during the first month of treatment among individuals who screened positive for depression (N = 3016) and/or anxiety (N = 2779) at intake.

RESULTS

A three-class solution best fit the data for anxiety symptoms and included the following trajectories: (1) persistent moderate-to-severe anxiety symptoms, (2) remitting severe anxiety symptoms, and (3) persistent minimal-to-mild anxiety symptoms. Similarly, a three-class solution best fit the data for depressive symptoms and included trajectories characterized by (1) persistent moderate-to-severe depressive symptoms, (2) persistent moderate depressive symptoms, and (3) mild/remitting depressive symptoms. Persistent moderate-to-severe anxiety and depressive symptoms were predicted by female gender and heavy past-month benzodiazepine co-use.

LIMITATIONS

Fine grained-information about substance use was not collected. Results may not be generalizable to individuals receiving treatment outside of specialty addiction clinics.

CONCLUSIONS

Analysis of anxiety and depression symptom trajectories in early treatment suggest that a subset of individuals entering treatment for opioid use experienced persistent and significant anxiety and depressive symptoms, whereas others experience a remission of symptoms. Interventions designed to target individuals at the greatest risk, such as women and individuals reporting opioid/benzodiazepine co-use, may help improve mental health symptoms in early OUD treatment.

Psychiatric Comorbidity and Psychopathology of Methamphetamine Users—Are There Gender Differences?

Methamphetamine use disorder is associated with severe psychiatric symptoms and psychosocial problems. Women seem to be more affected than men. Therefore, this study examined psychiatric comorbidities and psychopathology, drug use patterns, and treatment outcomes in women addicted to methamphetamine compared to men. Data on methamphetamine-dependent inpatients were collected in two centers specialized for addiction treatment at admission (T0) and discharge (T1, after treatment for 24 weeks). Sociodemographic and clinical measures were collected with the semi-structured clinical interview I at baseline; the self-reported standardized questionnaire (SCL-90-R) was administered at admission and discharge and after 24 weeks. During the entire treatment procedure, treatment relevant aspects were monitored. Out of all 108 treatment-seeking participants (86 men, 22 women), 64 completed the study (51 men, 13 women; drop-out rate: 40.7% (n = 44)). Methamphetamine-dependent women used other stimulants more often than men, while men used hallucinogens significantly more frequently than women. Female inpatients differed significantly from men in various sociodemographic variables (e.g., having children, single parenting) and were significantly more often affected by current (p < 0.001) and lifetime mental stress disorders (p < 0.001), as well as specific psychiatric disorders (p < 0.001) (e.g., posttraumatic stress disorder). At discharge, mental symptoms decreased significantly in men but not in women. Both before and after treatment, women seem to be more vulnerable to psychiatric comorbidities and psychopathologic symptoms compared to men. Although this study only provides preliminary data on gender-specific characteristics of methamphetamine-dependent patients and their treatment, it seems appropriate to discuss the development of gender-specific treatment options. Further studies in this field are needed.

Gender Dynamics in Substance Use and Treatment: A Women's Focused Approach

Gender impacts substance use initiation, substance use disorder development, engagement with treatment, and harms related to drug and alcohol use. Using the biopsychosocial model of addiction, this review provides a broad summary of barriers and facilitators to addiction services among women. It also reviews substance use among pregnant and parenting women and approaches to care. Given the increasing rates of substance use among women, there is a need to implement and scale-up gender-responsive addiction programming and pursue advocacy at the policy level that addresses the root drivers of substance use inequities among women.

Sex Specific Sleep Parameters Among People With Substance Use Disorder

INTRODUCTION

Sleep can have substantial impacts in substance use disorder (SUD) pathogenesis, treatment, and recovery. Sex differences exist in both sleep and SUD, but how sleep is uniquely associated with SUD by sex is not known. The study objective was to compare, within sex, sleep parameters between individuals with SUD and non-substance misusing controls.

METHODS

Secondary analyses of a parent cross-sectional study examining the feasibility and acceptability of a novel neurocognitive phenotyping assessment battery were completed. SUD and control subjects were recruited through local advertising and an established research registry. Subjects with SUD were also recruited through a university-based outpatient SUD treatment clinic. Self-reported sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). Sex-stratified t-tests compared sleep between SUD and control subjects while Crosstab analyses explored group differences in the proportion of individuals reporting poor sleep (defined as PSQI ≥ 5).

RESULTS

Data from 162 males (44 controls, 118 SUD) and 146 females (64 controls, 82 SUD) were included in the present study. For females only, a significantly lower proportion of controls reported PSQI-defined poor sleep than individuals with any SUD or specifically with opioid use disorder. Male, but not female, controls reported shorter sleep latency, longer sleep duration, and less sleep disturbance than males with each SUD type.

DISCUSSION/IMPLICATIONS

Sleep holds promise as an avenue to address SUD within a biopsychosocial model. Future work at the intersection of SUD and sleep should prioritize investigations of their interplay with sex to identify targets for tailored SUD interventions.

Opioid Use Disorder in Women and the Implications for Treatment

Objective

The opioid epidemic continues to evolve and impact all groups of people. Moreover, there are concerning trends among women. The aim of this article is to provide a review of opioid use disorder in women and the implications for treatment.

Methods

A nonsystematic review of the literature as conducted to examine: (1) the epidemiology of opioid-related hospitalizations and deaths of women; (2) co-occurring pain, anxiety disorders, and trauma among women with opioid use disorder; (3) evidence for opioid agonist treatment of pregnant women with opioid use disorder; and (4) implications for treatment of women with opioid use disorder and next steps for research and practice.

Results

The current opioid epidemic has produced important differences by sex and gender with increased rates of use and overdose deaths in women. Significant mental health concerns for women include co-occurring psychiatric disorders and suicide. Expanding medication treatment for perinatal opioid use disorder is crucial. While effective treatments exist for opioid use disorder, they are often not accessible, and a minority of patients are treated.

Conclusions

The end to the opioid epidemic will require innovative multi-systemic solutions. There are significant practice gaps in preventing rising death rates among women by opioid overdose, treating co-occurring psychiatric disorders and pain, and treating perinatal women with opioid use disorder and their infants. Research on sex and gender differences, and the intersection with race/ethnicity and US region, is critically needed and should include treatment implementation studies to achieve wider access for women to effective prevention, early intervention, and treatment.

Estimating the impact on initiating medications for opioid use disorder of state policies expanding Medicaid and prohibiting substance use during pregnancy

BACKGROUND

Medicaid expansion increased access to addiction treatment services for pregnant women. However, states' imposition of civil or criminal child abuse sanctions for drug use during pregnancy could inhibit access to treatment. We estimated the effects of Medicaid expansion on pregnant women's medications for opioid use disorder (MOUD) use, and its interaction with statutes that prohibit substance use during pregnancy.

METHODS

Using the Treatment Episode Dataset for Discharge (2010-2018), we identified the initial treatment episode of pregnant women with opioid use disorder (OUD). We described changes in MOUD use and estimated adjusted difference-in-differences and event study models to evaluate differences in changes in MOUD between states that prohibit substance use during pregnancy and states that do not.

FINDINGS

Among a total of 16,070 treatment episodes for pregnant women with OUD from 2010 to 2018, most (74%) were in states that expanded Medicaid. By one year post-expansion, the proportion of episodes receiving MOUD in states not prohibit substance use during pregnancy increased by 8.7% points (95% CI: 2.7, 14.7) from the pre-expansion period compared to a 5.6% point increase in states prohibiting substance use during pregnancy (95% CI: -3.3, 14.8). In adjusted event study analysis, the expansion was associated with an increase in MOUD use by 15.3% by year 2 in states not prohibiting versus 1.5% percentage points in states prohibiting substance use during pregnancy, respectively.

CONCLUSIONS

State policies prohibiting substance use during pregnancy may limit the salutary effects of Medicaid expansion for pregnant women who could benefit from MOUD treatment.

Establishing preclinical withdrawal syndrome symptomatology following heroin self-administration in male and female rats

Opioid use disorder (OUD) is a significant health problem, and understanding mechanisms of various aspects of OUD including drug use and withdrawal is important. Preclinical models provide an ideal opportunity to evaluate mechanisms underlying opioid withdrawal. Current models are limited by their reliance upon forced opioid administration, focus on the acute (and not protracted) syndrome, and exclusion of females. In this study, male and female rats self-administered heroin (maintenance dose of 12.5 μg/kg/infusion) and opioid withdrawal after abrupt discontinuation was measured. In Phase 1, acute withdrawal symptoms were rated in male and female rats at 0, 16, 48, and 72 hr after the last self-administration session. Total somatic signs increased until 48 hr (predominantly in females), and heroin intake positively correlated with total somatic signs at the 48 and 72 hr timepoints. Measures of hyperactivity and anxiety-like behavior increased by 16 and 48 hr, respectively. In Phase 2, symptoms were assessed at baseline, acute, and protracted (168 and 312 hr after self-administration) timepoints in a subset of male and female rats from Phase 1. The total number of somatic signs did not differ across timepoints, though females displayed significantly higher body temperature at all timepoints compared with males, indicating sex-specific protracted withdrawal symptomatology. These data provide a thorough characterization of rodent opioid withdrawal symptomatology after self-administration and abrupt discontinuation that serve as a foundation for future studies designed to mimic the human experience, and demonstrate the importance of characterizing acute and protracted withdrawal with sex-specificity in preclinical models of opioid self-administration. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Recovery capital among people receiving treatment for opioid use disorder with buprenorphine

Background

Recovery is a multidimensional process that includes health, quality of life, and citizenship. Recovery capital is a strengths-based concept representing the sum of an individual’s resources that support recovery. This study (1) describes recovery capital, (2) examines the relationship between recovery capital and treatment duration, and (3) assesses differences by gender in recovery capital among people receiving medication for opioid use disorder (MOUD).

Methods

This is a secondary data analysis of a cross-sectional study, with survey and medical record review components, conducted with patients recruited from an office-based opioid treatment clinic between July and September 2019. Analyses included participants receiving MOUD with buprenorphine who completed the Brief Assessment of Recovery Capital (BARC-10; n = 130). Univariate analyses explored differences by gender. Multivariate linear regression assessed the relationship between BARC-10 total score and length of current treatment episode.

Results

Participants were 54.6% women and 67.4% Black with mean age of 42.4 years (SD = 12.3). Mean length of current MOUD treatment was 396.1 days (SD = 245.9). Total BARC-10 scores were high, but participants perceived low community-level resources. Women scored higher than men within the health and purpose recovery dimensions. While length of treatment was not associated with BARC-10 score, experiencing recent discrimination was associated with a significantly lower BARC-10 score.

Conclusions

Recovery capital among individuals receiving MOUD was high suggesting that participants have resources to support recovery, but gender differences and prevalent discrimination highlight areas for improved intervention. More work is needed to investigate recovery capital as an alternative treatment outcome to abstinence in outpatient MOUD populations.

Analysis of genetic and clinical factors associated with buprenorphine response

BACKGROUND

Buprenorphine, approved for treating opioid use disorder (OUD), is not equally efficacious for all patients. Candidate gene studies have shown limited success in identifying genetic moderators of buprenorphine treatment response.

METHODS

We studied 1616 European-ancestry individuals enrolled in the Million Veteran Program, of whom 1609 had an ICD-9/10 code consistent with OUD, a 180-day buprenorphine treatment exposure, and genome-wide genotype data. We conducted a genome-wide association study (GWAS) of buprenorphine treatment response [defined as having no opioid-positive urine drug screens (UDS) following the first prescription]. We also examined correlates of buprenorphine treatment response in multivariable analyses.

RESULTS

Although no variants reached genome-wide significance, 6 loci were nominally significant (p < 1 × 10^-5), four of which were located near previously characterized genes: rs756770 (ADAMTSL2), rs11782370 (SLC25A37), rs7205113 (CRISPLD2), and rs13169373 (LINC01947). A higher maximum daily buprenorphine dosage (aOR = 0.98; 95 %CI: 0.97, 0.995), greater number of UDS (aOR = 0.97; 95 %CI: 0.96, 0.99), and history of hepatitis C (HCV) infection (aOR = 0.71; 95 %CI: 0.57, 0.88) were associated with a reduced odds of buprenorphine response. Older age (aOR: 1.01; 95 %CI: 1.000, 1.02) was associated with increased odds of buprenorphine response.

CONCLUSIONS

This study had limited statistical power to detect genetic variants associated with a complex human phenotype like buprenorphine treatment response. Meta-analysis of multiple data sets is needed to ensure adequate statistical power for a GWAS of buprenorphine treatment response. The most robust phenotypic predictor of buprenorphine treatment response was intravenous drug use, a proxy for which was HCV infection.