Blunted Reward Sensitivity and Trait Disinhibition Interact to Predict Substance Use Problems

Breadth of substance use is associated with the selection of a larger food portion size via elevated impulsivity

Substance use is associated with altered or elevated food consumption and disordered eating. In the present study we examined whether breadth (variety) of drug use was associated with elevated portion size in a general population sample as it was in persons in recovery from substance use disorder. Furthermore, measures of emotional eating, impulsivity, food misuse, food craving were taken as possible mediators and reward responsiveness was examined as a potential moderator of this association. 444 adults (48.6 % women, mean age of 47.8 years) completed an online study in which they were asked to make judgements of ideal portion size for 6 different foods using a validated online tool that allowed participants to adjust the portion size of images of foods. Ideal portion size has been identified as a strong predictor of actual consumption. Participants were also asked to report the number of substances used in the past and provide anthropometric information. The results confirmed that breadth of drug use was associated with selection of higher portion size. Reward responsiveness was not a moderator of this relationship. Of the tested mediators, only impulsivity mediated the association between breadth of drug use and portion size. The results show that impulsivity may underlie the association between eating and substance use.

Variants of the P3 event-related potential operate as indicators of distinct mechanisms contributing to problematic alcohol use

Considerable research has linked relative reduction in the amplitude of the P3 event-related potential (ERP) during cognitive task performance (i.e., Target-P3) with increased risk of alcohol-related problems. A separate literature indicates that a relative increase in the amplitude of the P3 elicited by cues signaling alcohol availability (i.e., ACR-P3) also is associated with alcohol use and problems. To date, no research has integrated these seemingly discrepant findings. Here, we aimed to demonstrate that P3 amplitudes elicited in different task contexts reflect distinct domains of functioning relevant to problematic alcohol involvement (PAI), and therefore can inform heterogeneity in the etiology of PAI. 156 emerging adults (61% women; 88% White/Non-Hispanic) completed a mental rotation task and a picture-viewing task while ERPs were recorded. Participants also completed questionnaire measures of trait disinhibition, alcohol use, and alcohol-related problems. Findings from regression analyses indicated that (a) Target-P3 was negatively associated and ACR-P3 was positively associated with a PAI latent variable; (b) the two P3s accounted for unique variance in PAI, beyond that accounted for by recent drinking; and (c) the association between Target-P3 and PAI-but not ACR-P3 and PAI-was statistically mediated by trait disinhibition. The present findings highlight the unique contributions of distinct functional domains associated with disinhibition and incentive salience in the etiology of PAI. Moreover, findings are consistent with a nuanced understanding of the P3 ERP, whereby its specific meaning varies according to the task context in which it is elicited.

Dysfunctional feedback processing in male methamphetamine abusers: Evidence from neurophysiological and computational approaches

Methamphetamine use disorder (MUD) as a major public health risk is associated with dysfunctional neural feedback processing. Although dysfunctional feedback processing in people who are substance dependent has been explored in several behavioral, computational, and electrocortical studies, this mechanism in MUDs requires to be well understood. Furthermore, the current understanding of latent components of their behavior such as learning speed and exploration-exploitation dilemma is still limited. In addition, the association between the latent cognitive components and the related neural mechanisms also needs to be explored. Therefore, in this study, the underlying neurocognitive mechanisms of feedback processing of such impairment, and age/gender-matched healthy controls are evaluated within a probabilistic learning task with rewards and punishments. Mathematical modeling results based on the Q-learning paradigm suggested that MUDs show less sensitivity in distinguishing optimal options. Additionally, it may be worth noting that MUDs exhibited a slight decrease in their ability to learn from negative feedback compared to healthy controls. Also through the lens of underlying neural mechanisms, MUDs showed lower theta power at the medial-frontal areas while responding to negative feedback. However, other EEG measures of reinforcement learning including feedback-related negativity, parietal-P300, and activity flow from the medial frontal to lateral prefrontal regions, remained intact in MUDs. On the other hand, the elimination of the linkage between value sensitivity and medial-frontal theta activity in MUDs was observed. The observed dysfunction could be due to the adverse effects of methamphetamine on the cortico-striatal dopamine circuit, which is reflected in the anterior cingulate cortex activity as the most likely region responsible for efficient behavior adjustment. These findings could help us to pave the way toward tailored therapeutic approaches.

Midfrontal conflict theta and parietal P300 are linked to a latent factor of DSM externalising disorders

Psychiatric illnesses form spectra rather than categories, with symptoms varying continuously across individuals, i.e., there is no clear break between health and disorder. Dimensional measures of behaviour and brain activity are promising targets for studying biological mechanisms that are common across disorders. Here, we assessed the extent to which neural measures of the sensitivity of the three biological systems in the reinforcement sensitivity theory (RST) could account for individual differences in a latent general factor estimated from symptom counts across externalising disorders (EXTs). RST explanatory power was pitted against reduced P300, a reliable indicator of externalising per previous research. We assessed 206 participants for DSM-5 EXTs (antisocial personality disorder, conduct disorder, attention-deficit/hyperactivity disorder, intermittent explosive disorder symptoms, alcohol use disorder, and cannabis use disorder). Of the final sample, 49% met diagnostic criteria for at least one of the EXTs. Electroencephalographic measures of the sensitivities of the behavioural activation system (BAS), the fight/flight/freeze system, and the behavioural inhibition system (BIS), as well as P300 were extracted from the gold bar-lemon and stop-signal tasks. As predicted, we found that low neural BIS sensitivity and low P300 were uniquely and negatively associated with our latent factor of externalising. Contrary to prediction, neural BAS/"dopamine" sensitivity was not associated with externalising. Our results provide empirical support for low BIS sensitivity and P300 as neural mechanisms common to disorders within the externalising spectrum; but, given the low N involved, future studies should seek to assess the replicability of our findings and, in particular, the differential involvement of the three RST systems.

Trait Reward Sensitivity Modulates Connectivity with the Temporoparietal Junction and Anterior Insula during Strategic Decision Making

Many decisions happen in social contexts such as negotiations, yet little is understood about how people balance fairness versus selfishness. Past investigations found that activation in brain areas involved in executive function and reward processing was associated with people offering less with no threat of rejection from their partner, compared to offering more when there was a threat of rejection. However, it remains unclear how trait reward sensitivity may modulate activation and connectivity patterns in these situations. To address this gap, we used task-based fMRI to examine the relation between reward sensitivity and the neural correlates of bargaining choices. Participants (N = 54) completed the Sensitivity to Punishment (SP)/Sensitivity to Reward (SR) Questionnaire and the Behavioral Inhibition System/Behavioral Activation System scales. Participants performed the Ultimatum and Dictator Games as proposers and exhibited strategic decisions by being fair when there was a threat of rejection, but being selfish when there was not a threat of rejection. We found that strategic decisions evoked activation in the Inferior Frontal Gyrus (IFG) and the Anterior Insula (AI). Next, we found elevated IFG connectivity with the Temporoparietal junction (TPJ) during strategic decisions. Finally, we explored whether trait reward sensitivity modulated brain responses while making strategic decisions. We found that people who scored lower in reward sensitivity made less strategic choices when they exhibited higher AI-Angular Gyrus connectivity. Taken together, our results demonstrate how trait reward sensitivity modulates neural responses to strategic decisions, potentially underscoring the importance of this factor within social and decision neuroscience.

Neurocognitive reward processes measured via event-related potentials are associated with binge-eating disorder diagnosis and ecologically-assessed behavior

Altered reward processing has been implicated in the onset and maintenance of binge-eating disorder (BED). However, it is unclear which precise neurocognitive reward processes may contribute to BED. In the present study, 40 individuals with BED and 40 age-, sex-, and BMI-matched controls completed a reward (incentive delay) task while their neural activity was recorded using electroencephalography (EEG). Individuals with BED also completed a 10-day ecological momentary assessment (EMA) protocol assessing binge-eating behavior in the natural environment. Event-related potential (ERP) analysis of the EEG indicated that individuals with BED had stronger anticipatory (CNV) and outcome-related (RewP) neural reward activity to food and monetary rewards, compared to controls. However, within the BED group, greater frequency of binge eating during the EMA protocol was associated with stronger anticipatory (CNV) but weaker outcome-related (RewP) neural reward activity. These associations within the BED group were unique to food, and not monetary, rewards. Although preliminary, these results suggest that both anticipatory ("wanting") and outcome ("liking") reward processes may be generally amplified in BED. However, they also suggest that among individuals with BED, disorder severity may be associated with increased anticipatory reward processes ("wanting"), but relatively decreased reward-outcome processing ("liking"), of food rewards specifically.

Neural reward responsiveness and daily positive affect functioning in adolescent girls

Deficits in reward processing have been implicated in the development of many forms of psychopathology, especially major depressive disorder (MDD). One facet of reward processing, known as reward responsivity, has been associated with the development and maintenance of depression across development. The reward positivity (RewP) is an event-related potential derived from electroencephalogram (EEG), which is thought to reflect reward responsivity. An attenuated RewP has been observed in both currently depressed individuals and youth at risk for depression, suggesting it may represent a biomarker of depression. Despite this, little is known about how the RewP translates to behavior and affect in the real world. In the current study, we examined how the RewP relates to real world emotional functioning, measured using ecological momentary assessment (EMA). Thirty-eight female adolescents (ages 11-16, Mage = 13.9 years) participated in the study; approximately half of the sample were considered high risk due to maternal lifetime history of MDD. Adolescents completed a monetary reward task while EEG was recorded, followed by a 10-day period of EMA assessing daily affect and emotion regulation strategy use following positive events. Results revealed that the RewP was positively associated with subjective reports of positive, but not negative, daily affect. Results also revealed that the RewP was positively associated with focusing on positive feelings following a positive event (e.g., savoring). Findings from this preliminary study highlight how neural responses to reward in the lab relate to daily life emotional functioning, supporting the RewP as an ecologically valid marker of positive affect functioning among youth.

Emotion dysregulation and reward responsiveness as predictors of autonomic reactivity to an infant cry task among substance-using pregnant and postpartum women

Maternal substance use may interfere with optimal parenting, lowering maternal responsiveness during interactions with their children. Previous work has identified maternal autonomic nervous system (ANS) reactivity to parenting-relevant stressors as a promising indicator of real-world parenting behaviors. However, less is known about the extent to which individual differences in emotion dysregulation and reward processing, two mechanisms of substance use, relate to maternal ANS reactivity in substance-using populations. The current study examined associations among emotion dysregulation, reward responsiveness, and ANS reactivity to an infant cry task among 77 low-income and substance-using women who were either pregnant (n = 63) or postpartum (n = 14). Two indicators of ANS functioning were collected during a 9 min computerized infant cry task (Crybaby task): respiratory sinus arrhythmia (RSA) and pre-ejection period. Mothers also completed self-reported measures of emotion dysregulation and reward responsiveness. Analyses revealed that trait emotion regulation was associated with RSA reactivity to the Crybaby task, such that greater emotion dysregulation was associated with greater RSA reduction during the infant cry task than lower emotion dysregulation. Reward responsiveness was not significantly associated with either indicator of ANS reactivity to the task. Findings revealed distinct patterns of associations linking emotion dysregulation with ANS reactivity during a parenting-related computerized task, suggesting that emotion regulation may be a key intervention target for substance-using mothers.

Neural response to rewards moderates the within-person association between daily positive events and positive affect during a period of stress exposure

Stress and neural responses to reward can interact to predict psychopathology, but the mechanisms of this interaction are unclear. One possibility is that the strength of neural responses to reward can affect the ability to maintain positive affect during stress. In this study, 105 participants completed a monetary reward task to elicit the reward positivity (RewP), an event-related potential sensitive to rewards. Subsequently, during a stressful period, participants reported on their affect nine times a day and on daily positive and negative events for 10 days. Even during heightened stress, experiencing more positive events was associated with increased positive affect. The RewP significantly moderated this association: Individuals with a larger RewP reported greater increases in positive affect when they experienced more positive events, relative to individuals with a smaller RewP. A blunted RewP might contribute to stress susceptibility by affecting how much individuals engage in positive emotion regulation during stress.

Does reward processing moderate or mediate the link between childhood adversity and psychopathology: A longitudinal study

Childhood adversity is common and associated with elevated risk for transdiagnostic psychopathology. Reward processing has been implicated in the link between adversity and psychopathology, but whether it serves as a mediator or moderator is unclear. This study examined whether alterations in behavioral and neural reward processing function as a mechanism or moderator of psychopathology outcomes following adversity experiences, including threat (i.e., trauma) and deprivation. A longitudinal community sample of 10-15-year-old youths was assessed across two waves (Wave 1: n = 228; Wave 2: n = 206). Wave 1 assessed adverse experiences, psychopathology symptoms, reward processing on a monetary incentive delay task, and resting-state fMRI. At Wave 2, psychopathology symptoms were reassessed. Greater threat experiences were associated with blunted behavioral reward sensitivity, which, in turn, predicted increases in depression symptoms over time and mediated the prospective association between threat and depression symptoms. In contrast, reward sensitivity moderated the association between deprivation experiences and prospective externalizing symptoms such that the positive association of deprivation with increasing externalizing symptoms was absent for children with high levels of reward sensitivity.

Social Context and Reward Sensitivity Enhance Corticostriatal Function during Experiences of Shared Rewards

Although prior research has demonstrated enhanced striatal response when sharing rewards with close social connections, less is known about how individual differences affect ventral striatal (VS) activation and connectivity when experiencing rewards within social contexts. Given that self-reported reward sensitivity and level of substance use have been associated with differences in VS activation, we set out to investigate whether these factors would be independently associated with enhancements to neural reward responses within social contexts. In this pre-registered study, participants (N=45) underwent fMRI while playing a card guessing game in which correct or incorrect guesses resulted in monetary gains and losses that were shared evenly with either a close friend, stranger (confederate), or non-human partner. Consistent with our prior work, we found increased VS activation when sharing rewards with a socially close peer as opposed to an out-of-network stranger. As self-reported reward sensitivity increased, the difference in VS response to rewards shared with friends and strangers decreased. We also found enhanced connectivity between the VS and temporoparietal junction when sharing rewards with close friends as opposed to strangers. Finally, exploratory analyses revealed that as reward sensitivity and sub-clinical substance use increase, the difference in VS connectivity with the right fusiform face area increases as a function of social context. These findings demonstrate that responsivity to the context of close friends may be tied to individual reward sensitivity or sub-clinical substance use habits; together these factors may inform predictions of risk for future mental health disorders.

Parsing patterns of reward responsiveness: Initial evidence from latent profile analysis

Variation in reward responsiveness has been linked to psychopathology. Reward responsiveness is a complex phenomenon that encompasses different temporal dimensions (i.e., reward anticipation or consumption) that can be measured using multiple appetitive stimuli. Furthermore, distinct measures, such as neural and self-report measures, reflect related but distinct aspects of reward responsiveness. To understand reward responsiveness more comprehensively and better identify deficits in reward responsiveness implicated in psychopathology, we examined ways multiple measures of reward responsiveness jointly contribute to distinct psychological problems by using latent profile analysis. Specifically, we identified three profiles of reward responsiveness among 139 female participants based on their neural responses to money, food, social acceptance, and erotic images and self-reported responsiveness to reward anticipation and consumption. Profile 1 (n = 30) exhibited blunted neural responses to social rewards and erotic images, low self-reported reward responsiveness, but average neural responses to monetary and food rewards. Profile 2 (n = 71) showed elevated neural response to monetary rewards, average neural responses to other stimuli, and average self-reported reward responsiveness. Profile 3 (n = 38) showed more variable neural responses to reward (e.g., hypersensitivity to erotic images, hyposensitivity to monetary rewards), and high self-reported reward responsiveness. These profiles were differentially associated with variables generally linked to aberrations in reward responsiveness. For example, Profile 1 was most strongly associated with anhedonic depression and social dysfunction, whereas Profile 3 was associated with risk-taking behaviors. These preliminary findings may help to elucidate ways different measures of reward responsiveness manifest within and across individuals and identify specific vulnerabilities for distinct psychological problems.

Drinking alcohol by mid-adolescence is related to reduced reward reactivity: Novel evidence of positive valence system alterations in early initiating female youth

Initiation of alcohol use at younger ages is prognostic of later drinking problems. Reward system dysfunction is theorized to contribute to early initiation and escalation of drinking, but existing evidence supports both hyposensitivity and hypersensitivity as risk-markers; research employing effective indices of reward processing is needed for clarification. The reward positivity (RewP) is a well-established neurophysiological index of hedonic "liking," an important aspect of reward processing. Adult research has yielded conflicting findings, with different studies reporting reduced, enhanced, or null associations of RewP with engagement in or risk for harmful alcohol use. No study has examined relations between RewP and multiple indices of drinking in youth. Here, we examined how RewP measured in a gain/loss feedback task related to self-reported drinking initiation and past-month drinking, when accounting for age along with depression and externalizing symptoms, in 250 mid-adolescent females. Analyses showed that (1) compared to not-yet drinkers, adolescents endorsing drinking initiation responded less strongly to monetary gain (RewP) but not loss feedback (FN), and (2) past-month drinking was unrelated to both RewP and FN magnitude. These findings provide evidence for reduced hedonic "liking" as a concomitant of early drinking initiation in adolescent females and warrant further research with mixed-sex adolescent samples exhibiting greater drinking variability.

Sex differences in externalizing and internalizing traits and ventral striatal responses to monetary loss

Ventral striatum (VS) processes rewarding and punishing stimuli. Women and men vary in externalizing and internalizing traits, which may influence neural responses to reward and punishment. To investigate sex differences in how individual traits influence VS responses to reward and punishment, we curated the data of the Human Connectome Project and identified 981 (473 men) subjects evaluated by the Achenbach Adult Self-Report Syndrome Scales. We processed the imaging data with published routines and extracted VS response (β) to win and to loss vs. baseline in a gambling task for correlation with externalizing and internalizing symptom severity. Men vs. women showed more severe externalizing symptoms and higher VS response to monetary losses (VS-loss β) but not to wins. Men but not women showed a significant, positive correlation between VS-loss β and externalizing traits, and the sex difference was confirmed by a slope test. The correlations of VS-loss vs. externalizing and of VS-win vs. externalizing and those of VS-loss vs. externalizing and of VS-loss vs. internalizing traits both differed significantly in slope, confirming its specificity, in men. Further, the sex-specific relationship between VS-loss β and externalizing trait did not extend to activities during exposure to negative emotion in the face matching task. To conclude, VS responses to loss but not to win and their correlation with externalizing rather than internalizing symptom severity showed sex differences in young adults. The findings highlight the relationship of externalizing traits and VS response to monetary loss and may have implications for psychological models of externalizing behaviors in men.

An eye-tracking study of biased attentional processing of emotional faces in severe alcohol use disorder

BACKGROUND

Social cognition impairments in severe alcohol use disorder (SAUD) are increasingly established. However, fundamental aspects of social cognition, and notably the attentional processing of socio-affective information, remain unexplored, limiting our understanding of underlying mechanisms. Here, we determined whether patients with SAUD show attentional biases to specific socio-affective cues, namely emotional faces.

METHOD

In a modified dot-probe paradigm, 30 patients with SAUD and 30 demographically matched healthy controls (HC) were presented with pairs of neutral-emotional (angry, disgusted, happy, sad) faces while having their eye movements recorded. Indices of early/automatic (first fixations, latency to first fixations) and later/controlled (number of fixations, dwell-time) processes were computed.

RESULTS

Patients with SAUD did not differ from HC in their attention to angry/disgusted/sad vs. neutral faces. However, patients with SAUD fixated/dwelled less on happy vs. neutral faces in the first block of stimuli than HC, who presented an attentional bias to happy faces.

LIMITATIONS

Sample-size was determined to detect medium-to-large effects and subtler ones may have been missed. Further, our cross-sectional design provides no explanation as to whether the evidenced biases precede or are a consequence of SAUD.

CONCLUSIONS

These results extend the social cognition literature in SAUD to the attentional domain, by evidencing the absence of a controlled attentional bias toward positive social cues in SAUD. This may reflect reduced sensitivity to social reward and could contribute to higher order social cognition difficulties and social dysfunction.

An addictive disorders severity model: a chained mediation analysis using structural equation modeling

BACKGROUND

The clinical relevance of the degree of severity in addiction disorders supports the need to investigate the variables underlying this aspect of the phenomenon.

OBJECTIVE

This study aimed to explore the relationships between factors that may influence the severity of addiction disorder, with a particular focus on temperamental disinhibition, emotion dysregulation, interpersonal vulnerability, and their interactions.

METHODS

A clinical sample of 502 (77% males and 22% females) was involved. All participants received a DSM-5 clinical diagnosis of "Substance-Related and Addictive Disorders" and were recruited from the Italian National Health System. The collected data were analyzed by implementing a chained mediation model using structural equation modeling.

RESULTS

The statistical appropriateness of the hypothesized latent 4- factors model was confirmed. Specifically, temperamental disinhibition (composed of impulsiveness, compulsiveness, and obsessiveness), emotion dysregulation (composed of affect dysregulation, alexithymia, and dissociation), interpersonal vulnerability (composed of traumatic experiences, preoccupied, avoidant and unresolved attachment), and Addictive Disorders Severity (composed by substance use severity, alcohol use severity, gambling severity, and Internet use severity) were the four factors which have been identified. Furthermore, a total chained mediation model emerged, where emotion dysregulation and interpersonal vulnerability mediated the relationship between temperamental disinhibition and Addictive Disorders Severity.

CONCLUSIONS

Our findings offer a better understanding of the variables associated with addictive disorder severity, providing important indications for therapeutic interventions.

Dimensions of childhood maltreatment and adult risky behaviors: Differential affective and inhibitory control mechanisms

BACKGROUND

While childhood maltreatment has been identified as a robust risk factor for a myriad of poor outcomes, significant gaps in our understanding still remain regarding mechanisms of this risk transmission across the lifespan.

OBJECTIVE

Informed by recent dimensional models, the objective of this study was to examine how unique dimensions of childhood maltreatment relate to adult risky behaviors via interactions between cognitive control and affective processes across Positive and Negative Valence Systems.

PARTICIPANTS AND SETTING

Our sample consisted of 110 community adults (M/SD_age = 31.92/10.58 years old, 52.7 % male).

METHODS

Participants completed a neuropsychological test of inhibitory control and self-report measures of childhood maltreatment, recent adult risky behaviors, and indices of affective processing.

RESULTS

Moderated-mediation analyses revealed that childhood experiences of neglect and abuse exhibited distinct mechanisms of risk transmission related to adult risky behaviors. Specifically, disruptions in inhibitory control and reward-related processes were linked to adult risky behavior in the context of Childhood Deprivation (95%CI = -0.166/-0.002), whereas negative affective processes were associated with adult risky behavior in the context of Childhood Threat (95 % CI = 0.015/0.157).

CONCLUSIONS

Findings provide empirical support for novel dimensional theories of childhood maltreatment and suggest that distinct regulatory processes are impacted by these early life experiences, which may confer risk into adulthood.

The potential application of event-related potentials to enhance research on reward processes in eating disorders

OBJECTIVE

Reward-related processes have been posited as key mechanisms underlying the onset and persistence of eating disorders, prompting a growing body of research in this area. Existing studies have primarily utilized self-report, behavioral, and functional magnetic resonance imaging measures to interrogate reward among individuals with eating disorders. However, limitations inherent in each of these methods (e.g., poor temporal resolution) may obscure distinct neurocognitive reward processes, potentially contributing to underdeveloped models of reward dysfunction within eating disorders. The temporal precision of event-related potentials (ERPs), derived from electroencephalography, may thus offer a powerful complementary tool for elucidating the neurocognitive underpinnings of reward. Indeed, a considerable amount of research in other domains of psychopathology (e.g., depression, substance use disorders), as well as studies investigating food reward among non-clinical samples, highlights the utility of ERPs for probing reward processes. However, no study to date has utilized ERPs to directly examine reward functioning in eating disorders.

METHODS

In this paper, we review evidence underscoring the clinical utility of ERP measures of reward, as well as a variety of reward-related tasks that can be used to elicit specific ERP components with demonstrated relevance to reward processing. We then consider the ways in which these tasks/components may be used to help answer a variety of open questions within the eating disorders literature on reward.

RESULTS/DISCUSSION

Given the promise of ERP measures of reward to the field of eating disorders, we ultimately hope to spur and guide research in this currently neglected area.

PUBLIC SIGNIFICANCE

Abnormalities in reward functioning appear to contribute to eating disorders. Event-related potentials (ERPs) offer temporally precise measures of neurocognitive reward processing and thus may be important tools for understanding the relationship between reward and disordered eating. However, research in this area is currently lacking. This paper attempts to facilitate the use of ERPs to study reward among individuals with eating disorders by reviewing the relevant theories and methods.

Assessing general versus specific liability for externalizing problems in adolescence: Concurrent and prospective prediction of symptoms of conduct disorder, ADHD, and substance use

This study explored the generality versus specificity of two trait-liability factors for externalizing problems-disinhibition and callousness-in the concurrent and prospective prediction of symptoms of conduct disorder, attention-deficit/hyperactivity disorder (ADHD), and substance use (i.e., alcohol use disorder and history of illicit substance use). Disinhibition involves an impulsive, unrestrained cognitive-behavioral style; callousness entails a dispositional lack of social-emotional sensitivity. Participants were European adolescents from the multisite IMAGEN project who completed questionnaires and clinical interviews at ages 14 (N = 1,504, Mage = 14.41, 51.13% female) and 16 (N = 1,407, Mage = 16.46, 51.88% female). Disinhibition was related concurrently and prospectively to greater symptoms of conduct disorder, ADHD, and alcohol use disorder; higher scores on a general externalizing factor; and greater likelihood of having tried an illicit substance. Callousness was selectively related to greater conduct disorder symptoms. These findings indicate disinhibition confers broad liability for externalizing spectrum disorders, perhaps due to its affiliated deficits in executive function. In contrast, callousness appears to represent more specific liability for antagonistic (aggressive/exploitative) forms of externalizing, as exemplified by antisocial behavior. Results support the utility of developmental-ontogenetic and hierarchical-dimensional models of psychopathology and have important implications for early assessment of risk for externalizing problems. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Weight gain attempts and substance use behaviors among adults across five countries

Weight gain attempts are common among adolescents, yet a paucity of research has explored these behaviors among adults, particularly in relation to substance use behaviors. To address this gap in the literature, pooled data from the 2018 and 2019 International Food Policy Study (N = 42,108) were analyzed. The association of weight gain attempts in the past 12 months with four important and relatively common substance use behaviors (alcohol use, binge-drinking, cigarette smoking, marijuana use) was examined using multiple modified Poisson regression analyses that adjusted for theoretically relevant covariates. Among men and women, weight gain attempts were associated with a higher likelihood of cigarette smoking in the past 30 days, marijuana use in the past 12 months, and binge-drinking one or more times per month in the past 12 months among men only. Among women, weight gain attempts were associated with a lower likelihood of alcohol use one or more times per month in the past 12 months. Our findings contribute to the literature demonstrating that substance use behaviors are more prevalent among adults who report weight gain attempts in a large international sample.

Differential brain responses to alcohol-related and natural rewards are associated with alcohol use and problems: Evidence for reward dysregulation

Multiple theoretical perspectives posit that drug use leads to biased valuation of drug-related reward, at the expense of naturally occurring rewarding activities (i.e., reward dysregulation). Recent research suggests that the comparative balance of drug-related and nondrug-related reward valuation is a powerful determinant of substance misuse and addiction. We examined differential neurophysiological responses-indexed with the P3 component of the event-related potential (ERP)-elicited by visual alcohol cues and cues depicting natural reward as a neurobiological indicator of problematic drinking. Nondependent, young adult drinkers (N = 143, aged 18-30 years) completed questionnaire measures assessing alcohol use and problems, and viewed alcohol cues (pictures of alcoholic beverages), high-arousing natural reward cues (erotica, adventure scenes), nonalcoholic beverage cues, and neutral scenes (e.g., household items) while ERPs were recorded. When examined separately, associations of P3-ERP reactivity to alcohol cues and natural reward cues with alcohol use and problems were weak. However, differential P3 response to the two types of cues (i.e., reward dysregulation P3) showed consistent and robust associations with all indices of alcohol use and problems and differentiated high-risk from lower-risk drinkers. The current results support the idea that the differential incentive-motivational value of alcohol, relative to naturally rewarding activities, is associated with increased risk for substance misuse and dependence, and highlight a novel neurophysiological indicator-the reward dysregulation P3-of this differential reward valuation.

Internal consistency and test-retest reliability of the P3 event-related potential (ERP) elicited by alcoholic and non-alcoholic beverage pictures

Addiction researchers are interested in the ability of neural signals, like the P3 component of the ERP, to index individual differences in liability factors like motivational reactivity to alcohol/drug cues. The reliability of these measures directly impacts their ability to index individual differences, yet little attention has been paid to their psychometric properties. The present study fills this gap by examining within-session internal consistency reliability (ICR) and between-session test-retest reliability (TRR) of the P3 amplitude elicited by images of alcoholic beverages (Alcohol Cue P3) and non-alcoholic drinks (NADrink Cue P3) as well as the difference between them, which isolates alcohol cue-specific reactivity in the P3 (ACR-P3). Analyses drew on data from a large sample of alcohol-experienced emerging adults (session 1 N = 211, 55% female, aged 18-20 yr; session 2 N = 98, 66% female, aged 19-21 yr). Evaluated against domain-general thresholds, ICR was excellent (M ± SD; r= 0.902 ± 0.030) and TRR was fair (r = 0.706 ± 0.020) for Alcohol Cue P3 and NADrink Cue P3, whereas for ACR-P3, ICR and TRR were poor (r = 0.370 ± 0.071; r = 0.201 ± 0.042). These findings indicate that individual differences in the P3 elicited by cues for ingested liquid rewards are highly reliable and substantially stable over 8-10 months. Individual differences in alcohol cue-specific P3 reactivity were less reliable and less stable. The conditions under which alcohol/drug cue-specific reactivity in neural signals is adequately reliable and stable remain to be discovered.

The investigation of mechanisms underlying addictive behaviors: a case-control study

Background: The contradictory nature of behavioral addictions has sustained a nondefinitive debate regarding their construct validity. Objective(s): The current study aims at exploring mechanisms underlying two distinct classes of behaviors-behavioral addictions characterized by core alterations in reward processing systems (ARPS) and behaviors with a main function of maladaptive coping. Methods: This case-control study included 99 treatment-seeking individuals with a primary diagnosis of alcohol use disorder (male: N = 68; female: N = 31) and 74 healthy control (HC) subjects (male: N = 38; female: N = 36). The severity of maladaptive behaviors was measured through the Shorter PROMIS Questionnaire (SPQ). Latent mechanisms were assessed by the Disinhibition Domain of the Personality Inventory for DSM-5 (PID-5-DI) and the Acceptance and Action Questionnaire-II (AAQ-II). Results: The clinical group showed higher severity of behavioral addictions than HC. This difference was not replicated for the other class of maladaptive behaviors, except for compulsive buying. Ordinal regression analysis showed that the clinical group significantly predicted SPQ scores reflecting ARPS, SPQ shopping and starving subscales. This was not replicated for the overall SPQ score capturing maladaptive coping and binge eating behaviors. Controlling for PID-5-DI and AAQ-II scores, which were significantly associated to SPQ subscales, effects of the aforementioned clinical group were not significant. Conclusions: The study highlighted distinct and common mechanisms underlying different classes of maladaptive behaviors. Results supported future neuroscience research for clarifying the role of ARPS in compulsive sex and buying in order to consider them as addictive disorders.

Problematic smartphone use: The role of reward processing, depressive symptoms and self-control

The widespread adoption of smartphones has been associated with the emergence of problematic smartphone use. Problematic smartphone use is consistently associated with increased levels of depression and lower self-control, and pathological technology use more generally may be associated with reduced activity in the reward system, an effect that is also observed in depression and with poor self-control. The current study sought to examine the association between problematic smartphone use and event-related potentials (ERPs) related to reward processing, and to determine whether reward processing, depressive symptoms and self-control have shared or unique influences on problematic smartphone use. The sample was drawn from a university student population (N = 94, age M = 19.34, SD = 1.23 years, 67 female, 25 male, 1 gender non-conforming, 1 unidentified). Participants performed a gambling task while EEG was recorded and completed measures of smartphone pathology, depressive symptoms and self-control. The ERP data revealed that increasing problematic smartphone use was associated with reduced ERP amplitude for gains and losses when individuals were the agent of choice, but not when the computer chose. This may reflect a selective association between problematic smartphone use and neural prediction errors. Regression analyses revealed that reward processing, depressive symptoms and self-control were predictors of problematic smartphone use, possibly revealing multiple pathways to problematic smartphone use.

Evaluating the validity of brief prototype-based informant ratings of triarchic psychopathy traits in prisoners

The validity of self-report psychopathy assessment has been questioned, especially in forensic settings where clinical evaluations influence critical decision-making (e.g., institutional placement, parole eligibility). Informant-based assessment offers a potentially valuable supplement to self-report but is challenging to acquire in under-resourced forensic contexts. The current study evaluated, within an incarcerated sample (n = 322), the extent to which brief prototype-based informant ratings of psychopathic traits as described by the triarchic model (boldness, meanness, disinhibition; Patrick et al., 2009) converge with self-report trait scores and show incremental validity in predicting criterion measures. Self/informant convergence was robust for traits of boldness and disinhibition, but weaker for meanness. Informant-rated traits showed incremental predictive validity over self-report traits, both within and across assessment domains. These findings indicate that simple prototype-based informant ratings of the triarchic traits can provide a useful supplement to self-report in assessing psychopathy within forensic-clinical settings.

The startle reflex as an indicator of psychopathic personality from childhood to adulthood: A systematic review

The startle reflex has been suggested to operate as a psychophysiological marker of psychopathic personality, based on findings from studies using a range of different methodologies and participant samples. The present review aims at synthesizing existing evidence of the relationship between psychopathy and the startle reflex across task paradigms, psychopathic personality subtypes and subdimensions, participant samples (i.e., incarcerated/ clinical or non-offenders), and age groups using the triarchic model of psychopathy as a frame of reference. Systematic literature searches were conducted up until the 24th of March 2020 in PubMed, PsycINFO, and Web of Science. A total of 2311 potential studies were identified, out of which 40 met relevancy and quality criteria. Results indicate that reduced aversive startle potentiation is associated with psychopathic personality in general, but clusters of traits relating to the triarchic model constructs of boldness and meanness in particular. Available evidence suggest that startle paradigms could be meaningful for differentiating individuals with and without psychopathic personality. Findings support suggestions of psychopathic personality as a multifaceted, rather than a unitary construct. Reduced aversive startle potentiation has also been found in relation to psychopathic features in child-aged samples but work of this kind is limited and more research is needed. Future studies should focus on greater consistency in task paradigms and analytic strategies to enhance the capacity to compare and integrate findings across studies.

Single-trial modeling separates multiple overlapping prediction errors during reward processing in human EEG

Learning signals during reinforcement learning and cognitive control rely on valenced reward prediction errors (RPEs) and non-valenced salience prediction errors (PEs) driven by surprise magnitude. A core debate in reward learning focuses on whether valenced and non-valenced PEs can be isolated in the human electroencephalogram (EEG). We combine behavioral modeling and single-trial EEG regression to disentangle sequential PEs in an interval timing task dissociating outcome valence, magnitude, and probability. Multiple regression across temporal, spatial, and frequency dimensions characterized a spatio-tempo-spectral cascade from early valenced RPE value to non-valenced RPE magnitude, followed by outcome probability indexed by a late frontal positivity. Separating negative and positive outcomes revealed the valenced RPE value effect is an artifact of overlap between two non-valenced RPE magnitude responses: frontal theta feedback-related negativity on losses and posterior delta reward positivity on wins. These results reconcile longstanding debates on the sequence of components representing reward and salience PEs in the human EEG.

Neurobiology and the Hierarchical Taxonomy of Psychopathology: progress toward ontogenetically informed and clinically useful nosology

The Hierarchical Taxonomy of Psychopathology (HiTOP) is an empirical structural model of psychological symptoms formulated to improve the reliability and validity of clinical assessment. Neurobiology can inform assessments of early risk and intervention strategies, and the HiTOP model has greater potential to interface with neurobiological measures than traditional categorical diagnoses given its enhanced reliability. However, one complication is that observed biological correlates of clinical symptoms can reflect various factors, ranging from dispositional risk to consequences of psychopathology. In this paper, we argue that the HiTOP model provides an optimized framework for conducting research on the biological correlates of psychopathology from an ontogenetic perspective that distinguishes among indicators of liability, current symptoms, and consequences of illness. Through this approach, neurobiological research can contribute more effectively to identifying individuals at high dispositional risk, indexing treatment-related gains, and monitoring the consequences of mental illness, consistent with the aims of the HiTOP framework.


Validity and utility of Hierarchical Taxonomy of Psychopathology (HiTOP): II. Externalizing superspectrum

The Hierarchical Taxonomy of Psychopathology (HiTOP) is an empirical effort to address limitations of traditional mental disorder diagnoses. These include arbitrary boundaries between disorder and normality, disorder co-occurrence in the modal case, heterogeneity of presentation within dis-orders, and instability of diagnosis within patients. This paper reviews the evidence on the validity and utility of the disinhibited externalizing and antagonistic externalizing spectra of HiTOP, which together constitute a broad externalizing superspectrum. These spectra are composed of elements subsumed within a variety of mental disorders described in recent DSM nosologies, including most notably substance use disorders and "Cluster B" personality disorders. The externalizing superspectrum ranges from normative levels of impulse control and self-assertion, to maladaptive disinhibition and antagonism, to extensive polysubstance involvement and personality psychopathology. A rich literature supports the validity of the externalizing superspectrum, and the disinhibited and antagonistic spectra. This evidence encompasses common genetic influences, environmental risk factors, childhood antecedents, cognitive abnormalities, neural alterations, and treatment response. The structure of these validators mirrors the structure of the phenotypic externalizing superspectrum, with some correlates more specific to disinhibited or antagonistic spectra, and others relevant to the entire externalizing superspectrum, underlining the hierarchical structure of the domain. Compared with traditional diagnostic categories, the externalizing superspectrum conceptualization shows improved utility, reliability, explanatory capacity, and clinical applicability. The externalizing superspectrum is one aspect of the general approach to psychopathology offered by HiTOP and can make diagnostic classification more useful in both research and the clinic.

Electrocortical correlates of impaired motor inhibition and outcome processing are related in high binge-watching

Models posit problematic binge-watching to involve a vicious circle of low motivation for alternative activities, low sensitivity for the consequences of neglected goals, and low self-control. As such, simultaneously impaired feedback and inhibitory functioning might contribute to binge-watching. We tested the hypothesis that blunted feedback-related brain activity is coupled with attenuated inhibitory brain activity in binge-watchers. High (n = 32) and non-binge-watchers (n = 31) performed go/nogo (inhibition) and stop signal (stopping) tasks and a flanker paradigm with performance feedback during electroencephalography. We examined how neural correlates of inhibition and stopping were associated with outcome processing in each group. We assessed the temporospatial relationship using a single-trial regression approach. High binge-watchers, but not non-binge-watchers, who differentiated less between gains and losses at the neural level (feedback-P3b) also recruited less brain activity during both inhibition and stopping (inhibition-P3 and stopping-P3). Exploratory analyses suggested that these relationships were most prominent in high binge-watchers with high loss of control over watching. Main effects of the group in performance or EEG did not emerge. These results suggest a potentially problematic interaction between outcome and inhibitory functions in binge-watchers. Insensitivity to behavioral consequences along with inhibitory impairments may also confer a long-term risk for compulsive watching. Our multi-modal approach may be particularly suited to detect such an underlying risk marker.

Reprint of: Using a co-twin control design to evaluate alternative trait measures as indices of liability for substance use disorders

To establish a trait-dispositional variable as an indicator of liability for the development of substance use disorders (SUDs), the trait must share heritable variance with SUDs and its association should not be primarily attributable to a direct impact of SUDs on characteristics that define the trait. The current work applied a co-twin control (CTC) modeling approach to data from two monozygotic twin samples to investigate the degree to which different measures of trait-impulsiveness represent indicants of vulnerability to SUDs (liability indicators), or outcomes or concomitants of SUDs (exposure indicators). The Five Factor Model (FFM) trait of conscientiousness was assessed via self-report, and a counterpart neurobehavioral trait of disinhibition was assessed both through self-report and using self-report and brain response measures combined. FFM trait data were available for one twin sample (N = 298); data for variants of P3 brain response were available along with a scale measure of disinhibition in the other (N = 258). CTC analyses revealed only an exposure effect of SUD symptomatology on FFM conscientiousness, indicating that this self-report assessed trait does not index liability for SUDs. By contrast, the disinhibition scale measure showed pronounced liability and weaker exposure-based associations with SUDs - and when quantified using scale scores together with P3 brain response, the exposure-based association was eliminated, such that this disinhibition measure related to SUD symptoms exclusively as a function of liability influences. These findings highlight a distinct advantage of quantifying traits in neurobehavioral terms - namely, the capacity to effectively index dispositional liability for psychopathological outcomes.

Co-occurring tobacco and cannabis use in adolescents: Dissociable relationships with mediofrontal electrocortical activity during reward feedback processing

Differences in corticostriatal neural activity during feedback processing of rewards and losses have been separately related to cannabis and tobacco use but remain understudied relative to co-use in adolescents. Using high-density EEG (128 electrode system, 1000 Hz sampling), we examined event-related potentials (ERPs) elicited by monetary reward, neutral, and loss feedback during performance on a non-learning four-choice guessing task in a sample of non-deprived daily-cigarette-smoking adolescents (n = 36) who used tobacco and cannabis regularly (TC adolescents), and non-smoking healthy control adolescents (HCs) (n = 29). Peak amplitudes and latencies of mediofrontal ERPs indexing feedback-related negativities (FRNs) were used as outcomes in repeated-measures ANOVAs. No differences in FRNs were observed between TC and HC adolescents. Within TC adolescents, cannabis-use and tobacco-use variables had distinct relationships with the FRN, with cannabis-related problem severity being positively correlated with FRN amplitude during reward feedback and tobacco-related problem severity being negatively correlated with FRN latency during non-loss feedback (i.e., reward and neutral). These findings suggest that co-occurring cannabis and tobacco use may have dissociable relationships with feedback processing relating to each drug and support an incentive salience model of addiction severity related to cannabis use in adolescents.

The effort-doors task: Examining the temporal dynamics of effort-based reward processing using ERPs

Aberrant reward processing is a cardinal feature of various forms of psychopathology. However, recent research indicates that aberrant reward processing may manifest at temporally distinct substages and involve interdependent subcomponents of reward processing. To improve our understanding of both the temporal dynamics and distinct subcomponents of reward processing, we added an effort manipulation to the "doors" reward-task paradigm, to derive behavioral and event-related potential (ERP) measures of effort-based reward processing. Behavioral measures consisting of reaction time, response rate, and response rate change were used to index effort expenditure, and ERP measures were used to index attention allocated toward effort-completion cues, anticipation of reward, valuation of reward, and attention toward monetary feedback. Reduced response rate and slowing of response were evident during the high effort versus the low effort condition. ERP findings indicated increased attention to signals of high- compared to low-effort completion cues-as well as reduced anticipation of rewards, and reduced attention toward feedback information following high effort expenditure. Participants showing the most response-rate slowing evidenced the greatest reward devaluation following high versus low effort. Findings demonstrate that the addition of an effort expenditure manipulation to the doors reward paradigm produced reliable ERP and behavioral measures of effort-based reward processing, providing opportunities for future researchers to utilize the effort-doors task to parse the temporal dynamics of both anticipatory and consummatory reward processing components.

Environment-dependent behavioral traits and experiential factors shape addiction vulnerability

The transition from controlled drug use to drug addiction depends on an interaction between a vulnerable individual, their environment and a drug. Here we tested the hypothesis that conditions under which individuals live influence behavioral vulnerability traits and experiential factors operating in the drug taking environment to determine the vulnerability to addiction. The role of behavioral vulnerability traits in mediating the influence of housing conditions on the tendency to acquire cocaine self-administration was characterized in 48 rats housed in either an enriched (EE) or a standard (SE) environment. Then, the influence of these housing conditions on the individual vulnerability to develop addiction-like behavior for cocaine or alcohol was measured in 72 EE or SE rats after several months of cocaine self-administration or intermittent alcohol drinking, respectively. The determining role of negative experiential factors in the drug taking context was further investigated in 48 SE rats that acquired alcohol drinking to self-medicate distress in a schedule-induced polydipsia procedure. The environment influenced the acquisition of drug intake through its effect on behavioral markers of resilience to addiction. In contrast, the initiation of drug taking as a coping strategy or in a negative state occasioned by the contrast between enriched housing conditions and a relatively impoverished drug taking setting, facilitated the development of compulsive cocaine and alcohol intake. These data indicate that addiction vulnerability depends on environmentally determined experiential factors, and suggest that initiating drug use through negative reinforcement-based self-medication facilitates the development of addiction in vulnerable individuals. SIGNIFICANCE STATEMENT: The factors that underlie an individual's vulnerability to switch from controlled, recreational drug use to addiction are not well understood. We showed that in individuals housed in enriched conditions, the experience of drugs in the relative social and sensory impoverishment of the drug taking context, and the associated change in behavioral traits of resilience to addiction, exacerbate the vulnerability to develop compulsive drug intake. We further demonstrated that the acquisition of alcohol drinking as a mechanism to cope with distress increases the vulnerability to develop compulsive alcohol intake. Together these results demonstrate that experiential factors in the drug taking context shape the vulnerability to addiction.

The difference between trait disinhibition and impulsivity-and why it matters for clinical psychological science

In the psychological science field, there is substantial interest in quantifying individual differences in self-regulatory capacity because of its transdiagnostic relevance to various forms of psychopathology. Trait disinhibition and impulsiveness are popular conceptualizations of dispositions reflecting self-regulation of behavioral and emotional responding. In the literature, these constructs are often treated interchangeably because of their shared focus on general disconstraint and a lack of direct comparisons between measures of each. The current work used structural modeling to examine conceptual and empirical differences between 2 popular operationalizations of these traits in 2 samples (Ns = 400, 308), and employed regression and dominance analyses to compare their predictive relations with criterion measures of externalizing problems and negative affectivity (NA). Impulsigenic traits were related both to externalizing problems and NA, whereas trait disinhibition was selectively associated with externalizing. In a dominance analysis, trait disinhibition exhibited complete dominance over all impulsigenic traits in predicting externalizing problems. Conversely, multiple impulsigenic traits evidenced complete dominance over trait disinhibition in prediction of NA. The current work provides evidence that (a) disinhibition and impulsigenic traits are not interchangeable, (b) disinhibition specifically indexes propensity for externalizing problems, and (c) impulsigenic traits reflect a blend of externalizing and NA that appears relevant to diverse forms of psychopathology. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Reward processing modulates the association between trauma exposure and externalizing psychopathology

Childhood adversity is common and strongly associated with risk for psychopathology. Identifying factors that buffer children from experiencing psychopathology following adversity is critical for developing more effective intervention approaches. The present study examined several behavioral metrics of reward processing reflecting global approach motivation for reward and the degree to which reward responses scaled with reward value (i.e., behavioral sensitivity to reward value) as potential moderators of the association of multiple dimensions of adversity-including trauma, caregiver neglect, and food insecurity-with depression and externalizing psychopathology in a sample of youth aged 8-16 years (n = 132). Trauma exposure and externalizing problems were positively associated at low and moderate levels of reward reactivity, but this association became non-significant at high levels of reward reactivity. Our findings extend prior work, suggesting that high behavioral sensitivity to reward value may buffer against externalizing problems following exposure to trauma.

The Role of Social Reward and Corticostriatal Connectivity in Substance Use

This report describes an ongoing R03 grant that explores the links between trait reward sensitivity, substance use, and neural responses to social and nonsocial reward. Although previous research has shown that trait reward sensitivity and neural responses to reward are linked to substance use, whether this relationship is impacted by how people process social stimuli remains unclear. We are investigating these questions via a neuroimaging study with college-aged participants, using individual difference measures that examine the relation between substance use, social context, and trait reward sensitivity with tasks that measure reward anticipation, strategic behavior, social reward consumption, and the influence of social context on reward processing. We predict that substance use will be tied to distinct patterns of striatal dysfunction. Specifically, reward hyposensitive individuals will exhibit blunted striatal responses to social and non-social reward and enhanced connectivity with the orbitofrontal cortex; in contrast, reward hypersensitive individuals will exhibit enhanced striatal responses to social and non-social reward and blunted connectivity with the orbitofrontal cortex. We also will examine the relation between self-reported reward sensitivity, substance use, and striatal responses to social reward and social context. We predict that individuals reporting the highest levels of substance use will show exaggerated striatal responses to social reward and social context, independent of self-reported reward sensitivity. Examining corticostriatal responses to reward processing will help characterize the relation between reward sensitivity, social context and substance use while providing a foundation for understanding risk factors and isolating neurocognitive mechanisms that may be targeted to increase the efficacy of interventions.

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.

The reward positivity: Comparing visual and auditory feedback

Past work has demonstrated that the reward positivity (RewP) indexes a feedback-monitoring system sensitive to positive outcomes. Research on the RewP has frequently used simple guessing tasks. In the doors task, participants receive either feedback denoting monetary gain or loss on each trial after choosing one of two doors to "open." Typically, these tasks present visual stimuli on a computer monitor. The current study developed and validated a version of the doors task utilizing auditory stimuli to indicate gains and losses. Thirty-eight young adults completed both a standard visual doors task and a novel auditory doors task. Results indicated that the audio RewP was more positive and peaked earlier than the visual RewP. Additionally, the audio RewP both moderately correlated with and demonstrated similar internal consistency as the visual RewP. These results suggest that the auditory doors task elicits the same feedback-monitoring processes as the visual doors task.

Using a co-twin control design to evaluate alternative trait measures as indices of liability for substance use disorders

To establish a trait-dispositional variable as an indicator of liability for the development of substance use disorders (SUDs), the trait must share heritable variance with SUDs and its association should not be primarily attributable to a direct impact of SUDs on characteristics that define the trait. The current work applied a co-twin control (CTC) modeling approach to data from two monozygotic twin samples to investigate the degree to which different measures of trait-impulsiveness represent indicants of vulnerability to SUDs (liability indicators), or outcomes or concomitants of SUDs (exposure indicators). The Five Factor Model (FFM) trait of conscientiousness was assessed via self-report, and a counterpart neurobehavioral trait of disinhibition was assessed both through self-report and using self-report and brain response measures combined. FFM trait data were available for one twin sample (N = 298); data for variants of P3 brain response were available along with a scale measure of disinhibition in the other (N = 258). CTC analyses revealed only an exposure effect of SUD symptomatology on FFM conscientiousness, indicating that this self-report assessed trait does not index liability for SUDs. By contrast, the disinhibition scale measure showed pronounced liability and weaker exposure-based associations with SUDs - and when quantified using scale scores together with P3 brain response, the exposure-based association was eliminated, such that this disinhibition measure related to SUD symptoms exclusively as a function of liability influences. These findings highlight a distinct advantage of quantifying traits in neurobehavioral terms - namely, the capacity to effectively index dispositional liability for psychopathological outcomes.

Interfacing neural constructs with the Hierarchical Taxonomy of Psychopathology: 'Why' and 'how'

The Hierarchical Taxonomy of Psychopathology (HiTOP) represents a crucial step forward in the empirical refinement of psychiatric nosology. Although grounded in factor analyses of clinical symptoms and affiliated traits, HiTOP encourages research using measures of other types, including neural-system variables, to clarify coherent processes contributing to the hierarchical structure of psychopathology. However, systematic strategies for interfacing HiTOP dimensions with neural-system variables have not been put forth. We discuss reasons for considering neurobiological systems in relation to HiTOP (i.e. 'why') and propose alternative strategies that might be used to develop an interface between HiTOP and neurobiology (i.e. 'how'). In particular, we highlight potential advantages and limitations of establishing this interface through reference to (i) HiTOP dimensions themselves, or conventional personality trait models linked to HiTOP; (ii) alternative trait constructs designed to link conventional personality models and neurobiological measures; and (iii) mechanistic models of neurobiological processes relevant to HiTOP constructs, derived from computational modelling. We discuss the importance of establishing an interface between HiTOP and neurobiology to develop a more comprehensive, mechanistic understanding of psychopathology and to guide the refinement of the HiTOP model. Such efforts have the potential to guide the development and provision of effective, individualized psychological treatment.