Prenatal cocaine exposure, illicit-substance use and stress and craving processes during adolescence

Relationships Between Prenatal Cocaine Exposure, Cannabis-Use Onset and Emotional and Related Characteristics in Young/Emerging Adults

Background: Exposure to substances in utero may have significant early-life consequences. Less is known about the effects in emerging adulthood, particularly regarding patterns of substance use and related characteristics.Objectives: In this study, we recruited emerging adults, followed since birth, who had been prenatally exposed, or not, to cocaine. Individuals reported on their cannabis, alcohol, and tobacco use, and measures of impulsivity, anhedonia, emotional regulation, and mental health were obtained. Comparisons were made between emerging adults with prenatal cocaine exposure and those without. Correlations were performed between psychological measures and substance use, and regression analyses were conducted to determine potential pathways by which such measures may relate to prenatal exposure or substance use.Results: Individuals with prenatal cocaine exposure (vs. those without) used cannabis at younger ages, reported greater cannabis-use severity, and demonstrated higher impulsivity, state anxiety, and alexithymia. Earlier age of onset of cannabis use was associated with higher impulsivity, state anxiety, alexithymia, and social and physical anhedonia. Cannabis-use age-of-onset mediated the relationship between prenatal cocaine-exposure status and state anxiety and between prenatal cocaine-exposure status and cannabis-use severity in emerging adulthood but not relationships between prenatal cocaine-exposure status and impulsivity or alexithymia in emerging adulthood. Findings suggest that adults with prenatal cocaine exposure may use cannabis at younger ages, which may relate to increased anxiety and more severe use.Conclusions: These findings suggest both mechanisms and possible intervention targets to improve mental health in emerging adults with prenatal cocaine exposure.

Paternal methamphetamine exposure induces higher sensitivity to methamphetamine in male offspring through driving ADRB1 on CaMKII-positive neurons in mPFC

Paternal abuse of drugs, such as methamphetamine (METH), elevates the risk of developing addiction in subsequent generations, however, its underlying molecular mechanism remains poorly understood. Male adult mice (F0) were exposed to METH for 30 days, followed by mating with naïve female mice to create the first-generation mice (F1). When growing to adulthood, F1 were subjected to conditioned place preference (CPP) test. Subthreshold dose of METH (sd-METH), insufficient to induce CPP normally, were used in F1. Selective antagonist (betaxolol) for β1-adrenergic receptor (ADRB1) or its knocking-down virus were administrated into mPFC to regulate ADRB1 function and expression on CaMKII-positive neurons. METH-sired male F1 acquired sd-METH-induced CPP, indicating that paternal METH exposure induce higher sensitivity to METH in male F1. Compared with saline (SAL)-sired male F1, CaMKII-positive neuronal activity was normal without sd-METH, but strongly evoked after sd-METH treatment in METH-sired male F1 during adulthood. METH-sired male F1 had higher ADRB1 levels without sd-METH, which was kept at higher levels after sd-METH treatment in mPFC. Either inhibiting ADRB1 function with betaxolol, or knocking-down ADRB1 level on CaMKII-positive neurons (ADRB1CaMKII) with virus transfection efficiently suppressed sd-METH -evoked mPFC activation, and ultimately blocked sd-METH-induced CPP in METH-sired male F1. In the process, the p-ERK1/2 and ΔFosB may be potential subsequent signals of mPFC ADRB1CaMKII. The mPFC ADRB1CaMKII mediates paternal METH exposure-induced higher sensitivity to drug addiction in male offspring, raising a promising pharmacological target for predicting or treating transgenerational addiction.

An intergenerational lifespan perspective on the neuroscience of prenatal substance exposure

Prenatal substance exposure has the potential to impact a variety of domains, with neurobiological effects that last throughout the lifespan. Different substances may impact the brain in both specific and diffuse ways; however, the aberrant neural outcomes following exposure tend to coalesce in three areas: (1) sensorimotor development; (2) arousal, motivation, and reward; and (3) executive functioning, impulse control, and emotion regulation. This manuscript represents a summary and update of a previous review (Morie et al., 2019). We organize this piece by domain and summarize data from published neuroimaging studies that examine the neural correlates of prenatal exposure across developmental stages. While the published neuroimaging literature in the area of prenatal exposure has a range of sampling concerns that may limit generalizability as well as longitudinal prediction, the findings to date do point to domains of interest warranting further study. With this caveat, we synthesize the extant findings to describe ways in which prenatal substance exposure is associated with developmental psychopathology and implicated in potentially aberrant behavioral patterns beginning in infancy and persisting through childhood, adolescence, adulthood, and even parenthood. We also examine how substance abuse may impact parenting behaviors that in turn influences infant and child behavior in ways that may be additive or obscure the direct teratological effects of prenatal exposure. Given this observation, we offer an additional intergenerational lens through which prenatal substance exposure should be studied.

Affect-Related Brain Activity and Adolescent Substance Use: A Systematic Review

Purpose of review

This review aims to summarize the research on brain activity during affective processing (i.e., reward, negative emotional stimuli, loss) and adolescent substance use (SU).

Recent findings

Most research revealed links between altered neural activity in midcingulo-insular, frontoparietal and other network regions and adolescent SU. Increased recruitment of midcingulo-insular regions-particularly the striatum-to positive affective stimuli (e.g., monetary reward) was most often associated with initiation and low-level use of substances, whereas decreased recruitment of these regions was most often associated with SUD and higher risk SU. In regards to negative affective stimuli, most research demonstrated increased recruitment of midcingulo-insular network regions. There is also evidence that these associations may be sex-specific.

Summary

Future research should employ longitudinal designs that assess affect-related brain activity prior to and following SU initiation and escalation. Moreover, examining sex as as moderating variable may help clarify if affective neural risk factors are sex-specific.

Neural activation to loss and reward among alcohol naive adolescents who later initiate alcohol use

Adolescent alcohol use is associated with adverse psychosocial outcomes, including an increased risk of alcohol use disorder in adulthood. It is therefore important to identify risk factors of alcohol initiation in adolescence. Research to date has shown that altered neural activation to reward is associated with alcohol use in adolescence; however, few studies have focused on neural activation to loss and alcohol use. The current study examined neural activation to loss and reward among 64 alcohol naive 12−14 year olds that did (n = 20) and did not initiate alcohol use by a three year follow-up period. Results showed that compared to adolescents that did not initiate alcohol use, adolescents that did initiate alcohol use by the three year follow-up period had increased activation to loss in the left striatum (i.e., putamen), right precuneus, and the brainstem/pons when they were alcohol naive at baseline. By contrast, alcohol initiation was not associated with neural activation to winning a reward. These results suggest that increased activation in brain regions implicated in salience, error detection/self-referential processing, and sensorimotor function, especially to negative outcomes, may represent an initial vulnerability factor for alcohol use in adolescence.

Alexithymia, Emotion-Regulation Strategies, and Traumatic Experiences in Prenatally Cocaine-Exposed Young Adults

BACKGROUND AND OBJECTIVES

Exposure to early-life trauma may lead to maladaptive characteristics such as alexithymia, and thus to poorer emotional regulation. This relationship may also be influenced by exposure to substances prenatally. We hypothesized that increased alexithymia would be seen in those with prenatal cocaine exposure (PCE). Additionally, we hypothesized that early-life trauma would be associated with alexithymia, and that alexithymia would be associated with poor emotional reappraisal and emotional suppression.

METHODS

A moderated mediation model was developed to examine whether the hypothesized indirect relationship between trauma and emotional reappraisal through alexithymia was different in young adults with and without PCE (Total N = 57). Thirty-seven young adults with PCE and 20 with no such exposure, all of whom were members of a longitudinal cohort, were recruited for the study, and data concerning childhood trauma, alexithymia, and emotional regulation were collected. Intercorrelations were performed between the scores on each measure and moderated mediation models were constructed separately with emotional neglect or emotional abuse as the independent variable and emotional reappraisal or emotional suppression as the dependent variable.

RESULTS

PCE status was associated with alexithymia, and alexithymia mediated the relationship between emotional neglect and emotional reappraisal in individuals with PCE but not those without.

DISCUSSION AND CONCLUSIONS

The data suggest that alexithymia is a mechanism underlying poor use of emotional reappraisal in PCE individuals.

SCIENTIFIC SIGNIFICANCE

Individuals with early-life trauma and substance exposure may represent a vulnerable population, and alexithymia may play a key role in the development of emotional regulation skills in this population. (Am J Addict 2020;29:492-499).

Food craving, cortisol and ghrelin responses in modeling highly palatable snack intake in the laboratory

Overeating of highly palatable (HP) foods in the ubiquitous HP food cue environment and under stress is associated with weight gain and contributes to the global obesity epidemic. However, subjective and biobehavioral processes that may increase HP overeating are not clear. Using a novel experimental approach, we examined HP food motivation and intake and neuroendocrine responses in the context of food cues, stress and a control neutral relaxing cue exposure in healthy individuals.

METHODS

Twenty individuals (12 M; 8F; ages 18-45) with body mass index (BMI) in the lean (LN: N = 8; 3/8 female BMI: 18-24.9) or overweight/obese (OW: N = 12; 5/12 female; BMI: 25-37) range were enrolled in a controlled, hospital-based, 3-day laboratory experiment. On each day, subjects were exposed to a brief 5-min individualized guided imagery of stress, food cue or an active neutral-relaxing control cue script, followed by a food snack test (FST), with one imagery condition per day and order of imagery exposure randomized and counterbalanced across subjects. Subjective HP food craving and caloric intake, anxiety, cortisol and total ghrelin was assessed repeatedly during each test day.

RESULTS

Significant condition and condition × group effects for food craving, anxiety and HP calorie intake were observed, with food cue relative to neutral condition increasing HP food craving and intake across all subjects (p < .001), but stress relative to neutral condition increased HP food craving and intake in the OW but not LN group (p < .01). Pre-snack increases in food craving after exposure to food cues and to stress predicted greater subsequent HP food intake (p's < 0.01). Furthermore, ghrelin increased in the food cue and stress conditions (p < .01), but stress-induced increases in ghrelin was associated with HP food intake only in the OW/OB condition (p < .01). Finally, cortisol increased during food cue exposure and increased cortisol responses were associated with greater HP food caving and with intake (p's < 0.05).

CONCLUSIONS

These findings, while preliminary, validate a laboratory model of HP food motivation and intake and identify specific subjective and neuroendocrine responses that may play a role in HP snacking with implications for weight gain and obesity risk. (342 words).

Prenatal drug exposure from infancy through emerging adulthood: Results from neuroimaging

Prenatal drug exposure may have important repercussions across the lifespan for cognition and behavior. While alcohol is a recognized teratogen, the influences of other substances may also be substantial. The neural underpinnings of the influences of prenatal drug exposure have been examined using longitudinal approaches and multiple imaging techniques. Here we review the existing literature on the neural correlates of prenatal drug exposure. We focused the review on studies that have employed functional neuroimaging and electroencephalography and on substances other than alcohol. We also framed the review through the lens of four developmental life stages (infancy, childhood, adolescence and emerging adulthood). We included papers that have examined any drug use, including tobacco, opiates, cocaine, marijuana, methamphetamines, or polysubstance use. Data suggest that prenatal drug exposure has long-lasting, deleterious influences on cognition and reward processing in infancy and childhood that persist into adolescence and emerging adulthood and may underlie some behavioral tendencies, such as increased externalizing and risk-taking behaviors, seen in these groups.

Sex-Differentiated Associations among Negative Parenting, Emotion-Related Brain Function, and Adolescent Substance Use and Psychopathology Symptoms

Parenting is a critical factor in adolescent social-emotional development, with maladaptive parenting leading to risk for the development of psychopathology. However, the emotion-related brain mechanisms underlying the influence of parenting on psychopathology symptoms are unknown. The present study utilized functional magnetic resonance imaging and laboratory measures to examine sex-differentiated associations among parenting, adolescent emotion-related brain function, and substance use and psychopathology symptoms in 66 12-14 year olds. Maternal parenting behaviors (warmth, negative parenting) were observed in a laboratory task. Adolescent brain responses to negative emotional stimuli were assessed in emotion processing regions of interest (left [L] and right [R] amygdala, anterior insula, anterior cingulate cortex [ACC]). Adolescents reported on substance use and depressive, anxiety, and externalizing symptoms. Maternal negative parenting predicted adolescent brain activation differently by sex. For girls, negative parenting predicted heightened R ACC activation to negative emotional stimuli. For boys, negative parenting predicted blunted L and R anterior insula and L ACC activation. Furthermore, for girls, but not boys, heightened L anterior insula and heightened L and R ACC activation were associated with substance use and depressive symptoms, respectively. Findings suggest neural response to negative emotion as a possible sex-specific pathway from negative parenting to psychopathology.

Neuroendocrine and immune pathways from pre- and perinatal stress to substance abuse

Early life adversity is a documented risk factor for substance abuse and addiction. The pre- and perinatal period (i.e., from implantation, through pregnancy, to 6 months of age) is a critical period marked by high biological plasticity and vulnerability, making perinatal stress a particularly robust form of adversity. The neuroendocrine and immune systems are key mechanisms implicated in the transmission of addiction risk. We review animal and human studies that provide preliminary evidence for links between perinatal stress, neuroendocrine and immune dysregulation, and risk for substance abuse and addiction. A translational neuroscience perspective is employed to elucidate pre- and perinatally-induced biological mechanisms linked to addiction and discuss implications for prevention and intervention efforts. Significant evidence supports associations between pre- and perinatal stress and dysregulation of the hypothalamic-pituitary-adrenal axis and immune systems as well as links between neuroendocrine/immune functioning and addiction risk. More work is needed to explicitly examine the interplay between pre- and perinatal stress and neuroendocrine/immune disruptions that together heighten substance abuse risk. Future work is needed to fully understand how pre- and perinatal stress induces biological alterations to predispose individuals to higher risk for addiction. Such knowledge will strengthen theoretically-driven and empirically-supported prevention efforts for substance abuse and addiction.

Stress reactivity and the developmental psychopathology of adolescent substance use

Adolescence represents a period of risk for initiation of substance use and the development of substance use disorders (SUDs). In addition, during adolescence, there is rapid development of stress reactivity systems. This paper describes a conceptual model of the role of stress reactivity in the development of substance use in adolescence. It is proposed that some children develop maladaptive patterns of emotional, physiological, and neural reactivity to stressful situations that are either too high or too low and that their patterns of reactivity interact with increased stressful life events during adolescence to lead to potential for substance use and SUDs. In one pathway, youth develop a heightened reactivity to stress, which leads to high negative emotion and using substances to cope. In a second pathway, youth develop a blunted reactivity to stress, which leads to chronic under-arousal and using substances to increase sensation/arousal. We propose that girls may be more likely to take the high-reactivity pathway to substance use and boys may be more likely to take the low-reactivity pathway. We review existing studies of stress reactivity in adolescents, which support our theory that altered stress reactivity is correlated with and, in some cases, predictive of adolescent substance use, with some studies finding high stress reactivity and some finding low stress reactivity to be correlated with increased substance use and SUD risk. Some studies find that the blunted reactivity pathway to substance use occurs particularly for youth from high-risk contexts. Further, some evidence supports the proposed sex differences in stress reactivity pathways. We discuss future directions and implications of these findings for developing and refining developmentally-sensitive stress reactivity-focused SUD prevention programs.

Overweight adolescents' brain response to sweetened beverages mirrors addiction pathways

Many adolescents struggle with overweight/obesity, which exponentially increases in the transition to adulthood. Overweight/obesity places youth at risk for serious health conditions, including type 2 diabetes. In adults, neural substrates implicated in addiction (e.g., orbitofrontal cortex (OFC), striatum, amygdala, and ventral tegmental area) have been found to be relevant to risk for overweight/obesity. In this study, we examined three hypotheses to disentangle the potential overlap between addiction and overweight/obesity processing by examining (1) brain response to high vs. low calorie beverages, (2) the strength of correspondence between biometrics, including body mass index (BMI) and insulin resistance, and brain response and (3) the relationship between a measure of food addiction and brain response using an established fMRI gustatory cue exposure task with a sample of overweight/obese youth (M age = 16.46; M BMI = 33.1). Greater BOLD response was observed across the OFC, inferior frontal gyrus (IFG), nucleus accumbens, right amygdala, and additional frontoparietal and temporal regions in neural processing of high vs. low calorie beverages. Further, BMI scores positively correlated with BOLD activation in the high calorie > low calorie contrast in the right postcentral gyrus and central operculum. Insulin resistance positively correlated with BOLD activation across the bilateral middle/superior temporal gyrus, left OFC, and superior parietal lobe. No relationships were observed between measures of food addiction and brain response. These findings support the activation of parallel addiction-related neural pathways in adolescents' high calorie processing, while also suggesting the importance of refining conceptual and neurocognitive models to fit this developmental period.

Application of Research Domain Criteria to childhood and adolescent impulsive and addictive disorders: Implications for treatment

The Research Domain Criteria (RDoC) initiative provides a large-scale, dimensional framework for the integration of research findings across traditional diagnoses, with the long-term aim of improving existing psychiatric treatments. A neurodevelopmental perspective is essential to this endeavor. However, few papers synthesizing research findings across childhood and adolescent disorders exist. Here, we discuss how the RDoC framework may be applied to the study of childhood and adolescent impulsive and addictive disorders in order to improve neurodevelopmental understanding and to enhance treatment development. Given the large scope of RDoC, we focus on a single construct highly relevant to addictive and impulsive disorders - initial responsiveness to reward attainment. Findings from genetic, molecular, neuroimaging and other translational research methodologies are highlighted.

Is Neural Processing of Negative Stimuli Altered in Addiction Independent of Drug Effects? Findings From Drug-Naïve Youth with Internet Gaming Disorder

Difficulties in emotion regulation are commonly reported among individuals with alcohol and drug addictions and contribute to the acquisition and maintenance of addictive behaviors. Alterations in neural processing of negative affective stimuli have further been demonstrated among individuals with addictions. However, it is unclear whether these alterations are a general feature of addictions or are a result of prolonged exposure to drugs of abuse. To test the hypothesis of altered negative affect processing independent of drug effects, this study assessed neural function among drug-naïve youth with a behavioral addiction-Internet gaming disorder (IGD). Fifty-six young adults (28 with IGD, 28 matched controls) participated in fMRI scanning during performance of a well-validated emotion regulation task. Between-group differences in neural activity during task performance were assessed using a whole-brain, mixed-effects ANOVA with correction for multiple comparisons at currently recommended thresholds (voxel-level p<0.001, pFWE<0.05). Compared to controls, youth with IGD exhibited significantly blunted neural responses within distributed subcortical and cortical regions including the striatum, insula, lateral prefrontal cortex and anterior cingulate in response to negative affective cues, as well as during emotion regulation. Independent component analysis (ICA) further identified between-group differences in engagement of a fronto-cingulo-parietal network, involving decreased engagement in IGD youth relative to controls. Study findings are largely consistent with those from prior neuroimaging studies in substance-use disorders, thus raising the possibility that neural processing of negative affect may be blunted across drug and behavioral addictions independent of acute or chronic drug effects.

White-matter crossing-fiber microstructure in adolescents prenatally exposed to cocaine

BACKGROUND

Prenatal cocaine exposure (PCE) is associated with risk-taking behaviors, including increased initiation of substance use in adolescence. The neurobiological underpinnings of these behaviors in adolescents with PCE are not well understood. The goal of this study was to compare diffusion-weighted imaging data between adolescents with and without PCE using crossing-fiber models, which may provide more comprehensive estimates of white-matter microstructure within regions of multiple (e.g., primary and secondary) fiber orientations.

METHODS

Thirty-nine PCE individuals and 17 comparably aged prenatally non-drug-exposed (NDE) youths were recruited from a longitudinal cohort followed since birth. White matter was examined using tensor-derived and crossing-fiber models. Whole-brain investigations were performed, as were analyses on seven white-matter regions, which included the splenium, body and genu of the corpus callosum, bilateral cingulum, and the right and left superior longitudinal fasciculus (SLF).

RESULTS

Whole-brain analyses revealed no group differences. However, ROI analyses for anisotropy estimates derived from the crossing-fiber model revealed significant group differences for secondary fibers, with reduced anisotropy among PCE adolescents compared to prenatally non-exposed youth in the right cingulum and the left SLF, and increased anisotropy in the genu.

CONCLUSIONS

Our findings suggest that white-matter differences in PCE adolescents are subtle and localized primarily within secondary fiber orientations, perhaps arising from altered white-matter development.