Gender differences in substance use disorders

Simultaneous cocaine and ethanol self-administration promotes a sex-dimorphic pattern in drug-seeking behaviour and alters plasma amino acid profile related to glutamate homeostasis in young adult rats

The concurrent use of cocaine and alcohol is highly prevalent in Western countries and carries a substantial risk of relapse in recovering process. Craving, characterized as a strong desire for consuming drugs, is a core feature of cocaine and ethanol use disorders and presents a significant challenge to maintaining abstinence and preventing relapse. The primary objective of this study was to explore the behavioural patterns associated with the incubation of drug-seeking for a cocaine-ethanol combination and, secondarily, to examine the plasma amino acid profile that might be associated with this combination. To achieve this, we employed an extended-access intravenous self-administration model over 10 sessions with both substances, followed by withdrawal periods of 2 and 30 days in young adult rats in both sexes. After the subsequent drug-seeking test, changes in plasma amino acid concentrations were examined. Cocaine and ethanol co-administration resulted in a lower consumption rate among rats compared to those consuming cocaine alone. However, both groups exhibited incubation of drug-seeking behaviour. Sex differences were observed in self-administration patterns and in the incubation of drug-seeking behaviour. Notably, after 30 days of withdrawal, alterations were detected in plasma levels of several amino acids, including glutamine, glycine, serine, threonine, and glutamate, which are associated with glutamate homeostasis. This study aims to contribute to our understanding of potential changes in the plasma amino acid profile in cocaine users who also consume ethanol, particularly during abstinence and craving incubation.

L-type calcium channel blockade attenuates cue-induced cocaine-seeking in female rats

Periods of cocaine abstinence are associated with a high risk of relapse, often triggered by exposure to drug-associated cues. Previous research has implicated L-type calcium channels (LTCCs) in drug-seeking behaviors, yet their role in cue-induced relapse, particularly in females, remains underexplored. This study investigated the effects of LTCC inhibition on cue-induced cocaine-seeking behavior during abstinence in female Sprague-Dawley rats. Following a 10-day cocaine self-administration and a 14-day forced abstinence period, the rats were tested for cue-induced cocaine-seeking after receiving systemic administration of isradipine, a non-selective LTCC inhibitor (0.0 mg/kg, 0.1 mg/kg, 0.4 mg/kg, or 1.2 mg/kg, i.p.). Isradipine significantly reduced cue-induced cocaine-seeking in a dose-dependent manner without affecting cocaine-taking or natural reward-taking or seeking behaviors. Notably, these findings in females were comparable to our prior results observed in males, demonstrating that LTCC inhibition selectively attenuates the impact of cocaine-associated cues across sexes. These results highlight the translational potential of LTCCs as a therapeutic agent to reduce relapse risk in cocaine-dependent individuals. This study underscores the importance of considering sex-specific mechanisms in addiction treatment and calls for further research into LTCCs as a target for relapse prevention.

Exploring perceived gender norms about cannabis among treatment-seeking adults in the era of cannabis legalization in Canada: A qualitative analysis

INTRODUCTION

Prevalence of cannabis use has historically been higher among men than among women, yet the past few decades have seen a significant narrowing of this gender gap. The narrowing gender gap is likely attributable to multiple factors, including global and regional shifts in gender norms related to cannabis, which may be influenced by legalization of recreational cannabis use in many countries, including in Canada where the present study took place. The goal of this study was to explore perceived gender norms about cannabis use and how these norms might influence behavior.

METHODS

We conducted in-depth, one-to-one interviews with a sample of 23 adults in Toronto, Ontario, Canada who had been in treatment for cannabis-related harms. We used the Braun & Clarke method of reflexive thematic analysis and a theoretical framework grounded in Connell's masculinities science and more recent critical femininities scholarship to explore perceived gender norms about cannabis. In particular, we were interested in how perceived norms might influence behavior and how an understanding of changing norms can contribute to developing gender-responsive or gender-transformative interventions for cannabis use disorder (CUD).

RESULTS

Our analysis generated three main themes. Masculine Dominance of Cannabis Use demonstrates the social construction of recreational cannabis use (especially smoking cannabis) as a dominant masculine behavior. Cannabis Use as Deviation from Femininity demonstrates how increased stigma and social harms experienced by women and gender-diverse people is accomplished by framing their cannabis use as inauthentic and deviant. Finally, Rejecting and Reconfiguring Gender Norms about Cannabis suggests challenges to masculine dominance of cannabis use and how cannabis legalization may have catalyzed this process (possibly by increasing visibility of women using cannabis).

CONCLUSIONS

Our results suggest that gender continues to play a meaningful role in determining social cannabis norms, though relationships between gender and cannabis norms are clearly changing, possibly in connection to legalization of non-medical cannabis use. We end by discussing implications for treatment (e.g., norm-based interventions to encourage treatment-seeking among men) and public health (e.g., normalizing women's and gender-diverse people's cannabis use may reduce sociocultural harms associated with cannabis use).

Impact of sex and complex PTSD comorbidity on pharmacological treatment response in bipolar disorder patients

BACKGROUND

The prevalence of bipolar disorder (BD) is similar in men and women. However, factors such as sex and comorbid psychiatric conditions can influence its clinical presentation and treatment outcomes, including complex PTSD (cPTSD), a newly categorized trauma-related condition. Little is known about how sex and cPTSD comorbidity affect the response to mood stabilizers, a cornerstone treatment for BD. This observational, cross-sectional study examines the impact of sex and cPTSD comorbidity on clinical and behavioral BD features as well as their interplay in influencing pharmacological treatment response.

METHODS

A cohort of BD patients (females = 177, males = 166, age range: 19-76; BD-I = 253, BD-II = 90) was recruited over three years. Clinical assessments were conducted, and patients were administered the International Trauma Questionnaire to evaluate cPTSD comorbidity and the Alda Scale to assess response to mood stabilizers.

RESULTS

Our results show distinct clinical profiles based on sex and cPTSD. Female BD patients exhibit more hypomanic episodes, antidepressant-induced mania, and longer periods of untreated illness than males. Comorbid cPTSD was diagnosed in 154 patients (44.8 %), among which 69 were females. Patients with cPTSD display more severe BD symptoms, including earlier onset, more frequent episodes, and a higher prevalence of psychosis and suicidality. Importantly, comorbid cPTSD was associated with poorer mood stabilizer response, particularly in males, who otherwise responded better to treatment than females.

CONCLUSIONS

These findings underscore the importance of addressing trauma symptoms in BD treatment and highlight the need for individualized approaches considering both sex and comorbid trauma, as standard mood stabilizers may be insufficient for certain subgroups.

Distinct sex differences in ethanol consumption and operant self-administration in C57BL/6J mice with uniform regulation by glutamate AMPAR activity

Introduction

Considering sex as a biological variable (SABV) in preclinical research can enhance understanding of the neurobiology of alcohol use disorder (AUD). However, the behavioral and neural mechanisms underlying sex-specific differences remain unclear. This study aims to elucidate SABV in ethanol (EtOH) consumption by evaluating its reinforcing effects and regulation by glutamate AMPA receptor activity in male and female mice.

Methods

C57BL/6J mice (male and female) were assessed for EtOH intake under continuous and limited access conditions in the home cage. Acute sensitivity to EtOH sedation and blood clearance were evaluated as potential modifying factors. Motivation to consume EtOH was measured using operant self-administration procedures. Sex-specific differences in neural regulation of EtOH reinforcement were examined by testing the effects of a glutamate AMPA receptor antagonist on operant EtOH self-administration.

Results

Female C57BL/6J mice exhibited a time-dependent escalation in EtOH intake under both continuous and limited access conditions. They were less sensitive to EtOH sedation and had lower blood levels post-EtOH administration (4 g/kg) despite similar clearance rates. Females also showed increased operant EtOH self-administration and progressive ratio performance over a 30-day baseline period compared to males. The AMPAR antagonist GYKI 52466 (0-10 mg/kg, IP) dose-dependently reduced EtOH-reinforced lever pressing in both sexes, with no differences in potency or efficacy.

Discussion

These findings confirm that female C57BL/6J mice consume more EtOH than males in home-cage conditions and exhibit reduced acute sedation, potentially contributing to higher EtOH intake. Females demonstrated increased operant EtOH self-administration and motivation, indicating higher reinforcing efficacy. The lack of sex differences in the relative effects of GYKI 52466 suggests that AMPAR activity is equally required for EtOH reinforcement in both sexes.

Emotional processing in binge drinking, tobacco use disorder and their comorbidity in youth: A preregistered PRISMA scoping review

BACKGROUND

Binge drinking (BD) and tobacco use disorder (TUD) are prevalent among youth, with significant social and health implications. However, research into the emotional impairments associated with BD and TUD during adolescence is sparse and lacks integration within a comprehensive model of emotional processes. Moreover, the impact of comorbid BD and TUD on emotional deficits remains largely unexplored. We propose the first review focused on the variation of emotional deficits in BD, TUD, or their comorbidity among adolescents and we systematically explore differences across various emotional abilities.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews guidelines (PRISMA-ScR), we conducted a preregistered review of existing literature on emotional processing impairments in BD and/or TUD among adolescents. From 481 papers initially identified, 7 were included in this review. Additionally, we proposed experimental avenues for future research based on identified shortcomings in current literature.

RESULTS

Our scoping review indicates that emotional deficits are likely prevalent in both BD and TUD populations, affecting emotional appraisal/identification, response, and regulation. However, further investigation is necessary to ascertain the magnitude and scope of these deficits in adolescents and adults, as well as to delineate the distinct or combined influence of BD and TUD on emotional disturbances.

CONCLUSION

While some emotional deficits are apparent, we contend that examining emotional deficits in BD and TUD separately, as well as together, would offer a more comprehensive understanding of their nature and inform the development of novel treatment strategies.

The Mechanisms Underlying the Intergenerational Transmission of Substance Use and Misuse: An Integrated Research Approach

Substance use and substance use disorders run in families. While it has long been recognized that the etiology of substance use behaviors and disorders involves a combination of genetic and environmental factors, two key questions remain largely unanswered: (1) the intergenerational transmission through which these genetic predispositions are passed from parents to children, and (2) the molecular mechanisms linking genetic variants to substance use behaviors and disorders. This article aims to provide a comprehensive conceptual framework and methodological approach for investigating the intergenerational transmission of substance use behaviors and disorders, by integrating genetic nurture analysis, gene expression imputation, and weighted gene co-expression network analysis. We also additionally describe two longitudinal cohorts - the Brisbane Longitudinal Twin Study in Australia and the Lifelines Cohort Study in the Netherlands. By applying the methodological framework to these two unique datasets, our future research will explore the complex interplay between genetic factors, gene expression, and environmental influences on substance use behaviors and disorders across different life stages and populations.

Oral fentanyl consumption and withdrawal impairs fear extinction learning and enhances basolateral amygdala principal neuron excitatory-inhibitory balance in male and female mice

The number of opioid overdose deaths has increased over the past several years, mainly driven by an increase in the availability of highly potent synthetic opioids, like fentanyl, in the un-regulated drug supply. Over the last few years, changes in the drug supply, and in particular the availability of counterfeit pills containing fentanyl, have made oral use of opioids a more common route of administration. Here, we used a drinking in the dark (DiD) paradigm to model oral fentanyl self-administration using increasing fentanyl concentrations in male and female mice over 5 weeks. Fentanyl consumption peaked in both female and male mice at the 30 μg/mL dose, with female mice consuming significantly more fentanyl than male mice. Mice consumed sufficient fentanyl such that withdrawal was precipitated with naloxone, with males having increased withdrawal symptoms as compared to females, despite lower pharmacological exposure. We also performed behavioral assays to measure avoidance behavior and reward-seeking during fentanyl abstinence. Female mice displayed reduced avoidance behaviors in the open field assay, whereas male mice showed increased avoidance in the light/dark box assay. Female mice also exhibited increased reward-seeking in the sucrose preference test. Fentanyl-consuming mice of both sexes showed impaired cued fear extinction learning following fear conditioning and increased excitatory synaptic drive and increased excitability of BLA principal neurons. Our experiments demonstrate that long-term oral fentanyl consumption results in wide-ranging physiological and behavioral disruptions. This model could be useful to further study fentanyl withdrawal syndrome and behaviors and neuroplasticity associated with protracted fentanyl withdrawal.

Predictors of Suicidal Thoughts and Attempts among School-Going Thai Adolescents: A Sex-Specific Structural Equation Modelling Analysis

Adolescent suicide is a growing public health concern in Thailand. Identifying predictors of suicidal behaviors is essential for targeted prevention strategies. Using Structural Equation Modeling, this study explores the predictors of suicidal thoughts and attempts among a sample of 5657 Thai adolescents in grades 7-12, typically representing the age group 13-17 years, with nearly equal proportions of males (47%) and females (53%) participants. Data from the Thailand Global School-based Student Health Survey (GSHS) 2021 were analyzed. Explanatory Factor Analysis (EFA) identified key constructs, followed by SEM stratified by sex to examine relationships between constructs and suicidal behaviors. Reliability and validity were assessed using Cronbach's α and SEM fit indices. EFA identified five constructs: current substance use, history of violence, experiences of bullying, parental awareness, and poor mental health. SEM revealed poor mental health as a significant predictor for both sexes. Substance use, experiences of bullying, and a history of violence predicted suicidal behaviors in females. Parental vigilance was only a protective factor for males. The findings underscore the importance of gender-specific interventions and comprehensive mental health support to address the unique vulnerabilities of Thai adolescents, reducing suicidal thoughts and attempts.

Sex Differences in Home-Cage Ethanol Drinking and Operant Self-Administration in C57BL/6J Mice with Equivalent Regulation by Glutamate AMPAR Activity

Introduction

Considering sex as a biological variable (SABV) in preclinical research can enhance understanding of the neurobiology of alcohol use disorder (AUD). However, the behavioral and neural mechanisms underlying sex-specific differences remain unclear. This study aims to elucidate SABV in ethanol (EtOH) consumption by evaluating its reinforcing effects and regulation by glutamate AMPA receptor activity in male and female mice.

Methods

C57BL/6J mice (male and female) were assessed for EtOH intake under continuous and limited access conditions in the home cage. Acute sensitivity to EtOH sedation and blood clearance were evaluated as potential modifying factors. Motivation to consume EtOH was measured using operant self-administration procedures. Sex-specific differences in neural regulation of EtOH reinforcement were examined by testing the effects of a glutamate AMPA receptor antagonist on operant EtOH self-administration.

Results

Female C57BL/6J mice exhibited a time-dependent escalation in EtOH intake under both continuous and limited access conditions. They were less sensitive to EtOH sedation and had lower blood levels post-EtOH administration (4 g/kg) despite similar clearance rates. Females also showed increased operant EtOH self-administration and progressive ratio performance over a 30-day baseline period compared to males. The AMPAR antagonist GYKI 52466 (0-10 mg/kg, IP) dose-dependently reduced EtOH-reinforced lever pressing in both sexes, with no differences in potency or efficacy.

Discussion

These findings confirm that female C57BL/6J mice consume more EtOH than males in home-cage conditions and exhibit reduced acute sedation, potentially contributing to higher EtOH intake. Females demonstrated increased operant EtOH self-administration and motivation, indicating higher reinforcing efficacy. The lack of sex differences in the relative effects of GYKI 52466 suggests that AMPAR activity is equally required for EtOH reinforcement in both sexes.

Prevalence and correlates of severe problematic cannabis use: analysis of a population-based survey in Jamaica

Background

There is an increasing demand for the treatment of problematic cannabis use (PCU) in low-income and middle-income countries. Jamaica's historical inclination towards cannabis use underscores the need for research in addressing this issue.

Objectives

To determine the prevalence and patterns of cannabis use and assess the sociodemographic factors, psychosocial correlates, knowledge and perceptions associated with severe PCU among Jamaicans using nationally representative data.

Methods

This study involved a secondary data analysis of the last Jamaica National Drug Prevalence Survey. It included 786 participants who used cannabis in the past year and completed the Cannabis Abuse Screening Test (CAST). The CAST has been validated against the Diagnostic and Statistical Manual of Mental Disorders (DSM), with a score ≥ 7 meeting the criteria for severe PCU. CAST scores were dichotomized utilizing these thresholds, and data generated were analyzed with SPSS version 25 using Pearson's χ2 test and logistic regression.

Results

In the past year, 53.3% of Jamaicans who smoked cannabis had a score of 7 or higher on the CAST and smoked an average of 62.21 joints per month. Male respondents were twice as likely to have severe PCU as females. Additionally, young, middle, and older adults were respectively 3, 5 and 3 times more likely to report severe PCU compared to adolescent respondents. Participants who started cannabis use at 11 years and under, 12-17 years, and 18-25 years were respectively 5, 7 and 7 times more likely to report severe PCU than those at 26 years and older. Moreover, easy access to cannabis, a high perceived need for treatment, belief in increased national drug use prevalence, and awareness of the National Drug Control and Prevention Agency were associated with increased odds of reporting severe PCU.

Conclusion

One out of every two Jamaicans who used cannabis in the past year reported severe PCU and smoked an average of two cannabis joints per day. Early initiation increases the risk of severe PCU. Accordingly, a public health approach involving multiple sectors is needed to provide treatment options.

Heart rate variability: A primer for alcohol researchers

Problem alcohol drinking remains a major cost and burden for society. Also, rates of problem drinking in women have dramatically increased in recent decades, and women are at risk for more alcohol problems and comorbidities. The purpose of this commentary is to discuss the potential utility of cardiac measures, including heart rate (HR) and HR variability (HRV), as markers of individual and sex differences in the drive to drink alcohol. We recently used cardiac telemetry in female and male adult rats to determine whether different cardiac markers, including HR and HRV, would differently predict alcohol and anxiety-like behavior across the sexes. Indeed, female behaviors related to HRV measures that indicate more parasympathetic (PNS) influence (the "rest and digest" system). In contrast, male behaviors are associated more with sympathetic (SNS) indicators (the activation system). Remarkably, similar sex differences in PNS versus SNS engagement under challenge are seen in several human studies, suggesting strong cross-species convergence in differential autonomic regulation in females and males. Here, we describe the larger challenges that alcohol addiction presents, and how HRV measures may provide new biomarkers to help enhance development of more individualized and sex-specific treatments. We briefly explain the physiological systems underlying cardiac PNS and SNS states, and how specific HRV metrics are defined and validated, especially why particular HRV measures are considered to reflect more PNS versus SNS influence. Finally, we describe hormonal influences and sex differences in brain circuits related to cardiac autonomic regulation. Together, these findings show that HR and HRV have potential for uncovering key underlying mechanisms of sex and individual differences in autonomic drivers, which could guide more personalized treatment.

Self-stigma in alcohol dependence scale: development and validity of the short form

BACKGROUND

Self-stigma is associated with low self-esteem, high shame and reduced drinking-refusal self-efficacy in people with alcohol use disorder (AUD). The Self-Stigma in Alcohol-Dependence Scale-Short Form (SSAD-SF) was designed to enable a brief, but valid assessment of AUD self-stigma.

METHODS

We reduced the 64-item SSAD, originally derived from 16 stereotypes towards people with AUD, by removing the most offensive items based on perspectives of people with lived experience. The newly created scale was then assessed and validated in a cross-sectional study involving 156 people reporting alcohol issues in various treatment settings.

RESULTS

The 20-item SSAD-SF includes five stereotypes, with good internal consistency for each subscale and the overall scale. It reflects the four-stage progressive model of self-stigmatization with decreasing scores over the stages awareness of stereotypes, agreement with stereotypes, self-application of stereotypes, and harmful consequences for self-esteem, and highest correlations between adjacent stages. The subscales apply and harm were associated with internalized stigma, shame, reduced self-esteem, and lower drinking-refusal self-efficacy, as supported by multivariate regression models.

DISCUSSION

The SSAD-SF is a valid instrument for measuring the process of self-stigmatization in people with AUD. Self-stigma is a consistent predictor of reduced self-esteem, higher shame and lower drinking-refusal self-efficacy in people with AUD. We discuss merits of the progressive model for understanding and addressing self-stigma in AUD.

Diversity of ancestral brainstem noradrenergic neurons across species and multiple biological factors

The brainstem region, locus coeruleus (LC), has been remarkably conserved across vertebrates. Evolution has woven the LC into wide-ranging neural circuits that influence functions as broad as autonomic systems, the stress response, nociception, sleep, and high-level cognition among others. Given this conservation, there is a strong possibility that LC activity is inherently similar across species, and furthermore that age, sex, and brain state influence LC activity similarly across species. The degree to which LC activity is homogenous across these factors, however, has never been assessed due to the small sample size of individual studies. Here, we pool data from 20 laboratories (1,855 neurons) and show diversity across both intrinsic and extrinsic factors such as species, age, sex and brain state. We use a negative binomial regression model to compare activity from male monkeys, and rats and mice of both sexes that were recorded across brain states from brain slices ex vivo or under different anesthetics or during wakefulness in vivo. LC activity differed due to complex interactions of species, sex, and brain state. The LC became more active during aging, independent of sex. Finally, in contrast to the foundational principle that all species express two distinct LC firing modes ("tonic" or "phasic"), we discovered great diversity within spontaneous LC firing patterns. Different factors were associated with higher incidence of some firing modes. We conclude that the activity of the evolutionarily-ancient LC is not conserved. Inherent differences due to age and species-sex-brain state interactions have implications for understanding the role of LC in species-specific naturalistic behavior, as well as in psychiatric disorders, cardiovascular disease, immunology, and metabolic disorders.

Fentanyl self-administration is accelerated by methamphetamine co-use and results in worsened hypodopaminergia in male, but not female rats

Combined use of fentanyl and methamphetamine (FENT + METH) has increased in recent years and has been documented in a growing number overdose deaths each year. The impact of FENT + METH on behavior and neurobiology is not well understood. In this study, male and female Long Evans rats were tested on a limited access, fixed ratio 1 self-administration schedule for increasing doses (1.25-5 μg/kg/infusion; iv) of fentanyl, with and without a single dose (0.1 mg/kg/infusion; iv) of methamphetamine, for 15 days. FENT + METH abolished dose responsiveness to fentanyl in all rats and accelerated intake in males, resulting in patterns of responding that may be more likely to result in adverse effects. Ex vivo slice voltammetry in the nucleus accumbens core showed decreases in dopamine release and reuptake (Vmax) following FENT + METH exposure, compared with saline, fentanyl, and methamphetamine alone groups at baseline parameters. Further, significant decreases in dopamine release were observed across a range of stimulation intensities following FENT + METH exposure. Overall, male and female rats displayed sex-specific behavioral and neurobiological responses to FENT + METH exposure, with males displaying increased vulnerability.

Sex differences in age-varying trends of depressive symptoms, substance use, and their associations among South Korean adults: A Time-Varying Effect Modeling (TVEM) analysis of a nationwide sample

BACKGROUND

This study investigated sex differences in the age-varying trends of depressive symptoms, substance use, and their relationships throughout the adult lifespan. Using a nationwide sample from South Korea, this study aimed to confirm existing patterns and identify unique characteristics specific to the South Korean context.

METHOD

Time-Varying Effect Modeling (TVEM) was applied to data from 17,484 participants (9987 women and 7497 men) in the Korea National Health and Nutrition Examination Survey.

RESULTS

Consistent with global trends, the results revealed a higher prevalence of depressive symptoms among women and a greater prevalence of substance use among men. However, the findings also illuminated unique patterns within the South Korean context. Substance use among South Korean men peaked during their 40s, whereas South Korean women consistently exhibited lower rates of substance use. Additionally, a stronger association between depressive symptoms and substance use was identified in women compared to men.

LIMITATIONS

The study used cross-sectional data, limiting the analysis of temporal dynamics between depressive symptoms and substance use. Additionally, TVEM cannot distinguish between aging and cohort effects. Furthermore, the assessments of depressive symptoms and substance use were based on self-report. Finally, the study did not include adolescents or sex and gender minorities in its sample.

CONCLUSIONS

These results emphasize the need for targeted interventions, particularly among women in their 20s and older adulthood, where there is a heightened co-occurrence of depressive symptoms and substance use. These findings also highlight the importance of sex- and culture-sensitive approaches tailored to the South Korean context.

Levels of engagement among office-based opioid treatment (OBOT) patients with concurrent methamphetamine use

BACKGROUND AND OBJECTIVES

Recent increases in methamphetamine use among people seeking treatment for opioid use disorder (OUD) has created significant demand for effective approaches to support this clinical population. This study assessed the extent to which office-based opioid treatment (OBOT) patients, who were diagnosed with methamphetamine use disorder (MUD), engaged with providers.

METHODS

A retrospective analysis was conducted of adult patients (n = 470) seeking treatment for OUD who attended at least one visit between March 2020 and March 2023 at a rural regional OBOT provider. Approximately one quarter (28.7%) of patients were diagnosed with MUD in addition to receiving an OUD diagnosis. Bivariate methods and multivariate negative binomial regression models were estimated to examine the associations between clinical measures and the numbers of office visits, peer visits, and telehealth visits.

RESULTS

Regression results indicated patients who met criteria for MUD in addition to OUD attended a higher rate of peer visits (incidence rate ratio [IRR] = 2.63, p = .036) when compared to patients who did not meet criteria for MUD. In contrast, patients with MUD and OUD diagnoses displayed significantly lower (IRR = 0.68, p < .001) engagement rates through fewer office visits relative to those who did not meet MUD criteria.

DISCUSSION AND CONCLUSIONS

Patients seeking treatment for OUD who meet criteria for MUD are more likely to engage through peer support specialists rather than office visits.

SCIENTIFIC SIGNIFICANCE

This study demonstrates the ways patients who meet criteria for OUD and MUD engage with providers to receive treatment.

Diurnal sex differences in morphine withdrawal revealed by continuous assessment of voluntary home cage wheel running in the rat

Animal studies modeling recreational opioid use show more severe withdrawal symptoms in male compared to female rats, whereas our study modeling opioid use for pain showed a greater withdrawal-induced decrease in wheel running in female rats. The objective of this experiment was to determine whether sex differences in spontaneous morphine withdrawal are caused by differences in assessment method (i.e., wheel running vs. somatic symptoms). Twice daily injections of morphine (5 - 20 mg/kg, s.c.) for 5 days produced a dose and time dependent decrease in wheel running that was greater in male compared to female rats. Termination of morphine administration resulted in an overall decrease in running and a decrease in the amount of running during the dark phase of the light cycle from 95 % to approximately 75 %. In male rats, this decrease in the percent of dark running was caused by a large decrease in dark phase running, whereas female rats had a slightly higher increase in light phase running. Withdrawal also reduced maximal running speed and caused a decrease in body weight that was larger in male than female rats. Withdrawal symptoms were greatest on the day following the last morphine injection, but persisted for all 3 days of assessment. Morphine withdrawal produced a greater decrease in dark phase wheel running and body weight in male rats and a greater increase in light phase running in female rats. Voluntary home cage wheel running provides a continuous measure of opioid withdrawal that is consistent with other measures of opioid withdrawal.

Polygenic risk, childhood abuse and gene x environment interactions with depression development from middle to late adulthood: A U.S. national life-course study

OBJECTIVE

Utilizing national longitudinal data, this study examines how polygenic depression risk and childhood abuse interactively influence the life-course development of depressive conditions from middle to late adulthood.

METHOD

Data from 7512 participants (4323 females and 3189 males) of European ancestry aged 51-90, retrieved from the U.S. Health and Retirement Study (1992-2020), were analyzed. Childhood physical abuse and polygenic depression score were the primary predictors. Depressive symptoms were assessed using the Center for Epidemiologic Studies-Depression (CESD) scale, and clinical depression risk was a binary indicator. Growth-curve linear mixed and logit mixed-effects models were conducted for analysis.

RESULTS

Increasing polygenic depression scores were associated with elevated CES-D levels and potential risks of clinical depression. Males experienced more detrimental effects of childhood abuse on depression development from ages 51 to 90 years. In contract, non-maltreated females generally exhibited higher depressive symptoms and clinical depression risk than males. A significant interactive effect was found between polygenic depression risk and childhood abuse among males. Higher depression levels and clinical risk were observed with increasing polygenic depression score among maltreated males, surpassing those of females with standardized polygenic score ≥0 from age 51 to 90 years.

CONCLUSIONS

The interaction between childhood abuse and genetic factors significantly shaped lifelong depression trajectories in males, while the negative impact of abusive parenting remained constant regardless of polygenic depression risk among females. Individualized prevention and intervention strategies could be crucial in mitigating lifelong depression development, especially for high-genetic-risk males with a history of childhood physical abuse.

Sex- and estrous-related response patterns for alcohol depend critically on the level of compulsion-like challenge

Alcohol use disorder is a substantial social and economic burden. During the last years, the number of women with drinking problems has been increasing, and one main concern is that they are particularly more vulnerable to negative consequences of alcohol. However, little is known about female-specific response patterns for alcohol, and potential underlying differences in brain mechanisms, including for compulsion-like alcohol drinking (when intake persists despite adverse consequences). We used lickometry to assess behavioral microstructure in adult Wistar male and female rats (n = 28-30) during alcohol-only drinking or moderate- or higher-challenge alcohol compulsion (10 or 60 mg/l quinine in alcohol, respectively). Estrous stages were determined and related to drinking levels and patterns of responding to alcohol, as was ovariectomy. Our findings showed that females (where we didn't determine estrus stage) had similar total licks in a session as males, but significantly longer licking bouts under alcohol-only and moderate-challenge, suggesting greater persistence. Further, greater intake under alcohol-only and moderate-challenge was related to faster licking in males, while female consumption was not related to licking speed. Thus, females could have increased persistence without greater vigor, unlike males. However, under higher-challenge, faster licking did predict higher intake in females, similar to males. To better understand female higher-challenge responding, we examined drinking in relation to phases of the estrous cycle. Higher-challenge had longer bouts only in late diestrus. In addition, ovariectomy led to longer bouts only under higher-challenge, suggesting that conditions with reduced hormone levels could increase female persistence for alcohol under higher-challenge. However, ovariectomy also reduced alcohol-only and moderate-challenge drinking but did not reduce bout length. Thus, intake level and response strategy could be regulated somewhat differently by ovarian hormones. Finally, moderate-challenge licking speed was less variable during early diestrus, and we previously showed more stereotyped responding specifically under moderate-challenge in males. By combining behavioral microstructure and sex- and estrus-related changes in drinking patterns, our results suggest that females have greater persistence for alcohol under lower-challenge drinking, while late diestrus and ovariectomy unmasked greater persistence under higher-challenge. Together, our novel insights could help develop more effective and personalized treatments for problematic alcohol use.

Oral Fentanyl Consumption and Withdrawal Impairs Fear Extinction Learning and Enhances Basolateral Amygdala Principal Neuron Excitatory-Inhibitory Balance in Male and Female Mice

The number of opioid overdose deaths has increased over the past several years, mainly driven by an increase in the availability of highly potent synthetic opioids, like fentanyl, in the un-regulated drug supply. Over the last few years, changes in the drug supply, and in particular the availability of counterfeit pills containing fentanyl, have made oral use of opioids a more common route of administration. Here, we used a drinking in the dark (DiD) paradigm to model oral fentanyl self-administration using increasing fentanyl concentrations in male and female mice over 5 weeks. Fentanyl consumption peaked in both female and male mice at the 30 µg/mL dose, with female mice consuming significantly more fentanyl than male mice. Mice consumed sufficient fentanyl such that withdrawal was precipitated with naloxone, with males having more withdrawal symptoms, despite lower pharmacological exposure. We also performed behavioral assays to measure avoidance behavior and reward-seeking during fentanyl abstinence. Female mice displayed reduced avoidance behaviors in the open field assay, whereas male mice showed increased avoidance in the light/dark box assay. Female mice also exhibited increased reward-seeking in the sucrose preference test. Fentanyl-consuming mice of both sexes showed impaired cued fear extinction learning following fear conditioning and increased excitatory synaptic drive and increased excitability of BLA principal neurons. Our experiments demonstrate that long-term oral fentanyl consumption results in wide-ranging physiological and behavioral disruptions. This model could be useful to further study fentanyl withdrawal syndrome and behaviors and neuroplasticity associated with protracted fentanyl withdrawal.

Risk and protective factors for early dropout from telephone monitoring for individuals with drug convictions in community mental health centers in Japan

INTRODUCTION

Individuals involved with the criminal justice system face challenges in receiving and maintaining substance use disorder (SUD) treatment and support. Although telephone monitoring (TM) could reduce these barriers, data on TM for community-dwelling individuals involved with the criminal justice system and research on individuals who drop out of TM are scarce. We examined the factors associated with dropping out early from the Voice Bridges Project, which provides TM for individuals on probation for drug-related convictions through community mental health centers in Japan.

METHODS

Participants (n = 546) were individuals aged ≥20 years with methamphetamine-related convictions who were on probation. Univariate analyses examine the associations between one-year follow-up status and baseline variables, and multivariate Cox proportional hazards regression analyses identify the risk and protective factors associated with dropping out. Stratified analyses report results based on sex and halfway-house residency.

RESULTS

The one-year dropout rate was 43.6 % (n = 238). Multivariate analysis identified two risk factors for dropping out-halfway-house residency and suicide attempts in the past year, and two protective factors-higher education and the current use of SUD services. Sex-stratified analyses showed that halfway-house residency was a risk factor for both men and women. Attempted suicide was a risk factor for women. Conversely, higher education and current use of SUD services were protective factors for men.

CONCLUSIONS

Our results identify unique risk factors for women, such as a recent history of suicide attempts, and distinctive protective factors for men, including higher education and current use of SUD services, emphasizing the importance of sex-specific approaches. Furthermore, the study reveals that irrespective of sex, vulnerable individuals, such as halfway-house residents, are at a higher risk of dropping out from TM.

Examining associations between disordered eating and harmful substance use in a nationally representative sample of US veterans

OBJECTIVE

The association between eating disorders (EDs) and harmful substance use (substance use that causes psychosocial impairment) is well recognized in the literature, and military veterans may be at heightened risk for both issues due to deployment-related stressors. However, little is known about which ED-related symptoms are associated with harmful substance use in veterans, and whether gender plays a differential role in this relationship. Our aims were to: (1) examine gender differences in ED-related symptoms; and (2) examine whether ED-related symptoms differentially predict harmful substance use in US veteran men and women who had recently separated from service.

METHOD

This study was based on a nationally representative four-wave longitudinal sample of post-9/11 veterans (N = 835; 61.2% female). Longitudinal mixed modeling was used to test whether specific ED-related behaviors at baseline predicted harmful substance use at follow-ups.

RESULTS

We replicated gendered patterns of ED-related symptoms observed in civilian populations, wherein men had higher weight-and-body-related concerns (including excessive exercise and muscle building) and negative attitude toward obesity, and women had higher bulimic and restricting symptoms. For women, alcohol, drug, and marijuana problems were predicted by higher bulimic symptoms, whereas for men, these problems were predicted by higher restricting symptoms.

CONCLUSION

Gender played a differential role in the relationship between EDs and harmful substance use. Bulimic symptoms were the most robust predictor for harmful substance use among veteran women, whereas restricting was the most robust predictor for harmful substance use among veteran men.

PUBLIC SIGNIFICANCE

The current study found that veteran women had higher bulimic symptoms (characterized by binge eating and purging) and restricting than veteran men. In women, bulimic symptoms predicted future harmful use of alcohol, marijuana, and other drugs. In contrast, veteran men had higher weight-and-body-related concerns (characterized by excessive exercise and muscle building) than veteran women. In men, restricting symptoms predicted future harmful use of alcohol, marijuana, and other drugs.

Burden of drug use disorders in the United States from 1990 to 2021 and its projection until 2035: results from the GBD study

BACKGROUND

Drug use disorders (DUDs) have emerged as one of the most significant public health crises, exerting a substantial influence on both community health and socio-economic progress. The United States (US) also suffers a heavy burden, it is necessary to figure out the situation from multiple perspectives and take effective measures to deal with it. Therefore, using the data from the Global Burden of Diseases, Injuries, and Risk Factors (GBD) 2021, we evaluated this topic.

METHODS

Annual data on DUDs-related burden were collected from the GBD study 2021. We calculated the indicator of estimated annual percentage change (EAPC) to evaluate the changing trend of burden. The Bayesian model for age-period-cohort was introduced to forecast the burden.

RESULTS

In 2021, the number and age-standardized rate of prevalence were particularly prominent, with 12,146.95 thousand and 3821.43 per 100,000, respectively. Higher burden was also observed in males, 15-45 years old populations, and opioid use disorders subtype. From 1990 to 2021, the DUDs-related burden increased in the US and all states, especially in West Virginia; and the national death-related burden with the highest increase (EAPC = 7.96). Other significant inverse associations were seen between EAPC, age-standardized rates, and socio-demographic index (SDI). Moreover, in the next 14 years, the projected DUDs burden remains exigent.

CONCLUSIONS

The burden of DUDs in the US is heavy and has been enlarging. This study proposes that greater attention should be paid to the strategies in males, the younger population, opioid use disorders, and low-SDI states implemented by decision-makers to achieve goals such as reducing burden.

Corticostriatal responses to social reward are linked to trait reward sensitivity and subclinical substance use in young adults

Aberrant levels of reward sensitivity have been linked to substance use disorder and are characterized by alterations in reward processing in the ventral striatum (VS). Less is known about how reward sensitivity and subclinical substance use relate to striatal function during social rewards (e.g. positive peer feedback). Testing this relation is critical for predicting risk for development of substance use disorder. In this pre-registered study, participants (N = 44) underwent fMRI while completing well-matched tasks that assess neural response to reward in social and monetary domains. Contrary to our hypotheses, aberrant reward sensitivity blunted the relationship between substance use and striatal activation during receipt of rewards, regardless of domain. Moreover, exploratory whole-brain analyses showed unique relations between substance use and social rewards in temporoparietal junction. Psychophysiological interactions demonstrated that aberrant reward sensitivity is associated with increased connectivity between the VS and ventromedial prefrontal cortex during social rewards. Finally, we found that substance use was associated with decreased connectivity between the VS and dorsomedial prefrontal cortex for social rewards, independent of reward sensitivity. These findings demonstrate nuanced relations between reward sensitivity and substance use, even among those without substance use disorder, and suggest altered reward-related engagement of cortico-VS responses as potential predictors of developing disordered behavior.

Sexual minority disparities in psychosocial functioning following substance use recovery among a representative sample of US adults

Purpose

Sexual minority (SM; e.g., gay, lesbian, bisexual) individuals are disproportionately impacted by alcohol and other drug (AOD) use disorders and psychosocial factors that can exacerbate AOD use disorders and hinder recovery. This study examines SM sub-group differences (monosexual [gay/lesbian] versus bisexual) regarding adaptation to recovery measured by indices of psychosocial functioning. Identifying differential needs of gay/lesbian versus bisexual individuals could improve services to better meet the needs of SM individuals in recovery.

Methods

Using data from the National Recovery Study, a nationally representative cross-sectional sample of US adults who reported resolving an AOD problem (N = 2,002), we compared heterosexual to monosexual and bisexual SM individuals on socio-demographic characteristics, AOD use and treatment, and psychosocial variables.

Results

Bisexual individuals were significantly younger than heterosexual individuals (p = .002 and p ≤ 0.001 among men and women, respectively) and reported significantly fewer years since AOD problem resolution compared to heterosexual individuals (p = .004 and p = .003 among men and women, respectively). Most notably, bisexual individuals, but not gay/lesbian individuals, reported significantly lower quality of life (QOL), happiness, self-esteem, and significantly higher distress compared to heterosexual individuals.

Conclusion

Bisexual, but not monosexual, SM individuals in recovery from an AOD use disorder, were younger and reported worse psychosocial functioning than heterosexual individuals. Findings highlight significant differences between monosexual versus bisexual identified individuals with a notable disadvantage experienced by bisexual individuals. More needs to be learned about the challenges faced by bisexual individuals in recovery to better address their needs and support long-term AOD recovery.

Inbred rat heredity and sex affect oral oxycodone self-administration and augmented intake in long sessions: correlations with anxiety and novelty-seeking

Oxycodone abuse begins with prescription oral oxycodone, yet vulnerability factors determining abuse are largely undefined. We evaluated genetic vulnerability in a rat model of oral oxycodone self-administration (SA): increasing oxycodone concentration/session (0.025-0.1mg/ml; 1,4,16-h) followed by extinction and reinstatement. Active licks and oxycodone intake were greater in females than males during 4-h and 16-h sessions (p< 0.001). Each sex increased intake during 16-h vs 4-h sessions (p<2e-16), but a subset of strains dramatically augmented intake at 16-h (p=0.0005). Heritability (h 2) of active licks/4-h at increasing oxycodone dose ranged from 0.30-0.53. Under a progressive ratio schedule, breakpoints were strain-dependent (p<2e-16). Cued reinstatement was greater in females (p<0.001). Naive rats were assessed by elevated plus maze (EPM), open field (OF) and novel object interaction (NOI). We correlated these behaviors with 28 parameters of oxycodone SA. Anxiety-defining EPM traits were most associated with SA in both sexes, whereas more OF and NOI traits were SA-associated in males. Sex and heredity are major determinants of motivation to take and seek oxycodone; intake augments dramatically during extended access in specific strains; and pleiotropic genes affect anxiety and multiple SA parameters.

The role of brain serotonin signaling in excessive alcohol consumption and withdrawal: A call for more research in females

Alcohol Use Disorder (AUD) is a leading cause of death and disability worldwide, but current treatments are insufficient in fully addressing the symptoms that often lead to relapses in alcohol consumption. The brain's serotonin system has been implicated in AUD for decades and is a major regulator of stress-related behaviors associated with increased alcohol consumption. This review will discuss the current literature on the association between neurobiological adaptations in serotonin systems and AUD in humans as well as the effectiveness of serotonin receptor manipulations on alcohol-related behaviors like consumption and withdrawal. We will further discuss how these findings in humans relate to findings in animal models, including a comparison of systemic pharmacological manipulations modulating alcohol consumption. We next provide a detailed overview of brain region-specific roles for serotonin and serotonin receptor signaling in alcohol-related behaviors in preclinical animal models, highlighting the complexity of forming a cohesive model of serotonin function in AUD and providing possible avenues for more effective therapeutic intervention. Throughout the review, we discuss what is known about sex differences in the sequelae of AUD and the role of serotonin in these sequelae. We stress a critical need for additional studies in women and female animals so that we may build a clearer path to elucidating sex-specific serotonergic mechanisms and develop better treatments.

Exploring perceptions of self-stigma of substance use and current alcohol and marijuana use patterns among college students

BACKGROUND

While research has examined the effect of stigma from others towards individuals with substance use disorders, few studies have examined the relationship between perceived self-stigma and engagement in substance use more broadly, especially among non-clinical samples.

AIMS

The present study examined the relationships between perceptions of self-stigma if one were to develop a substance use disorder, consisting of negative self-esteem and negative self-efficacy, and alcohol or marijuana use behaviors and outcomes.

METHOD

Participants (n = 2,243; 71.5% female) were college students within the U.S. recruited to participate in an online survey on substance use with a special focus on alcohol and marijuana.

RESULTS

Results indicated no significant differences in stigma scores across individuals with different lifetime alcohol and marijuana use. Stigma ratings did differ between individuals with different profiles of last 30-day alcohol and marijuana use where, generally, individuals with lifetime use but no use in the last 30-day reported higher levels of self-stigma. Correlation analyses indicated that perceived impact of substance use disorder on sense of self-efficacy and self-esteem related negatively to nearly all observed factors of alcohol and marijuana use.

CONCLUSIONS

Though self-stigma, and stigma more broadly, has been shown to have negative implications for people with substance use disorders, the present study suggests that for non-clinical populations there may be some protective association between perceived self-stigma and alcohol or marijuana use engagement. This is not to say that self-stigma is a positive clinical intervention. Rather, we interpret these findings to indicate that negative perceptions of substance use disorder on the sense of self may be associated with distinct alcohol and marijuana use behaviors among young adults.

Avoidance biases for vaping stimuli among college students with electronic-cigarette use

Previous research has suggested that individuals who smoke demonstrate a behavioral tendency to approach rather than avoid smoking-related stimuli (i.e., approach bias). This study assessed whether 149 undergraduates with varying levels of e-cigarette use demonstrated an approach bias for vaping-related stimuli on an Approach-Avoidance Task (AAT). In contrast to our hypotheses, participants with e-cigarette use demonstrated a significant avoidance bias to vaping-related stimuli, and this effect appeared to be primarily driven by female e-cigarette users. Further, we found that more severe e-cigarette use was associated with numerous adverse outcomes, including reduced quality of life and increased vaping cravings, depressive symptoms, perceived stress, and cannabis use severity. Overall, our findings elucidate various negative impacts of e-cigarette use and suggest a potential role for sex differences in approach-avoidance tendencies toward vaping-related stimuli among young adults.

Destination Matters More: Relapse following Hospital-Based Treatment of Substance Use Disorders With and Without Co-Occurring Disorders

OBJECTIVES

Addressing substance use in psychiatric care encounters significant barriers, but the emergence of specialized services offers an opportunity to advance and scale up the integration of addiction services within psychiatric settings. However, research gaps still exist in this field, particularly in understanding the substance relapse rates of people with co-occurring disorders after a psychiatric hospitalization. This study aimed to investigate and compare the relapse rates of patients under inpatient care with exclusively addiction-related issues and those with co-occurring disorders after a hospitalization in a psychiatric ward and gain insights into differences in outcomes for these two patient groups.

METHODS

This retrospective analysis examined electronic medical records of patients admitted to the Acute Psychiatry Ward of the Hospital Clinic of Barcelona with a substance use disorder diagnosis between January 2019 and February 2021. Cox regression was used to identify variables independently associated with the first relapse episode.

RESULTS

From a total of 318 admissions (79.2% with psychiatric comorbidity), 76.1% relapsed during the study follow-up, with a median survival time of 54 days. Younger age, female gender, voluntary admission, and outpatient follow-up were independently associated with relapse. The presence of a co-occurring disorder was not associated with relapse.

CONCLUSION

This study highlights the need for interventions aimed at improving post-discharge abstinence rates for addiction-related hospitalizations. It also challenges the notion that co-occurring disorders automatically imply a worsened prognosis and emphasizes the importance of addressing addiction and psychiatric comorbidity in a comprehensive, integrated, and specialized manner.

Sex differences and driving impairment related to psychoactive substances

OBJECTIVE

The first aim of the study was to identify sex differences in the use of psychoactive substances among subjects with a previous driving under the influence (DUI) episode. The secondary objective was to propose specific strategies for medico-legal improvements.

METHODS

This was a retrospective observational study that took place between June 1, 2019, and August 31, 2023. It was conducted on DUI subjects examined for reinstatement of their driver's license using an integrated medico-legal and toxicological approach. Ethyl glucuronide (EtG) and illicit psychoactive substances were determined from hair samples. We performed descriptive statistical analyses for the entire sample as well as separately by sex. Additionally, we conducted binary logistic regression analyses separately for males and females to identify protective/risk factors associated with previous road accidents and judgments of unfitness to drive due to excessive alcohol consumption (EtG ≥ 30 pg/mg).

RESULTS

The study included 2,221 subjects, comprising 1,970 men and 251 women. Men exhibited a higher prevalence of tobacco, alcohol, and illicit psychoactive substance use. Women were more frequently co-users of alcohol and psychoactive substances and involved in road accidents at the time of DUI. Among the men, being married or having a partner was found to be a protective factor concerning past traffic accidents. For both sexes, a DUI episode with a blood alcohol concentration (BAC) exceeding 1.5 g/L or the co-ingestion of alcohol and drugs was identified as a risk factor for road accident involvement. For men, smoking more than 20 cigarettes per day and, for women, having a DUI episode with a BAC over 1.5 g/L were the main factors indicating unfitness to drive, as determined through high hair EtG levels (> 30 pg/mg). Women with a previous history of road accidents were less likely to have EtG levels of 30 pg/mg or more.

CONCLUSIONS

The study confirmed sex differences in subjects with a previous DUI episode. A BAC exceeding 1.5 g/L or the simultaneous use of alcohol and drugs at the time of DUI necessitate careful assessment of both men and women seeking driver's license reinstatement. In women, a BAC exceeding 1.5 g/L is considered a risk factor for a subsequent judgment of unfitness to drive. The medico-legal assessment should also involve a thorough investigation of smoking habits in men, as these habits could be related to an increased risk of excessive alcohol consumption.

Corticostriatal Responses to Social Reward are Linked to Trait Reward Sensitivity and Subclinical Substance Use in Young Adults

Aberrant levels of reward sensitivity have been linked to substance use disorder and are characterized by alterations in reward processing in the ventral striatum (VS). Less is known about how reward sensitivity and subclinical substance use relate to striatal function during social rewards (e.g., positive peer feedback). Testing this relation is critical for predicting risk for development of substance use disorder. In this pre-registered study, participants (N=44) underwent fMRI while completing well-matched tasks that assess neural response to reward in social and monetary domains. Contrary to our hypotheses, aberrant reward sensitivity blunted the relationship between substance use and striatal activation during receipt of rewards, regardless of domain. Moreover, exploratory whole-brain analyses showed unique relations between substance use and social rewards in temporoparietal junction. Psychophysiological interactions demonstrated that aberrant reward sensitivity is associated with increased connectivity between the VS and ventromedial prefrontal cortex during social rewards. Finally, we found that substance use was associated with decreased connectivity between the VS and dorsomedial prefrontal cortex for social rewards, independent of reward sensitivity. These findings demonstrate nuanced relations between reward sensitivity and substance use, even among those without substance use disorder, and suggest altered reward-related engagement of cortico-VS responses as potential predictors of developing disordered behavior.

Global epidemiology of cannabis use disorders and its trend from 1990 to 2019: Benchmarking analysis of the global burden of disease study

Introduction

Cannabis is one of the most widely used psychoactive substances globally, with an increasing trend in its legalization for both medical and recreational purposes in various countries. While cannabis offers potential therapeutic benefits, its regular use can lead to the development of Cannabis Use Disorders (CUDs). Understanding the epidemiology of CUDs is crucial in assessing the public health burden associated with cannabis use.

Methods

Epidemiological parameters of CUDs were assessed using the Global Burden of Disease (GBD) methodology across different age-groups, years, sexes, and locations worldwide from 1990-2019.

Results

Globally, for both sexes combined, prevalent cases of CUDs increased steadily from 17.1 million(95%UI=12.7-22.8million) in 1990 to 23.8-million(95%UI=17.8-30.9 million) in 2019. All age-adjusted highest number of incidence observed in High-Income-North-America(HINA)(121/100,000), followed by Australasia(100/100,000), Oceania(83.97/100,000), Tropical Latin America(69.59/100,000). Globally, age-standardized disability-adjusted life years rate(ASDR) observed higher in HINA, followed by Australasia, and Western-Europe. In male, all-age incidence counts increased from 1.7 million(95%UI=1.3-2.4million) in 1990 to 2.4 million(95%UI=1.8-3.2 million) in 2019. The highest annual percentage of change in age-standardized incidence rate(ASIR) was found in East-Asia (22%) followed by Middle-East and North-Africa(MENA)(15%). The age group of 15-24 years exhibited the highest burden of CUDs.

Conclusion

The widespread occurrence of CUDs on a global scale poses a substantial challenge to public health. Understanding the impact of CUDs and implementing evidence-based interventions is crucial in mitigating the associated individual, societal, and economic burdens. Continued research, collaboration, and knowledge dissemination are essential to inform policies, prevention efforts, and treatment strategies aimed at addressing CUDs on a global-scale.

Insomnia as a Risk Factor for Substance Use Disorders in Women

Gender differences exist for both insomnia and substance use disorders. Women show a higher prevalence of insomnia and increased susceptibility to the effects of drugs than men. Importantly, a growing body of evidence suggests that insufficient sleep predicts and puts individuals at a higher risk for substance use and associated psychosocial problems. However, the role of insomnia in substance use disorders among women remains poorly understood. The present article discusses gender differences in insomnia and in substance use disorders and reviews evidence suggesting that an increased prevalence of insomnia may be a risk factor for substance use disorders in women.

Integrated Supports for Women and Girls Experiencing Substance Use and Complex Needs

There is strong research to support integrated and gender-sensitive harm reduction approaches for supporting women, girls, and gender diverse people. For individuals who are pregnant, flexible and integrated treatment approaches may be especially important. In this study, we report on an integrated program in rural Canada designed to support pregnant women, girls, and gender diverse people experiencing substance use and other complex needs. Program data (N = 393) from the 2nd Floor Women's Recovery Centre (2nd Floor) at the Lakeland Centre for Fetal Alcohol Spectrum Disorder (LCFASD) was analyzed with several aims. Study goals were to (1) describe characteristics and needs of clients, (2) identify factors associated with program completion, and (3) for a subset of clients, examine resources, wellbeing, and social and behavioral outcomes after treatment. Clients (Mage = 27.4 years, range 15-64) presented at the 2nd Floor with complex medical and mental health needs, and experiences of significant socioenvironmental adversity. However, almost two-thirds (63.4%) successfully completed the program, which was more likely for clients who had stable housing at intake and a possible or confirmed diagnosis of FASD. After treatment, clients reported high levels of wellbeing, and most were connected to health care and community resources. In the year after program completion, clients who were contacted for follow-up maintained strong connection to resources and reported notable improvements in social and behavioral functioning. Many were working or volunteering, most were in stable home environments, rates of substance use and legal involvement were substantially reduced, and many clients were actively caring for their children. This study offers important findings to inform future research, practice, and policy for supporting health and wellbeing for women, children, families, and communities.

Sex-Specific and Traumatic Brain Injury Effects on Dopamine Receptor Expression in the Hippocampus

Traumatic brain injury (TBI) is a major health concern. Each year, over 50 million individuals worldwide suffer from TBI, and this leads to a number of acute and chronic health issues. These include affective and cognitive impairment, as well as an increased risk of alcohol and drug use. The dopaminergic system, a key component of reward circuitry, has been linked to alcohol and other substance use disorders, and previous research indicates that TBI can induce plasticity within this system. Understanding how TBI modifies the dopaminergic system may offer insights into the heightened substance use and reward-seeking behavior following TBI. The hippocampus, a critical component of the reward circuit, is responsible for encoding and integrating the spatial and salient aspects of rewarding stimuli. This study explored TBI-related changes in neuronal D2 receptor expression within the hippocampus, examining the hypothesis that sex differences exist in both baseline hippocampal D2 receptor expression and its response to TBI. Utilizing D2-expressing tdTomato transgenic male and female mice, we implemented either a sham injury or the lateral fluid percussion injury (FPI) model of TBI and subsequently performed a region-specific quantification of D2 expression in the hippocampus. The results show that male mice exhibit higher baseline hippocampal D2 expression compared to female mice. Additionally, there was a significant interaction effect between sex and injury on the expression of D2 in the hippocampus, particularly in regions of the dentate gyrus. Furthermore, TBI led to significant reductions in hippocampal D2 expression in male mice, while female mice remained mostly unaffected. These results suggest that hippocampal D2 expression varies between male and female mice, with the female dopaminergic system demonstrating less susceptibility to TBI-induced plasticity.

Epigenetic inheritance of phenotypes associated with parental exposure to cocaine

Parental exposure to drugs of abuse induces changes in the germline that can be transmitted across subsequent generations, resulting in enduring effects on gene expression and behavior. This transgenerational inheritance involves a dynamic interplay of environmental, genetic, and epigenetic factors that impact an individual's vulnerability to neuropsychiatric disorders. This chapter aims to summarize recent research into the mechanisms underlying the inheritance of gene expression and phenotypic patterns associated with exposure to drugs of abuse, with an emphasis on cocaine. We will first define the epigenetic modifications such as DNA methylation, histone post-translational modifications, and expression of non-coding RNAs that are impacted by parental cocaine use. We will then explore how parental cocaine use induces heritable epigenetic changes that are linked to alterations in neural circuitry and synaptic plasticity within reward-related circuits, ultimately giving rise to potential behavioral vulnerabilities. This discussion will consider phenotypic differences associated with gestational as well as both maternal and paternal preconception drug exposure and will emphasize differences based on offspring sex. In this context, we explore the complex interactions between genetics, epigenetics, environment, and biological sex. Overall, this chapter consolidates the latest developments in the multigenerational effects and long-term consequences of parental substance abuse.

Work accident effect on the use of psychotropic drugs: the case of benzodiazepines

BACKGROUND

A work accident constitutes a shock to health, likely to alter mental states and affect the use of psychotropic drugs. We focus on the use of benzodiazepines, which are a class of drugs commonly used to treat anxiety and insomnia. Prolonged use can lead to dependence. Our objective is to determine the extent to which work accidents lead to benzodiazepine use and overuse (i.e. exceedance of medical guidelines).

METHOD

We use a two-step selection model (the Heckman method) based on data from the French National Health Data System (Système National des Données de Santé, SNDS). Our study sample includes all general plan members who experienced a single work accident in 2016 (and not since 2007). This sample includes 350,000 individuals in the work accident group and more than 1.1 million people randomly drawn from the population without work accidents from 2007 to 2017 (the non-work accident group).

RESULTS

The occurrence of a work accident leads to an increase in benzodiazepine use and overuse the following year. The selection model shows a clear influence of the accident on the use probability (+ 39%), but a very slight impact on the risk of overuse among users (+ 1.7%), once considered the selection effect. The effect on overuse risk is higher for more severe accidents and among women.

CONCLUSION

The increase in the risk of benzodiazepine overuse is due to an increase in the likelihood of using benzodiazepines after a work accident that leads to overuse, rather than an increase in likelihood of overuse among people who use benzodiazepines. Results call for targeting the first-time prescription to limit the risk of overuse after a work accident.

Aversion-associated drug and alcohol seeking in females

Compulsive drug intake is characterized by the continuation of use regardless of negative consequences. This is modeled preclinically using procedures where a negative stimulus is delivered contingently with consumption of the reinforcer. In humans, women and men exhibit different drug taking behavior as it pertains to overall use, withdrawal symptoms, and rate of dependence. In substance use research, females have often been excluded from many studies due to concerns that circulating sex hormones may affect drug seeking behavior. However, the more recent inclusion of females in preclinical studies has identified interesting sex differences in aversion-resistant intake of drugs and alcohol. This review will serve to summarize key findings in aversion-related intake of alcohol, psychostimulants, and opioids in females by examining studies that have included female subjects. Further discussion will examine the effect of intake model, neuroanatomical pathways, and sex hormones in the expression of aversion-resistant drug and alcohol consumption.

Poor inhibitory control predicts sex-specific vulnerability to nicotine rewarding properties in mice

RATIONALE

The risk of becoming addicted to tobacco varies greatly from individual to individual, raising the possibility of behavioural biomarkers capable of predicting sensitivity to nicotine reward, a crucial step in the development of nicotine addiction. Amongst all of nicotine's pharmacological properties, one of central importance is the enhancement of cognitive performances, which depend on the balance between attentional processes and inhibitory control. However, whether the cognitive enhancement effects of nicotine are predictive of sensitivity to its rewarding properties is still unknown.

OBJECTIVE

Using male and female mice, we investigated whether the effects of nicotine on cognitive performances are predictive of sensitivity to the rewarding properties of nicotine and, if so, whether this relationship is sex dependent.

METHODS

Naïve male and female mice were first assessed for their performances in both baseline conditions and following nicotine injection (0.15 and 0.30 mg/kg) in a cued-Fixed Consecutive Number task (FCNcue) measuring both optimal (attention) and premature (inhibitory control) responding. Next, all mice underwent nicotine-induced conditioned place preference (CPP) in order to evaluate inter-individual differences in response to nicotine reward (0.30 mg/kg).

RESULTS

Results showed that males and females benefited from the effect of nicotine as a cognitive enhancer in the FCNcue task. However, only those males displaying poor inhibitory control, namely high-impulsive animals, subsequently displayed sensitivity to nicotine reward. In females, sensitivity to nicotine reward was independent of FCNcue performances, in both basal and nicotine conditions.

CONCLUSION

Thus, our study suggests that poor inhibitory control and its modulation by nicotine may be a behavioural biomarker for sensitivity to nicotine reward and consequent vulnerability to nicotine addiction in males but not females.

Using lickometry to infer differential contributions of salience network regions during compulsion-like alcohol drinking

Alcohol use disorder extracts substantial personal, social and clinical costs, and continued intake despite negative consequences (compulsion-like consumption) can contribute strongly. Here we discuss lickometry, a simple method where lick times are determined across a session, while analysis across many aspects of licking can offer important insights into underlying psychological and action strategies, including their brain mechanisms. We first describe studies implicating anterior insula (AIC) and dorsal medial prefrontal cortex (dMPF) in compulsion-like responding for alcohol, then review work suggesting that AIC/ventral frontal cortex versus dMPF regulate different aspects of behavior (oral control and overall response strategy, versus moment-to-moment action organization). We then detail our lickometer work comparing alcohol-only drinking (AOD) and compulsion-like drinking under moderate- or higher-challenge (ModChD or HiChD, using quinine-alcohol). Many studies have suggested utilization of one of two main strategies, with higher motivation indicated by more bouts, and greater palatability suggested by longer, faster bouts. Instead, ModChD shows decreased variability in many lick measures, which is unexpected but consistent with the suggested importance of automaticity for addiction. Also surprising is that HiChD retains several behavior changes seen with ModChD, reduced tongue variability and earlier bout start, even though intake is otherwise disrupted. Since AIC-related measures are retained under both moderate- and higher-challenge, we propose a novel hypothesis that AIC sustains overall commitment regardless of challenge level, while disordered licking during HiChD mirrors the effects of dMPF inhibition. Thus, while AIC provides overall drive despite challenge, the ability to act is ultimately determined within the dMPF.

An FSCV Study on the Effects of Targeted Typical and Atypical DAT Inhibition on Dopamine Dynamics in the Nucleus Accumbens Shell of Male and Female Mice

Understanding the neurochemistry underlying sex differences in psychostimulant use disorders (PSUD) is essential for developing related therapeutics. Many psychostimulants, like cocaine, inhibit the dopamine transporter (DAT), which is largely thought to account for actions related to their misuse and dependence. Cocaine-like, typical DAT inhibitors preferentially bind DAT in an outward-facing conformation, while atypical DAT inhibitors, like modafinil, prefer a more inward-facing DAT conformation. Modafinil and R-modafinil have emerged as potential therapeutic options for selected populations of individuals affected by PSUD. In addition, analogs of modafinil (JJC8-088 and JJC8-091) with different pharmacological profiles have been explored as potential PSUD medications in preclinical models. In this work, we employ fast scan cyclic voltammetry (FSCV) to probe nucleus accumbens shell (NAS) dopamine (DA) dynamics in C57BL/6 male and female mice. We find that cocaine slowed DA clearance in both male and female mice but produced more robust increases in evoked NAS DA in female mice. R-Modafinil produced mild increases in evoked NAS DA and slowed DA clearance across the sexes. The modafinil analog JJC8-088, a typical DAT inhibitor, produced increases in evoked NAS DA in female and male mice. Finally, JJC8-091, an atypical DAT inhibitor, produced limited increases in evoked NAS DA and slowed DA clearance in both sexes. In this work we begin to tease out how sex differences may alter the effects of DAT targeting and highlight how this may help focus research toward effective treatment options for PSUD.

Role of social context in addiction etiology and recovery

While social context has long been considered central to substance use disorder prevention and treatment and many drug-taking events occur in social settings, experimental research on social context has historically been limited. Recent years have seen an emergence of concerted preclinical and human laboratory research documenting the direct impact of social context on substance use, delineating behavioral and neurobiological mechanisms underlying social influence's role. We review this emerging preclinical and human laboratory literature from a theoretical lens that considers distinct stages of the addiction process including drug initiation/acquisition, escalation, and recovery. A key conclusion of existing research is that the impact of the social environment is critically moderated by the drug-taking behavior and drug use history of a social peer. Specifically, while drug-free social contexts can reduce the likelihood of drug use initiation and act as a competitive non-drug alternative preventing escalation, drug-using peers can equally facilitate initiation and escalation through peer modeling as a contingent reward of use. Likewise, social context may facilitate recovery or serve as a barrier that increases the chances of a return to regular use. We conclude by discussing evidence-based treatments and recovery support services that explicitly target social mechanisms or that have identified social context as a mechanism of change within treatment. Ultimately, new areas for research including the expansion of drug classes studied and novel human laboratory designs are needed to further translate emerging findings into clinical practice.

Are There Prevalent Sex Differences in Psychostimulant Use Disorder? A Focus on the Potential Therapeutic Efficacy of Atypical Dopamine Uptake Inhibitors

Psychostimulant use disorders (PSUD) affect a growing number of men and women and exert sizable public health and economic burdens on our global society. Notably, there are some sex differences in the onset of dependence, relapse rates, and treatment success with PSUD observed in preclinical and clinical studies. The subtle sex differences observed in the behavioral aspects of PSUD may be associated with differences in the neurochemistry of the dopaminergic system between sexes. Preclinically, psychostimulants have been shown to increase synaptic dopamine (DA) levels and may downregulate the dopamine transporter (DAT). This effect is greatest in females during the high estradiol phase of the estrous cycle. Interestingly, women have been shown to be more likely to begin drug use at younger ages and report higher levels of desire to use cocaine than males. Even though there is currently no FDA-approved medication, modafinil, a DAT inhibitor approved for use in the treatment of narcolepsy and sleep disorders, has shown promise in the treatment of PSUD among specific populations of affected individuals. In this review, we highlight the therapeutic potential of modafinil and other atypical DAT inhibitors focusing on the lack of sex differences in the actions of these agents.

The relationship between depressed affect, parental monitoring, and sex on cannabis use among American Indian youth

BACKGROUND AND OBJECTIVES

American Indian (AI) adolescents report higher rates of cannabis use than national US adolescents. Previous study examined interactive relationships between depressed affect and family factors on AI adolescent alcohol use. These factors have not been investigated for cannabis use. We examined whether parental monitoring dampened risk for cannabis use due to depressed affect, and potential moderation by sex.

METHODS

We measured cannabis use, depressed affect, parental monitoring, and sex among reservation area AI youth among students in grades 7-12 attending 45 schools. We used censor-inflated regression models to identify parental monitoring as a moderator of the relationship between depressed affect and cannabis use.

RESULTS

In the logistic portion of censor-inflated models, level of depressed affect and parental monitoring significantly related to last 30-day cannabis use. Higher levels of parental monitoring at lower levels of depressed affect related to lower likelihood of cannabis use. Female students had greater likelihood of endorsing cannabis use at higher levels of depressed affect. In the linear portion of the censor-inflated regression models, sex and level of parental monitoring significantly related to cannabis use frequency. Male students endorsed more frequent cannabis use while higher levels of parental monitoring related to lower frequency of use.

DISCUSSION AND CONCLUSIONS

Parental monitoring may dampen the effect of depressed affect on cannabis use among AI youth on reservations.

SCIENTIFIC SIGNIFICANCE

Future interventions should foster skill-building prevention efforts directed at coping with depression, along with parental training for effective monitoring. Special attention to AI female adolescents may be indicated.

Cocaine-induced sensitization and glutamate plasticity in the nucleus accumbens core: effects of sex

BACKGROUND

The development and persistence of addiction is mediated in part by drug-induced alterations in nucleus accumbens (NAc) function. AMPA-type glutamate receptors (AMPARs) provide the main source of excitatory drive to the NAc and enhancements in transmission of calcium-permeable AMPARs (CP-AMPARs) mediate increased cue-triggered drug-seeking following prolonged withdrawal. Cocaine treatment regimens that result in psychomotor sensitization enhance subsequent drug-seeking and drug-taking behaviors. Furthermore, cocaine-induced locomotor sensitization followed by 14 days of withdrawal results in an increase in glutamatergic synaptic transmission. However, very few studies have examined cocaine-induced alterations in synaptic transmission of females or potential effects of experimenter-administered cocaine on NAc CP-AMPAR-mediated transmission in either sex.

METHODS

Male and female rats were given repeated systemic cocaine injections to induce psychomotor sensitization (15 mg/kg, i.p. 1 injection/day, 8 days). Controls received repeated saline (1 mL/kg, i.p). After 14-16 days of withdrawal brain slices were prepared and whole-cell patch-clamp approaches in the NAc core were used to measure spontaneous excitatory post-synaptic currents (sEPSC), paired pulse ratio, and CP-AMPAR transmission. Additional female rats from this same cohort were also given a challenge injection of cocaine at withdrawal day 14 to assess the expression of sensitization.

RESULTS

Repeated cocaine produced psychomotor sensitization in both sexes. In males this was accompanied by an increase in sEPSC frequency, but not amplitude, and there was no effect on the paired pulse ratio. Males treated with cocaine and saline had similar sensitivity to Naspm. In contrast, in females there were no significant differences between cocaine and saline groups on any measure, despite females showing robust psychomotor sensitization both during the induction and expression phase.

CONCLUSIONS

Overall, these data reveal striking sex differences in cocaine-induced NAc glutamate plasticity that accompany the induction of psychomotor sensitization. This suggests that the neural adaptations that contribute to sensitization vary by sex.

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.

Increased heroin intake and relapse vulnerability in intermittent relative to continuous self-administration: Sex differences in rats

BACKGROUND AND PURPOSE

Studies using intermittent-access drug self-administration show increased motivation to take and seek cocaine and fentanyl, relative to continuous access. In this study, we examined the effects of intermittent- and continuous-access self-administration on heroin intake, patterns of self-administration and cue-induced heroin-seeking, after forced or voluntary abstinence, in male and female rats. We also modelled brain levels of heroin and its active metabolites.

EXPERIMENTAL APPROACH

Rats were trained to self-administer a palatable solution and then heroin (0.075 mg·kg^-1 per inf) either continuously (6 h·day^-1 ; 10 days) or intermittently (6 h·day^-1 ; 5-min access every 30-min; 10 days). Brain levels of heroin and its metabolites were modelled using a pharmacokinetic software. Next, heroin-seeking was assessed after 1 or 21 abstinence days. Between tests, rats underwent either forced or voluntary abstinence. The oestrous cycle was measured using a vaginal smear test.

KEY RESULTS

Intermittent access exacerbated heroin self-administration and was characterized by a burst-like intake, yielding higher brain peaks of heroin and 6-monoacetylmorphine concentrations. Moreover, intermittent access increased cue-induced heroin-seeking during early, but not late abstinence. Heroin-seeking was higher in females after intermittent, but not continuous access, and this effect was independent of the oestrous cycle.

CONCLUSIONS AND IMPLICATIONS

Intermittent heroin access in rats resembles critical features of heroin use disorder: a self-administration pattern characterized by repeated large doses of heroin and higher relapse vulnerability during early abstinence. This has significant implications for refining animal models of substance use disorder and for better understanding of the neuroadaptations responsible for this disorder.

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.