Adolescent behavioral and neural reward sensitivity: a test of the differential susceptibility theory

A critical review of hot executive functioning in youth attention-deficit/hyperactivity disorder: Methodological limitations, conceptual considerations, and future directions

Hot executive functioning (EF) - EF under emotionally or motivationally salient conditions - is a putative etiology of attention-deficit/hyperactivity disorder (ADHD), disruptive behavior problems (DBPs), and their related impairments. Despite two decades of research, the present study is the first review of the construct in youth ADHD, with a particular focus on the role of task design, age, and DBPs, as well as relevant conceptual and methodological considerations. While certain hot EF tasks have been investigated extensively (e.g., choice impulsivity), substantial inconsistency in measurement of the broader construct remains, severely limiting conclusions. Future research should a) consider the extent to which various hot EF tasks relate to one another, a higher order factor, and other related constructs; b) further investigate task design, particularly the elicitation of emotion or motivation and its anticipated effect on EF; and c) incorporate multiple levels of analysis to validate similarities and differences among tasks with regard to the affective experiences and cognitive demands they elicit. With improved measurement and conceptual clarity, hot EF has potential to advance the literature on etiological pathways to ADHD, DBPs and associated impairments and, more broadly, may represent a useful tool for understanding the influence of emotion and motivation on cognition.

Neural sensitivity to social reward predicts links between social behavior and loneliness in youth during the COVID-19 pandemic

Neural reward network sensitivity in youth is proposed to differentially impact the effects of social environments on social outcomes. The COVID-19 pandemic provided an opportunity to test this hypothesis within a context of diminished in-person social interaction. We examined whether neural sensitivity to interactive social reward moderates the relationship between a frequency of interactive or passive social activity and social satisfaction. Survey reports of frequency of interactions with friends, passive social media use, and loneliness and social satisfaction were gathered in 2020 during mandated precautions limiting in-person contact. A subset of participants (age = 10-17) previously participated in a functional magnetic resonance imaging (fMRI) study examining social-interactive reward during a simulated peer interaction (survey n = 76; survey + fMRI n = 40). We found evidence of differential response to social context, such that youth with higher neural reward sensitivity showed a negative association between a frequency of interactive connections with friends and a combined loneliness and social dissatisfaction component (LSDC) score, whereas those with lower sensitivity showed the opposite effect. Further, high reward sensitivity was associated with greater LSDC as passive social media use increased, whereas low reward sensitivity showed the opposite. This indicates that youth with greater sensitivity to social-interactive reward may be more susceptible to negative effects of infrequent contact than their low reward-sensitive counterparts, who instead maintain social well-being through passive viewing of social content. These differential outcomes could have implications for supporting youth during times of major social disruption as well as ensuring mental health and well-being more broadly.

Heart rate variability moderates the effects of COVID-19-related stress and family adversity on emotional problems in adolescents: Testing models of differential susceptibility and diathesis stress

The COVID-19 pandemic is a unique period of stress, uncertainty, and adversity that will have significant implications for adolescent mental health. Nevertheless, stress and adversity related to COVID-19 may be more consequential for some adolescents' mental health than for others. We examined whether heart rate variability (HRV) indicated differential susceptibility to mental health difficulties associated with COVID-19 stress and COVID-19 family adversity. Approximately 4 years prior to the pandemic, we assessed resting HRV and HRV reactivity to a well-validated stress paradigm in 87 adolescents. During the pandemic, these adolescents (ages 13-19) reported on their health-related stress and concerns about COVID-19, family adversity related to COVID-19, and their recent emotional problems. The association between COVID-19 stress and emotional problems was significantly stronger for adolescents who previously exhibited higher resting HRV or higher HRV reactivity. For adolescents who exhibited lower resting HRV or HRV augmentation, COVID-19 stress was not associated with emotional problems. Conversely, lower resting HRV indicated vulnerability to the effect of COVID-19 family adversity on emotional problems. Different patterns of parasympathetic functioning may reflect differential susceptibility to the effects of COVID-19 stress versus vulnerability to the effects of COVID-19 family adversity on mental health during the pandemic.

Testosterone and estradiol affect adolescent reinforcement learning

During adolescence, gonadal hormones influence brain maturation and behavior. The impact of 17β-estradiol and testosterone on reinforcement learning was previously investigated in adults, but studies with adolescents are rare. We tested 89 German male and female adolescents (mean age ± sd = 14.7 ± 1.9 years) to determine the extent 17β-estradiol and testosterone influenced reinforcement learning capacity in a response time adjustment task. Our data showed, that 17β-estradiol correlated with an enhanced ability to speed up responses for reward in both sexes, while the ability to wait for higher reward correlated with testosterone primary in males. This suggests that individual differences in reinforcement learning may be associated with variations in these hormones during adolescence, which may shift the balance between a more reward- and an avoidance-oriented learning style.

Genetic variations influence brain changes in patients with attention-deficit hyperactivity disorder

Attention-deficit hyperactivity disorder (ADHD) is a neurological and neurodevelopmental childhood-onset disorder characterized by a persistent pattern of inattentiveness, impulsiveness, restlessness, and hyperactivity. These symptoms may continue in 55-66% of cases from childhood into adulthood. Even though the precise etiology of ADHD is not fully understood, it is considered as a multifactorial and heterogeneous disorder with several contributing factors such as heritability, auxiliary to neurodevelopmental issues, severe brain injuries, neuroinflammation, consanguineous marriages, premature birth, and exposure to environmental toxins. Neuroimaging and neurodevelopmental assessments may help to explore the possible role of genetic variations on ADHD neuropsychobiology. Multiple genetic studies have observed a strong genetic association with various aspects of neuropsychobiological functions, including neural abnormalities and delayed neurodevelopment in ADHD. The advancement in neuroimaging and molecular genomics offers the opportunity to analyze the impact of genetic variations alongside its dysregulated pathways on structural and functional derived brain imaging phenotypes in various neurological and psychiatric disorders, including ADHD. Recently, neuroimaging genomic studies observed a significant association of brain imaging phenotypes with genetic susceptibility in ADHD. Integrating the neuroimaging-derived phenotypes with genomics deciphers various neurobiological pathways that can be leveraged for the development of novel clinical biomarkers, new treatment modalities as well as therapeutic interventions for ADHD patients. In this review, we discuss the neurobiology of ADHD with particular emphasis on structural and functional changes in the ADHD brain and their interactions with complex genomic variations utilizing imaging genetics methodologies. We also highlight the genetic variants supposedly allied with the development of ADHD and how these, in turn, may affect the brain circuit function and related behaviors. In addition to reviewing imaging genetic studies, we also examine the need for complementary approaches at various levels of biological complexity and emphasize the importance of combining and integrating results to explore biological pathways involved in ADHD disorder. These approaches include animal models, computational biology, bioinformatics analyses, and multimodal imaging genetics studies.

Interactions between methodological and interindividual variability: How Monetary Incentive Delay (MID) task contrast maps vary and impact associations with behavior

INTRODUCTION

Phenomena related to reward responsiveness have been extensively studied in their associations with substance use and socioemotional functioning. One important task in this literature is the Monetary Incentive Delay (MID) task. By cueing and delivering performance-contingent reward, the MID task has been demonstrated to elicit robust activation of neural circuits involved in different phases of reward responsiveness. However, systematic evaluations of common MID task contrasts have been limited to between-study comparisons of group-level activation maps, limiting their ability to directly evaluate how researchers' choice of contrasts impacts conclusions about individual differences in reward responsiveness or brain-behavior associations.

METHODS

In a sample of 104 participants (Age Mean = 19.3, SD = 1.3), we evaluate similarities and differences between contrasts in: group- and individual-level activation maps using Jaccard's similarity index, region of interest (ROI) mean signal intensities using Pearson's r, and associations between ROI mean signal intensity and psychological measures using Bayesian correlation.

RESULTS

Our findings demonstrate more similarities than differences between win and loss cues during the anticipation contrast, dissimilarity between some win anticipation contrasts, an apparent deactivation effect in the outcome phase, likely stemming from the blood oxygen level-dependent undershoot, and behavioral associations that are less robust than previously reported.

CONCLUSION

Consistent with recent empirical findings, this work has practical implications for helping researchers interpret prior MID studies and make more informed a priori decisions about how their contrast choices may modify results.

Reward sensitivity, affective neuroscience personality, symptoms of attention-deficit/hyperactivity disorder, and TPH2-703G/T (rs4570625) genotype

OBJECTIVE

Reward sensitivity is an increasingly used construct in psychiatry, yet its possible inner structure and relationship with other affective variables are not well known.

METHODS

A reward sensitivity measurement scale was constructed on the basis of large item pool collected from birth cohort representative samples (the Estonian Children Personality Behaviour and Health Study; original n = 1238). Affective Neuroscience Personality Scale (ANPS) and the Adult Attention deficit hyperactivity disorder (ADHD) Self-Report Scale (ASRS) were administered in young adulthood. A variant (rs4570625) of the gene encoding tryptophan hydroxylase 2 (TPH2) that is responsible for the synthesis of central serotonin was genotyped.

RESULTS

Reward sensitivity consisted of two orthogonal components, operationally defined as Openness to Rewards and Insatiability by Reward, that respectively characterise the striving towards multiple rewards and the strong pursuit and fixation to a particular reward. While SEEKING and PLAY (and to lower extent CARE) of the ANPS co-varied with Openness to Rewards, FEAR, SADNESS, and ANGER were related to Insatiability by Reward. The total score of ASRS was moderately correlated with Insatiability by Reward, while the association with Openness to Rewards was negligible. However, ASRS Inattention had some negative relationship with the Social Experience facet of Openness to Rewards. The T/T homozygotes for the TPH2 promoter polymorphism had lower Insatiability by Reward but not Openness to Rewards.

CONCLUSIONS

Behaviours sensitive to rewards are separable to the components of variability and fixation, and these components are differentially related to affective aspects of personality, attention, and hyperactivity as well as to TPH2 genotype.

Developmental trajectories to reduced activation of positive valence systems: A review of biological and environmental contributions

Reduced activation of positive valence systems (PVS), including blunted neural and physiological responses to pleasant stimuli and rewards, has been shown to prospectively predict the development of psychopathology. Yet, little is known about how reduced PVS activation emerges across development or what implications it has for prevention. We review genetic, temperament, parenting, and naturalistic and laboratory stress research on neural measures of PVS and outline developmentally-informed models of trajectories of PVS activation. PVS function is partly heritable and appears to reflect individual differences in early-emerging temperament traits. Although lab-induced stressors blunt PVS activation, effects of parenting and naturalistic stress on PVS are mixed and depend on the type of stressor, developmental timing, and interactions amongst risk factors. We propose that there may be multiple, dynamic developmental trajectories to reduced PVS activation in which combinations of genes, temperament, and exposure to severe, prolonged, or uncontrollable stress may exert direct and interactive effects on PVS function. Critically, these risk factors may alter PVS developmental trajectories and/or PVS sensitivity to proximal stressors. Distinct factors may converge such that PVS activation proceeds along a typical, accelerated, chronically low, or stress-reactive trajectory. Finally, we present directions for future research with translational implications.

Gene-Environment Interactions in Psychiatry: Recent Evidence and Clinical Implications

PURPOSE OF REVIEW

We identify the recent evidence for gene-by-environment interaction studies in relation to psychiatric disorders. We focus on the key genotypic data as well as environmental exposures and how they interact to predict psychiatric disorders and psychiatric symptomatology. We direct our focus on the psychiatric outcomes that were focused on by the Psychiatric Genetics Consortium.

RECENT FINDINGS

Many of the studies focus on candidate gene approaches, with most of the studies drawing upon previous literature to decide the genes of interest. Other studies used a genome-wide approach. While some studies demonstrated positive replication of previous findings, replication is still an issue within gene-by-environment interaction studies. Gene-by-environment interaction research in psychiatry globally suggests some susceptibility to environmental exposures based on genotype; however, greater clarity is needed around the idea that genetic risk may not be disorder specific.

Emotional insecurity as a mediator of the moderating role of dopamine genes in the association between interparental conflict and youth externalizing problems

This study tested whether the association between interparental conflict and adolescent externalizing symptoms was moderated by a polygenic composite indexing low dopamine activity (i.e., 7-repeat allele of DRD4; Val alleles of COMT; 10-repeat variants of DAT1) in a sample of seventh-grade adolescents (Mean age = 13.0 years) and their parents. Using a longitudinal, autoregressive design, observational assessments of interparental conflict at Wave 1 predicted increases in a multi-informant measurement of youth externalizing symptoms 2 years later at Wave 3 only for children who were high on the hypodopaminergic composite. Moderation was expressed in a “for better” or “for worse” form hypothesized by differential susceptibility theory. Thus, children high on the dopaminergic composite experienced more externalizing problems than their peers when faced with more destructive conflicts but also fewer externalizing problems when exposed to more constructive interparental conflicts. Mediated moderation findings indicated that adolescent reports of their emotional insecurity in the interparental relationship partially explained the greater genetic susceptibility experienced by these children. More specifically, the dopamine composite moderated the association between Wave 1 interparental conflict and emotional insecurity 1 year later at Wave 2 in the same “for better” or “for worse” pattern as externalizing symptoms. Adolescent insecurity at Wave 2, in turn, predicted their greater externalizing symptoms 1 year later at Wave 3. Post hoc analyses further revealed that the 7-repeat allele of the dopamine receptor D4 (DRD4) gene was the primary source of plasticity in the polygenic composite. Results are discussed as to how they advance process-oriented Gene x Environment models of emotion regulation.

Testing differential susceptibility: Plasticity genes, the social environment, and their interplay in adolescent response inhibition

OBJECTIVES

Impaired inhibitory control is a key feature of attention-deficit/hyperactivity disorder (ADHD). We investigated gene-environment interaction (GxE) as a possible contributing factor to response inhibition variation in context of the differential susceptibility theory. This states individuals carrying plasticity gene variants will be more disadvantaged in negative, but more advantaged in positive environments.

METHODS

Behavioural and neural measures of response inhibition were assessed during a Stop-signal task in participants with (N = 197) and without (N = 295) ADHD, from N = 278 families (age M = 17.18, SD =3.65). We examined GxE between candidate plasticity genes (DAT1, 5-HTT, DRD4) and social environments (maternal expressed emotion, peer affiliation).

RESULTS

A DRD4 × Positive peer affiliation interaction was found on the right fusiform gyrus (rFG) activation during successful inhibition. Further, 5-HTT short allele carriers showed increased rFG activation during failed inhibitions. Maternal warmth and positive peer affiliation were positively associated with right inferior frontal cortex activation during successful inhibition. Deviant peer affiliation was positively related to the error rate.

CONCLUSIONS

While a pattern of differential genetic susceptibility was found, more clarity on the role of the FG during response inhibition is warranted before firm conclusions can be made. Positive and negative social environments were related to inhibitory control. This extends previous research emphasizing adverse environments.