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

The hidden-zero effect in male individuals with opioid use disorder

Background: Explicitly expressing the hidden opportunity cost in intertemporal choice significantly reduces healthy participants' delay discounting - a phenomenon named the "hidden-zero effect," which is undetermined in individuals with substance use disorder (SUD).Objectives: This study aimed to determine whether the hidden-zero effect occurs among individuals with opioid use disorder (OUD) and the degree to which this effect differs between the OUD group and healthy controls.Methods: In two different experiments, Exp#1) 29 male individuals with OUD (13.5 ± 6.0 months abstinence) and 29 male controls performed an intertemporal choice task (ICT); Exp#2) 28 male individuals with OUD (17.5 ± 5.6 months abstinence) and 27 male controls performed a delay discounting task (DDT). The OUD group was recruited from a mandatory treatment, and controls from WeChat. There were two choice conditions in both two tasks: the hidden-zero (H0) condition (standard), and the explicit-zero (E0) condition (explicitly expressing opportunity cost).Results: Compared with the H0 condition, all participants' delay discounting was significantly decreased in the E0 condition (ps < .05, ηp2 = 0.254, 0.110). There was no significant difference in the changed degree between these two groups in either experiment (ps > .05). The delay discounting of the OUD group was significantly higher than that of controls only in Experiment 2 (p < .001, ηp2 = 0.376).Conclusion: This study extended the population in which the hidden-zero effect occurs to individuals with OUD. With respect to delay discounting, the hidden-zero effect benefit did not differ in OUD and control participants.

Brain Anatomical Alterations in Young Cannabis Users: Is it All Hype? A Meta-Analysis of Structural Neuroimaging Studies

Introduction: Cannabis use has a high prevalence in young youth and is associated with poor psychosocial outcomes. Such outcomes have been ascribed to the impact of cannabis exposure on the developing brain. However, findings from individual studies of volumetry in youth cannabis users are equivocal. Objectives: Our primary objective was to systematically review the evidence on brain volume differences between young cannabis users and nonusers aged 12-26 where profound neuromaturation occurs, accounting for the role of global brain volumes (GBVs). Our secondary objective was to systematically integrate the findings on the association between youth age and volumetry in youth cannabis users. Finally, we aimed to evaluate the quality of the evidence. Materials and Methods: A systematic search was run in three databases (PubMed, Scopus, and PsycINFO) and was reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We run meta-analyses (with and without controlling for GBV) of brain volume differences between young cannabis users and nonusers. We conducted metaregressions to explore the role of age on volumetric differences. Results: Sixteen studies were included. The reviewed samples included 830 people with mean age 22.5 years (range 14-26 years). Of these, 386 were cannabis users (with cannabis use onset at 15-19 years) and 444 were controls. We found no detectable group differences in any of the GBVs (intracranium, total brain, total white matter, and total gray matter) and regional brain volumes (i.e., hippocampus, amygdala, orbitofrontal cortex, and total cerebellum). Age and cannabis use level did not predict (standardized mean) volume group differences in metaregression. We found little evidence of publication bias (Egger's test p>0.1). Conclusions: Contrary to evidence in adult samples (or in samples mixing adults and youth), previous single studies in young cannabis users, and meta-analyses of brain function in young cannabis users, this early evidence suggests nonsignificant volume differences between young cannabis users and nonusers. While prolonged and long-term exposure to heavy cannabis use may be required to detect gross volume alterations, more studies in young cannabis users are needed to map in detail cannabis-related neuroanatomical changes.

Turning Vicious Cycles Into Virtuous Ones: the Potential for Schools to Improve the Life Course

Adolescence is a critical transition period that sets the stage for adulthood and future health outcomes. Marked by key developmental milestones in brain maturation, increasing independence from parents, and greater connections to peers, adolescence is also a time of heightened risk for behavioral health problems, including substance use, violence, delinquency, and mental health issues. High school completion is a significant life course event and a powerful social determinant of health and health disparities. Jessor's Theory of Problem Behavior suggests that adolescent health behaviors and mental health problems are closely tied to poor educational outcomes and peer network formation in a reinforcing feedback loop, or vicious cycle, often leading to school failure, school disengagement, and drop-out. Schools are a novel platform through which vicious cycles can be disrupted and replaced with virtuous ones, simultaneously improving education and health. This article describes the potential for schools to transform health trajectories through interventions creating positive and supportive school climates. In addition, new models such as the Whole School Whole Community Whole Child Model promote whole child well-being, including cognitive, social, emotional, psychological, and physical development. Full-service community schools can serve as a hub coordinating and integrating all available resources to better respond to the needs of children and families. Present in every neighborhood, schools are a way to reach every school-age child and improve their health trajectories, providing an important platform for life course intervention research.

Portable Neuroimaging-Guided Noninvasive Brain Stimulation of the Cortico-Cerebello-Thalamo-Cortical Loop—Hypothesis and Theory in Cannabis Use Disorder

Background: Maladaptive neuroplasticity-related learned response in substance use disorder (SUD) can be ameliorated using noninvasive brain stimulation (NIBS); however, inter-individual variability needs to be addressed for clinical translation. Objective: Our first objective was to develop a hypothesis for NIBS for learned response in SUD based on a competing neurobehavioral decision systems model. The next objective was to develop the theory by conducting a computational simulation of NIBS of the cortico-cerebello-thalamo-cortical (CCTC) loop in cannabis use disorder (CUD)-related dysfunctional “cue-reactivity”—a construct closely related to “craving”—that is a core symptom. Our third objective was to test the feasibility of a neuroimaging-guided rational NIBS approach in healthy humans. Methods: “Cue-reactivity” can be measured using behavioral paradigms and portable neuroimaging, including functional near-infrared spectroscopy (fNIRS) and electroencephalogram (EEG) metrics of sensorimotor gating. Therefore, we conducted a computational simulation of NIBS, including transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS) of the cerebellar cortex and deep cerebellar nuclei (DCN) of the CCTC loop for its postulated effects on fNIRS and EEG metrics. We also developed a rational neuroimaging-guided NIBS approach for the cerebellar lobule (VII) and prefrontal cortex based on a healthy human study. Results: Simulation of cerebellar tDCS induced gamma oscillations in the cerebral cortex, while transcranial temporal interference stimulation induced a gamma-to-beta frequency shift. A preliminary healthy human study (N = 10) found that 2 mA cerebellar tDCS evoked similar oxyhemoglobin (HbO) response in the range of 5 × 10⁻⁶ M across the cerebellum and PFC brain regions (α = 0.01); however, infra-slow (0.01–0.10 Hz) prefrontal cortex HbO-driven phase–amplitude-coupled (PAC; 4 Hz, ±2 mA (max)) cerebellar tACS evoked HbO levels in the range of 10⁻⁷ M that were statistically different (α = 0.01) across these brain regions. Conclusion: Our healthy human study showed the feasibility of fNIRS of cerebellum and PFC and closed-loop fNIRS-driven ctACS at 4 Hz, which may facilitate cerebellar cognitive function via the frontoparietal network. Future work needs to combine fNIRS with EEG for multi-modal imaging for closed-loop NIBS during operant conditioning.

Amygdalar Activation as a Neurobiological Marker of Differential Sensitivity in the Effects of Family Rearing Experiences on Socioemotional Adjustment in Youths

BACKGROUND

Substantial heterogeneity exists in how rearing environments influence youths' socioemotional outcomes. This heterogeneity, as suggested by the biological sensitivity to context theory and the differential susceptibility theory, is associated with emotional reactivity patterns and underlying neural functions. The present study investigated amygdalar reactivity to emotional stimuli as a neural signature that amplified the influence of rearing environments on youths' socioemotional outcomes.

METHODS

To increase replicability and generalizability, this investigation included two independent studies that methodologically complemented each other. Study 1 employed a large, national, longitudinal dataset (the Adolescent Brain Cognitive Development study; N = 11,875). Study 2 used a community sample of youths (N = 123) with multimethod and multireporter assessments.

RESULTS

In study 1, high left amygdalar reactivity to positive stimuli significantly amplified the impact of parental warmth on youths' prosocial behaviors. In study 2, left and right amygdalar reactivity to positive stimuli significantly intensified the associations between family functioning and youths' internalizing problems. These findings were consistent with the biological sensitivity to context theory/differential susceptibility theory hypothesis because significant socioemotional differences were observed at both negative and positive extremes of rearing environments. Additionally, study 2 partially supported the diathesis-stress hypothesis by showing significant differences in youths' vulnerability to negative family environments. Specifically, left amygdalar response to negative stimuli exacerbated the associations between unbalanced family functioning and heightened internalizing/externalizing symptoms. Left amygdalar reactivity to positive stimuli intensified the link between unbalanced family functioning and elevated externalizing problems.

CONCLUSIONS

Among youths and adolescents, amygdalar emotional reactivity may serve as a biomarker of differential sensitivity to rearing environments.

Effects of substance misuse and current family history of substance use disorder on brain structure in adolescents and young adults with attention-deficit/hyperactivity disorder

BACKGROUND

Alterations in brain structure in attention-deficit/hyperactivity disorder (ADHD) show considerable overlap with those observed in substance use disorder (SUD). These overlapping structural alterations in ADHD and SUD might be explained by family history (FH-trait) effects of SUD, and/or substance misuse (state) effects. Our aim was to investigate effects of 1) current parental SUD (SUD-FH) and 2) recent substance misuse (SM) on brain structure in a cohort of ADHD patients and controls.

DESIGN

Cortical thickness and subcortical volumes were measured using structural MRI. We compared ADHD subjects and controls with or without SUD-FH (aim 1) and additionally explored differences between SUD-FH- and SUD-FH + subjects with one versus two parents with SUD. We also compared ADHD groups with and without SM (ADHD + SM and ADHD-only, respectively) and controls (aim 2).

FINDINGS

There was no association between SUD-FH and brain structure. Exploratory analysis on SUD-FH showed decreased IFG thickness (p = 0.032) and nucleus accumbens (NAcc) volume (p = 0.017) in subjects with two versus one SUD parent, regardless of ADHD. ADHD + SM showed decreased inferior frontal gyrus (IFG) thickness compared to controls (pars opercularis p = 0.025, pars orbitalis p = 0.010, pars triangularis p = 0.049), while no difference was found between ADHD-only and either ADHD + SM or controls.

CONCLUSIONS

Despite negative findings in the primary trait-analysis, exploratory trait-analysis on SUD-FH loading suggested potential SUD trait-effects on IFG thickness and NAcc volume. Substance misuse state effects in ADHD were linked to lower IFG thickness. Future studies should confirm these findings and investigate their clinical relevance, including the functional consequences of decreased IFG thickness.

Bidirectional links between adolescent brain function and substance use moderated by cognitive control

BACKGROUND

No clear consensus exists as to whether neurodevelopmental abnormalities among substance users reflect predisposing neural risk factors, neurotoxic effects of substances, or both. Using a longitudinal design, we examined developmental patterns of the bidirectional links between neural mechanisms and substance use throughout adolescence.

METHOD

167 adolescents (aged 13-14 years at Time 1, 53% male) were assessed annually four times. Risk-related neural processing was assessed by blood-oxygen-level-dependent responses in the insula during a lottery choice task, cognitive control by behavioral performance during the Multi-Source Interference Task, and substance use by adolescents' self-reported cigarette, alcohol, and marijuana use.

RESULTS

Latent change score modeling indicated that greater substance use predicted increased insula activation during risk processing, but the effects of insula activation on changes in substance use were not significant. The coupling effect from substance use to insula activation was particularly strong for adolescents with low cognitive control, which supports the theorized moderating role of cognitive control.

CONCLUSIONS

Our results elucidate how substance use may alter brain development to be biased toward maladaptive decision-making, particularly among adolescents with poor cognitive control. Furthermore, the current findings underscore that cognitive control may be an important target in the prevention and treatment of adolescent substance use given its moderating role in the neuroadaptive effects of substance use on brain development.

Convergent Evidence for Predispositional Effects of Brain Gray Matter Volume on Alcohol Consumption

BACKGROUND

Alcohol use has been reliably associated with smaller subcortical and cortical regional gray matter volumes (GMVs). Whether these associations reflect shared predisposing risk factors or causal consequences of alcohol use remains poorly understood.

METHODS

Data came from 3 neuroimaging samples (N = 2423), spanning childhood or adolescence to middle age, with prospective or family-based data. First, we identified replicable GMV correlates of alcohol use. Next, we used family-based and longitudinal data to test whether these associations may plausibly reflect a predispositional liability for alcohol use or a causal consequence of alcohol use. Finally, we used heritability, gene-set enrichment, and transcriptome-wide association study approaches to evaluate whether genome-wide association study-defined genomic risk for alcohol consumption is enriched for genes that are preferentially expressed in regions that were identified in our neuroimaging analyses.

RESULTS

Smaller right dorsolateral prefrontal cortex (DLPFC) (i.e., middle and superior frontal gyri) and insula GMVs were associated with increased alcohol use across samples. Family-based and prospective longitudinal data suggest that these associations are genetically conferred and that DLPFC GMV prospectively predicts future use and initiation. Genomic risk for alcohol use was enriched in gene sets that were preferentially expressed in the DLPFC and was associated with replicable differential gene expression in the DLPFC.

CONCLUSIONS

These data suggest that smaller DLPFC and insula GMV plausibly represent genetically conferred predispositional risk factors for, as opposed to consequences of, alcohol use. DLPFC and insula GMV represent promising biomarkers for alcohol-consumption liability and related psychiatric and behavioral phenotypes.