Risk taking and the adolescent reward system: a potential common link to substance abuse

From individual motivation to substance use initiation: A longitudinal cohort study assessing the associations between reward sensitivity and subsequent risk of substance use initiation among US adolescents

BACKGROUND

Substance use in youth remains a pressing problem in the United States. Existing studies have shown the importance of neuropathways responsible for affective response and reward motivation in adolescents' substance use initiation and maintenance. However, limited observational studies have explored the relationship between aspects of behavioral motivation traits and the likelihood of substance use initiation in adolescents. In this prospective cohort study, we assessed the associations between behavioral motivation traits based on the Behavioral Inhibition and Approach Systems (BIS-BAS) Scale and substance use initiation using data from the Adolescent Brain Cognitive Development (ABCD) study.

METHOD

In the 9216 eligible sample population, we assessed the associations between mean Behavioral Inhibition System (BIS) / Behavioral Approach System (BAS) scores measured at year 2 of the ABCD study and substance use initiation at year 3 of the ABCD study using multivariable logistic regressions adjusting for ABCD study site, sampling weights, as well as sociodemographic characteristics.

RESULTS

We found that higher BIS mean score was associated with higher odds of initiating substance use at year 3 (AOR=1.20, 95 % CI: 1.03, 1.40). Out of three BAS measure categories, only BAS Fun-seeking mean score was positively associated with higher odds of initiating substance use at year 3 (AOR=1.23, 95 % CI: 1.07, 1.43).

CONCLUSION

Our study showed that inhibitory and fun-seeking behavioral tendencies are associated with an increased likelihood of substance use initiation in adolescents. Our findings suggest a potential pathway linking emotional traits to early substance initiation in adolescents.

Mindfulness facets are differentially related with reward processing stages in striatum and alcohol use in adolescence

Attenuated functional processing of non-drug rewards in striatal regions is an important mechanism in the transition from normal to hazardous alcohol use. Recent interventions seek to enhance nondrug reward processing through mindfulness, a mechanism that targets attention regulation and self-regulatory processes. It is yet unclear which specific aspects of mindfulness and which stages of reward processing are relevant preventive targets, particularly in adolescence, where alcohol use is often initiated and reward relating processing streams undergo continuous maturation. Fifty-four 14- and 16-year-old adolescents (54% female) completed the monetary incentive delay task (MID) during event-related functional magnetic resonance imaging. Alcohol use and dispositional mindfulness facets were measured using self-report instruments. Mindful Attention Regulation was positively associated with anticipatory reward processing in ventral striatum, whereas feedback-related processing in dorsal striatum was associated with the mindfulness facet Body-Listening. Only Attention Regulation was additionally associated with frequency of alcohol consumption and mediated the relationship between functional activation in ventral striatum during reward anticipation and alcohol use. Attention Regulation, beyond other mindfulness facets, might contribute to potentially triggering neural mechanisms of anticipatory, but not feedback-related reward processing and alcohol use, presenting a potential target for preventive efforts in combating transitions to substance-related disorders in adolescents.

Changes in Rest-Activity Rhythms in Adolescents as They Age: Associations With Brain and Behavioral Changes in the ABCD Study

OBJECTIVE

Adolescents with disrupted rest-activity rhythms (RARs), including shorter sleep duration, later sleep timing, and low physical activity levels, are at greater risk for mental health and behavioral problems. It remains unclear whether the same associations can be observed for within-subject changes in RARs.

METHOD

This longitudinal investigation on RARs used Fitbit data from the Adolescent Brain Cognitive Development (ABCD) Study at the 2-year follow-up (FL2) (ages 10-13 years) and 4-year follow-up (FL4) (ages 13-16 years). Good-quality Fitbit data were available for 963 youths at both time points. Changes in RARs from FL2 to FL4, their environmental and demographic contributors, and brain and behavioral correlates were examined.

RESULTS

From FL2 to FL4, adolescents showed decreases in sleep duration and physical activity as well as delayed sleep timing (Cohen d = 0.44-0.75). Contributions of environmental and demographic factors to RAR changes were greatest for sleep timing (explained 10% variance) and least for sleep duration (explained 1% variance). Delays in sleep timing had stronger correlations with behavioral problems including impulsivity and poor academic performance than reductions in sleep duration or physical activity. Additionally, the various brain measures differed in their sensitivity to RAR changes. Reductions in sleep duration were associated with decreased functional connectivity between subcortical regions and sensorimotor and cingulo-opercular networks and with enhanced functional connectivity between sensorimotor, visual, and auditory networks. Delays in sleep timing were mainly associated with gray matter changes in subcortical regions.

CONCLUSION

The current findings corroborate the importance of sleep and physical activity in brain neurodevelopment and behavioral problems in adolescents. RARs might serve as biomarkers for monitoring behavioral problems and be potential therapeutic targets for mental disorders in adolescents.

Sex differences in variables affecting short-term success in substance use disorder treatment

Because of the stigma surrounding patients with substance use disorder (SUD) and difficulties with follow-up, data on outcomes is limited. We explore real-world data from a prospectively collected database to determine characteristics that contribute to the completion of acute treatment. Our cohort consisted of data from 1039 patients treated at a single facility. Success was defined as successful discharge from the program. Failure was defined as relapse or signing out against medical advice during treatment. We examined 43 distinct features collected at time of treatment using multivariate analysis. In the total cohort and both sexes, longer length of stay (p ≤ 0.01) was linked to treatment failure. When we examined the cohort by sex, variables associated with success and failure differed between groups. Among females, goal-directed thinking (p ≤ 0.05) correlated with treatment success. Taking unnecessary risks (p < 0.05), having a detailed suicide plan (p ≤ 0.001), and constricted thinking (p ≤ 0.01) predicted treatment failure. In males, prior arrest for driving under the influence (p ≤ 0.05), and presence of phobias, paranoias, and delusions (p ≤ 0.05) were associated with treatment failure. Identifying patients prone to acute therapy failure may guide more personalized treatment, thereby increasing success rates. When considering SUD treatments for patients, we must stratify based on patient characteristics.

Neural response to monetary incentives in acquired adolescent depression after mild traumatic brain injury: Stage 2 Registered Report

Depression is a common consequence of traumatic brain injury. Separately, spontaneous depression-arising without brain injury-has been linked to abnormal responses in motivational neural circuitry to the anticipation or receipt of rewards. It is unknown if post-injury and spontaneously occurring depression share similar phenotypic profiles. This issue is compounded by the fact that nearly all examinations of these psychiatric sequelae are post hoc: there are rarely any prospective assessments of mood and neural functioning before and after a brain injury. In this Stage 2 Registered Report, we used the Adolescent Brain Cognitive Development Consortium dataset to examine if a disruption in functional neural responses to rewards is present in patients with depression after a mild traumatic brain injury. Notably, this study provides an unparalleled opportunity to examine the trajectory of neuropsychiatric symptoms longitudinally within-subjects. This allowed us to isolate mild traumatic brain injury-specific variance independent from pre-existing functioning. Here, we focus on a case-control comparison between 43 youth who experienced a mild traumatic brain injury between MRI visits, and 43 well-matched controls. Contrary to pre-registered predictions (https://osf.io/h5uba/), there was no statistically credible increase in depression in mild traumatic brain injury cases relative to controls. Mild traumatic brain injury was associated with subtle changes in motivational neural circuit recruitment during the anticipation of incentives on the Monetary Incentive Delay paradigm. Specifically, changes in neural recruitment appeared to reflect a failure to deactivate 'task-negative' brain regions (ventromedial prefrontal cortex), alongside blunted recruitment of 'task-positive' regions (anterior cingulate, anterior insula and caudate), during the anticipation of reward and loss in adolescents following mild brain injuries. Critically, these changes in brain activity were not correlated with depressive symptoms at either visit or depression change scores before and after the brain injury. Increased time since injury was associated with a recovery of cognitive functioning-driven primarily by processing speed differences-but depression did not scale with time since injury. These cognitive changes were also uncorrelated with neural changes after mild traumatic brain injury. This report provides evidence that acquired depression may not be observed as commonly after a mild traumatic brain injury in late childhood and early adolescence, relative to findings in adult cases. Several reasons for these differing findings are considered, including sampling enrichment in retrospective cohort studies, under-reporting of depressive symptoms in parent-report data, and neuroprotective factors in childhood and adolescence.

Early adversity and sexual diversity: the importance of self-reported and neurobiological sexual reward sensitivity

Work shows that sexually-diverse individuals face high rates of early life adversity and in turn increased engagement in behavioral outcomes traditionally associated with adversity, such as sexual risk taking. Recent theoretical work suggests that these associations may be attributable to heightened sexual reward sensitivity among adversity-exposed women. We aimed to test these claims using a combination of self-report and EEG measures to test the relationship between early adversity, sexual reward sensitivity (both self-reported and EEG measured) and sexual risk taking in a sexually diverse sample of cis-gender women (N = 208) (Mage = 27.17, SD = 6.36). Results showed that childhood SES predicted self-reported sexual reward sensitivity which in turn predicted numbers of male and female sexual partners. In contrast we found that perceived childhood unpredictability predicted neurobiological sexual reward sensitivity as measured by EEG which in turn predicted male sexual partner number. The results presented here provide support for the notion that heightened sexual reward sensitivity may be a pathway through which early life adversity augments future sexual behavior, and underscores the importance of including greater attention to the dynamics of pleasure and reward in sexual health promotion.

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

Background

Adolescents with disrupted rest-activity rhythms (RAR) including shorter sleep duration, later sleep timing and low physical activity levels have higher risk for mental and behavioral problems. However, it remains unclear whether the same associations can be observed for within-subject changes in RAR.

Methods

Our longitudinal investigation on RAR used Fitbit data from the Adolescent Brain Cognitive Development (ABCD) Study at the 2-year (FL2: aged 10-13 years) and 4-year follow-up (FL4: aged 13-16 years). 963 youths had good-quality Fitbit data at both time points. In this study we examined changes in RAR from FL2 to FL4, their environmental and demographic contributors as well as brain and behavioral correlates.

Results

From FL2 to FL4, adolescents showed decreases in sleep duration and physical activity as well as delayed sleep timing (Cohen's d .44-.75). The contributions of environmental and demographic factors to RAR changes were greatest to sleep timing (explained 10% variance) and least to sleep duration (explained 1% variance). Delays in sleep timing had stronger correlations with behavioral problems including greater impulsivity and poor academic performance than reductions in sleep duration or physical activity. Additionally, the various brain measures differed in their sensitivity to RAR changes. Reductions in sleep duration were associated with decreased brain functional connectivity between subcortical regions and sensorimotor and cingulo-opercular networks and with enhanced functional connectivity between sensorimotor, visual and auditory networks. Delays in sleep timing were mainly associated with grey matter changes in subcortical regions.

Conclusions

The current findings corroborate the role of sleep and physical activity in adolescent's brain neurodevelopment and behavior problems. RAR might serve as biomarkers for monitoring behavioral problems in adolescents and to serve as potential therapeutic targets for mental disorders.

Prevalence of substance use disorders and associations with mindfulness, impulsive personality traits and psychopathological symptoms in a representative sample of adolescents in Germany

Adolescence is a critical phase for the development of substance use disorders (SUDs). For Europe and Germany, there are limited data on problematic substance use from representative youth samples. Trait mindfulness is relevant in buffering against substance use-related problems and associated deficits in self-regulatory control. The objective of this study is to estimate 12-month prevalence rates for SUDs in a representative sample of adolescents in Germany and to examine associations with mindfulness and related factors such as stress, impulsivity, sensation seeking and symptoms of psychopathology. A sample of 4001 adolescents aged 12-18 years from Germany was surveyed based on DSM-IV diagnostic criteria for SUDs. Logistic regression analyses were used to examine associations with mindfulness-related variables. Criteria of at least one of the assessed SUDs were endorsed by 11.2% of the adolescents. Alcohol use disorders had the highest prevalence rate (10.1%) followed by cannabis use disorders (2.6%). For both substances, the criteria for abuse were met about twice as often as those for dependence. The prevalence of cigarette dependence was 1.7%, while the prevalence for e-cigarette dependence was only 0.1%. Prevalence rates were higher for male youth and increasing with age. SUD prevalence was also related to mindfulness, impulsivity and sensation seeking and externalizing symptoms of psychopathology. The statistically significant associations varied across different SUDs. SUDs appear highly prevalent among German adolescents. The results have public health implications with regard to treatment needs and prevention measures in the youth population in Germany.

Family history of substance use disorder and parental impulsivity are differentially associated with neural responses during risky decision-making

Background

Risky decision-making is associated with the development of substance use behaviors during adolescence. Although prior work has investigated risky decision-making in adolescents at familial high risk for developing substance use disorders (SUDs), little research has controlled for the presence of co-morbid externalizing disorders (EDs). Additionally, few studies have investigated the role of parental impulsivity in offspring neurobiology associated with risky decision-making.

Methods

One-hundred twenty-five children (28 healthy controls, 47 psychiatric controls with EDs without a familial history of SUD, and 50 high-risk children with co-morbid EDs with a familial history of SUD) participated in the Balloon Analog Risk Task while undergoing functional magnetic resonance imaging. Impulsivity for parents and children was measured using the UPPS-P Impulsive Behavior Scale.

Results

We found that individuals in the psychiatric control group showed greater activation, as chances of balloon explosion increased, while making choices, relative to the healthy control and high-risk groups in the rostral anterior cingulate cortex (rACC) and lateral orbitofrontal cortex (lOFC). We also found a positive association between greater activation and parental impulsivity in these regions. However, within rACC, this relationship was moderated by group, such that there was a positive relationship between activation and parental impulsivity in the HC group, but an inverse relationship in the HR group.

Conclusions

These findings suggest that there are key differences in the neurobiology underlying risky decision-making in individuals with EDs with and without a familial history of SUD. The current findings build on existing models of neurobiological factors influencing addiction risk by integrating parental factors. This work paves the way for more precise risk models in which to test preventive interventions.

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.

Substance Abuse in Emerging Adults: The Role of Neuromelanin and Ventral Striatal Response to Social and Monetary Rewards

Perturbations in dopamine system function may increase risk of substance use disorder (SUD). We recently demonstrated that neuromelanin (NM) MRI signal in the substantia nigra, a non-invasive index of dopamine system function, is elevated in long term cocaine users (Cassidy et al., 2020). However, it is unclear whether elevated NM-MRI signal is linked to risk of SUD, or is a byproduct of long-term drug use. Our prior work failed to show relations between NM-MRI signal and functional engagement of ventral striatum during a monetary reward task. However, social experiences are commonly linked to drug use and relapse. Given that, NM-MRI signal may be more closely linked to ventral striatal engagement during social, rather than monetary reward processing. Emerging adults (n = 33, 21.88 ± 4.35 years) with varying levels of substance abuse, but without SUD, underwent NM-MRI and fMRI during social and monetary reward processing tasks. Voxelwise analysis within the substantia nigra (SN) demonstrated lower NM-MRI signal was associated with more severe substance abuse. Lower right ventral striatal engagement to social reward was also associated with more severe substance abuse. This relation was moderated by SN NM-MRI signal such that diminished striatal response to reward was associated with greater substance abuse among those with low NM-MRI signal, but lower substance abuse among those with high NM-MRI signal. Unexpectedly, higher right ventral striatal engagement during monetary reward was associated with more severe substance abuse. This relation was moderated by SN NM-MRI signal such that greater striatal response to reward was associated with greater substance abuse among those with low NM-MRI signal. Taken together, we provide preliminary evidence that, in emerging adults, low rather than high dopamine system function may increase risk of substance abuse, and strengthen the association between substance use and the brain's sensitivity to social and monetary outcomes in different ways.

Structural brain morphometry as classifier and predictor of ADHD and reward-related comorbidities

Attention deficit/hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders, and around two-thirds of affected children report persisting problems in adulthood. This negative trajectory is associated with high comorbidity with disorders like obesity, depression, or substance use disorder (SUD). Decreases in cortical volume and thickness have also been reported in depression, SUD, and obesity, but it is unclear whether structural brain alterations represent unique disorder-specific profiles. A transdiagnostic exploration of ADHD and typical comorbid disorders could help to understand whether specific morphometric brain changes are due to ADHD or, alternatively, to the comorbid disorders. In the current study, we studied the brain morphometry of 136 subjects with ADHD with and without comorbid depression, SUD, and obesity to test whether there are unique or common brain alterations. We employed a machine-learning-algorithm trained to classify subjects with ADHD in the large ENIGMA-ADHD dataset and used it to predict the diagnostic status of subjects with ADHD and/or comorbidities. The parcellation analysis demonstrated decreased cortical thickness in medial prefrontal areas that was associated with presence of any comorbidity. However, these results did not survive correction for multiple comparisons. Similarly, the machine learning analysis indicated that the predictive algorithm grouped most of our ADHD participants as belonging to the ADHD-group, but no systematic differences between comorbidity status came up. In sum, neither a classical comparison of segmented structural brain metrics nor an ML model based on the ADHD ENIGMA data differentiate between ADHD with and without comorbidities. As the ML model is based in part on adolescent brains, this might indicate that comorbid disorders and their brain changes are not captured by the ML model because it represents a different developmental brain trajectory.

Investigating the association between smoking, environmental tobacco smoke exposure and reward-related brain activity in adolescent experimental smokers

Reduced anticipatory reward‐related activity, especially in the ventral striatum (VS), may underly adolescent vulnerability to develop nicotine dependence. It remains unclear whether nicotine uptake caused by environmental tobacco smoke (ETS) exposure, known to be associated with future smoking, might prompt similar changes in the brain's reward system, rendering adolescents vulnerable for development of nicotine dependence. To address this question, we tested whether current ETS exposure and monthly smoking are associated with VS hypoactivity for non‐drug rewards in experimental smoking adolescents. One‐hundred adolescents performed a monetary incentive delay task while brain activity was measured using fMRI. To test the hypothesized relationship, we used a variety of approaches: (1) a whole‐brain voxel‐wise approach, (2) an region‐of‐interest approach in the VS using frequentist and Bayesian statistics and (3) a small volume voxel‐wise approach across the complete striatum. The results converged in revealing no significant relationships between monthly smoking, ETS exposure and reward‐related brain activation across the brain or in the (ventral) striatum specifically. However, Bayesian statistics showed only anecdotal evidence for the null hypothesis in the VS, providing limited insight into the (non‐)existence of the hypothesized relationship. Based on these results, we speculate that blunted VS reward‐related activity might only occur after relatively high levels of exposure or might be associated with more long term effects of smoking. Future studies would benefit from even larger sample sizes to reliably distinguish between the null and alternative models, as well as more objective measures of (environmental) smoking via using devices such as silicone wristbands.

Characterizing reward system neural trajectories from adolescence to young adulthood

Mixed findings exist in studies comparing brain responses to reward in adolescents and adults. Here we examined the trajectories of brain response, functional connectivity and task-modulated network properties during reward processing with a large-sample longitudinal design. Participants from the IMAGEN study performed a Monetary Incentive Delay task during fMRI at timepoint 1 (T1; n = 1304, mean age=14.44 years old) and timepoint 2 (T2; n = 1241, mean age=19.09 years). The Alcohol Use Disorders Identification Test (AUDIT) was administrated at both T1 and T2 to assess a participant’s alcohol use during the past year. Voxel-wise linear mixed effect models were used to compare whole brain response as well as functional connectivity of the ventral striatum (VS) during reward anticipation (large reward vs no-reward cue) between T1 and T2. In addition, task-modulated networks were constructed using generalized psychophysiological interaction analysis and summarized with graph theory metrics. To explore alcohol use in relation to development, participants with no/low alcohol use at T1 but increased alcohol use to hazardous use level at T2 (i.e., participants with AUDIT≤2 at T1 and ≥8 at T2) were compared against those with consistently low scores (i.e., participants with AUDIT≤2 at T1 and ≤7 at T2). Across the whole sample, lower brain response during reward anticipation was observed at T2 compared with T1 in bilateral caudate nucleus, VS, thalamus, midbrain, dorsal anterior cingulate as well as left precentral and postcentral gyrus. Conversely, greater response was observed bilaterally in the inferior and middle frontal gyrus and right precentral and postcentral gyrus at T2 (vs. T1). Increased functional connectivity with VS was found in frontal, temporal, parietal and occipital regions at T2. Graph theory metrics of the task-modulated network showed higher inter-regional connectivity and topological efficiency at T2. Interactive effects between time (T1 vs. T2) and alcohol use group (low vs. high) on the functional connectivity were observed between left middle temporal gyrus and right VS and the characteristic shortest path length of the task-modulated networks. Collectively, these results demonstrate the utility of the MID task as a probe of typical brain response and network properties during development and of differences in these features related to adolescent drinking, a reward-related behaviour associated with heightened risk for future negative health outcomes.

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Imaging data during reward anticipation at T1 (age 14) and T2 (age 19) was compared.

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Brain response decreased in subcortical areas and increased in cortical areas at T2.

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Functional connectivity (FC) with the ventral striatum increased at T2.

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Topological efficiency of task-modulated network increased at T2.

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The developmental pattern was altered in those who increased drinking most at T2.

Exploring the genetic overlap of suicide-related behaviors and substance use disorders

Suicide-related behaviors are heterogeneous and transdiagnostic, and may demonstrate varying levels of genetic overlap with different substance use disorders (SUDs). We used linkage disequilibrium score regression, genomic structural equation models, and Mendelian randomization to examine the genetic relationships between several SUDs and suicide-related behaviors. Our analyses incorporated summary statistics from the largest genome-wide association studies (GWAS) of problematic alcohol use, the Fagerström test for nicotine dependence, cannabis use disorder, and opioid use disorder (Ns ranging from 46,213-435,563) and GWAS of ever self-harmed, suicide attempt, and suicide death (Ns ranging from 18,223-117,733). We also accounted for genetic liability to depression (N = 500,199) and risk tolerance (N = 315,894). Suicide-related behaviors were significantly genetically correlated with each other and each SUD, but there was little evidence of causal relationships between the traits. Simultaneously correlating a common SUD factor with each specific suicide indicator while controlling for depression and risk tolerance revealed significant, positive genetic correlations between the SUD factor and suicide-related behaviors (rg  = 0.26-0.45, SE = 0.08-0.09). In the model, depression's association with suicide death (β = 0.42, SE = 0.06) was weaker compared to ever-self harmed and suicide attempt (β = 0.58, SE = 0.05 and β = 0.50, SE = 0.06, respectively). We identify a general level of genetic overlap between SUDs and suicide-related behaviors, which is independent of depression and risk tolerance. Additionally, our findings suggest that genetic and behavioral contributions to suicide death may somewhat differ from nonlethal suicide-related behaviors.

Shorter Duration and Lower Quality Sleep Have Widespread Detrimental Effects on Developing Functional Brain Networks in Early Adolescence

Sleep is critical for cognitive health, especially during complex developmental periods such as adolescence. However, its effects on maturating brain networks that support cognitive function are only partially understood. We investigated the impact of shorter duration and reduced quality sleep, common stressors during development, on functional network properties in early adolescence-a period of significant neural maturation, using resting-state functional magnetic resonance imaging from 5566 children (median age = 120.0 months; 52.1% females) in the Adolescent Brain Cognitive Development cohort. Decreased sleep duration, increased sleep latency, frequent waking up at night, and sleep-disordered breathing symptoms were associated with lower topological efficiency, flexibility, and robustness of visual, sensorimotor, attention, fronto-parietal control, default-mode and/or limbic networks, and with aberrant changes in the thalamus, basal ganglia, hippocampus, and cerebellum (P < 0.05). These widespread effects, many of which were body mass index-independent, suggest that unhealthy sleep in early adolescence may impair neural information processing and integration across incompletely developed networks, potentially leading to deficits in their cognitive correlates, including attention, reward, emotion processing and regulation, memory, and executive control. Shorter sleep duration, frequent snoring, difficulty waking up, and daytime sleepiness had additional detrimental network effects in nonwhite participants, indicating racial disparities in the influence of sleep metrics.

Reward Processing in Novelty Seekers: A Transdiagnostic Psychiatric Imaging Biomarker

BACKGROUND

Dysfunctional reward processing is implicated in multiple mental disorders. Novelty seeking (NS) assesses preference for seeking novel experiences, which is linked to sensitivity to reward environmental cues.

METHODS

A subset of 14-year-old adolescents (IMAGEN) with the top 20% ranked high-NS scores was used to identify high-NS-associated multimodal components by supervised fusion. These features were then used to longitudinally predict five different risk scales for the same and unseen subjects (an independent dataset of subjects at 19 years of age that was not used in predictive modeling training at 14 years of age) (within IMAGEN, n ≈1100) and even for the corresponding symptom scores of five types of patient cohorts (non-IMAGEN), including drinking (n = 313), smoking (n = 104), attention-deficit/hyperactivity disorder (n = 320), major depressive disorder (n = 81), and schizophrenia (n = 147), as well as to classify different patient groups with diagnostic labels.

RESULTS

Multimodal biomarkers, including the prefrontal cortex, striatum, amygdala, and hippocampus, associated with high NS in 14-year-old adolescents were identified. The prediction models built on these features are able to longitudinally predict five different risk scales, including alcohol drinking, smoking, hyperactivity, depression, and psychosis for the same and unseen 19-year-old adolescents and even predict the corresponding symptom scores of five types of patient cohorts. Furthermore, the identified reward-related multimodal features can classify among attention-deficit/hyperactivity disorder, major depressive disorder, and schizophrenia with an accuracy of 87.2%.

CONCLUSIONS

Adolescents with higher NS scores can be used to reveal brain alterations in the reward-related system, implicating potential higher risk for subsequent development of multiple disorders. The identified high-NS-associated multimodal reward-related signatures may serve as a transdiagnostic neuroimaging biomarker to predict disease risks or severity.

Characterising the shared genetic determinants of bipolar disorder, schizophrenia and risk-taking

Increased risk-taking is a central component of bipolar disorder (BIP) and is implicated in schizophrenia (SCZ). Risky behaviours, including smoking and alcohol use, are overrepresented in both disorders and associated with poor health outcomes. Positive genetic correlations are reported but an improved understanding of the shared genetic architecture between risk phenotypes and psychiatric disorders may provide insights into underlying neurobiological mechanisms. We aimed to characterise the genetic overlap between risk phenotypes and SCZ, and BIP by estimating the total number of shared variants using the bivariate causal mixture model and identifying shared genomic loci using the conjunctional false discovery rate method. Summary statistics from genome wide association studies of SCZ, BIP, risk-taking and risky behaviours were acquired (n = 82,315-466,751). Genomic loci were functionally annotated using FUMA. Of 8.6-8.7 K variants predicted to influence BIP, 6.6 K and 7.4 K were predicted to influence risk-taking and risky behaviours, respectively. Similarly, of 10.2-10.3 K variants influencing SCZ, 9.6 and 8.8 K were predicted to influence risk-taking and risky behaviours, respectively. We identified 192 loci jointly associated with SCZ and risk phenotypes and 206 associated with BIP and risk phenotypes, of which 68 were common to both risk-taking and risky behaviours and 124 were novel to SCZ or BIP. Functional annotation implicated differential expression in multiple cortical and sub-cortical regions. In conclusion, we report extensive polygenic overlap between risk phenotypes and BIP and SCZ, identify specific loci contributing to this shared risk and highlight biologically plausible mechanisms that may underlie risk-taking in severe psychiatric disorders.

Galvanic Vestibular Stimulation influences risk-taking behaviour

Risk-taking behaviour is an essential aspect of our interactions with the environment. Here we investigated whether vestibular inputs influence behavioural measurement of risk-taking propensity. We have combined bipolar Galvanic Vestibular Stimulation (GVS) with a well-known and established risk-taking behaviour task, namely the Balloon Analogue Risk Task (BART). A sham stimulation was used to control for non-specific effects. Left-anodal and right-cathodal GVS (L-GVS), which preferentially activates the vestibular projections in the right hemisphere, decreased the willingness to take risk during the BART compared with right-anodal and left-cathodal GVS (R-GVS), which activates the left hemisphere. This proved a specific vestibular effect which depends on GVS polarity. Conversely, no generic vestibular effect, defined as the adjusted average of L-GVS and R-GVS conditions compared to sham, emerged, excluding non-specific vestibular effects. Our results confirmed recent findings of a vestibular contribution to decision-making and strategy control behaviour. We suggest that the vestibular-mediated balancing of risk seeking behaviour is an important element of the brain's capacity to adapt to the environment.

Transdiagnostic neuroimaging of reward system phenotypes in ADHD and comorbid disorders

ADHD is a disorder characterized by changes in the reward system and which is highly comorbid with other mental disorders, suggesting common neurobiological pathways. Transdiagnostic neuroimaging findings could help to understand whether a dysregulated reward pathway might be the actual link between ADHD and its comorbidities. We here synthesize ADHD neuroimaging findings on the reward system with findings in obesity, depression, and substance use disorder including their comorbid appearance regarding neuroanatomical features (structural MRI) and activation patterns (resting-state and functional MRI). We focus on findings from monetary-incentive-delay (MID) and delay-discounting (DD) tasks and then review data on striatal connectivity and volumetry. Next, for better understanding of comorbidity in adult ADHD, we discuss these neuroimaging features in ADHD, obesity, depression and substance use disorder and ask whether ADHD heterogeneity and comorbidity are reflected by a common dysregulation in the reward system. Finally, we highlight conceptual issues related to heterogeneous paradigms, different phenotyping, longitudinal prediction and highlight some promising future directions for using striatal reward functioning as a clinical biomarker.

Substance Use Initiation, Particularly Alcohol, in Drug-Naive Adolescents: Possible Predictors and Consequences From a Large Cohort Naturalistic Study

OBJECTIVE

It is unclear whether deviations in brain and behavioral development, which may underpin elevated substance use during adolescence, are predispositions for or consequences of substance use initiation. Here, we examine behavioral and neuroimaging indices at early and mid-adolescence in drug-naive youths to identify possible predisposing factors for substance use initiation and its possible consequences.

METHOD

Among 304 drug-naive adolescents at baseline (age 14 years) from the IMAGEN dataset, 83 stayed drug-naive, 133 used alcohol on 1 to 9 occasions, 42 on 10 to 19 occasions, 27 on 20 to 39 occasions, and 19 on >40 occasions at follow-up (age 16 years). Baseline measures included brain activation during the Monetary Incentive Delay task. Data at both baseline and follow-up included measures of trait impulsivity and delay discounting.

RESULTS

From baseline to follow-up, impulsivity decreased in the 0 and 1- to 9-occasions groups (p < .004), did not change in the 10- to 19-occasions and 20- to 29-occasions groups (p > .294), and uncharacteristically increased in the >40-occasions group (p = .046). Furthermore, blunted medial orbitofrontal cortex activation during reward outcome at baseline significantly predicted higher alcohol use frequency at follow-up, above and beyond behavioral and clinical variables (p = .008).

CONCLUSION

These results suggest that the transition from no use to frequent drinking in early to mid-adolescence may disrupt normative developmental changes in behavioral control. In addition, blunted activity of the medial orbitofrontal cortex during reward outcome may underscore a predisposition toward the development of more severe alcohol use in adolescents. This distinction is clinically important, as it informs early intervention efforts in preventing the onset of substance use disorder in adolescents.

Regulatory Focus and Substance Use in Adolescents: Protective Effects of Prevention Orientation

Substance use is a major risk factor for negative health and functioning outcomes among middle schoolers. The purpose of this study was to assess whether individual differences in the adolescents' goal orientation are associated with elevated or attenuated risk for substance use. Regulatory focus theory stipulates that individuals vary in their strength of orientation toward promotion goals ("making good things happen") and prevention goals ("keeping bad things from happening"). Objectives: We sought to examine the association between individual differences in regulatory focus and adolescents' reports of their own and their friends' substance use. Methods: Participants were 241 seventh grade students who completed measures of regulatory focus (promotion and prevention orientation), self-reported substance use, perceived substance use habits of peers, and demographics. Logistic regression models were used to examine adjusted odds of lifetime tobacco use, alcohol use, and marijuana use for both participants' own use and their reports of friends' use. Results: Prevention orientation was associated with lower odds of all self-reported lifetime substance use outcomes (tobacco, alcohol, and marijuana). Prevention orientation was also associated with lower odds of reporting all types of substance use among friends. Promotion orientation was not associated with any self-reported substance use outcome, and was only associated with higher odds of reporting lifetime alcohol use among friends. Conclusions: These findings underscore the importance of regulatory focus as it relates to adolescent substance use. Future research may seek to incorporate regulatory focus within interventions intended to prevent or delay initiation of substance use in adolescents.

[Neurobiological effects of childhood abuse and neglect as a predisposing factor to substance use disorder]

The article presents data from research literature on the neurobiological consequences of abuse and neglect in childhood. It is shown that early life stress affects the trajectory of brain development, changes the patterns of cognitive behavioral control and reception of rewards, potentially increasing the risk of substance misuse. The combination of this factor with an immature prefrontal cortex can dramatically increase the liability to the development of substance dependence.

The IMAGEN study: a decade of imaging genetics in adolescents

Imaging genetics offers the possibility of detecting associations between genotype and brain structure as well as function, with effect sizes potentially exceeding correlations between genotype and behavior. However, study results are often limited due to small sample sizes and methodological differences, thus reducing the reliability of findings. The IMAGEN cohort with 2000 young adolescents assessed from the age of 14 onwards tries to eliminate some of these limitations by offering a longitudinal approach and sufficient sample size for analyzing gene-environment interactions on brain structure and function. Here, we give a systematic review of IMAGEN publications since the start of the consortium. We then focus on the specific phenotype 'drug use' to illustrate the potential of the IMAGEN approach. We describe findings with respect to frontocortical, limbic and striatal brain volume, functional activation elicited by reward anticipation, behavioral inhibition, and affective faces, and their respective associations with drug intake. In addition to describing its strengths, we also discuss limitations of the IMAGEN study. Because of the longitudinal design and related attrition, analyses are underpowered for (epi-) genome-wide approaches due to the limited sample size. Estimating the generalizability of results requires replications in independent samples. However, such densely phenotyped longitudinal studies are still rare and alternative internal cross-validation methods (e.g., leave-one out, split-half) are also warranted. In conclusion, the IMAGEN cohort is a unique, very well characterized longitudinal sample, which helped to elucidate neurobiological mechanisms involved in complex behavior and offers the possibility to further disentangle genotype × phenotype interactions.

Neural response to rewards predicts risk-taking in late but not early adolescent females

Risk-taking peaks in adolescence and reflects, in part, hyperactivity of the brain's reward system. However, it has not been established whether the association between reward-related brain activity and risk-taking varies across adolescence. The present study investigated how neural reward sensitivity is associated with laboratory risk-taking in a sample of female adolescents as a function of age. Sixty-three female adolescents ages 10-19 completed the Balloon Analogue Risk Task, a laboratory measure of risk-taking behavior, as well as a forced choice monetary gambling task while an electroencephalogram (EEG) was recorded. This gambling task elicits the reward positivity (RewP), a frontocentral event-related potential component that is sensitive to feedback signaling reward. We observed a negative quadratic association between age and risk-taking, such that those in early and late adolescence had lower relative risk-taking compared to mid-adolescence, with risk-taking peaking at around 15 years of age. In predicting risk-taking, we observed an interaction between age and RewP, such that reward-related brain activity was not associated with risk-taking in early adolescence but was associated with a greater propensity for risk in later adolescence. These findings suggest that for females, neural response to rewards is an important factor in predicting risk-taking only in later adolescence.

[Mindfulness in Development-oriented Approaches to Substance Use Prevention and Therapy: Rationale, Design and Objectives of the Research Consortium IMAC-Mind]

Mindfulness in Development-oriented Approaches to Substance Use Prevention and Therapy: Rationale, Design and Objectives of the Research Consortium IMAC-Mind Substance use disorders (SUD) are a major contributor to morbidity and mortality. They are typically initiated during adolescence and can have fatal implications for healthy development. Despite substantial scientific advances, there remains a need to prioritize research directed at reducing risks for SUD, particularly in vulnerable periods and populations from a developmental perspective. Research indicates that reward sensitivity, impulsivity, deficient self-regulation, and stress reactivity develop markedly in childhood and adolescence and play an important role in the initiation and maintenance of SUD. A growing number of research results suggest that these factors can be favorably influenced by mindfulness-based interventions and that mindfulness-based exercises can be successfully integrated into established prevention and treatment programs. In this paper we summarize the conceptual relationships between the development and maintenance of addiction disorders and mindfulness, discuss existing empirical findings with regard to childhood and adolescence, and present the aims, study designs and intervention models of the subprojects from the ongoing research network "IMAC-Mind: Improving Mental Health and Reducing Addiction in Childhood and Adolescence through Mindfulness: Mechanisms, Prevention and Treatment".

Neural substrates of smoking and reward cue reactivity in smokers: a meta-analysis of fMRI studies

Smoking is partly attributed to alterations of reward processing. However, findings on the neurobiological mechanisms that underlie smoking-related and smoking-unrelated reward processing in smokers have been inconsistent. Neuroimaging experiments that used functional magnetic resonance imaging (fMRI) and reported brain responses to smoking-related cues and nonsmoking reward-related cues in smokers and healthy controls as coordinates in a standard anatomic reference space were identified by searching the PubMed, Embase, and Web of Science databases up to December 2018. Three meta-analyses were performed using random-effect nonparametric statistics with Seed-based d Mapping software, with brain activity contrast from individual studies as the input. The striatum showed higher activation in response to smoking-related cues compared with neutral cues in 816 smokers from 28 studies and lower activation in response to nonsmoking reward-related cues in 275 smokers compared with 271 healthy control individuals from 13 studies. The relative reactivity of the putamen to smoking-related cues increased in 108 smokers compared with 107 healthy controls from seven studies. Meta-regression showed that smokers with a greater severity of nicotine dependence exhibited less engagement of the striatum in response to both smoking-related cues and nonsmoking reward-related cues. The present results reveal the disruption of reward system function in smokers and provide new insights into diverging theories of addiction. With the escalation of nicotine dependence, nicotine appears to exert dynamic effects on reward processing, based on incentive sensitization theory and reward deficiency syndrome theory.

Cannabis-dependent adolescents show differences in global reward-associated network topology: A functional connectomics approach

Adolescence may be a period of increased vulnerability to the onset of drug misuse and addiction due to changes in developing brain networks that support cognitive and reward processing. Cannabis is a widely misused illicit drug in adolescence which can lead to dependence and alterations in reward-related neural functioning. Concerns exist that cannabis-related alterations in these reward networks in adolescence may sensitize behaviour towards all forms of reward that increase the risk of further drug use. Taking a functional connectomics approach, we compared an acutely abstinent adolescent cannabis-dependent (CAN) group with adolescent controls (CON) on global measures of network topology associated with anticipation on a monetary incentive delay task. In the presence of overall superior accuracy, the CAN group exhibited superior global connectivity (clustering coefficient, efficiency, characteristic path length) during monetary gain anticipation compared with the CON group. Additional analyses showed that the CAN group exhibited significantly greater connectivity strength during monetary gain anticipation across a subnetwork that included mesocorticolimbic nodes involving both interhemispheric and intrahemispheric connections. We discuss how these differences in reward-associated connectivity may allude to subtle functional alterations in network architecture in adolescent cannabis-dependence that could enhance the motivation for nondrug reward during acute abstinence.

Does a mindfulness-augmented version of the German Strengthening Families Program reduce substance use in adolescents? Study protocol for a randomized controlled trial

BACKGROUND

Mindfulness training (MT) for parents of adolescents has been shown to improve mental health and stress-related outcomes in individuals and their families. Studies of MT among young people are mainly delivered in educational or clinical settings, and there is a need for controlled studies on both parent-directed and adolescent-directed approaches. It is unclear whether MT has preventive effects for substance use outcomes. The primary objective of this trial is to evaluate the effectiveness of family-based MT targeting both adolescents and their parents to prevent adolescent substance use and enhance neurobehavioral self-regulation skills that play a major role in addiction development and mental health.

METHODS/DESIGN

The trial design is a superiority, two-arm, randomized controlled trial in which families will participate either in the full curriculum of the evidence-based Strengthening Families Program 10-14 (SFP 10-14, German adaptation) or in a mindfulness-enhanced version of this program (SFP-Mind). Both seven-session interventions are highly structured and will each be delivered over a period of approximately 7 weeks. The experimental intervention SFP-Mind is a modified version of the SFP 10-14 in which some elements were eliminated or changed to enable the inclusion of additional parent-directed and adolescent-directed mindfulness components. The primary outcome is adolescent self-reported alcohol use based on an alcohol initiation index at 18-month follow-up. Dispositional mindfulness, impulsivity, and emotion regulation will be included as secondary outcomes and potential mechanisms of action. The study will recruit and randomize 216 adolescents, aged 10-14 years, and their parents who will be followed up for 18 months.

DISCUSSION

This trial aims to evaluate the effectiveness of SFP-Mind for family-based prevention of substance use and promoting mental health in adolescence.

TRIAL REGISTRATION

German Register of Clinical Studies, DRKS00015678. Registered on 25 February 2019.

The Predictive Value of Impulsivity and Risk-Taking Measures for Substance Use in Substance Dependent Offenders

Impulsivity and risk-taking are known to have an important impact on problematic substance use and criminal behavior. This study examined the predictive value of baseline self-report and behavioral impulsivity and risk-taking measures [Delay Discounting Task (DDT), Balloon Analogue Risk Task (BART) and Behavioral Inhibition, Behavioral Activation Scale (BIS/BAS)] in 12-months follow-up substance use outcomes (e.g., use of alcohol, cannabis and other substances) and criminal recidivism (yes/no). Participants were 213 male offenders with a substance use disorder (SUD) under probation supervision. Bivariate regression analyses showed that BIS and BAS levels were associated (respectively) with the use of alcohol and cannabis. Multiple regression analysis showed that BIS was negatively associated with alcohol use at follow-up, whereas cannabis use at baseline and BAS predicted cannabis use at follow-up. At a trend level, interactions between delay discounting and risk-taking, and interactions between baseline cannabis use and BAS and BART predicted cannabis use at follow-up. Other substance use at follow-up was solely predicted by baseline other substance use. Overall, the findings provide marginal support for the predictive utility of impulsivity and risk-taking in accounting for variability in substance use among offenders with a SUD. This may be partly explained by the fact that only a limited number of psychological factors was assessed in this study. The studied population consists of a severe group, in which relapse into substance use or criminal behavior likely is related to complex, interacting biopsychosocial factors, of which impulsivity measures play a relatively small part.

The neurobiology of impulsivity and substance use disorders: implications for treatment

Impulsivity is strongly associated with substance use disorders (SUDs). Our review discusses impulsivity as an underlying vulnerability marker for SUDs, and treatment of co-occurring impulsivity in SUDs. Three factors should be considered for the complex relationship between impulsivity and a SUD: (1) the trait effect of impulsivity, centering on decreased cognitive and response inhibition, (2) the state effect resulting from either acute or chronic substance use on brain structure and function, and (3) the genetic and environmental factors (e.g., age and sex) may influence impulsive behavior associated with SUDs. Both subjective and objective measures are used to assess impulsivity. Together, treatment developments (pharmacological, behavioral, and neurophysiological) should consider these clinically relevant dimensions assessed by a variety of measures, which have implications for treatment matching in individuals with SUD. Despite its heterogeneity, impulsivity is a marker associated with SUDs and may be understood as an imbalance of bottom-up and top-down neural systems. Further investigation of these relationships may lead to more effective SUD treatments.

Adolescent cocaine exposure enhances the GABAergic transmission in the prelimbic cortex of adult mice

We have recently shown in rats that adolescent cocaine exposure induces prolonged modifications on synapses in medial prefrontal cortex (mPFC), which might contribute to long-term behavioral outcomes in adulthood. In this study, we further investigated the molecular mechanisms underlying adolescent cocaine exposure-related psychiatric problems in adulthood, especially focusing on the alterations of GABAergic transmission in prelimbic cortex (PrL), 1 subregion of mPFC. Consistent with a previous study, adolescent cocaine-exposed mice exhibited enhanced anxiety-like behaviors in their adulthood. In the same mice models, depression-like behaviors increased as well, but the conditioned place preference formed normally. In parallel, activities of pyramidal neurons at layer V of PrL were reduced after adolescent cocaine exposure, accompanied by an increase in the percentage of symmetric synapses in PrL of adult mice. Additionally, miniature inhibitory postsynaptic currents rather than miniature excitatory postsynaptic currents were increased on these pyramidal neurons, and increased levels of GABA were found in adult PrL. The molecules in the GABAergic system in adult PrL were also changed by adolescent cocaine use, as indicated by increased glutamate decarboxylase 67 kDa, GABA_A-α1, and decreased GABA transporter 1. In the same mice, some regulators to GABAergic transmission such as neuregulin 1/ErbB4 signals were heightened as well. Collectively, these findings revealed that adolescent cocaine exposure results in permanent enhancement of GABAergic transmission on pyramidal neurons in PrL, which subsequently attenuate the activities of these neurons and ultimately contributes to the development of psychiatric disorders in later life.-Shi, P., Nie, J., Liu, H., Li, Y., Lu, X., Shen, X., Ge, F., Yuan, T.-F., Guan, X. Adolescent cocaine exposure enhances the GABAergic transmission in the prelimbic cortex of adult mice.

Modulation of orbitofrontal-striatal reward activity by dopaminergic functional polymorphisms contributes to a predisposition to alcohol misuse in early adolescence

BACKGROUND

Abnormalities in reward circuit function are considered a core feature of addiction. Yet, it is still largely unknown whether these abnormalities stem from chronic drug use, a genetic predisposition, or both.

METHODS

In the present study, we investigated this issue using a large sample of adolescent children by applying structural equation modeling to examine the effects of several dopaminergic polymorphisms of the D1 and D2 receptor type on the reward function of the ventral striatum (VS) and orbital frontal cortex (OFC), and whether this relationship predicted the propensity to engage in early alcohol misuse behaviors at 14 years of age and again at 16 years of age.

RESULTS

The results demonstrated a regional specificity with which the functional polymorphism rs686 of the D1 dopamine receptor (DRD1) gene and Taq1A of the ANKK1 gene influenced medial and lateral OFC activation during reward anticipation, respectively. Importantly, our path model revealed a significant indirect relationship between the rs686 of the DRD1 gene and early onset of alcohol misuse through a medial OFC × VS interaction.

CONCLUSIONS

These findings highlight the role of D1 and D2 in adjusting reward-related activations within the mesocorticolimbic circuitry, as well as in the susceptibility to early onset of alcohol misuse.

Neural mechanisms of risky decision making in adolescents reporting frequent alcohol and/or marijuana use

Because adolescence is a period of heightened exploration of new behaviors, there is a natural increase in risk taking including initial use of alcohol and marijuana. In order to better understand potential differences in neurocognitive functioning among adolescents who use drugs, the current study aimed to identify the neural substrates of risky decision making that differ among adolescents who are primary users of alcohol or marijuana, primary users of both alcohol and marijuana, and controls who report primary use of neither drug. Participants completed the Balloon Analogue Risk Task (BART) while undergoing functional magnetic resonance imaging. Comparison of brain activation during risky decisions versus non-risky decisions across all subjects revealed greater response to risky decisions in dorsal anterior cinguate cortex (dACC), anterior insula, ventral striatum, and lateral prefrontal cortex. Group comparisons across non-using controls, primary marijuana, primary alcohol, and alcohol and marijuana users revealed several notable differences in the recruitment of brain regions. Adolescents who use both alcohol and marijauna show decreased response during risky decision making compared to controls in insula, striatum, and thalamus, and reduced differentiation of increasing risk in dACC, insula, striatum, and superior parietal lobe compared to controls. These results provide evidence of differential engagement of risky decision making circuits among adolescents with varying levels of alcohol and marijuana use, and may provide useful targets for longitudinal studies that explicitly address causality of these differences.

Cooperative versus competitive influences of emotion and cognition on decision making: A primer for psychiatry research

Clinical research across the developmental spectrum increasingly reveals the nuanced ways in which emotion and cognition can work to either support or derail rational (i.e., healthy or goal-consistent) decision making. However, psychological theories offer discrepant views on how these processes interact, and on whether emotion is helpful or harmful to rational decision making. In order to translate theoretical predictions from basic psychology to clinical research, an understanding of theoretical perspectives on emotion and cognition, as informed by experimental psychology, is needed. Here, I review the ways in which dual-process theories have incorporated emotion into the process of decision making, discussing how they account for both positive and negative influences. I first describe seven theoretical perspectives that make explicit assumptions and predictions about the interaction between emotion and cognition: affect as information, the affect heuristic, risk as feelings, hot versus cool cognition, the somatic parker hypothesis, prospect theory, and fuzzy-trace theory. I then discuss the conditions under which each theoretical perspective conceptualizes emotion as beneficial or harmful to decision making, providing examples from research on psychiatric disorders.

Highlighting the Role of Cognitive and Brain Reserve in the Substance use Disorder Field

BACKGROUND

Cognitive reserve (CR) refers to the ability of an individual to cope with brain pathology remaining free of cognitive symptoms. This protective factor has been related to compensatory and more efficient brain mechanisms involved in resisting brain damage. For its part, Brain reserve (BR) refers to individual differences in the structural properties of the brain which could also make us more resilient to suffer from neurodegenerative and mental diseases.

OBJECTIVE

This review summarizes how this construct, mainly mediated by educational level, occupational attainment, physical and mental activity, as well as successful social relationships, has gained scientific attention in the last years with regard to diseases, such as neurodegenerative diseases, stroke or traumatic brain injury. Nevertheless, although CR has been studied in a large number of disorders, few researches have addressed the role of this concept in drug addiction.

METHODS

We provide a selective overview of recent literature about the role of CR and BR in preventing substance use onset. Likewise, we will also discuss how variables involved in CR (healthy leisure, social support or job-related activities, among others) could be trained and included as complementary activities of substance use disorder treatments.

RESULTS

Evidence about this topic suggests a preventive role of CR and BR on drug use onset and when drug addiction is established, these factors led to less severe addiction-related problems, as well as better treatment outcomes.

CONCLUSION

CR and BR are variables not taken yet into account in drug addiction. However, they could give us a valuable information about people at risk, as well as patient's prognosis.

Blunted Frontostriatal Blood Oxygen Level-Dependent Signals Predict Stimulant and Marijuana Use

BACKGROUND

Occasional recreational stimulant (amphetamine and cocaine) use is an important public health problem among young adults because 16% of those who experiment develop stimulant use disorder. This study aimed to determine whether behavioral and/or neural processing measures can forecast the transition from occasional to problematic stimulant use.

METHODS

Occasional stimulant users completed a Risky Gains Task during functional magnetic resonance imaging and were followed up 3 years later. Categorical analyses tested whether blood oxygen level-dependent (BOLD) responses differentiated occasional stimulant users who became problem stimulant users (n = 35) from those who desisted from stimulant use (n = 75) at follow-up. Dimensional analyses (regardless of problem stimulant user or desisted stimulant use status; n = 144) tested whether BOLD responses predicted baseline and follow-up stimulant and marijuana use.

RESULTS

Categorical results indicated that relative to those who desisted from stimulant use, problem stimulant users 1) made riskier decisions after winning feedback; 2) exhibited lower frontal, insular, and striatal BOLD responses to win/loss feedback after making risky decisions; and 3) displayed lower thalamic but greater temporo-occipital BOLD responses to risky losses than to risky wins. In comparison, dimensional results indicated that lower BOLD signals to risky choices than to safe choices in frontal, striatal, and additional regions predicted greater marijuana use at follow-up.

CONCLUSIONS

Taken together, blunted frontostriatal signals during risky choices may quantify vulnerability to future marijuana consumption, whereas blunted frontostriatal signals to risky outcomes mark risk for future stimulant use disorder. These behavioral and neural processing measures may prove to be useful for identifying ultra-high risk individuals prior to onset of problem drug use.

Mapping adolescent reward anticipation, receipt, and prediction error during the monetary incentive delay task

The functional neuroanatomy and connectivity of reward processing in adults are well documented, with relatively less research on adolescents, a notable gap given this developmental period's association with altered reward sensitivity. Here, a large sample (n = 1,510) of adolescents performed the monetary incentive delay (MID) task during functional magnetic resonance imaging. Probabilistic maps identified brain regions that were reliably responsive to reward anticipation and receipt, and to prediction errors derived from a computational model. Psychophysiological interactions analyses were used to examine functional connections throughout reward processing. Bilateral ventral striatum, pallidum, insula, thalamus, hippocampus, cingulate cortex, midbrain, motor area, and occipital areas were reliably activated during reward anticipation. Bilateral ventromedial prefrontal cortex and bilateral thalamus exhibited positive and negative activation, respectively, during reward receipt. Bilateral ventral striatum was reliably active following prediction errors. Previously, individual differences in the personality trait of sensation seeking were shown to be related to individual differences in sensitivity to reward outcome. Here, we found that sensation seeking scores were negatively correlated with right inferior frontal gyrus activity following reward prediction errors estimated using a computational model. Psychophysiological interactions demonstrated widespread cortical and subcortical connectivity during reward processing, including connectivity between reward-related regions with motor areas and the salience network. Males had more activation in left putamen, right precuneus, and middle temporal gyrus during reward anticipation. In summary, we found that, in adolescents, different reward processing stages during the MID task were robustly associated with distinctive patterns of activation and of connectivity.

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

INTRODUCTION

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

METHOD

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

RESULTS

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

CONCLUSION

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

The anticipation and outcome phases of reward and loss processing: A neuroimaging meta-analysis of the monetary incentive delay task

The processing of rewards and losses are crucial to everyday functioning. Considerable interest has been attached to investigating the anticipation and outcome phases of reward and loss processing, but results to date have been inconsistent. It is unclear if anticipation and outcome of a reward or loss recruit similar or distinct brain regions. In particular, while the striatum has widely been found to be active when anticipating a reward, whether it activates in response to the anticipation of losses as well remains ambiguous. Furthermore, concerning the orbitofrontal/ventromedial prefrontal regions, activation is often observed during reward receipt. However, it is unclear if this area is active during reward anticipation as well. We ran an Activation Likelihood Estimation meta‐analysis of 50 fMRI studies, which used the Monetary Incentive Delay Task (MIDT), to identify which brain regions are implicated in the anticipation of rewards, anticipation of losses, and the receipt of reward. Anticipating rewards and losses recruits overlapping areas including the striatum, insula, amygdala and thalamus, suggesting that a generalised neural system initiates motivational processes independent of valence. The orbitofrontal/ventromedial prefrontal regions were recruited only during the reward outcome, likely representing the value of the reward received. Our findings help to clarify the neural substrates of the different phases of reward and loss processing, and advance neurobiological models of these processes.

Momentary Associations Between Reported Craving and Valuing Health in Daily Smokers

Introduction

Research suggests that a blunted response to nondrug rewards, especially under conditions associated with strong cigarette cravings, is associated with reduced abstinence motivation in daily smokers. One limitation of previous studies is that they have largely focused on monetary rewards as broad representative of nondrug rewards. It remains unclear whether craving dampens responses to more abstract nondrug rewards, such as personal values. Personal values often have a positive valence and are frequently assumed to remain stable across time and situations. However, there may be time-varying and contextual influences on smokers' appraisal of values in daily life. Characterizing fluctuations in value importance in relation to relapse precipitants (eg, craving) may inform interventions that leverage personal values as motivation for cessation.

Methods

Daily smokers (n = 18) completed ecological momentary assessment surveys measuring the importance of specific personal values and smoking-related variables during 8 days of monetarily reinforced cigarette abstinence. We hypothesized that value ratings would demonstrate adequate within-person heterogeneity for multilevel modeling and that within-person fluctuations in craving would be negatively related to valuing personal health.

Results

All values demonstrated adequate within-person variability for multilevel modeling. Within-person craving was negatively related to health valuation (p = .012) and a cross-level interaction (p > .0001) suggested this effect is stronger for individuals who report greater overall craving.

Conclusions

Greater craving is associated with decreased importance of personal health in the moment, particularly for those with high average levels of craving. Timely interventions that bolster importance of health during moments of elevated craving can potentially improve cessation outcomes.

Implications

This study builds on research highlighting the positive influence of personal values in motivating behavior change. Values are an often used, but poorly studied, construct that has considerable utility in smoking cessation. Valuing personal health is frequently reported as a primary motivator for a quit attempt. Inasmuch as personal health is a distal nondrug reward used to motivate smoking abstinence, naturalistic evaluation of health importance, and motivators for continued smoking (ie, craving) could inform the timing and content of smoking treatment. This study is among the first to evaluate momentary assessment of personal values and craving within daily life.

Structural neuroimaging correlates of alcohol and cannabis use in adolescents and adults

BACKGROUND AND AIMS

Chronic alcohol use is associated with lower gray matter volume, and we reported recently that alcohol use showed negative associations with widespread gray matter (GM) volume even among young adults. The current study aimed to test the strength of association between (1) alcohol use and GM volume; (2) alcohol use and white matter (WM) integrity; (3) cannabis use and GM volume; and (4) cannabis use and WM integrity among adults and adolescents.

DESIGN AND SETTING

General linear models within large pooled cross-sectional samples of adolescents and adults who had participated in studies collecting substance use and neuroimaging data in the southwestern United States.

PARTICIPANTS

The current analysis included adults aged 18-55 years (n = 853) and adolescents aged 14-18 years (n = 439) with a range of alcohol and cannabis use.

MEASUREMENTS

The dependent variable was GM volume or WM integrity, with key predictors of alcohol use [Alcohol Use Disorders Identification Test (AUDIT) score] and cannabis use (past 30-day use).

FINDINGS

Alcohol use showed large clusters of negative associations (η_p²  = 0.028-0.145, P < 0.001) with GM volume among adults and to a lesser extent (one cluster; η_p²  = 0.070, P < 0.05) among adolescents. Large clusters showed significant associations (η_p²  = 0.050-0.124, P < 0.001) of higher alcohol use with poorer WM integrity, whereas adolescents showed no significant associations between alcohol use and WM. No associations were observed between structural measures and past 30-day cannabis use in adults or adolescents.

CONCLUSIONS

Alcohol use severity is associated with widespread lower gray matter volume and white matter integrity in adults, and with lower gray matter volume in adolescents.

Predictive modeling for classification of positive valence system symptom severity from initial psychiatric evaluation records

In response to the challenges set forth by the CEGS N-GRID 2016 Shared Task in Clinical Natural Language Processing, we describe a framework to automatically classify initial psychiatric evaluation records to one of four positive valence system severities: absent, mild, moderate, or severe. We used a dataset provided by the event organizers to develop a framework comprised of natural language processing (NLP) modules and 3 predictive models (two decision tree models and one Bayesian network model) used in the competition. We also developed two additional predictive models for comparison purpose. To evaluate our framework, we employed a blind test dataset provided by the 2016 CEGS N-GRID. The predictive scores, measured by the macro averaged-inverse normalized mean absolute error score, from the two decision trees and Naïve Bayes models were 82.56%, 82.18%, and 80.56%, respectively. The proposed framework in this paper can potentially be applied to other predictive tasks for processing initial psychiatric evaluation records, such as predicting 30-day psychiatric readmissions.

Optogenetic Inhibition Reveals Distinct Roles for Basolateral Amygdala Activity at Discrete Time Points during Risky Decision Making

Decision making is a multifaceted process, consisting of several distinct phases that likely require different cognitive operations. Previous work showed that the basolateral amygdala (BLA) is a critical substrate for decision making involving risk of punishment; however, it is unclear how the BLA is recruited at different stages of the decision process. To this end, the current study used optogenetics to inhibit the BLA during specific task phases in a model of risky decision making (risky decision-making task) in which rats choose between a small, "safe" reward and a large reward accompanied by varying probabilities of footshock punishment. Male Long-Evans rats received intra-BLA microinjections of viral vectors carrying either halorhodopsin (eNpHR3.0-mCherry) or mCherry alone (control) followed by optic fiber implants and were trained in the risky decision-making task. Laser delivery during the task occurred during intertrial interval, deliberation, or reward outcome phases, the latter of which was further divided into the three possible outcomes (small, safe; large, unpunished; large, punished). Inhibition of the BLA selectively during the deliberation phase decreased choice of the large, risky outcome (decreased risky choice). In contrast, BLA inhibition selectively during delivery of the large, punished outcome increased risky choice. Inhibition had no effect during the other phases, nor did laser delivery affect performance in control rats. Collectively, these data indicate that the BLA can either inhibit or promote choice of risky options, depending on the phase of the decision process in which it is active.SIGNIFICANCE STATEMENT To date, most behavioral neuroscience research on neural mechanisms of decision making has used techniques that preclude assessment of distinct phases of the decision process. Here we show that optogenetic inhibition of the BLA has opposite effects on choice behavior in a rat model of risky decision making, depending on the phase in which inhibition occurs. BLA inhibition during a period of deliberation between small, safe and large, risky outcomes decreased risky choice. In contrast, BLA inhibition during receipt of the large, punished outcome increased risky choice. These findings highlight the importance of temporally targeted approaches to understand neural substrates underlying complex cognitive processes. More importantly, they reveal novel information about dynamic BLA modulation of risky choice.

Neurofinance

Neurofinance is a relatively new area of research that strives to understand financial decision making by combining insights from psychology and neuroscience with theories of finance. Using behavioral experiments, neurofinance studies how we evaluate information about financial options that are uncertain, time-constrained, risky, and strategic in nature and how financial decisions are influenced by emotions, psychological biases, stress, and individual differences (such as gender, genes, neuroanatomy, and personality). In addition, it studies how the brain processes financial information and how individual decisions arise within it. Finally, by combining these experiments with computational models, neurofinance aims to provide an alternative explanation for the apparent failure of classic finance theories. Here we provide an introduction to neurofinance and look at how it is rooted in different fields of study. We review early findings and implications and conclude with open questions in neurofinance.

Children's brain activation during risky decision-making: A contributor to substance problems?

OBJECTIVE

Among young children excessive externalizing behaviors often predict adolescent conduct and substance use disorders. Adolescents with those disorders show aberrant brain function when choosing between risky or cautious options. We therefore asked whether similarly aberrant brain function during risky decision-making accompanies excessive externalizing behaviors among children, hypothesizing an association between externalizing severity and regional intensity of brain activation during risky decision-making.

METHOD

Fifty-eight (58) 9-11 year-old children (both sexes), half community-recruited, half with substance-treated relatives, had parent-rated Child Behavior Checklist Externalizing scores. During fMRI, children repeatedly chose between doing a cautious behavior earning 1 point or a risky behavior that won 5 or lost 10 points. Conservative permutation-based whole-brain regression analyses sought brain regions where, during decision-making, activation significantly associated with externalizing score, with sex, and with their interaction.

RESULTS

Before risky responses higher externalizing scores were significantly, negatively associated with neural activation (t's: 2.91-4.76) in regions including medial prefrontal cortex (monitors environmental reward-punishment schedules), insula (monitors internal motivating states, e.g., hunger, anxiety), dopaminergic striatal and midbrain structures (anticipate and mediate reward), and cerebellum (where injuries actually induce externalizing behaviors). Before cautious responses there were no significant externalizing:activation associations (except in post hoc exploratory analyses), no significant sex differences in activation, and no significant sex-by-externalizing interactions.

CONCLUSIONS

Among children displaying more externalizing behaviors extensive decision-critical brain regions were hypoactive before risky behaviors. Such neural hypoactivity may contribute to the excessive real-life risky decisions that often produce externalizing behaviors. Substance exposure, minimal here, was a very unlikely cause.

Reward-related neural activity and structure predict future substance use in dysregulated youth

BACKGROUND

Identifying youth who may engage in future substance use could facilitate early identification of substance use disorder vulnerability. We aimed to identify biomarkers that predicted future substance use in psychiatrically un-well youth.

METHOD

LASSO regression for variable selection was used to predict substance use 24.3 months after neuroimaging assessment in 73 behaviorally and emotionally dysregulated youth aged 13.9 (s.d. = 2.0) years, 30 female, from three clinical sites in the Longitudinal Assessment of Manic Symptoms (LAMS) study. Predictor variables included neural activity during a reward task, cortical thickness, and clinical and demographic variables.

RESULTS

Future substance use was associated with higher left middle prefrontal cortex activity, lower left ventral anterior insula activity, thicker caudal anterior cingulate cortex, higher depression and lower mania scores, not using antipsychotic medication, more parental stress, older age. This combination of variables explained 60.4% of the variance in future substance use, and accurately classified 83.6%.

CONCLUSIONS

These variables explained a large proportion of the variance, were useful classifiers of future substance use, and showed the value of combining multiple domains to provide a comprehensive understanding of substance use development. This may be a step toward identifying neural measures that can identify future substance use disorder risk, and act as targets for therapeutic interventions.