Functional brain imaging of development-related risk and vulnerability for substance use in adolescents

Navigating Exploitative Traps: Unveiling the Uncontrollable Reward Seeking of Individuals With Internet Gaming Disorder

BACKGROUND

Internet gaming disorder (IGD) involves an imbalance in the brain's dual system, characterized by heightened reward seeking and diminished cognitive control, which lead to decision-making challenges. The exploration-exploitation strategy is key to decision making, but how IGD affects this process is unclear.

METHODS

To investigate the impact of IGD on decision making, a modified version of the 2-armed bandit task was employed. Participants included 41 individuals with IGD and 44 healthy control individuals. The study assessed the strategies used by participants in the task, particularly focusing on the exploitation-exploration strategy. Additionally, functional magnetic resonance imaging was used to examine brain activation patterns during decision-making and estimation phases.

RESULTS

The study found that individuals with IGD demonstrated greater reliance on exploitative strategies in decision making due to their elevated value-seeking tendencies and decreased cognitive control. Individuals with IGD also displayed heightened activation in the presupplementary motor area and the ventral striatum compared with the healthy control group in both decision-making and estimation phases. Meanwhile, the prefrontal cortex showed more inhibition in individuals with IGD than in the healthy control group during exploitative strategies. This inhibition decreased as cognitive control diminished.

CONCLUSIONS

The imbalance in the development of the dual system in individuals with IGD may lead to an overreliance on exploitative strategies. This imbalance, marked by increased reward seeking and reduced cognitive control, contributes to difficulties in decision making and value-related behavioral processes in individuals with IGD.

Neuroscience-informed classification of prevention interventions in substance use disorders: An RDoC-based approach

Neuroscience has contributed to uncover the mechanisms underpinning substance use disorders (SUD). The next frontier is to leverage these mechanisms as active targets to create more effective interventions for SUD treatment and prevention. Recent large-scale cohort studies from early childhood are generating multiple levels of neuroscience-based information with the potential to inform the development and refinement of future preventive strategies. However, there are still no available well-recognized frameworks to guide the integration of these multi-level datasets into prevention interventions. The Research Domain Criteria (RDoC) provides a neuroscience-based multi-system framework that is well suited to facilitate translation of neurobiological mechanisms into behavioral domains amenable to preventative interventions. We propose a novel RDoC-based framework for prevention science and adapted the framework for the existing preventive interventions. From a systematic review of randomized controlled trials using a person-centered drug/alcohol preventive approach for adolescents, we identified 22 unique preventive interventions. By teasing apart these 22 interventions into the RDoC domains, we proposed distinct neurocognitive trajectories which have been recognized as precursors or risk factors for SUDs, to be targeted, engaged and modified for effective addiction prevention.

The profile of adolescent patients presenting to a tertiary maternal mental health clinic

Background

Between March 2021 and April 2022, there were 90 037 documented adolescent pregnancies in South Africa. Statistics SA reports that this number is growing. Pregnancy places adolescents at greater risk of psychiatry-related morbidity and may have far-reaching consequences for their children. To date, there is no published data describing the patient profile of adolescent pregnancies in Gauteng Province, South Africa.

Aim

To describe the patient profile (demographics, schooling history and type of accommodation), pregnancy-related factors, substance use habits and contraceptive use in pregnant adolescents seen at a tertiary care maternal mental health clinic (MMHC).

Setting

The MMHC at Chris Hani Baragwanath Academic Hospital, Soweto, Johannesburg, South Africa.

Methods

A retrospective file review of all pregnant adolescents referred to the MMHC between January and June 2022.

Results

The mean age of the patients was 15.2 years; 72% attended school and 97.4% planned to return. Most pregnancies were unplanned (97.9%), wanted (84%) and presented in the second (41.24%) and third (51.55%) trimesters. Most did not report using substances (76.7%). Fifty percent of the participants met the criteria for a major depressive disorder. Repeating a grade was an identifiable risk factor for an increased Edinburgh depression score. An unplanned pregnancy was associated with a higher risk factor assessment.

Conclusion

Pregnant adolescents represent a vulnerable population group. A greater understanding of this patient profile may inform early psychiatric and psychosocial interventions, improved service delivery and help-seeking behaviour.

Contribution

This study gives significant insights into the challenges faced, as well as the health and social needs of pregnant adolescents. This contributes to wholistic care and opportunities for early intervention, including awareness of contraceptive use and the risks of substance use and adolescent pregnancy on mental health, benefiting all South African adolescents.

A prospective investigation of youth alcohol experimentation and reward responsivity in the ABCD study

Rationale

Greater risk-taking behaviors, such as alcohol experimentation, are associated with different patterns of brain functioning in regions implicated in reward (nucleus accumbens, NA) and cognitive control (inferior frontal gyrus, IFG). These neural features have been observed in youth with greater risk-taking tendencies prior to substance use initiation, suggesting NA-IFG disruption may serve as an early marker for subsequent substance use disorders. Prospective studies are needed to determine if NA-IFG neural disruption predicts future substance use in school-age children, including those with minimal use of alcohol (e.g., sipping). The present large-sample prospective study sought to use machine learning to: (1) examine alcohol sipping at ages 9, 10 as a potential behavioral indicator of concurrent underlying altered neural responsivity to reward, and (2) determine if alcohol sipping and NA-IFG activation at ages 9, 10 can be used to predict which youth reported increased alcohol use at ages 11, 12. Additionally, low-level alcohol use and brain functioning at ages 9, 10 were examined as predictors of substance use and brain functioning at ages 11, 12.

Design and methods

This project used data from the baseline (Time 1) and two-year follow-up (Time 2) assessments of the Adolescent Brain Cognitive Development (ABCD) Study (Release 3.0). Support Vector Machine (SVM) learning determined if: (1) NA-IFG neural activity could correctly identify youth who reported alcohol sipping at Time 1 (n = 7409, mean age = 119.34 months, SD = 7.53; 50.27% female), and (2) NA-IFG and alcohol sipping frequency at Time 1 could correctly identify youth who reported drinking alcohol at Time 2 (n = 4000, mean age = 143.25 months, SD = 7.63; 47.53% female). Linear regression was also used to examine the relationship between alcohol sipping and NA-IFG activity at Time 1 and substance use and NA-IFG activity at Time 2. Data were also examined to characterize the environmental context in which youth first tried sips of alcohol (e.g., with or without parental permission, as part of a religious experience).

Results

Approximately 24% of the sample reported having tried sips of alcohol by ages 9, 10. On average, youth reported trying sips of alcohol 4.87 times (SD = 23.19) with age of first sip occurring at 7.36 years old (SD = 1.91). The first SVM model classified youth according to alcohol sipping status at Time 1 no better than chance with an accuracy of 0.35 (balanced accuracy = 0.52, sensitivity = 0.24, specificity = 0.80). The second SVM model classified youth according to alcohol drinking status at Time 2 with an accuracy of 0.76 (balanced accuracy = 0.56, sensitivity = 0.21, specificity = 0.91). Linear regression demonstrated that frequency of alcohol sipping at Time 1 predicted frequency of alcohol use at Time 2 (p < 0.001, adjusted R 2 = 0.075). Alcohol sipping at Time 1 was not linearly associated with NA or IFG activity at Time 2 (all ps > 0.05), and NA activity at Time 1 and Time 2 were not related (all ps > 0.05). Activity in the three subsections of the IFG at Time 1 predicted activity in those same regions at Time 2 (all ps < 0.02).

Conclusions and implications

Early sips of alcohol appear to predict alcohol use in early adolescence. Findings do not provide strong evidence for minimal early alcohol use (sipping) as a behavioral marker of underlying alterations in NA-IFG neural responsivity to reward. Improving our understanding of the neural and behavioral factors that indicate a greater propensity for future substance use is crucial for identifying at-risk youth and potential targets for preventative efforts.

Eating Behavior Associated with Food Intake in European Adolescents Participating in the HELENA Study

Adolescence is recognized as a time of rapid physiological and behavioral change. In this transition, eating behavior is still being formed and remains an integral part of a person’s lifestyle throughout his or her life. This study aims to assess eating behavior and associations with food intake in European adolescents. We included 2194 adolescents (45.9% boys), aged 12.5 to 17.5 years, from the cross-sectional HELENA study, with two completed 24 h recalls and complete questionnaire data on their eating behavior (Eating Behavior and Weight Problems Inventory for Children- EWI-C). Three subscales of the EWI were evaluated; they measured Strength and motivation to eat (EWI 1), Importance and impact of eating (EWI 2), and Eating as a means of coping with emotional stress (EWI 3). Since these subscales were specially focused on eating behavior, participants were classified as either Low (≤P75) or High (>P75) on each of the subscales. Our results showed a higher consumption of different types of food, in the EWI 1 scales, linked to the hunger and interest in eating, and we observed a relationship with the consumption of energy-dense products. This result was repeated in EWI 3, the subscale linked to emotional eating, where we also found higher consumption of energy-dense products. This study suggests that special features of eating behavior are associated with food intake in adolescents.

Impairment of spatial memory and dorsal hippocampal synaptic plasticity in adulthood due to adolescent morphine exposure

Opioid exposure during adolescence, a crucial period of neurodevelopment, has lasting neurological and behavioral consequences and affects the cognitive functions in adulthood. This study investigated the effects of adolescent morphine exposure in spatial learning and memory and synaptic plasticity of the CA1 area of the dorsal hippocampus. Adolescent Wistar rats received increasing doses of morphine for 1, 5, and 10 days. Acute morphine group was injected 2.5 mg/kg morphine for 1 day, subchronic morphine group for 5 days, with an increasing dose of 2.5 mg/kg and reached to the dose of 12.5 mg/kg and chronic morphine group for 10 days that began with an increasing dose of 2.5 mg/kg and reached to the dose of 25 mg/kg. Then after 25 days and reaching adulthood, spatial learning and memory were evaluated via the Morris water maze (MWM) test. Moreover, we test the electrophysiological properties of dorsal hippocampal plasticity in adult rats by in vitro field potential recordings. Subchronic and chronic adolescent morphine exposure impaired spatial learning and memory in the MWM test. Baseline synaptic responses in the chronic morphine group were increased and long-term potentiation (LTP) impaired in the CA1 area in subchronic and chronic morphine groups. In adulthood, the slope of the field excitatory postsynaptic potential (fEPSP) required to elicit a half-maximal population spike (PS) amplitude was significantly larger in subchronic and chronic adolescent morphine exposure compared to the saline group. Therefore, subchronic and chronic adolescent morphine exposure altered synaptic transmission and plasticity in addition to learning and memory. Long-term morphine exposure during adolescence can interfere with neurodevelopment, making a persistent impression on plasticity and cognitive capability in adulthood.

Subtyping youngsters with obesity: A theory-based cluster analysis

Psychological mechanisms play a crucial role in explaining weight gain. Aim of the present study was to identify subtypes in youngsters with obesity in line with these mechanisms. Defining homogeneous clusters within this heterogeneous group provides relevant information for personalized treatments. Data were collected in N = 572 participants (51% boys, aged 7-19) with extreme obesity (%BMI M = 187.8; SD = 30.9) recruited in an inpatient treatment centre. Based on psychological models of overweight/obesity, the Affect Regulation Model, the Reward Deficiency Model and The Dual Pathway Model, cluster variables were selected assessing emotional eating, reward reactivity and regulative capacities. Youngsters reported on emotional eating (DEBQ Emotional Eating) and reward sensitivity (BAS), while parents reported on children's regulative Executive Functions (BRIEF). Characteristics of the different clusters were examined concerning weight variables (pre and post treatment) and variables indexing problematic eating (DEBQ External Eating, Ch-EDE), affect regulation (FEEL-KJ) and depressive symptoms (CDI). Hierarchical cluster analyses supported the presence of three clusters, further evaluated by K-means cluster analyses. The cluster solutions differed according to age and sex (boys 7-13, boys 14-19, girls 7-13, girls 14-19). In all four age and gender subsamples, an "Emotional Eating" cluster displaying a vulnerable profile (high depression, maladaptive emotion regulation, problematic eating) and a "Reward Deficiency" cluster displaying a more resilient profile were detected. In girls 7-13, a "Weak Executive Functioning" indicative of insufficient self-regulative capacities, showed moderate to high emotional problems and problematic eating. In the other subgroups, the "Mean Level Functioning" cluster also showed elevated emotional problems and problematic eating. Given that different clusters can be identified, and given that these clusters have different profiles on emotional problems and problematic eating, subtyping youngsters with severe obesity is indicated, setting the stage for personalized treatments.

Interactions among Reward Sensitivity and Fast-Food Access on Healthy Eating Index Scores in Adolescents: A Cross-Sectional Study

Food cues in the environment may contribute to obesity as the consumption of unhealthy foods may reinforce reward pathways in the brain. To understand how person-level differences in reward sensitivity may be associated with diet quality, this study aimed to examine the moderating role of the availability of fast food in the environment on the relationship between reward sensitivity and diet quality in adolescents. Participants (n = 152; 55% female; Mage: 12.5 ± 0.93 y) completed the drive and reward subscales of the Behavioral Inhibition System (BIS)/Behavioral Activation System (BAS) Scale to assess reward sensitivity and completed two 24 h dietary recalls from which Healthy Eating Index (HEI) scores (total score and subscales of adequacy and moderation) were calculated. Fast-food environment (FFE) was operationalized as the total number of fast-food outlets within 1 km around participants' home address. Linear regressions were used to examine the main effects and interactions between reward sensitivity and FFE in relation to HEI score. Interactions were found between FFE and BAS drive (p = 0.02) and BAS reward (p < 0.01) on HEI adequacy. There were no interaction effects on HEI moderation or HEI total scores. For individuals who had lower access exposure to fast-food outlets (-1 SD), there was a stronger positive association between higher BAS drive (t = 2.85, p = 0.01, 95% CI (0.35, 1.94)) and HEI adequacy scores and between higher BAS reward (t = 3.27, p > 0.01, 95% CI (0.72, 2.93)) and HEI adequacy scores. By examining reward sensitivity to potential food cues in residential neighborhood food environments, it is possible to understand which adolescents are more sensitive to environmental food cues and implement interventions to buffer these influences.

Delay discounting and neurocognitive correlates among inner city adolescents with and without family history of substance use disorder

Adolescents with a family history (FH+) of substance use disorder (SUD) are at a greater risk for SUD, suggested to be partly due to the transmission of behavioral impulsivity. We used a delay discounting task to compare impulsivity in decision-making and its associated brain functioning among FH+ and FH - minority adolescents. Participants chose between Smaller Sooner (SS) and Larger Later (LL) rewards. The SS was available immediately (Now trials) or in the future (Not-Now trials), allowing for greater differentiation between impulsive decisions. The FH+ group showed greater impatience by responding SS more frequently than the FH - group, only on the Now trials, and even when the relative reward differences (RRD) increased. Surprisingly, there were no differences in brain activity between the groups. Combined, the groups showed greater reward activity during the Now vs. Not-Now trials in medial prefrontal/anterior cingulate, posterior cingulate, precuneus, and inferior frontal gyrus (i.e., an immediacy effect). As the RRD increased activation in the reward network decreased, including the striatum, possibly reflecting easy decision-making. These results indicate that risk for SUD, seen behaviorally among FH+ adolescents, may not yet be associated with discernable brain changes, suggesting that early intervention has the potential to reduce this risk.

A latent class analysis of changes in adolescent substance use between 1988 and 2011 in Sweden: associations with sex and psychosomatic problems

AIMS

To characterize changes in patterns of adolescent substance use in Sweden between 1988 and 2011, and to assess whether sex and psychosomatic problems were associated with substance use and whether these associations changed over time.

DESIGN

Secondary analysis of repeated cross-sectional survey data. Survey data were collected eight times and analyzed as four cohorts (1988-91, 1995-98, 2002-05 and 2008-11).

SETTING AND PARTICIPANTS

The sample included all 15-16-year-olds in Värmland County, Sweden (n = 20 057).

MEASUREMENTS

Binary-coded substance use measures included life-time use of alcohol and tobacco, getting drunk and past school year use of inhalants. An eight-item scale was used to assess psychosomatic problems.

FINDINGS

A three-class model fitted the data best (i.e. non/low use, mainly alcohol use and polysubstance use). The patterns of substance use were different among cohorts; most notably, adolescents in the last cohort had lower odds of being included in the alcohol and polysubstance use classes rather than the non/low use class than in the earlier cohorts (all Ps < 0.001). Males had higher odds than females of being in the polysubstance use class rather than the non/low use class among the first three cohorts (all Ps < 0.001) but not the last. Sex was not associated with inclusion in the alcohol use class rather than the non/low use class. Adolescents who reported more psychosomatic problems had higher odds of being included in the alcohol and polysubstance use classes rather than the non/low use class (all Ps < 0.001). The associations of sex and psychosomatic problems with class inclusion did not change during the study period.

CONCLUSIONS

Between 1988 and 2011, patterns of substance use among adolescents in Sweden shifted away from polysubstance use and alcohol use to non-use or low use. Associations between patterns of substance use and sex and psychosomatic problems remained largely consistent across the study period.

Adolescent development of inhibitory control and substance use vulnerability: A longitudinal neuroimaging study

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Characterized inhibitory control development in adolescents at-risk for substance use.

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Externalizing psychopathology is associated with lower antisaccade accuracy and shorter latencies in early adolescence.

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Externalizing-associated inhibitory control performance differences normalize by late adolescence.

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Externalizing psychopathology is associated with prefrontal hypo-activation across development.

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Externalizing psychopathology moderates age-related increases in posterior parietal cortex activity.

Previous research indicates that risk for substance use is associated with poor inhibitory control. However, it remains unclear whether at-risk youth follow divergent patterns of inhibitory control development. As part of the longitudinal National Consortium on Adolescent Neurodevelopment and Alcohol study, participants (N = 113, baseline age: 12–21) completed a rewarded antisaccade task during fMRI, with up to three time points. We examined whether substance use risk factors, including psychopathology (externalizing, internalizing) and family history of substance use disorder, were associated with developmental differences in inhibitory control performance and BOLD activation. Among the examined substance use risk factors, only externalizing psychopathology exhibited developmental differences in inhibitory control performance, where higher scores were associated with lower correct response rates (p = .013) and shorter latencies (p < .001) in early adolescence that normalized by late adolescence. Neuroimaging results revealed higher externalizing scores were associated with developmentally-stable hypo-activation in the left middle frontal gyrus (p < .05 corrected), but divergent developmental patterns of posterior parietal cortex activation (p < .05 corrected). These findings suggest that early adolescence may be a unique period of substance use vulnerability via cognitive and phenotypic disinhibition.

Do Adolescents Use Substances to Relieve Uncomfortable Sensations? A Preliminary Examination of Negative Reinforcement among Adolescent Cannabis and Alcohol Users

Alcohol and cannabis use are highly prevalent among adolescents and associated with negative consequences. Understanding motivations behind substance use in youth is important for informing prevention and intervention efforts. The present study aims to examine negative reinforcement principles of substance use among adolescent cannabis and alcohol users by pairing a cue reactivity paradigm with an aversive interoceptive stimulus. Adolescents (ages 15–17), classified as controls (CTL; n = 18), cannabis and/or alcohol experimenters (CAN+ALC-EXP; n = 16), or individuals meeting clinical criteria for cannabis and/or alcohol use disorder (CAN+ALC-SUD; n = 13) underwent functional magnetic resonance imaging during which they experienced an aversive interoceptive probe delivered via breathing load while simultaneously performing a cue reactivity paradigm. Participants also provided self-report ratings of how their substance use is positively or negatively reinforced. While experiencing the breathing load, CAN+ALC-SUD exhibited greater (p < 0.05) deactivation in the right amygdala, the left inferior frontal gyrus, and the left parahippocampal gyrus than CAN+ALC-EXP and CTL, who did not differ. Across all substance users, activation during the breathing load within the left parahippocampal gyrus negatively correlated with cannabis and alcohol lifetime use episodes and the left inferior frontal gyrus activity negatively correlated with lifetime alcohol use episodes. CAN+ALC-SUD reported experiencing more positive and negative reinforcement of using their substance of choice than CAN+ALC-EXP; both user groups reported higher levels of positive than negative reinforcement. Adolescents with a cannabis/alcohol use disorder demonstrate an altered response to interoceptive perturbations. However, adolescent cannabis/alcohol use does not appear to be driven by negative reinforcement, as viewing substance images did not dampen this response. Based on self-report data, the experience of positive reinforcement may be stronger for adolescents. Future studies should examine whether positive reinforcement contributes to adolescent substance use.

Reward-Related Brain Activity Prospectively Predicts Increases in Alcohol Use in Adolescents

OBJECTIVE

Altered activity within reward-related neural regions, including the ventral striatum (VS) and medial prefrontal cortex (mPFC), is associated with concurrent problematic substance use. The aims of the present study were (a) to identify patterns of reward-related neural activity that prospectively predicted changes in alcohol use 2 years after magnetic resonance imaging in a sample of adolescents, and (b) to examine whether these patterns differed by sex. We also tested whether depression symptoms or impulsivity mediated associations between neural activity and future alcohol use.

METHOD

Participants were 262 adolescents (129 male and 133 female) of Mexican origin who completed the Monetary Incentive Delay task during a functional magnetic resonance imaging scan at age 16. Participants reported on their alcohol use at ages 16 and 18.

RESULTS

Results indicated that different patterns of reward-related neural activity predicted future increases in alcohol use for male and female adolescents. In boys, higher VS activity during reward anticipation and average ventral mPFC activity during reward feedback predicted increases in alcohol use from age 16 to 18 years; in girls, higher dorsal mPFC activity and blunted VS activity during reward anticipation predicted increases in alcohol use from age 16 to 18 years. Depression symptoms or impulsivity did not mediate these associations.

CONCLUSION

The results suggest that different pathways of risk may lead to problematic alcohol use for adolescent boys and girls. These sex differences in neural risk pathways have important implications for prevention and intervention approaches targeting Mexican-origin youth.

Neurocognitive Precursors of Substance Misuse Corresponding to Risk, Resistance, and Resilience Pathways: Implications for Prevention Science

Studies of substance misuse prevention generally focus on characteristics that typify risk, with the assumption that the prevalence of the problem will be optimally reduced by identifying, targeting, and reducing or eliminating risk factors. However, this risk-centered approach neglects variations in individual-level and environmental characteristics that portend differential pathways that are distinguishable by timing of substance use initiation (e.g., early versus delayed), the likelihood of use escalation versus eventual desistance, and enduring abstinence, despite exposure to significant risk factors. Considering the various underpinnings of these distinct substance use trajectories is critical to a more nuanced understanding of the effects, potency, and malleability of factors that are known to increase risk or confer protection. Here, we discuss three pathways relative to substance use patterns and predictors in the context of adversity, a well-known, highly significant influence on propensity for substance misuse. The first pathway is designated as "high risk" based on early onset of substance use, rapid escalation, and proneness to substance use disorders. Individuals who defy all odds and eventually exhibit adaptive developmental outcomes despite an initial maladaptive reaction to adversity, are referred to as "resilient." However, another categorization that has not been adequately characterized is "resistant." Resistant individuals include those who do not exhibit problematic substance use behaviors (e.g., early onset and escalation) and do not develop substance use disorders or other forms of psychopathology, despite significant exposure to factors that normally increase the propensity for such outcomes (e.g. trauma and/or adversity). In this paper, we apply this conceptualization of risk, resistance, and resilience for substance misuse to a more fine-grained analysis of substance use pathways and their corresponding patterns (e.g., non-use, initiation, escalation, desistance). The significance of the progression of neurocognitive functioning over the course of development is discussed as well as how this knowledge may be translated to make a science-based determination of intervention targets. This more encompassing theoretical model has direct implications for primary prevention and clinical approaches to disrupt risk pathways and to optimize long-term outcomes.

Incentives facilitate developmental improvement in inhibitory control by modulating control-related networks

Adolescence is a period of heightened sensitivity to incentives and relatively weak cognitive control, which may contribute to risky behaviors. Studies of brain activity have generally identified greater activation of the ventral striatum to rewards and less activation of prefrontal regions during control tasks in adolescents compared to adults. Little is known, however, about age-related changes in the functional brain networks underlying incentive processing and cognitive control. This cross-sectional study characterized the effects of incentives on inhibitory control during an oculomotor task using whole-brain functional connectivity analyses. During an fMRI scan, one hundred forty typically developing individuals completed an incentivized antisaccade task consisting of incentive cue, preparation, and response phases. We found that task modulation of control networks increased gradually from childhood to adulthood, whereas a network including ventral striatum and ventromedial prefrontal cortex displayed an adolescent-specific peak in response to the receipt of outcomes, consistent with dual-systems models. Notably, however, greater modulation of salience and motor networks during the preparation phase mediated age-related improvements in antisaccade accuracy, whereas adolescent enhancement of value-related circuitry did not. Relative to neutral cues, both reward and loss cues enhanced task-related connectivity of the salience network when preparing to inhibit a saccade. Altogether, our findings suggest that incentives facilitate inhibitory control by enhancing the salience of one's responses and that over development, the recruitment of functional networks involved in saliency and motor preparation supports better performance.

Trajectories of Adolescent Alcohol Use: The Effect of Individual and Social Risk Factors by Race

This study examined racial differences across African American, Hispanic, and White participants in the impact that individualand social risk factorshave on drinking behaviortrajectories.Data from the National Longitudinal Study of Adolescent Health was usedfrom 7-9^th graders (N = 4,372).Participants reported on frequency of drinking across the four waves and risk factors at wave 1. Growth mixture modeling revealed four trajectories for alcohol use that includedAbstainers, Early Starters, Late Starters, and De-Escalators. Social and individual indicators of risk were differently predictive of group membership to the problematic drinking trajectories. Differences across racial groups suggested that a lack of future orientation may be a salient risk factor for African Americanand Hispanicyouth's alcohol use, and peer alcohol use may be a salient risk factor for White youth's alcohol use. The findings of this study suggest that there may be individual differences in risk factors that provide insight for prevention efforts.

Adding a reward increases the reinforcing value of fruit

Adolescents' snack choices could be altered by increasing the reinforcing value (RV) of healthy snacks compared with unhealthy snacks. This study assessed whether the RV of fruit increased by linking it to a reward and if this increased RV was comparable with the RV of unhealthy snacks alone. Moderation effects of sex, hunger, BMI z-scores and sensitivity to reward were also explored. The RV of snacks was assessed in a sample of 165 adolescents (15·1 (sd 1·5) years, 39·4 % boys and 17·4 % overweight) using a computerised food reinforcement task. Adolescents obtained points for snacks through mouse clicks (responses) following progressive ratio schedules of increasing response requirements. Participants were (computer) randomised to three experimental groups (1:1:1): fruit (n 53), fruit+reward (n 60) or unhealthy snacks (n 69). The RV was evaluated as total number of responses and breakpoint (schedule of terminating food reinforcement task). Multilevel regression analyses (total number of responses) and Cox's proportional hazard regression models (breakpoint) were used. The total number of responses made were not different between fruit+reward and fruit (b -473; 95 % CI -1152, 205, P=0·17) or unhealthy snacks (b410; 95 % CI -222, 1043, P=0·20). The breakpoint was slightly higher for fruit than fruit+reward (HR 1·34; 95 % CI 1·00, 1·79, P=0·050), whereas no difference between unhealthy snacks and fruit+reward (HR 0·86; 95 % CI 0·62, 1·18, P=0·34) was observed. No indication of moderation was found. Offering rewards slightly increases the RV of fruit and may be a promising strategy to increase healthy food choices. Future studies should however, explore if other rewards, could reach larger effect sizes.

Socioeconomic disparities in adolescent substance use: Role of enjoyable alternative substance-free activities

OBJECTIVE

To examine whether reduced substance-free enjoyable activity (i.e., 'alternative reinforcers') is a mediating mechanism linking lower socioeconomic status and adolescent substance use risk.

METHOD

High school students in Los Angeles, CA (N = 2,553, 2013-2014, M age baseline = 14.1) were administered three semiannual surveys. Socioeconomic status was measured by highest parental education reported at Wave 1 (the beginning of 9th grade). Three elements of alternative reinforcement at Wave 2 (six-month follow-up) were assessed as mediators: ratings of frequency of engagement, level of enjoyment, and frequency × enjoyment product scores of substance-free typically pleasant activities (like participation in sports teams or school clubs). Study outcomes included prior six-month alcohol, marijuana, tobacco, and other substance use at Wave 3 (twelve-month follow-up). Logistic regression models adjusting for alternative reinforcers and substance use from the preceding wave as well as other co-factors were used to examine the association of Wave 1 parental education with Wave 3 substance use and mediation by Wave 2 alternative reinforcement.

RESULTS

Lower parental education at Wave 1 was associated with a greater likelihood of reporting alcohol (β = -0.122, 95% CI = -0.234, -0.009) and marijuana (β = -0.168, 95% CI = -0.302, -0.034) use at Wave 3. The inverse association between parental education and substance use was statistically mediated by each element of diminished alternative reinforcement at Wave 2. Lower parental education at Wave 1 was associated with lower alternative reinforcement at Wave 2, which in turn was associated with greater likelihood of alcohol (range of β_{indirect effects} : -0.007 [95% CI = -0.016, -0.001] to -0.01 [95% CI = -0.018, -0.004]) and marijuana (βs: -0.011 [95% CI = -0.022,-0.002] to -0.018 [95% CI = -0.035, -0.005]) use at Wave 3. Parental education was not associated with use of combustible tobacco products or other drugs at Wave 3 adjusting for Wave 1 combustible tobacco and other drug use, respectively (ps ≥ 0.061).

CONCLUSION

Diminished access to and engagement in substance-free enjoyable activity may in part underlie socioeconomic disparities in adolescent alcohol and marijuana use risk. Increasing substance-free enjoyable activities may be useful in substance abuse prevention in socioeconomically disadvantaged youth.

Striatum on the anxiety map: Small detours into adolescence

Adolescence is the most sensitive period for the development of pathological anxiety. Moreover, specific neural changes associated with the striatum might be related to adolescent vulnerability to anxiety. Up to now, the study of anxiety has primarily focused on the amygdala, bed nucleus of the stria terminalis (BNST), hippocampus and ventromedial prefrontal cortex (vmPFC), while the striatum has typically not been considered as part of the anxiety system. This review proposes the addition of the striatum, a complex, multi-component structure, to the anxiety network by underscoring two lines of research. First, the co-occurrence of the adolescent striatal development with the peak vulnerability of adolescents to anxiety disorders might potentially reflect a causal relationship. Second, the recognition of the role of the striatum in fundamental behavioral processes that do affect anxiety supports the putative importance of the striatum in anxiety. These behavioral processes include (1) attention, (2) conditioning/prediction error, and (3) motivation. This review proposes a simplistic schematic representation of the anxiety circuitry that includes the striatum, and aims to promote further work in this direction, as the role of the striatum in shaping an anxiety phenotype during adolescence could have critical implications for understanding and preventing the peak onset of anxiety disorders during this period. This article is part of a Special Issue entitled SI: Adolescent plasticity.

Using a gamified monitoring app to change adolescents' snack intake: the development of the REWARD app and evaluation design

BACKGROUND

As the snacking pattern of European adolescents is of great concern, effective interventions are necessary. Till now health promotion efforts in children and adolescents have had only limited success in changing adolescents' eating patterns and anthropometrics. Therefore, the present study proposes an innovative approach to influence dietary behaviors in youth based on new insights on effective behavior change strategies and attractive intervention channels to engage adolescents. This article describes the rationale, the development, and evaluation design of the 'Snack Track School' app. The aim of the app is to improve the snacking patterns of Flemish 14- to 16-year olds.

METHODS

The development of the app was informed by the systematic, stepwise, iterative, and collaborative principles of the Intervention Mapping protocol. A four week mHealth intervention was developed based on the dual-system model with behavioral change strategies targeting both the reflective (i.e., active learning, advance organizers, mere exposure, goal-setting, monitoring, and feedback) and automatic processes (i.e., rewards and positive reinforcement). This intervention will be evaluated via a controlled pre-post design in Flemish schools among 1400 adolescents.

DISCUSSION

When this intervention including strategies focused on both the reflective and automatic pathway proves to be effective, it will offer a new scientifically-based vision, guidelines and practical tools for public health and health promotion (i.e., incorporation of learning theories in intervention programs).

TRIAL REGISTRATION

NCT02622165 registrated November 15, 2015 on clinicaltrials.gov.

Sensitivity to reward and adolescents' unhealthy snacking and drinking behavior: the role of hedonic eating styles and availability

Background

Although previous research found a positive association between sensitivity to reward (SR) and adolescents’ unhealthy snacking and drinking behavior, mechanisms explaining these associations remain to be explored. The present study will therefore examine whether the associations between SR and unhealthy snack and/or sugar-sweetened beverage (SSB) intake are mediated by external and/or emotional eating and if this mediation is moderated by availability at home or at school.

Methods

Cross-sectional data on snacking, availability of snacks at home and at school, SR (BAS drive scale) and external and emotional eating (Dutch eating behavior questionnaire) of Flemish adolescents (n = 1104, mean age = 14.7 ± 0.8 years; 51 % boys; 18.0 % overweight) in 20 schools spread across Flanders were collected. Moderated mediation analyses were conducted using generalized structural equation modeling in three steps: (1) direct association between SR and unhealthy snack or SSB intake, (2) mediation of either external or emotional eating and (3) interaction of home or school availability and emotional or external eating.

Results

Partial mediation of external eating (a*b = 0.69, p < 0.05) and of emotional eating (a*b = 0.92, p < 0.01) in the relation between SR and intake of unhealthy snacks was found (step 2). The relation between SR and SSB intake was not mediated by external or emotional eating (step 2). No moderation effects of home or school availability were found (step 3).

Conclusion

Our findings indicate that the association between SR and the consumption of unhealthy snacks is partially explained by external and emotional eating in a population-based sample of adolescents irrespective of the home or school availability of these foods.

Iowa Gambling Task Performance and Executive Function Predict Low-income Urban Preadolescents' Risky Behaviors

This study examines preadolescents' reports of risk-taking as predicted by two different, but related inhibitory control systems involving sensitivity to reward and loss on the one hand, and higher order processing in the context of cognitive conflict, known as executive functioning (EF), on the other. Importantly, this study examines these processes with a sample of inner-city, low-income preadolescents and as such examines the ways in which these processes may be related to risky behaviors as a function of children's levels of both concurrent and chronic exposure to household poverty. As part of a larger longitudinal study, 382 children (ages 9 -11) provided a self-report of risky behaviors and participated in the Iowa Gambling task, assessing bias for infrequent loss (preference for infrequent, high magnitude versus frequent, low magnitude loss) and the Hearts and Flowers task assessing executive functioning. Results demonstrated that a higher bias for infrequent loss was associated with higher risky behaviors for children who demonstrated lower EF. Furthermore, bias for infrequent loss was most strongly associated with higher risk-taking for children facing highest levels of poverty. Implications for early identification and prevention of risk-taking in inner-city preadolescents are discussed.

fMRI functional connectivity applied to adolescent neurodevelopment

The exponential rise in the number of functional brain connectivity studies, particularly those examining intrinsic functional connectivity (iFC) at rest, and the promises of this work for unraveling the ontogeny of functional neural systems motivate this review. Shortly before this explosion in functional connectivity research, developmental neuroscientists had proposed theories based on neural systems models to explain behavioral changes, particularly in adolescence. The current review presents recent advances in imaging in brain connectivity research, which provides a unique tool for the study of neural systems. Understanding the potential of neuroimaging for refining neurodevelopmental models of brain function requires a description of various functional connectivity approaches. In this review, we describe task-based and resting-state functional magnetic resonance imaging (fMRI) analytic strategies, but we focus on iFC findings from resting-state data to describe general developmental trajectories of brain network organization. Finally, we use the example of drug addiction to frame a discussion of psychopathology that emerges in adolescence.

Age-related changes in the intrinsic functional connectivity of the human ventral vs. dorsal striatum from childhood to middle age

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Striatal resting state iFC in 106 healthy individuals ranging from 9 to 44 years.

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Findings cohere with a dorsal–ventral functional dissociation of the striatum.

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Ventral striatal (VS) iFC with insula and anterior cingulate decreased with age.

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Dorsal striatal (DS) iFC with posterior cingulate increased with age.

The striatum codes motivated behavior. Delineating age-related differences within striatal circuitry can provide insights into neural mechanisms underlying ontogenic behavioral changes and vulnerabilities to mental disorders. To this end, a dual ventral/dorsal model of striatal function was examined using resting state intrinsic functional connectivity (iFC) imaging in 106 healthy individuals, ages 9–44. Broadly, the dorsal striatum (DS) is connected to prefrontal and parietal cortices and contributes to cognitive processes; the ventral striatum (VS) is connected to medial orbitofrontal and anterior cingulate cortices, and contributes to affective valuation and motivation. Findings revealed patterns of age-related changes that differed between VS and DS iFCs. We found an age-related increase in DS iFC with posterior cingulate cortex (pCC) that stabilized after the mid-twenties, but a decrease in VS iFC with anterior insula (aIns) and dorsal anterior cingulate cortex (dACC) that persisted into mid-adulthood. These distinct developmental trajectories of VS vs. DS iFC might underlie adolescents’ unique behavioral patterns and vulnerabilities to psychopathology, and also speaks to changes in motivational networks that extend well past 25 years old.

Beyond simple models of self-control to circuit-based accounts of adolescent behavior

Adolescence is the transition from childhood to adulthood that begins around the onset of puberty and ends with relative independence from the parent. This developmental period is one when an individual is probably stronger, of higher reasoning capacity, and more resistant to disease than ever before, yet when mortality rates increase by 200%. These untimely deaths are not due to disease but to preventable deaths associated with adolescents putting themselves in harm's way (e.g., accidental fatalities). We present evidence that these alarming health statistics are in part due to diminished self-control--the ability to inhibit inappropriate desires, emotions, and actions in favor of appropriate ones. Findings of adolescent-specific changes in self-control and underlying brain circuitry are considered in terms of how evolutionarily based biological constraints and experiences shape the brain to adapt to the unique intellectual, physical, sexual, and social challenges of adolescence.

Are there reciprocal relationships between substance use risk personality profiles and alcohol or tobacco use in early adolescence?

AIM

We examined whether reciprocal relationships were present between the SURPS personality profiles and substance use in early adolescence.

METHODS

Longitudinal data of four-waves of a broader effectiveness study were used from 1068 early adolescents.

RESULTS

Our cross-lagged models indicated that sensation seeking and impulsivity show strongest reciprocal associations with substance use during early adolescence. In contrast, no reciprocity was present between substance use and anxiety sensitivity and only one reciprocal relationship was present between substance use and hopelessness.

CONCLUSIONS

In trying to prevent early adolescents from alcohol and tobacco use, it might be of key importance to acknowledge the mutual influence between certain personality profiles and substance use. Specifically, sensation seeking and impulsivity are relevant during early adolescence and awareness of early adolescents' vulnerability for these personality predispositions is warranted.

Alcohol and tobacco use and heart rate reactivity to a psychosocial stressor in an adolescent population

BACKGROUND

Few studies have investigated physiological stress (re)activity in relation to substance use, especially in adolescents. Using substances is one way to stimulate physiological arousal, therefore inherent hypo-arousal may be associated with substance use in adolescents. The purpose of this study was to examine the relation of autonomic nervous system (ANS) activity with alcohol and tobacco use in adolescents.

METHODS

ANS activity and perceived stress during a social stress procedure were examined in relation to substance use. 275 Dutch adolescents from a general population study provided complete data. Heart rate was recorded continuously during a pre-task rest period, a stressful task period and a post-task recovery period. Alcohol and tobacco use were self-reported.

RESULTS

Adolescents who consumed a medium and high number of alcoholic drinks per week (more than two) exhibited lower heart rates during the entire stress procedure as compared to those who consumed a low number of alcoholic drinks. Adolescents who smoked every day portrayed blunted heart rate reactivity to stress as compared to adolescents who smoked less frequently or not at all. Perceived stress was not related to alcohol or tobacco use.

CONCLUSIONS

Overall lower heart rate in adolescents who drank more and blunted heart rate reactivity to stress in those who used tobacco every day may indicate inherent hypo-arousal of the ANS system in those vulnerable to use substances more often. These adolescents may actively seek out substances in order to achieve a more normalized state of arousal.

Neural systems underlying motivated behavior in adolescence: implications for preventive medicine

OBJECTIVE

Although a time of increased independence and autonomy, adolescence is also a time of vulnerabilities, through increased risk-taking and the emergence of psychopathology. Neurodevelopmental changes during this period may provide a neurobiological basis for this normative rise in deleterious behaviors. Thus, the objective of this review was to identify neurodevelopmental processes underlying the emergence of risk-taking and psychopathology in adolescence, and discuss implications of these findings for prevention.

METHOD

This article reviews literature examining developmental and contextual factors influencing neural functioning in systems mediating threat, reward, and cognitive control. This literature is discussed from the perspective of the Triadic Neural Systems Model of motivated behavior.

RESULTS

Neuroimaging research suggests that neurodevelopmental and contextual factors both contribute to a shift in the functional equilibrium among the Triadic nodes. This equilibrium shift may contribute to negative outcomes of adolescent risk behavior. Most importantly, the balance of this equilibrium and its sensitivity to social and appetitive contexts may be exploited to facilitate prevention of deleterious outcomes.

CONCLUSION

Understanding developmental and contextual factors that influence functioning in motivational neural circuits can inform research on adolescent risk-taking, and may provide targets for novel preventions, for example through the use of incentives to reduce deleterious outcomes.

Nucleus accumbens, thalamus and insula connectivity during incentive anticipation in typical adults and adolescents

Reward neurocircuitry links motivation with complex behavioral responses. Studies of incentive processing have repeatedly demonstrated activation of nucleus accumbens (NAc), thalamus, and anterior insula, three key components of reward neurocircuitry. The contribution of the thalamus to this circuitry in humans has been relatively ignored, a gap that needs to be filled, given the central role of this structure in processing and filtering information. This study aimed to understand how these three regions function as a network during gain or loss anticipation in adults and youth. Towards this goal, functional magnetic resonance imaging (fMRI) and dynamic causal modeling (DCM) were used to examine effective connectivity among these three nodes in healthy adults and adolescents who performed the monetary incentive delay (MID) task. Seven connectivity models, based on anatomic connections, were tested. They were estimated for incentive anticipation and underwent Bayesian Model Selection (BMS) to determine the best-fit model for each adult and adolescent group. Connection strengths were extracted from the best-fit model and examined for significance in each group. These variables were then entered into a linear mixed model to test between-group effects on effective connectivity in reward neurocircuitry. The best-fit model for both groups included all possible anatomic connections. Three main findings emerged: (1) Across the task, thalamus and insula significantly influenced NAc; (2) A broader set of significant connections was found for the loss-cue condition than the gain-cue condition in both groups; (3) Finally, between-group comparisons of connectivity strength failed to detect statistical differences, suggesting that adults and adolescents use this incentive-processing network in a similar manner. This study demonstrates the way in which the thalamus and insula influence the NAc during incentive processing in humans. Specifically, this is the first study to demonstrate in humans the key role of thalamus projections onto the NAc in support of reward processing. Our results suggest that anticipation of gain/loss involves an 'alerting' signal (thalamus) that converges with interoceptive information (insula) to shape action selection programs in the ventral striatum.

Does age of onset of impairment impact on neuropsychological and personality features of adult ADHD?

The consideration of age of onset of impairment as part of the ADHD diagnosis is controversial and has been a revisited issue with the emergence of the new classifications in Psychiatry. The aim of this study is to compare patients with early and late onset of ADHD impairment in terms of neuropsychological and personality characteristics. Adult patients with ADHD (n = 415) were evaluated in the ADHD outpatient program at Hospital de Clínicas de Porto Alegre, Brazil. The diagnostic process for ADHD and comorbidities was based on DSM-IV criteria. The comparison between the two ages of onset groups (before 7; n = 209 or from 7 to 12 years; n = 206) was performed with ANOVA, followed by Stepwise forward regression analyses to restrict the number of comparisons and access the possible effect of multiple confounders. Patients with early onset ADHD present higher scores in novelty seeking in both analyses (respectively P = 0.016 and P = 0.002), but similar cognitive and attention features as compared with the late onset group. These data add to previous evidence that despite a more externalizing profile of early onset ADHD, the overall performance is similar reinforcing the need for awareness and inclusion of the late onset group in DSM-V diagnostic criteria.

Enhancing response inhibition by incentive: comparison of adolescents with and without substance use disorder

Effective response inhibition is a key component of recovery from addiction. Some research suggests that response inhibition can be enhanced through reward contingencies. We examined the effect of monetary incentive on response inhibition among adolescents with and without substance use disorder (SUD) using a fast event-related fMRI antisaccade reward task. The fMRI task permits investigation of how reward (monetary incentive) might modulate inhibitory control during three task phases: cue presentation (reward or neutral trial), response preparation, and response execution. Adolescents with lifetime SUD (n=12; 100% marijuana use disorder) were gender and age-matched to healthy controls (n=12). Monetary incentive facilitated inhibitory control for SUD adolescents; for healthy controls, the difference in error rate for neutral and reward trials was not significant. There were no significant differences in behavioral performance between groups across reward and neutral trials, however, group differences in regional brain activation were identified. During the response preparation phase of reward trials, SUD adolescents, compared to controls, showed increased activation of prefrontal and oculomotor control (e.g., frontal eye field) areas, brain regions that have been associated with effective response inhibition. Results indicate differences in brain activation between SUD and control youth when preparing to inhibit a prepotent response in the context of reward, and support a possible role for incentives in enhancing response inhibition among youth with SUD.

Neurobiology of the adolescent brain and behavior: implications for substance use disorders

OBJECTIVE

Adolescence is a developmental period that entails substantial changes in risk-taking behavior and experimentation with alcohol and drugs. Understanding how the brain is changing during this period relative to childhood and adulthood and how these changes vary across individuals are key in predicting risk for later substance abuse and dependence.

METHOD

This review discusses recent human imaging and animal work in the context of an emerging view of adolescence as characterized by a tension between early emerging "bottom-up" systems that express exaggerated reactivity to motivational stimuli and later maturing "top-down" cognitive control regions. Behavioral, clinical, and neurobiological evidences are reported for dissociating these two systems developmentally. The literature on the effects of alcohol and its rewarding properties in the brain is discussed in the context of these two systems.

RESULTS

Collectively, these studies show curvilinear development of motivational behavior and the underlying subcortical brain regions, with a peak inflection from 13 to 17 years. In contrast, prefrontal regions, important in top-down regulation of behavior, show a linear pattern of development well into young adulthood that parallels that seen in behavioral studies of impulsivity.

CONCLUSIONS

The tension or imbalance between these developing systems during adolescence may lead to cognitive control processes being more vulnerable to incentive-based modulation and increased susceptibility to the motivational properties of alcohol and drugs. As such, behavior challenges that require cognitive control in the face of appetitive cues may serve as useful biobehavioral markers for predicting which teens may be at greater risk for alcohol and substance dependence.