Social Reward in Youth at Risk for Depression: A Preliminary Investigation of Subjective and Neural Differences

Neural Sensitivity to Social and Monetary Reward in Depression: Clarifying General and Domain-Specific Deficits

Reward dysfunction is thought to be play a critical role in the pathogenesis of depression. Multiple studies have linked depression to abnormal neural sensitivity to monetary rewards, but it remains unclear whether this reward dysfunction is generalizable to other rewards types. The current study begins to address this gap by assessing abnormal sensitivity to both monetary and social rewards in relation to depressive symptoms. We recorded event-related potentials (ERPs) during two incentive delay tasks, one with monetary reward and one with social reward. Both tasks were administered within the same sample, enabling a direct comparison of reward types. ERPs elicited by social and nonsocial rewards were morphologically similar across several stages of processing: cue salience, outcome anticipation, early outcome evaluation, outcome salience. Moderation analyses showed depression was linked with a pattern of general deficits across social and monetary rewards, specifically for the stages of outcome anticipation (stimulus-preceding negativity) and outcome salience (feedback-P3); self-reported reward sensitivity was generally associated with early outcome evaluation (reward positivity). Regression analyses modeling task-specific variance, however, showed a unique association between depression and outcome salience for social rewards, controlling for monetary rewards. The findings from this study underscore the importance of assessing neural sensitivity to multiple reward types in depression, particularly social reward. Characterizing the profile of reward functioning in depression across reward types may help to link laboratory-based deficits to relatively global vs. focal difficulties in real-world functioning.

I Knew You Weren't Going to Like Me! Neural Response to Accurately Predicting Rejection Is Associated With Anxiety and Depression

Anxiety and depression often emerge in adolescence. A normative increase in the desire for peer acceptance may be one of many contributing factors. These shifts occur during a phase of development in which neural reward networks, including structures such as the ventral striatum, undergo critical changes. Despite the salience of peer feedback during adolescence, neural responses to reward have largely been examined in the monetary domain, leaving many open questions about responses to social rewards. Moreover, most paradigms do not tease apart different aspects of reward processing (e.g., receiving feedback, being correct). Anxiety and depression are also associated with alterations in reward networks; however, little is known about how anxiety and depression in adolescence relate to differences in social vs. non-social reward processing. In this study, adolescents (n = 28) underwent fMRI while completing novel monetary and social feedback tasks, which tease apart reward domain (social/monetary), valence (positive/negative), and outcome (correct/incorrect). Participants were shown a pair of stimuli (doors/age-matched peers) and asked to indicate which stimulus would provide positive (win money/social like) or negative (lose money/social dislike) feedback. Participants then received feedback about the purported accuracy of their response. Region-of-interest analyses showed that left ventral striatum response varied by domain (social/monetary), valence (positive/negative), and outcome (correct/incorrect) of reward. Additionally, unique associations between anxiety, depression, and brain function were observed for correct, but not for incorrect trials, in the social, but not monetary task. Specifically, adolescents with high anxiety symptoms, but low depression, displayed greater left ventral striatum activation when correctly identifying peers who gave dislike (vs. like) feedback. Thus, anxious youth exhibited enhanced activation in a brain region implicated in reward processing when they accurately predicted someone was going to dislike them. Higher levels of both depression and anxiety symptoms were associated with greater striatal activation to correctly identifying peers who gave like (vs. dislike) feedback. These results suggest a neural mechanism by which negative prediction biases may be reinforced in anxious youth.

Neural Activation to Parental Praise Interacts With Social Context to Predict Adolescent Depressive Symptoms

Negative relationships with parents and peers are considered risk factors for depression in adolescence, yet not all adolescents perceiving negative social relationships develop depression. In line with neurobiological susceptibility to social context models, we examined how individual differences in neural processing of parental praise, a unique form of social reward, might explain variability in susceptibility to perceived maternal acceptance and peer victimization. During neuroimaging, 38 11- to 17-year-olds with a history of anxiety listened to audio clips of a parent (predominately mothers) providing personalized praise and neutral statements. Average activation during parental praise clips relative to neutral clips was extracted from several anatomically-defined reward-related regions-of-interest (ROIs): the subgenual anterior cingulate cortex, caudate nucleus, amygdala, nucleus accumbens, and insula. Moderation models included direct effects and interactions between neural activation to social reward, peer victimization, and maternal acceptance at the time of scanning on depressive symptoms 1 year later. Results showed a significant three-way interaction for the bilateral caudate such that peer victimization was associated with depressive symptoms only for individuals with higher caudate response to praise who perceived maternal acceptance as low. Consistent with neurobiological susceptibility to social context models, caudate activation to social reward could represent a neural marker that helps explain variability in adolescent sensitivity to social contexts. High caudate activation to praise could reflect a history of negative experiences with parents and/or peers that places youth at greater risk for depressive symptoms. Findings suggest that interactions between neural response to reward and salient social contexts may help us understand changes in depressive symptoms during a period of development marked by significant biopsychosocial change.

The Positive Valence Systems Scale: Development and Validation

We present the Positive Valence Systems Scale (PVSS), a measure of the National Institute of Mental Health's Research Domain Criteria Positive Valence Systems domain. An initial long form of the scale (45 items) providing a broad assessment of the domain was distilled into a short form (21 items) measuring responses to a wide range of rewards (Food, Physical Touch, Outdoors, Positive Feedback, Social Interactions, Hobbies, and Goals). Across three diverse samples, the PVSS-21 demonstrated strong internal consistency, retest reliability, and factorial validity. It was more strongly related to reward than punishment sensitivity, positive than negative affect, and depression than anxiety. PVSS-21 scores discriminated depressed from nondepressed individuals and predicted anhedonia severity even when controlling for depression status. Hobbies emerged as the strongest predictor of clinical outcomes and the best differentiator of depressed and nondepressed individuals. Results highlight the potential of the PVSS for advancing understanding of reward-related abnormalities in depression and other disorders.

Adolescent suicide attempts and ideation are linked to brain function during peer interactions

Understanding the neural correlates of social interaction among depressed adolescents with suicidal tendencies might help personalize treatment. We tested whether brain function during social interaction is disrupted for depressed adolescents with (1) high suicide ideation and (2) recent attempts. Depressed adolescents with high suicide ideation, including attempters (n = 45;HS) or low suicide ideation (n = 42;LS), and healthy adolescents (n = 39;HC), completed a version of the Cyberball peer interaction task during an fMRI scan. Groups were compared on brain activity during peer exclusion and inclusion versus a non-social condition. During peer exclusion and inclusion, HS youth showed significantly lower activity in precentral and postcentral gyrus, superior temporal gyrus, medial frontal gyrus, insula, and putamen compared to LS youth; and significantly reduced activity in caudate and anterior cingulate cortex compared to HC youth. In a second analysis, suicide attempters (n = 26;SA) were compared to other groups. SA adolescents showed significantly higher activity in ACC and superior and middle frontal gyrus than all other groups. Brain activity was significantly correlated with negative emotionality, social functioning, and cognitive control. Conclusions: Adolescent suicide ideation and attempts were linked to altered neural function during positive and negative peer interactions. We discuss the implications of these findings for suicide prevention efforts.

Behavioral and Neural Dysregulation to Social Rewards and Links to Internalizing Symptoms in Adolescents

Adolescence is a time of unique sensitivity to socially salient stimuli such as social rewards. This period overlaps with the onset of psychopathology such as internalizing and externalizing symptoms. In the current studies, we examined behavioral and neural patterns of dysregulation to social rewards and threats, and links to internalizing and externalizing symptoms in youths. In study 1, we used a social Go/NoGo cognitive control task using peer faces to test for age-related behavioral differences in inhibitory failures in adolescents (N = 53, Mage = 13.37 years), and adults (N = 51, Mage = 43.71 years). In study 2, an independent adolescent sample (N = 51, Mage = 13.98 years) completed a similar social Go/NoGo cognitive control task during fMRI. Results show that adolescents had greater inhibitory failures - as measured by false alarm rate - to both social reward and threat cues than adults, and more so to social reward than threat cues. Greater inhibitory failures to social reward than threat cues were associated with greater internalizing symptoms, but were not significantly related to externalizing symptoms. At the neural level, greater inhibitory failures to social reward than threat cues as well as greater internalizing symptoms were both associated with heightened amygdala-ventral striatum connectivity. Our findings indicate that subcortico-subcortical connectivity, which is deemed to occur chronologically earlier and thus necessary for subcortico-cortical circuits, may serve as an early biomarker for emotion dysregulation and a risk factor for internalizing symptoms.

Adolescents' neural response to social reward and real-world emotional closeness and positive affect

Feeling emotionally close to others during social interactions is a ubiquitous and meaningful experience that can elicit positive affect. The present study integrates functional magnetic resonance imaging (fMRI) and ecological momentary assessment (EMA) to investigate whether neural response to social reward (1) is related to the experience of emotional closeness and (2) moderates the association between emotional closeness and positive affect during and following social interactions. In this study, 34 typically developing adolescents (ages 14-18 years) completed a social-reward fMRI task, a monetary-reward fMRI task, and a 2-week EMA protocol regarding their social and affective experiences. Adolescents with greater right posterior superior temporal sulcus/temporoparietal junction (pSTS/TPJ) response to social reward reported greater mean momentary emotional closeness. Neural response to social reward in the right pSTS/TPJ moderated how strongly momentary emotional closeness was associated with both concurrent positive affect and future peak happiness, but in different ways. Although emotional closeness had a significant positive association with concurrent positive affect among adolescents at both high and low right pSTS/TPJ response based on a follow-up simple slopes test, this association was stronger for adolescents with low right pSTS/TPJ response. In contrast, emotional closeness had a significant positive association with future peak happiness among adolescents with high right pSTS/TPJ response, but not among those with low right pSTS/TPJ response. These findings demonstrate the importance of neural response to social reward in key social processing regions for everyday experiences of emotional closeness and positive affect in the context of social interactions.

Bidirectional Associations Between Stress and Reward Processing in Children and Adolescents: A Longitudinal Neuroimaging Study

BACKGROUND

Aberrations in both neural reward processing and stress reactivity are associated with increased risk for mental illness; yet, how these two factors relate to each other remains unclear. Several studies suggest that stress exposure impacts reward function, thus increasing risk for psychopathology. However, the alternative hypothesis, in which reward dysfunction impacts stress reactivity, has been rarely examined. The current study aimed to test both hypotheses using a longitudinal design.

METHODS

Participants were 38 children (23 girls; 61%) from a prospective cohort study. A standard stress-exposure measure was collected at 7 years of age. Children performed a well-validated imaging reward paradigm at age 10, and a standardized acute psychological stress laboratory protocol was administered both at age 10 and at age 13. Structural equation modeling was used to examine bidirectional associations between stress and neural response to reward anticipation.

RESULTS

Higher exposure to stressful life events at age 7 predicted lower neural response to reward anticipation in regions of the basal ganglia at age 10, which included ventral caudate, nucleus accumbens, putamen, and globus pallidus. Lower response to reward anticipation in medial prefrontal and anterior cingulate cortex predicted higher stress reactivity at age 13.

CONCLUSIONS

Our findings provide support for bidirectional associations between stress and reward processing, in that stress may impact reward anticipation, but also in that reduced reward anticipation may increase susceptibility to stress.

Peer Victimization and Dysfunctional Reward Processing: ERP and Behavioral Responses to Social and Monetary Rewards

Peer victimization (or bullying) is a known risk factor for depression, especially among youth. However, the mechanisms connecting victimization experience to depression symptoms remains unknown. As depression is known to be associated with neural blunting to monetary rewards, aberrant responsiveness to social rewards may be a key deficit connecting socially stressful experiences with later depression. We, therefore, sought to determine whether adolescents’ experiences with social stress would be related to their current response to social rewards over less socially relevant monetary rewards. Neural responses to monetary and social rewards were measured using event-related potentials (ERPs) to peer acceptance and rejection feedback (Island Getaway task) and to monetary reward and loss feedback (Doors task) in a sample of 56 late adolescents/emerging young adults followed longitudinally since preschool. In the Island Getaway task, participants voted whether to “keep” or “kick out” each co-player, providing an index of prosocial behavior, and then received feedback about how each player voted for the participant. Analyses tested whether early and recent peer victimization was related to response to rewards (peer acceptance or monetary gains), residualized for response to losses (peer rejection or monetary losses) using the reward positivity (RewP) component. Findings indicated that both experiencing greater early and greater recent peer victimization were significantly associated with participants casting fewer votes to keep other adolescents (“Keep” votes) and that greater early peer victimization was associated with reduced neural response to peer acceptance. Early and recent peer victimization were significantly more associated with neural response to social than monetary rewards. Together, these findings suggest that socially injurious experiences such as peer victimization, especially those occurring early in childhood, relate to two distinct but important findings: that early victimization is associated with later reduced response to peer acceptance, and is associated with later tendency to reject peers. Findings also suggest that there is evidence of specificity to reward processing of different types; thus, future research should expand studies of reward processing beyond monetary rewards to account for the possibility that individual differences may be related to other, more relevant, reward types.

Maternal Affective Expression and Adolescents' Subjective Experience of Positive Affect in Natural Settings

This study investigated the association between maternal affective expression during laboratory-based interaction tasks and adolescents' experience of positive affect (PA) in natural settings. Participants were 80 healthy adolescents and their mothers. Durations of maternal positive (PA) and negative affective (NA) expressions were observed during a conflict resolution task and a positive event planning interaction task. Ecological momentary assessment (EMA) procedures were employed to assess adolescents' momentary and peak experience of PA in daily life. Results indicated that maternal NA, but not maternal PA, was related to adolescents' EMA-reported PA. Adolescents whose mothers expressed more NA experienced less PA in daily environments. Results suggest that adolescents' exposure to maternal negative affective behavior is associated with adolescents' subjective daily well-being.

Effort-cost decision-making in psychosis and depression: could a similar behavioral deficit arise from disparate psychological and neural mechanisms?

Motivational impairment is a common feature of both depression and psychosis; however, the psychological and neural mechanisms that give rise to motivational impairment in these disorders are poorly understood. Recent research has suggested that aberrant effort-cost decision-making (ECDM) may be a potential contributor to motivational impairment in both psychosis and depression. ECDM refers to choices that individuals make regarding the amount of 'work' they are willing to expend to obtain a certain outcome or reward. Recent experimental work has suggested that those with psychosis and depression may be less willing to expend effort to obtain rewards compared with controls, and that this effort deficit is related to motivational impairment in both disorders. In the current review, we aim to summarize the current literature on ECDM in psychosis and depression, providing evidence for transdiagnostic impairment. Next, we discuss evidence for the hypothesis that a seemingly similar behavioral ECDM deficit might arise from disparate psychological and neural mechanisms. Specifically, we argue that effort deficits in psychosis might be largely driven by deficits in cognitive control and the neural correlates of cognitive control processes, while effort deficits in depression might be largely driven by reduced reward responsivity and the associated neural correlates of reward responsivity. Finally, we will provide some discussion regarding future directions, as well as interpretative challenges to consider when examining ECDM transdiagnostically.

A comparison of the electrocortical response to monetary and social reward

Affective science research on reward processing has primarily focused on monetary rewards. There has been a growing interest in evaluating the neural basis of social decision-making and reward processing. The present study employed a within-subject design and compared the reward positivity (RewP), an event-related potential component that is present following favorable feedback and absent or reduced following unfavorable feedback, during monetary and social reward tasks. Specifically, 114 participants (75 females) completed a monetary reward task and a novel social reward task that were matched on trial structure, timing, and feedback stimuli in a counterbalanced order. Results indicated that the monetary and social RewP were of similar magnitude, positively correlated and demonstrated comparable psychometric properties, including reliability and dependability. Across both the monetary and social tasks, women demonstrated a greater RewP compared with men. This study provides a novel methodological approach toward examining the electrocortical response to social reward that is comparable to monetary reward.

Neural responses to social and monetary reward in early adolescence and emerging adulthood

Reward processing is often considered to be a monolithic construct, with different incentive types eliciting equivalent neural and behavioral responses. The majority of the literature on reward processing has used monetary incentives to elicit reward-related activity, yet social incentives may be particularly important due to their powerful ability to shape behavior. Findings from studies comparing social and monetary rewards have identified both overlapping and distinct responses. In order to explore whether reward processing is domain general or category specific (i.e., the same or different across reward types), the present study recorded ERPs from early adolescents (ages 12-13) and emerging adults (ages 18-25) while they completed social and monetary reward tasks. Temporospatial principal components analysis revealed morphologically similar reward positivities (RewPs) in the social and monetary reward tasks in each age group. In early adolescents, no significant difference was found between the magnitude of the RewP to social and monetary rewards. In emerging adults, however, the RewP to monetary rewards was significantly larger than the RewP to social rewards. Additionally, responses to feedback between the two tasks were not significantly correlated in either age group. These results suggest that both domain-general and category-specific processes underlie neural responses to rewards and that the relative incentive value of different types of rewards may change across development. Findings from this study have important implications for understanding the role that neural response to rewards plays in the development of psychopathology during adolescence.

"Why don't they 'like' me more?": Comparing the time courses of social and monetary reward processing

Humans possess a strong tendency towards social affiliation and interpersonal interaction. Yet, we know far less about how rewards in one's social environment affect functioning as we do with other types of rewards, presumably due to the inherent complexity of measuring social phenomena in laboratory settings. Here, we adapted a social reward paradigm (social incentive delay [SID]) for use in event-related potential (ERP) research, enabling a direct comparison of social and monetary reward processing. We found that social and monetary rewards elicit comparable ERP latencies and scalp topographies across several processing stages (reward cue, outcome anticipation, and outcome evaluation), highlighting the possibility of a common neural network. We also found evidence of latent reward sensitivity, as analogous monetary and social ERPs were correlated and associations were uniquely driven by reward signals. The SID is a promising and viable paradigm that is capable of disentangling multiple stages of social reward processing. The capacity to measure social processes will be critical as we broaden efforts to incorporate multiple contexts in reward sensitivity, which will enable us to gain important new insights into human functioning and dysfunction.

The indirect assessment of social anhedonia in Chinese adolescents: Preliminary findings

Nearly all self-report measures of anhedonia have been developed for use in adults. Recently we developed an age and developmentally appropriate measure of social/interpersonal pleasure for adolescents (ACIPS-A), whereby lower scores are indicative of social anhedonia. However the scale had not been administered to Eastern samples. The adolescent version of the Anticipatory and Consummatory Interpersonal Pleasure Scale (ACIPS-A) was administered to a general, community-derived Chinese adolescent sample of 442 students, including 186 males (44%), who ranged in age from 12 to 18 years old. The 20-item Chinese Temporal Experience of Pleasure (TEPS) was also administered to the sample. Exploratory factor analysis revealed that three factors (Casual bonding, Close relationships, and Shared interests) accounted for nearly 69% of the variance. The total ACIPS-A showed excellent internal consistency, with ordinal alpha = 0.94. Scores on the adolescent version of the ACIPS were positively and significantly associated with total scores on the four Chinese TEPS subscales. The ACIPS-A is a sufficiently robust measure to be useful and valid in Chinese samples as well as in Western (i.e. European and U.S.) samples.

Social processing in early adolescence: Associations between neurophysiological, self-report, and behavioral measures

Peer relationships play a major role in adolescent development, but few methods exist for measuring social processing at the neurophysiological level. This study extends our pilot study of Island Getaway, a task for eliciting event-related potentials (ERPs) to peer feedback. We differentiated ERPs using principal components analysis (PCA) and examined associations with behavioral and self-report measures in young adolescents (N=412). PCA revealed an early negativity in the ERP enhanced for rejection feedback, followed by a series of positivities (consistent with reward positivity [RewP], P300, and late positive potential) that were enhanced for acceptance feedback. Greater self-reported task engagement correlated with a larger RewP to acceptance and lower rates of rejecting peers. Youth higher in depressive symptoms exhibited a blunted RewP to social acceptance and reported lower engagement. Results highlight ERP components sensitive to peer feedback that may inform understanding of social processes relevant to typical and atypical development.

Time-Frequency Reward-Related Delta Prospectively Predicts the Development of Adolescent-Onset Depression

BACKGROUND

A blunted reward positivity (RewP), an event-related potential elicited by feedback indicating monetary gain relative to loss, was recently shown to prospectively predict the development of adolescent-onset depression. Time-frequency-based representations of this activity (e.g., reward-related delta) have also been associated with depression. This study is a reanalysis of the time-domain RewP investigation to examine the incremental value of time-frequency indices in the prediction of adolescent-onset depression.

METHODS

The sample included 444 13- to 15-year-old girls with no lifetime history of a depressive disorder. At baseline, adolescents completed a monetary guessing task, and both time-domain and time-frequency analyses were conducted on the event-related potential response to gain and loss feedback. Lifetime psychiatric history in the adolescent and a biological parent were evaluated with diagnostic interviews, and adolescents' current depressive symptoms were assessed using a self-report questionnaire. Adolescents were interviewed again approximately 18 months later to identify first-onset depressive disorder.

RESULTS

Blunted reward-related delta predicted first-onset depressive disorder 18 months later, independent of the time-domain RewP and psychosocial risk factors (i.e., adolescent baseline depressive symptoms, adolescent and parental psychiatric history). In contrast, loss-related theta did not predict the development of depression. Reward-related delta increased sensitivity (73.8% to 82.8%) and positive predictive value (45.0% to 70.9%) for first-onset depressive disorder when applied in parallel and in series, respectively, with baseline depressive symptoms and the time-domain RewP.

CONCLUSIONS

This study provides evidence that frequency-based representations of event-related potentials provide incremental value in the prediction of psychiatric disorders.

Reward processing and mood-related symptoms: An RDoC and translational neuroscience perspective

BACKGROUND

Two objectives of the NIMH Research Domain Criteria (RDoC) initiative are to identify (a) mechanisms that are common to multiple psychiatric disorders, and (b) mechanisms that are unique to specific psychiatric symptoms, and that reflect markers of differential risk for these symptoms. With respect to these objectives, a brain-behavior dimension that has received considerable attention and that is directly relevant to the Positive Valence Systems domain of the RDoC initiative involves reward processing.

METHODS

The present review paper first examines the relationship between reward processing and mood-related symptoms from an RDoC perspective. We then place this work in a larger context by examining the relationship between reward processing abnormalities and psychiatric symptoms defined broadly, including mood-related symptoms, schizophrenia, and addiction.

RESULTS

Our review suggests that reward hyposensitivity relates to a subtype of anhedonia characterized by motivational deficits in unipolar depression, and reward hypersensitivity relates to a cluster of hypo/manic symptoms characterized by excessive approach motivation in the context of bipolar disorder. Integrating this perspective with research on reward processing abnormalities in schizophrenia and addiction, we further argue that the principles of equifinality and multifinality may be preferable to a transdiagnostic perspective for conceptualizing the relationship between reward processing and psychiatric symptoms defined broadly.

CONCLUSION

We propose that vulnerability to either motivational anhedonia or approach-related hypo/manic symptoms involve extreme and opposite profiles of reward processing. We further propose that an equifinality and multifinality perspective may serve as a useful framework for future research on reward processing abnormalities and psychiatric symptoms.

Neural correlates of RDoC reward constructs in adolescents with diverse psychiatric symptoms: A Reward Flanker Task pilot study

BACKGROUND

There has been growing interest under the Research Domain Criteria initiative to investigate behavioral constructs and their underlying neural circuitry. Abnormalities in reward processes are salient across psychiatric conditions and may precede future psychopathology in youth. However, the neural circuitry underlying such deficits has not been well defined. Therefore, in this pilot, we studied youth with diverse psychiatric symptoms and examined the neural underpinnings of reward anticipation, attainment, and positive prediction error (PPE, unexpected reward gain). Clinically, we focused on anhedonia, known to reflect deficits in reward function.

METHODS

Twenty-two psychotropic medication-free youth, 16 with psychiatric symptoms, exhibiting a full range of anhedonia, were scanned during the Reward Flanker Task. Anhedonia severity was quantified using the Snaith-Hamilton Pleasure Scale. Functional magnetic resonance imaging analyses were false discovery rate corrected for multiple comparisons.

RESULTS

Anticipation activated a broad network, including the medial frontal cortex and ventral striatum, while attainment activated memory and emotion-related regions such as the hippocampus and parahippocampal gyrus, but not the ventral striatum. PPE activated a right-dominant fronto-temporo-parietal network. Anhedonia was only correlated with activation of the right angular gyrus during anticipation and the left precuneus during PPE at an uncorrected threshold.

LIMITATIONS

Findings are preliminary due to the small sample size.

CONCLUSIONS

This pilot characterized the neural circuitry underlying different aspects of reward processing in youth with diverse psychiatric symptoms. These results highlight the complexity of the neural circuitry underlying reward anticipation, attainment, and PPE. Furthermore, this study underscores the importance of RDoC research in youth.

Vulnerability to Depression in Youth: Advances from Affective Neuroscience

Vulnerability models of depression posit that individual differences in trait-like vulnerabilities emerge early in life and increase risk for the later development of depression. In this review, we summarize advances from affective neuroscience using neural measures to assess vulnerabilities in youth at high risk for depression due to parental history of depression or temperament style, as well as prospective designs evaluating the predictive validity of these vulnerabilities for symptoms and diagnoses of depression across development. Evidence from multiple levels of analysis indicates that healthy youth at high risk for depression exhibit abnormalities in components of the Research Domain Criteria (RDoC) positive valence systems, including blunted activation in the striatum during reward anticipation and feedback, and that some of these measures can be used to predict later symptoms. In addition, alterations in components of RDoC's negative valence systems, including neural processing of sadness, loss, and threat, have been observed in risk for depression, though effects appear to be more task and method dependent. Within the social processes domain, preliminary evidence indicates that neural processing of social feedback, including heightened reactivity to exclusion and blunted response to social reward, may be related to depression vulnerability. These studies indicate that affective neuroscience can inform understanding of developmental pathways to depression and identify altered emotional processing among youth at high risk. We provide an integrated summary of consistent findings from this literature, along with recommendations for future directions and implications for early intervention.

Role of Reward Sensitivity and Processing in Major Depressive and Bipolar Spectrum Disorders

Since Costello's (1972) seminal Behavior Therapy article on loss of reinforcers or reinforcer effectiveness in depression, the role of reward sensitivity and processing in both depression and bipolar disorder has become a central area of investigation. In this article, we review the evidence for a model of reward sensitivity in mood disorders, with unipolar depression characterized by reward hyposensitivity and bipolar disorders by reward hypersensitivity. We address whether aberrant reward sensitivity and processing are correlates of, mood-independent traits of, vulnerabilities for, and/or predictors of the course of depression and bipolar spectrum disorders, covering evidence from self-report, behavioral, neurophysiological, and neural levels of analysis. We conclude that substantial evidence documents that blunted reward sensitivity and processing are involved in unipolar depression and heightened reward sensitivity and processing are characteristic of hypomania/mania. We further conclude that aberrant reward sensitivity has a trait component, but more research is needed to clearly demonstrate that reward hyposensitivity and hypersensitivity are vulnerabilities for depression and bipolar disorder, respectively. Moreover, additional research is needed to determine whether bipolar depression is similar to unipolar depression and characterized by reward hyposensitivity, or whether like bipolar hypomania/mania, it involves reward hypersensitivity.

Future Research Directions in the Positive Valence Systems: Measurement, Development, and Implications for Youth Unipolar Depression

The Positive Valence Systems (PVS) have been introduced by the National Institute of Mental Health as a domain to help organize multiple constructs focusing on reward-seeking behaviors. However, the initial working model for this domain is strongly influenced by adult constructs and measures. Thus, the present review focuses on extending the PVS into a developmental context. Specifically, the review provides some hypotheses about the structure of the PVS, how PVS components may change throughout development, how family history of depression may influence PVS development, and potential means of intervening on PVS function to reduce onsets of depression. Future research needs in each of these areas are highlighted.

Reward Processing and Risk for Depression Across Development

Striatal response to reward has been of great interest in the typical development and psychopathology literatures. These parallel lines of inquiry demonstrate that although typically developing adolescents show robust striatal response to reward, adolescents with major depressive disorder (MDD) and those at high risk for MDD show a blunted response to reward. Understanding how these findings intersect is crucial for the development and application of early preventative interventions in at-risk children, ideally before the sharp increase in the rate of MDD onset that occurs in adolescence. Robust findings relating blunted striatal response to reward and MDD risk are reviewed and situated within a normative developmental context. We highlight the need for future studies investigating longitudinal development, specificity to MDD, and roles of potential moderators and mediators.