Sex disparities in substance abuse research: Evaluating 23 years of structural neuroimaging studies

Interneuron-Selective HCN Channel Knockdown in Prelimbic Cortex of Female Rats Mimics Effects of Chronic Ethanol Exposure

Our laboratory has previously shown that chronic ethanol exposure elicits enhanced working memory performance in female, but not male, adult Sprague-Dawley rats, indicative of a fundamental sex difference in cortical plasticity. Recent studies have furthermore revealed that females display markedly reduced HCN-mediated channel activity in inhibitory Martinotti interneurons after chronic ethanol exposure that is similarly not observed in males. From these observations we hypothesized that alcohol elicits facilitated working memory performance via down-regulation of these channels' activity specifically within interneurons. To test this hypothesis, we employed a Pol-II compatible shRNA expression system to elicit targeted knockdown of HCN channel activity in these cells, and measured performance on a delayed Non-Match-to-Sample (NMS) T-maze test to gauge effects on working memory performance. A significant baseline enhancement of working memory performance with HCN channel knockdown was observed, indicative of a critical role for interneuron-expressed HCNs in maintaining optimal cortical network activity during cognitively-demanding tasks. Consistent with previous observations, ethanol exposure resulted in enhanced NMS T-maze performance, however elevated working memory performance was observed in both scram- and hcn-shRNA infected groups after alcohol administration. We therefore conclude that interneuron-expressed HCN channels, despite representing a minor population of total cortical HCN expression, contribute substantially to maintaining working memory processes. Downregulated HCN channel activity, though, does not alone appear sufficient to manifest alcohol-induced enhancement of working memory performance observed in female rats during acute withdrawal.

Gender differences in illicit drug access, use and use disorder: Analysis of National Survey on Drug Use and Health data

Although gender differences in the prevalence of substance use disorders (SUD) have been well-characterized, little is known about when gender differences emerge along the continuum of substance use. Understanding the contribution of gender to risk at key transition points across this continuum is needed to identify potential mechanisms underlying gender differences and to inform improved gender-responsive interventions. To characterize gender differences in the progression of cannabis, cocaine, and heroin use, the current study used data from the United States-based 2015-2019 National Survey on Drug Use and Health to quantify gender differences in: (1) perceived access to drugs, (2) lifetime drug use among individuals with at least some access, and (3) past-year SUD among those who had ever used each drug. Logistic regressions were conducted for each drug to examine gender differences across all three stages, controlling for sociodemographic factors and survey year. Compared to women, men had higher odds of reporting access to and lifetime use of all three drug types. Men also had higher odds of past-year cannabis and cocaine use disorders compared to women. Results suggest gender differences emerge in the earliest stage of drug use (access) and may accumulate across the stages of use. The magnitude of gender differences varied across stages, with the largest differences observed for odds of drug initiation among those with perceived access to each drug. Longitudinal data will be needed to confirm these findings and to provide insight into potential contributors to gender-specific risk and intervention targets across the continuum of drug use severity.

Sex differences in alcohol's effects on fronto-amygdalar functional connectivity during processing of emotional stimuli

BACKGROUND

Amygdala function underlying emotion processing has been shown to vary with an individuals' biological sex. Expanding upon functional magnetic resonance imaging (fMRI) findings reported previously where a low level of response was the focus, we examined alcohol and sex effects on functional connectivity between the amygdala and other brain regions. The central hypothesis predicted that sex would influence alcohol's effects on frontal-limbic functional circuits underlying the processing of negative and positive facial emotions.

METHODS

Secondary analyses were conducted on data from a double-blind, placebo controlled, within-subjects, cross-over study in 54 sex-matched pairs (N = 108) of 18- to 25-year-old individuals without an alcohol use disorder at baseline. Participants performed an emotional faces fMRI processing task after placebo or approximately 0.7 mL/kg of ethanol. Psychophysiological interaction analyses examined functional connectivity between the amygdala with other brain regions.

RESULTS

There were significant alcohol-by-sex interactions when processing negatively valenced faces. Whereas intoxicated men exhibited decreased functional connectivity between the amygdala and ventral and dorsal anterior cingulate, angular gyrus, and middle frontal gyrus connectivity was increased in intoxicated women. There was also a main sex effect where women exhibited less functional connectivity in the middle insula than men regardless of whether they received alcohol or placebo. For happy faces, main effects of both sex and alcohol were observed. Women exhibited less amygdala functional connectivity in the right inferior frontal gyrus than men. Both men and women exhibited greater functional connectivity in the superior frontal gyrus in response to alcohol than placebo.

CONCLUSIONS

Alcohol's effects on amygdala functional circuits that underlying emotional processing vary by sex. Women had higher functional connectivity than men following exposure to a moderate dose of alcohol which could indicate that women are better than men at processing affectively laden stimuli when intoxicated.

Sex differences in neural responses to stress and drug cues predicts future drug use in individuals with substance use disorder

BACKGROUND

Substance use disorders (SUDs) are chronically recurring illnesses, where stress and drug cues significantly increase drug craving and risk of drug use recurrence. This study examined sex differences in functional magnetic resonance imaging (fMRI) brain responses to stress and drug cue exposure and assessed their prospective association with future drug use post-treatment.

METHODS

Inpatient, treatment engaged men (N = 46) and women (N = 26) with SUDs, including alcohol, cocaine and/or cannabis use disorders, participated in an fMRI scan that assessed subjective (anxiety, drug craving), heart rate and neural responses to brief individualized script-driven imagery of stress, drug, and neutral-relaxing trials. Prospective follow-up interviews post-treatment assessed future drug use recurrence over 90 days.

RESULTS

During fMRI, stress and drug versus neutral cue exposure led to increased anxiety, heart rate and craving responses (p's < 0.004) in both men and women, but greater drug cue-induced anxiety (p < .017) and higher drug use days during follow-up (p < .006) in women relative to men. In whole brain analyses of stress and drug cues (p < .05 FWE corrected), and in whole brain correlation (p < .05, FWE corrected) with drug use days, significant sex differences revealed drug cue-related striatal hyperactivation (caudate, putamen) in men, but drug cue-related cortico-limbic (insula and dorsolateral prefrontal cortex) hypoactivation and stress-related hypoactivation in the ventromedial prefrontal cortex (VmPFC) in women; and these were significantly associated with higher future drug use days.

CONCLUSIONS

Findings indicate sex-specific pathophysiology of SUD recurrence and support the need for differential treatment development for men and women with SUD to improve drug use outcomes.

Evaluating the evidence for sex differences: a scoping review of human neuroimaging in psychopharmacology research

Although sex differences in psychiatric disorders abound, few neuropsychopharmacology (NPP) studies consider sex as a biological variable (SABV). We conducted a scoping review of this literature in humans by systematically searching PubMed to identify peer-reviewed journal articles published before March 2020 that (1) studied FDA-approved medications used to treat psychiatric disorders (or related symptoms) and (2) adequately evaluated sex differences using in vivo neuroimaging methodologies. Of the 251 NPP studies that included both sexes and considered SABV in analyses, 80% used methodologies that eliminated the effect of sex (e.g., by including sex as a covariate to control for its effect). Only 20% (50 studies) adequately evaluated sex differences either by testing for an interaction involving sex or by stratifying analyses by sex. Of these 50 studies, 72% found statistically significant sex differences in at least one outcome. Sex differences in neural and behavioral outcomes were studied more often in drugs indicated for conditions with known sex differences. Likewise, the majority of studies conducted in those drug classes noted sex differences: antidepressants (13 of 16), antipsychotics (10 of 12), sedative-hypnotics (6 of 10), and stimulants (6 of 10). In contrast, only two studies of mood stabilizers evaluated SABV, with one noting a sex difference. By mapping this literature, we bring into sharp relief how few studies adequately evaluate sex differences in NPP studies. Currently, all NIH-funded studies are required to consider SABV. We urge scientific journals, peer reviewers, and regulatory agencies to require researchers to consider SABV in their research. Continuing to ignore SABV in NPP research has ramifications both in terms of rigor and reproducibility of research, potentially leading to costly consequences and unrealized benefits.

Common and gender-specific associations with cocaine use on gray matter volume: Data from the ENIGMA addiction working group

Gray matter volume (GMV) in frontal cortical and limbic regions is susceptible to cocaine-associated reductions in cocaine-dependent individuals (CD) and is negatively associated with duration of cocaine use. Gender differences in CD individuals have been reported clinically and in the context of neural responses to cue-induced craving and stress reactivity. The variability of GMV in select brain areas between men and women (e.g., limbic regions) underscores the importance of exploring interaction effects between gender and cocaine dependence on brain structure. Therefore, voxel-based morphometry data derived from the ENIGMA Addiction Consortium were used to investigate potential gender differences in GMV in CD individuals compared to matched controls (CTL). T1-weighted MRI scans and clinical data were pooled from seven sites yielding 420 gender- and age-matched participants: CD men (CDM, n = 140); CD women (CDW, n = 70); control men (CTLM, n = 140); and control women (CTLW, n = 70). Differences in GMV were assessed using a 2 × 2 ANCOVA, and voxelwise whole-brain linear regressions were conducted to explore relationships between GMV and duration of cocaine use. All analyses were corrected for age, total intracranial volume, and site. Diagnostic differences were predominantly found in frontal regions (CD < CTL). Interestingly, gender × diagnosis interactions in the left anterior insula and left lingual gyrus were also documented, driven by differences in women (CDW < CTLW). Further, lower right hippocampal GMV was associated with greater cocaine duration in CDM. Given the importance of the anterior insula to interoception and the hippocampus to learning contextual associations, results may point to gender-specific mechanisms in cocaine addiction.

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 Differences in Substance Use Disorders: A Neurobiological Perspective

Clinical studies provide fundamental knowledge of substance use behaviors (substance of abuse, patterns of use, relapse rates). The combination of neuroimaging approaches reveal correlation between substance use disorder (SUD) and changes in neural structure, function, and neurotransmission. Here, we review these advances, placing special emphasis on sex specific findings from structural neuroimaging studies of those dependent on alcohol, nicotine, cannabis, psychostimulants, or opioids. Recent clinical studies in SUD analyzing sex differences reveal neurobiological changes that are differentially impacted in common reward processing regions such as the striatum, hippocampus, amygdala, insula, and corpus collosum. We reflect on the contribution of sex hormones, period of drug use and abstinence, and the potential impact of these factors on the interpretation of the reported findings. With the overall recognition that SUD impacts the brains of females and males differentially, it is of fundamental importance that future research is designed with sex as a variable of study in this field. Improved understanding of neurobiological changes in males and females in SUD will advance knowledge underlying sex-specific susceptibility and the neurobiological impact in these disorders. Together these findings will inform future treatments that are tailor designed for improved efficacy in females and males with SUD.

Publication bias is the consequence of a lack of diversity, equity, and inclusion

Publication bias has been shown to exist in research across medical and surgical specialties. Bias can occur at any stage of the publication process and can be related to race, ethnicity, age, religion, sex, gender, or sexual orientation. Although some improvements have been made toward addressing this issue, bias still spans the publication process from authors and peer reviewers, to editorial board members and editors, with poor inclusion of women and underrepresented minorities throughout. The result of bias remaining unchecked is the publication of research that leaves out certain groups, is not applicable to all people, and can result in harm to some populations. We have highlighted the current landscape of publication bias and strived to demonstrate the importance of addressing it. We have also provided solutions for reducing bias at multiple stages throughout the publication process. Increasing diversity, equity, and inclusion throughout all aspects of the publication process, requiring diversity, equity, and inclusion statements in reports, and providing specific education and guidelines will ensure the identification and eradication of publication bias. By following these measures, we hope that publication bias will be eliminated, which will reduce further harm to certain populations and promote better, more effective research pertinent to all people.

Sex and dependence related neuroanatomical differences in regular cannabis users: findings from the ENIGMA Addiction Working Group

Males and females show different patterns of cannabis use and related psychosocial outcomes. However, the neuroanatomical substrates underlying such differences are poorly understood. The aim of this study was to map sex differences in the neurobiology (as indexed by brain volumes) of dependent and recreational cannabis use. We compared the volume of a priori regions of interest (i.e., amygdala, hippocampus, nucleus accumbens, insula, orbitofrontal cortex (OFC), anterior cingulate cortex and cerebellum) between 129 regular cannabis users (of whom 70 were recreational users and 59 cannabis dependent) and 114 controls recruited from the ENIGMA Addiction Working Group, accounting for intracranial volume, age, IQ, and alcohol and tobacco use. Dependent cannabis users, particularly females, had (marginally significant) smaller volumes of the lateral OFC and cerebellar white matter than recreational users and controls. In dependent (but not recreational) cannabis users, there was a significant association between female sex and smaller volumes of the cerebellar white matter and OFC. Volume of the OFC was also predicted by monthly standard drinks. No significant effects emerged the other brain regions of interest. Our findings warrant future multimodal studies that examine if sex and cannabis dependence are specific key drivers of neurobiological alterations in cannabis users. This, in turn, could help to identify neural pathways specifically involved in vulnerable cannabis users (e.g., females with cannabis dependence) and inform individually tailored neurobiological targets for treatment.

Gender-related neuroanatomical differences in alcohol dependence: findings from the ENIGMA Addiction Working Group

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We tested gender differences in brain volumes of alcohol dependent vs control groups.

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Group differences in brain volumes emerged as gross and widespread.

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Group-by-gender effects emerged in selected brain regions (cerebellum, amygdala)

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In dependent users, greater alcohol use predicted smaller amygdala and larger cerebellum GM volume.

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Our results highlight the need to account for gender differences in MRI studies of alcohol dependence.

Gender-related differences in the susceptibility, progression and clinical outcomes of alcohol dependence are well-known. However, the neurobiological substrates underlying such differences remain unclear. Therefore, this study aimed to investigate gender differences in the neuroanatomy (i.e. regional brain volumes) of alcohol dependence. We examined the volume of a priori regions of interest (i.e., orbitofrontal cortex, hippocampus, amygdala, nucleus accumbens, caudate, putamen, pallidum, thalamus, corpus callosum, cerebellum) and global brain measures (i.e., total grey matter (GM), total white matter (WM) and cerebrospinal fluid). Volumes were compared between 660 people with alcohol dependence (228 women) and 326 controls (99 women) recruited from the ENIGMA Addiction Working Group, accounting for intracranial volume, age and education years. Compared to controls, individuals with alcohol dependence on average had (3–9%) smaller volumes of the hippocampus (bilateral), putamen (left), pallidum (left), thalamus (right), corpus callosum, total GM and WM, and cerebellar GM (bilateral), the latter more prominently in women (right). Alcohol-dependent men showed smaller amygdala volume than control men, but this effect was unclear among women. In people with alcohol dependence, more monthly standard drinks predicted smaller amygdala and larger cerebellum GM volumes. The neuroanatomical differences associated with alcohol dependence emerged as gross and widespread, while those associated with a specific gender may be confined to selected brain regions. These findings warrant future neuroscience research to account for gender differences in alcohol dependence to further understand the neurobiological effects of alcohol dependence.

Sex differences in the neuroanatomy of alcohol dependence: hippocampus and amygdala subregions in a sample of 966 people from the ENIGMA Addiction Working Group

Males and females with alcohol dependence have distinct mental health and cognitive problems. Animal models of addiction postulate that the underlying neurobiological mechanisms are partially distinct, but there is little evidence of sex differences in humans with alcohol dependence as most neuroimaging studies have been conducted in males. We examined hippocampal and amygdala subregions in a large sample of 966 people from the ENIGMA Addiction Working Group. This comprised 643 people with alcohol dependence (225 females), and a comparison group of 323 people without alcohol dependence (98 females). Males with alcohol dependence had smaller volumes of the total amygdala and its basolateral nucleus than male controls, that exacerbated with alcohol dose. Alcohol dependence was also associated with smaller volumes of the hippocampus and its CA1 and subiculum subfield volumes in both males and females. In summary, hippocampal and amygdalar subregions may be sensitive to both shared and distinct mechanisms in alcohol-dependent males and females.

Sex and Age Effects on Neurobehavioral Toxicity Induced by Binge Alcohol

Historically, most alcohol neurotoxicity studies were conducted in young adult males and focused on chronic intake. There has been a shift towards studying the effects of alcohol on the adolescent brain, due to alcohol consumption during this formative period disrupting the brain's developmental trajectory. Because the most typical pattern of adolescent alcohol intake is heavy episodic (binge) drinking, there has also been a shift towards the study of binge alcohol-induced neurobehavioral toxicity. It has thus become apparent that binge alcohol damages the adolescent brain and there is increasing attention to sex-dependent effects. Significant knowledge gaps remain in our understanding of the effects of binge alcohol on the female brain, however. Moreover, it is unsettling that population-level studies indicate that the prevalence of binge drinking is increasing among American women, particularly those in older age groups. Although study of adolescents has made it apparent that binge alcohol disrupts ongoing brain maturational processes, we know almost nothing about how it impacts the aging brain, as studies of its effects on the aged brain are relatively scarce, and the study of sex-dependent effects is just beginning. Given the rapidly increasing population of older Americans, it is crucial that studies address age-dependent effects of binge alcohol, and given the increase in binge drinking in older women who are at higher risk for cognitive decline relative to men, studies must encompass both sexes. Because adolescence and older age are both characterized by age-typical brain changes, and because binge drinking is the most common pattern of alcohol intake in both age groups, the knowledge that we have amassed on binge alcohol effects on the adolescent brain can inform our study of its effects on the aging brain. In this review, we therefore cover the current state of knowledge of sex and age-dependent effects of binge alcohol, as well as statistical and methodological considerations for studies aimed at addressing them.

Deep learning identifies morphological determinants of sex differences in the pre-adolescent brain

The application of data-driven deep learning to identify sex differences in developing brain structures of pre-adolescents has heretofore not been accomplished. Here, the approach identifies sex differences by analyzing the minimally processed MRIs of the first 8144 participants (age 9 and 10 years) recruited by the Adolescent Brain Cognitive Development (ABCD) study. The identified pattern accounted for confounding factors (i.e., head size, age, puberty development, socioeconomic status) and comprised cerebellar (corpus medullare, lobules III, IV/V, and VI) and subcortical (pallidum, amygdala, hippocampus, parahippocampus, insula, putamen) structures. While these have been individually linked to expressing sex differences, a novel discovery was that their grouping accurately predicted the sex in individual pre-adolescents. Another novelty was relating differences specific to the cerebellum to pubertal development. Finally, we found that reducing the pattern to a single score not only accurately predicted sex but also correlated with cognitive behavior linked to working memory. The predictive power of this score and the constellation of identified brain structures provide evidence for sex differences in pre-adolescent neurodevelopment and may augment understanding of sex-specific vulnerability or resilience to psychiatric disorders and presage sex-linked learning disabilities.

Sex/gender differences in brain function and structure in alcohol use: A narrative review of neuroimaging findings over the last 10 years

Over the last 10 years, rates of alcohol use disorder (AUD) have increased in women by 84% relative to a 35% increase in men. Rates of alcohol use and high-risk drinking have also increased in women by 16% and 58% relative to a 7% and 16% increase in men, respectively, over the last decade. This robust increase in drinking among women highlights the critical need to identify the underlying neural mechanisms that may contribute to problematic alcohol consumption across sex/gender (SG), especially given that many neuroimaging studies are underpowered to detect main or interactive effects of SG on imaging outcomes. This narrative review aims to explore the recent neuroimaging literature on SG differences in brain function and structure as it pertains to alcohol across positron emission tomography, magnetic resonance imaging, and functional magnetic resonance imaging modalities in humans. Additional work using magnetic resonance spectroscopy, diffusion tensor imaging, and event-related potentials to examine SG differences in AUD will be covered. Overall, current research on the neuroimaging of AUD, alcohol consumption, or risk of AUD is limited, and findings are mixed regarding the effect of SG on neurochemical, structural, and functional mechanisms associated with AUD. We address SG disparities in the neuroimaging of AUD and propose a call to action to include women in brain imaging research. Future studies are crucial to our understanding of the neurobiological underpinnings of AUD across neural systems and the vulnerability for AUD among women and men.

Sex differences in stress-related alcohol use

Rates of alcohol use disorder (AUD) have increased in women by 84% over the past ten years relative to a 35% increase in men. This substantive increase in female drinking is alarming given that women experience greater alcohol-related health consequences compared to men. Stress is strongly associated with all phases of alcohol addiction, including drinking initiation, maintenance, and relapse for both women and men, but plays an especially critical role for women. The purpose of the present narrative review is to highlight what is known about sex differences in the relationship between stress and drinking. The critical role stress reactivity and negative affect play in initiating and maintaining alcohol use in women is addressed, and the available evidence for sex differences in drinking for negative reinforcement as it relates to brain stress systems is presented. This review discusses the critical structures and neurotransmitters that may underlie sex differences in stress-related alcohol use (e.g., prefrontal cortex, amygdala, norepinephrine, corticotropin releasing factor, and dynorphin), the involvement of sex and stress in alcohol-induced neurodegeneration, and the role of ovarian hormones in stress-related drinking. Finally, the potential avenues for the development of sex-appropriate pharmacological and behavioral treatments for AUD are identified. Overall, women are generally more likely to drink to regulate negative affect and stress reactivity. Sex differences in the onset and maintenance of alcohol use begin to develop during adolescence, coinciding with exposure to early life stress. These factors continue to affect alcohol use into adulthood, when reduced responsivity to stress, increased affect-related psychiatric comorbidities and alcohol-induced neurodegeneration contribute to chronic and problematic alcohol use, particularly for women. However, current research is limited regarding the examination of sex in the initiation and maintenance of alcohol use. Probing brain stress systems and associated brain regions is an important future direction for developing sex-appropriate treatments to address the role of stress in AUD.

PET imaging reveals lower kappa opioid receptor availability in alcoholics but no effect of age

Opioid receptors are implicated in alcoholism, other addictions, withdrawal, and depression, and are considered potential pharmacological targets for treatment. Our goal in the present study was to compare the availability of kappa opioid receptors (KOR) between an alcohol-dependent cohort (AD) and a healthy control cohort (HC). Sixty-four participants-36 AD and 28 HC-underwent PET scans with [11C]LY2795050, a selective kappa antagonist tracer. Partial-volume correction was applied to all PET data to correct for atrophy. Volume of distribution (VT) of the tracer was estimated regionally as a measure of KOR availability. VT values of AD versus HC were compared for 15 defined ROIs. Multivariate analysis showed a main effect of group on VT across these 15 ROIs. Post hoc tests showed that AD had significantly lower VT and thus a lower KOR availability than HC in amygdala and pallidum (corrected for multiple comparisons). Exploratory analysis of change in VT with age was conducted; VT was not found to vary significantly with age in any region. Our findings of lower VT in AD versus HC in multiple regions are in contrast to findings in the mu and delta opioid receptor systems of higher VT in AD versus HC. Although age-related decline in receptors has previously been observed in the mu opioid receptor system, we found that KOR availability does not change with age.

Sex bias: Is it pervasive in otolaryngology clinical research?

OBJECTIVES/HYPOTHESIS

Recent initiatives highlight substantial sex bias in biomedical research. The objective was to determine whether sex bias is present in otolaryngology and whether sex is appropriately analyzed as an independent variable in otolaryngology clinical research.

STUDY DESIGN

Literature review.

METHODS

We systematically reviewed all 2016 articles in three major otolaryngology journals: The Laryngoscope, JAMA Otolaryngology-Head and Neck Surgery, and Otolaryngology-Head and Neck Surgery. Extracted data included study origin, location, subspecialty, number/sex of subjects, ≥50% sex matching (SM_≥50 ), and sex-based statistical analysis.

RESULTS

Six hundred of 1,209 articles comprising original clinical research were reviewed including 8,997,345,495 subjects (males: 3,898,559,264 [43.3%]; females: 5,095,592,583 [56.6%]; and unknown: 3,193,648 [0.04%]). There were 533/600 (88.8%) studies that included both sexes, eight (1.3%) included females only, five (0.8%) included males only, and 56 (9.3%) did not document participant sex. Only 280 studies (46.7%) analyzed data by sex, and 330 studies (60.7%) had SM_{≥ 50} . Sex-based statistical analysis and SM_{≥ 50} were similar in domestic and international studies (48.7% vs. 42.8% and 60.9% vs. 62%, respectively). Database studies performed sex-based statistical analysis more frequently than single and multi-institutional studies (79.1% vs. 40.4% and 43.4%, P < .00001). Analysis by sex was more frequently performed in head and neck surgery (53.6%) and pediatric otolaryngology (51.3%), whereas SM_≥50 was highest in pediatric otolaryngology (86.8%) and otology (82.4%).

CONCLUSIONS

Sex bias exists in the clinical otolaryngology literature, with less than half the studies analyzing sex. Acknowledging the intertwinement of sex with disease pathophysiology and outcomes is important. Eliminating sex bias in research and clinical care should become a major focus for otolaryngologists.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:858-864, 2019.

Age sensitive associations of adolescent substance use with amygdalar, ventral striatum, and frontal volumes in young adulthood

INTRODUCTION

This study evaluated an age sensitive model of substance use across adolescence to determine if substance use was associated with smaller volumes for an earlier developing brain region, the amygdala, a later developing region, the inferior frontal gyrus, and the ventral striatum.

METHOD

Participants (N = 110) were African American young adults who were members of a longitudinal cohort across childhood and adolescence. Measures of substance use were collected across early (ages 12-15 yrs.), middle (ages 16-18 yrs.), and later (ages 19-21 yrs.) adolescence; then, at age 25, a representative subset of the sample completed magnetic resonance imaging (MRI) that assessed regional brain volumes.

RESULTS

Higher levels of substance use during early adolescence, but not middle or later adolescence, were significantly associated with smaller amygdalar volume in young adulthood. Higher levels of substance use during middle adolescence, but not early or later adolescence, were significantly associated with smaller pars opercularis volume. Substance use was not associated with the pars triangularis or ventral striatum.

CONCLUSION

These findings support age sensitive associations between substance use and smaller gray matter volumes at age 25 and are consistent with literature supporting the differential nature of substance use and brain maturation across adolescence and into young adulthood.

Recruiting the ABCD sample: Design considerations and procedures

The ABCD study is a new and ongoing project of very substantial size and scale involving 21 data acquisition sites. It aims to recruit 11,500 children and follow them for ten years with extensive assessments at multiple timepoints. To deliver on its potential to adequately describe adolescent development, it is essential that it adopt recruitment procedures that are efficient and effective and will yield a sample that reflects the nation’s diversity in an epidemiologically informed manner. Here, we describe the sampling plans and recruitment procedures of this study. Participants are largely recruited through the school systems with school selection informed by gender, race and ethnicity, socioeconomic status, and urbanicity. Procedures for school selection designed to mitigate selection biases, dynamic monitoring of the accumulating sample to correct deviations from recruitment targets, and a description of the recruitment procedures designed to foster a collaborative attitude between the researchers, the schools and the local communities, are provided.

Sex differences in daily life stress and craving in opioid-dependent patients

BACKGROUND

Responses to stress and drug craving differ between men and women. Differences in the momentary experience of stress in relation to craving are less well-understood.

OBJECTIVES

Using ecological momentary assessment (EMA), we examined sex differences in real-time in two areas: (1) causes and contexts associated with stress, and (2) the extent to which stress and drug cues are associated with craving.

METHODS

Outpatients on opioid-agonist treatment (135 males, 47 females) reported stress, craving, and behavior on smartphones for 16 weeks. They initiated an entry each time they felt more stressed than usual (stress event) and made randomly prompted entries 3 times/day. In stress-event entries, they identified the causes and context (location, activity, companions), and rated stress and craving severity.

RESULTS

The causes reported for stress events did not differ significantly by sex. Women reported arguing and being in a store more often during stress events, and men reported working more often during stress events, compared to base rates (assessed via random prompts). Women showed a greater increase in opioid craving as a function of stress (p < 0.0001) and had higher stress ratings in the presence of both stress and drug cues relative to men (p < 0.01). Similar effects were found for cocaine craving in men (p < 0.0001).

CONCLUSION

EMA methods provide evidence based on real-time activities and moods that opioid-dependent men and women experience similar contexts and causes for stress but differ in stress- and cue-induced craving. These findings support sex-based tailoring of treatment, but because not all participants conformed to the overall pattern of sex differences, any such tailoring should also consider person-level differences.

Sex and gender differences in substance use disorders

The gender gap in substance use disorders (SUDs), characterized by greater prevalence in men, is narrowing, highlighting the importance of understanding sex and gender differences in SUD etiology and maintenance. In this critical review, we provide an overview of sex/gender differences in the biology, epidemiology and treatment of SUDs. Biological sex differences are evident across an array of systems, including brain structure and function, endocrine function, and metabolic function. Gender (i.e., environmentally and socioculturally defined roles for men and women) also contributes to the initiation and course of substance use and SUDs. Adverse medical, psychiatric, and functional consequences associated with SUDs are often more severe in women. However, men and women do not substantively differ with respect to SUD treatment outcomes. Although several trends are beginning to emerge in the literature, findings on sex and gender differences in SUDs are complicated by the interacting contributions of biological and environmental factors. Future research is needed to further elucidate sex and gender differences, especially focusing on hormonal factors in SUD course and treatment outcomes; research translating findings between animal and human models; and gender differences in understudied populations, such as those with co-occurring psychiatric disorders and gender-specific populations, such as pregnant women.