Investigation of [11C]carfentanil for mu opioid receptor quantification in the rat brain.

[11C]Carfentanil ([11C]CFN) is the only selective carbon-11 labeled radiotracer currently available for positron emission tomography (PET) imaging of mu opioid receptors (MORs). Though used extensively in clinical research, [11C]CFN has not been thoroughly characterized as a tool for preclinical PET imaging. As we were occasionally observing severe vital sign instability in rat [11C]CFN studies, we set out to investigate physiological effects of CFN mass and to explore its influence on MOR quantification. In anesthetized rats (n = 15), significant dose-dependent PCO2 increases and heart rate decreases were observed at a conventional tracer dose range (IV, > 100 ng/kg). Next, we conducted baseline and retest [11C]CFN PET scans over a wide range of molar activities. Baseline [11C]CFN PET studies (n = 27) found that nondisplaceable binding potential (BPND) in the thalamus was positively correlated to CFN injected mass, demonstrating increase of MOR availability at higher injected CFN mass. Consistently, when CFN injected mass was constrained < 40 ng/kg (~ 10% MOR occupancy in rats), baseline MOR availability was significantly decreased. For test-retest variability (TRTV), better reproducibility was achieved by controlling CFN injected mass to limit the difference between scans. Taken together, we report significant cardiorespiratory depression and a paradoxical influence on baseline MOR availability at conventional tracer doses in rats. Our findings might reflect changes in cerebral blood flow, changes in receptor affinity, or receptor internalization, and merits further mechanistic investigation. In conclusion, rat [11C]CFN PET requires stringent quality assurance of radiotracer synthesis and mass injected to avoid pharmacological effects and limit potential influences on MOR quantification and reproducibility.

Childhood obesity's impact on cognition and brain connectivity worsens with low family income.

Childhood obesity and its adverse health consequences have risen worldwide, with low socioeconomic status increasing the risk in high-income countries like the US. Understanding the interplay between childhood obesity, cognition, socioeconomic factors, and the brain is crucial for prevention and treatment. Using data from the ABCD study, we investigated how body mass index (BMI) relates to brain structural and functional connectivity metrics. Obese/overweight children (n = 2,356) were more likely to live in poverty and exhibited lower cognitive performance compared to normal weight children (n = 4,754). Higher BMI was associated with multiple brain measures that were strongest for lower longitudinal diffusivity in corpus callosum, increased activity in cerebellum, insula, and somatomotor cortex, and decreased functional connectivity in multimodal brain areas, with effects more pronounced among children from low-income families. Notably, nearly 80% of the association of low income and 70% of the association of impaired cognition on BMI were mediated by higher brain activity in somatomotor areas. Increased resting activity in somatomotor areas and decreased structural and functional connectivity likely contribute to the higher risk of overweight/obesity among children from low-income families. Supporting low-income families and implementing educational interventions to improve cognition may promote healthy brain function and reduce the risk of obesity.

Major Gaps in the Cascade of Care for Opioid Use Disorder: Implications for Clinical Practice.

This Viewpoint examines a recent report that used data from the 2022 National Survey on Drug Use and Health to estimate the opioid cascade of care, a framework to characterize the adult US populations who needed and received opioid use disorder (OUD) treatment, as well as discusses ways in which clinicians can close gaps in care.

The mGlu5 receptor negative allosteric modulator mavoglurant reduces escalated cocaine self-administration in male and female rats.

RATIONALE: Cocaine use disorder (CUD) is a brain disorder for which there is no Food and Drug Administration-approved pharmacological treatment. Evidence suggests that glutamate and metabotropic glutamate receptor subtype 5 (mGlu5) play critical roles in synaptic plasticity, neuronal development, and psychiatric disorders. OBJECTIVE: In the present study, we tested the hypothesis that the mGlu5 receptor is functionally involved in intravenous cocaine self-administration and assessed the effects of sex and cocaine exposure history. METHODS: We used a preclinical model of CUD in rats that were allowed long access (LgA; 6 h/day) or short access (ShA; 1 h/day) to intravenous cocaine (750 µg/kg/infusion [0.1 ml]) self-administration. Rats received acute intraperitoneal or oral administration of the mGlu5 receptor negative allosteric modulator mavoglurant (1, 3, and 10 mg/kg) or vehicle. RESULTS: Both intraperitoneal and oral mavoglurant administration dose-dependently reduced intravenous cocaine self-administration in the first hour and in the entire 6 h session in rats in the LgA group, with no effect on locomotion. In the ShA group, mavoglurant decreased locomotion but had no effects on cocaine self-administration. We did not observe significant sex × treatment interactions. CONCLUSIONS: These findings suggest that the mGlu5 receptor is involved in escalated cocaine self-administration. These findings support the development of clinical trials of mavoglurant to evaluate its potential therapeutic benefits for CUD.

Imaging neuroinflammation in individuals with substance use disorders.

Increasing evidence suggests a role of neuroinflammation in substance use disorders (SUDs). This Review presents findings from neuroimaging studies assessing brain markers of inflammation in vivo in individuals with SUDs. Most studies investigated the translocator protein 18 kDa (TSPO) using PET; neuroimmune markers myo-inositol, choline-containing compounds, and N-acetyl aspartate using magnetic resonance spectroscopy; and fractional anisotropy using MRI. Study findings have contributed to a greater understanding of neuroimmune function in the pathophysiology of SUDs, including its temporal dynamics (i.e., acute versus chronic substance use) and new targets for SUD treatment.

Treatment for Opioid Use Disorder: Population Estimates - United States, 2022.

In 2022, 81,806 opioid-involved overdose deaths were reported in the United States, more than in any previous year. Medications for opioid use disorder (OUD), particularly buprenorphine and methadone, substantially reduce overdose-related and overall mortality. However, only a small proportion of persons with OUD receive these medications. Data from the 2022 National Survey on Drug Use and Health were applied to a cascade of care framework to estimate and characterize U.S. adult populations who need OUD treatment, receive any OUD treatment, and receive medications for OUD. In 2022, 3.7% of U.S. adults aged ≥18 years needed OUD treatment. Among these, only 25.1% received medications for OUD. Most adults who needed OUD treatment either did not perceive that they needed it (42.7%) or received OUD treatment without medications for OUD (30.0%). Compared with non-Hispanic Black or African American and Hispanic or Latino adults, higher percentages of non-Hispanic White adults received any OUD treatment. Higher percentages of men and adults aged 35-49 years received medications for OUD than did women and younger or older adults. Expanded communication about the effectiveness of medications for OUD is needed. Increased efforts to engage persons with OUD in treatment that includes medications are essential. Clinicians and other treatment providers should offer or arrange evidence-based treatment, including medications, for patients with OUD. Pharmacists and payors can work to make these medications available without delays.

Associations of semaglutide with incidence and recurrence of alcohol use disorder in real-world population.

Alcohol use disorders are among the top causes of the global burden of disease, yet therapeutic interventions are limited. Reduced desire to drink in patients treated with semaglutide has raised interest regarding its potential therapeutic benefits for alcohol use disorders. In this retrospective cohort study of electronic health records of 83,825 patients with obesity, we show that semaglutide compared with other anti-obesity medications is associated with a 50%-56% lower risk for both the incidence and recurrence of alcohol use disorder for a 12-month follow-up period. Consistent reductions were seen for patients stratified by gender, age group, race and in patients with and without type 2 diabetes. Similar findings are replicated in the study population with 598,803 patients with type 2 diabetes. These findings provide evidence of the potential benefit of semaglutide in AUD in real-world populations and call for further randomized clinicl trials.

Estimated Number of Children Who Lost a Parent to Drug Overdose in the US From 2011 to 2021.

Importance: Parents' overdose death can have a profound short- and long-term impact on their children, yet little is known about the number of children who have lost a parent to drug overdose in the US. Objective: To estimate the number and rate of children who have lost a parent to drug overdose from 2011 to 2021 overall and by parental age, sex, and race and ethnicity. Design, Setting, and Participants: This was a cross-sectional study of US community-dwelling persons using data from the National Survey on Drug Use and Health (2010-2014 and 2015-2019) and the National Vital Statistics System (2011-2021). Data were analyzed from January to June 2023. Exposure: Parental drug overdose death, stratified by age group, sex, and race and ethnicity. Main Outcomes and Measures: Numbers, rates, and average annual percentage change (AAPC) in rates of children losing a parent aged 18 to 64 years to drug overdose, overall and by age, sex, and race and ethnicity. Results: From 2011 to 2021, 649 599 adults aged 18 to 64 years died from a drug overdose (mean [SD] age, 41.7 [12.0] years; 430 050 [66.2%] male and 219 549 [33.8%] female; 62 606 [9.6%] Hispanic, 6899 [1.1%] non-Hispanic American Indian or Alaska Native, 6133 [0.9%] non-Hispanic Asian or Pacific Islander, 82 313 [12.7%] non-Hispanic Black, 485 623 [74.8%] non-Hispanic White, and 6025 [0.9%] non-Hispanic with more than 1 race). Among these decedents, from 2011 to 2021, an estimated 321 566 (95% CI, 276 592-366 662) community-dwelling children lost a parent aged 18 to 64 years to drug overdose. The rate of community-dwelling children who lost a parent to drug overdose per 100 000 children increased from 27.0 per 100 000 in 2011 to 63.1 per 100 000 in 2021. The highest rates were found among children of non-Hispanic American Indian or Alaska Native individuals, who had a rate of 187.1 per 100 000 in 2021, more than double the rate among children of non-Hispanic White individuals (76.5 per 100 000) and non-Hispanic Black individuals (73.2 per 100 000). While rates increased consistently each year for all parental age, sex, and race and ethnicity groups, non-Hispanic Black parents aged 18 to 25 years had the largest AAPC (23.8%; 95% CI, 16.5-31.6). Rates increased for both fathers and mothers; however, more children overall lost fathers (estimated 192 459; 95% CI, 164 081-220 838) than mothers (estimated 129 107; 95% CI, 112 510-145 824). Conclusions and Relevance: An estimated 321 566 children lost a parent to drug overdose in the US from 2011 to 2021, with significant disparities evident across racial and ethnic groups. Given the potential short- and long-term negative impact of parental loss, program and policy planning should ensure that responses to the overdose crisis account for the full burden of drug overdose on families and children, including addressing the economic, social, educational, and health care needs of children who have lost parents to overdose.

Seasonality in regional brain glucose metabolism.

BACKGROUND: Daylength and the rates of changes in daylength have been associated with seasonal fluctuations in psychiatric symptoms and in cognition and mood in healthy adults. However, variations in human brain glucose metabolism in concordance with seasonal changes remain under explored. METHODS: In this cross-sectional study, we examined seasonal effects on brain glucose metabolism, which we measured using 18F-fluorodeoxyglucose-PET in 97 healthy participants. To maximize the sensitivity of regional effects, we computed relative metabolic measures by normalizing the regional measures to white matter metabolism. Additionally, we explored the role of rest-activity rhythms/sleep-wake activity measured with actigraphy in the seasonal variations of regional brain metabolic activity. RESULTS: We found that seasonal variations of cerebral glucose metabolism differed across brain regions. Glucose metabolism in prefrontal regions increased with longer daylength and with greater day-to-day increases in daylength. The cuneus and olfactory bulb had the maximum and minimum metabolic values around the summer and winter solstice respectively (positively associated with daylength), whereas the temporal lobe, brainstem, and postcentral cortex showed maximum and minimum metabolic values around the spring and autumn equinoxes, respectively (positively associated with faster daylength gain). Longer daylength was associated with greater amplitude and robustness of diurnal activity rhythms suggesting circadian involvement. CONCLUSIONS: The current findings advance our knowledge of seasonal patterns in a key indicator of brain function relevant for mood and cognition. These data could inform treatment interventions for psychiatric symptoms that peak at specific times of the year.

Changes in rest-activity rhythms in adolescents as they age: associations with brain changes and behavior in the ABCD study.

Background: Adolescents with disrupted rest-activity rhythms (RAR) including shorter sleep duration, later sleep timing and low physical activity levels have higher risk for mental and behavioral problems. However, it remains unclear whether the same associations can be observed for within-subject changes in RAR. Methods: Our longitudinal investigation on RAR used Fitbit data from the Adolescent Brain Cognitive Development (ABCD) Study at the 2-year (FL2: aged 10-13 years) and 4-year follow-up (FL4: aged 13-16 years). 963 youths had good-quality Fitbit data at both time points. In this study we examined changes in RAR from FL2 to FL4, their environmental and demographic contributors as well as brain and behavioral correlates. Results: From FL2 to FL4, adolescents showed decreases in sleep duration and physical activity as well as delayed sleep timing (Cohen's d .44-.75). The contributions of environmental and demographic factors to RAR changes were greatest to sleep timing (explained 10% variance) and least to sleep duration (explained 1% variance). Delays in sleep timing had stronger correlations with behavioral problems including greater impulsivity and poor academic performance than reductions in sleep duration or physical activity. Additionally, the various brain measures differed in their sensitivity to RAR changes. Reductions in sleep duration were associated with decreased brain functional connectivity between subcortical regions and sensorimotor and cingulo-opercular networks and with enhanced functional connectivity between sensorimotor, visual and auditory networks. Delays in sleep timing were mainly associated with grey matter changes in subcortical regions. Conclusions: The current findings corroborate the role of sleep and physical activity in adolescent's brain neurodevelopment and behavior problems. RAR might serve as biomarkers for monitoring behavioral problems in adolescents and to serve as potential therapeutic targets for mental disorders.

Associations of cannabis use, use frequency, and cannabis use disorder with violent behavior among young adults in the United States.

BACKGROUND: Most violent crimes (52 %) are committed by adults aged 18-34, who account for 23 % of the US population and have the highest prevalence of cannabis use and cannabis use disorder (CUD). We examined whether and how associations of cannabis use, use frequency, and CUD with violent behavior (i.e., attacking someone with the intent to harm seriously) vary by sex in U.S. young adults. METHODS: Data were from 113,454 participants aged 18-34 in the 2015-2019 US National Surveys on Drug Use and Health, providing nationally representative data on cannabis use, CUD (using DSM-IV criteria), and violent behavior. Descriptive analyses and bivariate and multivariable logistic regression analyses were conducted. RESULTS: Among U.S. adults aged 18-34, 28.9 % (95 % CI = 28.5-29.2 %) reported past-year cannabis use (with/without CUD), including 20.5 % (95 % CI = 20.2-20.8 %) with non-daily cannabis without CUD, 4.7 % (95 % CI = 4.5-4.8 %) with daily cannabis use without CUD, 2.1 % (95 % CI = 1.9-2.2 %) with non-daily cannabis use and CUD, and 1.7 % (95 % CI = 1.5-1.8 %) with daily cannabis use and CUD. Past-year adjusted prevalence of violent behavior was higher among males with daily cannabis use but without CUD (2.9 %, 95 % CI = 2.4-2.7 %; adjusted prevalence ratio (PR) = 1.7, 95 % CI = 1.3-2.2) and males with daily cannabis use and CUD (3.1 %, 95 % CI = 2.3-4.0 %; adjusted PR = 1.8, 95 % CI = 1.3-2.4) than males without past-year cannabis use (1.7 %, 95 % CI = 1.6-1.9 %). Adjusted prevalence of violent behavior was higher among females with cannabis use regardless of daily cannabis use/CUD status (adjusted prevalence = 1.6-2.4 %, 95 % CIs = 0.9-3.2 %; adjusted PRs = 1.6-2.4, 95 % CI = 1.3-3.2) than females without past-year cannabis use (1.0 %, 95 % CI = 0.9-1.1 %). CONCLUSIONS: Research is needed to ascertain the directionality of the associations between cannabis use and violent behavior and underlying sex-specific mechanism(s). Our results point to complex sex-specific relationships between cannabis use frequency, CUD, and violent behavior and highlight the importance of early screening for and treatment of CUD and of preventive interventions addressing cannabis misuse.

Association of semaglutide with reduced incidence and relapse of cannabis use disorder in real-world populations: a retrospective cohort study.

Cannabis is the most frequently used illicit drug in the United States with more than 45 million users of whom one-third suffer from a cannabis use disorder (CUD). Despite its high prevalence, there are currently no FDA-approved medications for CUD. Patients treated with semaglutide, a glucagon-like peptide-1 receptor agonist (GLP-1RA) approved for treating type 2 diabetes (T2D) and for weight management have reported reduced desire to drink and smoke. Preclinical studies have shown that semaglutide decreased nicotine and alcohol consumption. Preclinical and preliminary clinical evidence of semaglutide's potential beneficial effects on various substance use disorders led us to evaluate if it pertained to CUD. In this retrospective cohort study of electronic health records (EHRs) from the TriNetX Analytics Network, a global federated health research network of approximately 105.3 million patients from 61 large healthcare organizations in the US, we aimed to assess the associations of semaglutide with both incident and recurrent CUD diagnosis compared to non-GLP-1RA anti-obesity or anti-diabetes medications. Hazard ratio (HR) and 95% confidence intervals (CI) of incident and recurrent CUD were calculated for 12-month follow-up by comparing propensity-score matched patient cohorts. The study population included 85,223 patients with obesity who were prescribed semaglutide or non-GLP-1RA anti-obesity medications, with the findings replicated in 596,045 patients with T2D. In patients with obesity (mean age 51.3 years, 65.6% women), semaglutide compared with non-GLP-1RA anti-obesity medications was associated with lower risk for incident CUD in patients with no prior history CUD (HR: 0.56, 95% CI: 0.42-0.75), and recurrent CUD diagnosis in patients with a prior history CUD (HR: 0.62, 95% CI: 0.46-0.84). Consistent reductions were seen for patients stratified by gender, age group, race and in patients with and without T2D. Similar findings were replicated in the study population with T2D when comparing semaglutide with non-GLP-1RA anti-diabetes medications for incident CUD (HR: 0.40, 95% CI: 0.29-0.56) and recurrent CUD (HR: 0.66, 95% CI: 0.42-1.03). While these findings provide preliminary evidence of the potential benefit of semaglutide in CUD in real-world populations, further preclinical studies are warranted to understand the underlying mechanism and randomized clinical trials are needed to support its use clinically for CUD.

Associations between handedness and brain functional connectivity patterns in children.

Handedness develops early in life, but the structural and functional brain connectivity patterns associated with it remains unknown. Here we investigate associations between handedness and the asymmetry of brain connectivity in 9- to 10-years old children from the Adolescent Brain Cognitive Development (ABCD) study. Compared to right-handers, left-handers had increased global functional connectivity density in the left-hand motor area and decreased it in the right-hand motor area. A connectivity-based index of handedness provided a sharper differentiation between right- and left-handers. The laterality of hand-motor connectivity varied as a function of handedness in unimodal sensorimotor cortices, heteromodal areas, and cerebellum (P < 0.001) and reproduced across all regions of interest in Discovery and Replication subsamples. Here we show a strong association between handedness and the laterality of the functional connectivity patterns in the absence of differences in structural connectivity, brain morphometrics, and cortical myelin between left, right, and mixed handed children.

Neurovascular effects of cocaine: relevance to addiction.

Cocaine is a highly addictive drug, and its use is associated with adverse medical consequences such as cerebrovascular accidents that result in debilitating neurological complications. Indeed, brain imaging studies have reported severe reductions in cerebral blood flow (CBF) in cocaine misusers when compared to the brains of healthy non-drug using controls. Such CBF deficits are likely to disrupt neuro-vascular interaction and contribute to changes in brain function. This review aims to provide an overview of cocaine-induced CBF changes and its implication to brain function and to cocaine addiction, including its effects on tissue metabolism and neuronal activity. Finally, we discuss implications for future research, including targeted pharmacological interventions and neuromodulation to limit cocaine use and mitigate the negative impacts.

Ketogenic diet reduces a neurobiological craving signature in inpatients with alcohol use disorder.

Background and aims: Increasing evidence suggests that a ketogenic (high-fat, low-carbohydrate) diet (KD) intervention reduces alcohol withdrawal severity and alcohol craving in individuals with alcohol use disorder (AUD) by shifting brain energetics from glucose to ketones. We hypothesized that the KD would reduce a neurobiological craving signature when individuals undergoing alcohol detoxification treatment were exposed to alcohol cues. Methods: We performed a secondary analysis of functional magnetic resonance data of 33 adults with an AUD who were randomized to a KD (n = 19) or a standard American diet (SA; n = 14) and underwent 3 weeks of inpatient alcohol detoxification treatment. Once per week, participants performed an alcohol cue-reactivity paradigm with functional magnetic resonance imaging. We extracted brain responses to food and alcohol cues and quantified the degree to which each set of brain images shared a pattern of activation with a recently established 'Neurobiological Craving Signature' (NCS). We then performed a group-by-time repeated measures ANOVA to test for differences in craving signature expression between the dietary groups over the three-week treatment period. We also correlated these expression patterns with self-reported wanting ratings for alcohol cues. Results: For alcohol relative to food cues, there was a main effect of group, such that the KD group showed lower NCS expression across all 3 weeks of treatment. The main effect of time and the group-by-time interaction were not significant. Self-reported wanting for alcohol cues reduced with KD compared to SA but did not correlate with the NCS score. Conclusion: A ketogenic diet reduces self-reported alcohol wanting, and induced lower NCS to alcohol cues during inpatient treatment for AUD. However, in the KD group alcohol wanting continued to decrease across the 3 weeks of abstinence while the NCS scores remained stable, suggesting that this cue-induced NCS may not fully capture ongoing, non-cue-induced alcohol desire.