Dimensional anhedonia and the adolescent brain: reward and aversion anticipation, effort and consummation

The neural representations of valence transformation in indole processing

Indole is often associated with a sweet and floral odor typical of jasmine flowers at low concentrations and an unpleasant, animal-like odor at high concentrations. However, the mechanism whereby the brain processes this opposite valence of indole is not fully understood yet. In this study, we aimed to investigate the neural mechanisms underlying indole valence encoding in conversion and nonconversion groups using the smelling task to arouse pleasantness. For this purpose, 12 conversion individuals and 15 nonconversion individuals participated in an event-related functional magnetic resonance imaging paradigm with low (low-indole) and high (high-indole) indole concentrations in which valence was manipulated independent of intensity. The results of this experiment showed that neural activity in the right amygdala, orbitofrontal cortex and insula was associated with valence independent of intensity. Furthermore, activation in the right orbitofrontal cortex in response to low-indole was positively associated with subjective pleasantness ratings. Conversely, activation in the right insula and amygdala in response to low-indole was positively correlated with anticipatory hedonic traits. Interestingly, while amygdala activation in response to high-indole also showed a positive correlation with these hedonic traits, such correlation was observed solely with right insula activation in response to high-indole. Additionally, activation in the right amygdala in response to low-indole was positively correlated with consummatory pleasure and hedonic traits. Regarding olfactory function, only activation in the right orbitofrontal cortex in response to high-indole was positively correlated with olfactory identification, whereas activation in the insula in response to low-indole was negatively correlated with the level of self-reported olfactory dysfunction. Based on these findings, valence transformation of indole processing in the right orbitofrontal cortex, insula, and amygdala may be associated with individual hedonic traits and perceptual differences.

Anticipatory and consummatory pleasure in avoidant/restrictive food intake disorder

BACKGROUND

Recent research suggests that individuals with eating disorders (EDs) report elevated anhedonia, or loss of pleasure. Although individuals with avoidant/restrictive food intake disorder (ARFID) often express that they do not look forward to eating, it is unclear whether they experience lower pleasure than those without EDs. Thus, identifying whether individuals with ARFID experience anhedonia may yield important insights that inform clinical conceptualization and treatment.

METHODS

A sample of 71 participants ages 10-23 with full and subthreshold ARFID and 33 healthy controls (HCs) completed the Pica, ARFID, and Rumination Disorder Interview, a diagnostic interview to assess ARFID profile severity (lack of interest in food, sensory sensitivity, fear of aversive consequences) and the Temporal Experience of Pleasure Scale (TEPS), a self-report measure of consummatory and anticipatory pleasure. Statistical analyses were performed using the full TEPS and also the TEPS with food-related items removed.

RESULTS

The ARFID group reported significantly lower anticipatory and consummatory pleasure compared to HCs, but these differences were no longer significant after controlling for depression, nor after removing food items from the TEPS. Within the ARFID sample, greater ARFID severity was associated with lower anticipatory pleasure across analyses, and greater endorsement of the lack of interest in food profile was related to lower anticipatory pleasure. ARFID severity was also associated with lower consummatory pleasure using the full TEPS, but this relationship was no longer significant with food items removed.

CONCLUSIONS

These results provide initial evidence for lower pleasure before potentially pleasurable events in individuals with more severe ARFID, particularly those with the lack of interest phenotype. Our findings also suggest that depression is likely to contribute low pleasure in this population. Future research should seek to further characterize how dimensions of pleasure relate to the maintenance and treatment of ARFID symptoms.

Transdiagnostic considerations of the relationship between reward sensitivity and psychopathological symptoms - a cross-lagged panel analysis

BACKGROUND

Reward sensitivity constitutes a potential key mechanism regarding the etiology and maintenance of mental disorders, especially depression. However, due to a lack of longitudinal studies, the temporal dynamics are not clear yet. Although some evidence indicates that reward processing could be a transdiagnostic mechanism of disorders, these observations could be also a product of comorbidity with depression. This study aimed at investigating the temporal dynamics of reward sensitivity and the course of psychopathological symptoms in a longitudinal investigation, while taking a possible mediating role of depression into account.

METHODS

We conducted a three-wave longitudinal online survey with a 4-week interval. A total of N = 453 participants filled out all three questionnaires. Reward sensitivity was assessed with the Positive Valence System Scale-21 (PVSS-21), depression with the Patient Health Questionnaire (PHQ-9), eating disorder symptoms with the Eating Disorder Examination-Questionnaire-8 (EDE-Q-8), social anxiety with the Mini-social phobia inventory (Mini-SPIN) and alcohol consumption with the Alcohol Use Disorders Identification Test-Consumption (AUDIT-C). Cross-lagged panels and mediation analyses were calculated using path analyses.

RESULTS

Depressive and eating disorder symptoms predicted reward insensitivity at later points in time. Effects were larger from T2 to T3. A bidirectional relationship concerning social anxiety was found. Higher alcohol consumption predicted higher reward sensitivity. Depression at T2 fully mediated the association between psychopathological symptoms at T1 and reward sensitivity at T3 for social anxiety and eating disorder symptoms.

CONCLUSIONS

Our findings imply that reduced reward sensitivity seems to be a consequence rather than an antecedent of psychopathological symptoms. Comorbid depression plays a crucial role in other mental disorders regarding observed hyposensitivity towards rewards. Therefore, our results do not support a transdiagnostic notion of reward sensitivity, but they indicate a potential role of reward sensitivity for symptom persistence.

TRIAL REGISTRATION

The study was preregistered at the Open Science Framework (OSF) ( https://archive.org/details/osf-registrations-6n3s8-v1 ; registration DOI https://doi.org/10.17605/OSF.IO/6N3S8 ).

Depression and approach-avoidance decisions to emotional displays: The role of anhedonia

Depression is linked to dysfunctional appetitive and aversive motivational systems and effort-based decision-making, yet whether such deficits extend to social decisions remains unclear. Participants (23 non-depressed, 48 depressed - 24 with a past history of suicide attempt) completed a social decision-making task consisting in freely choosing whether to approach or avoid individuals displaying happy or angry expressions. Occasionally, participants had to make a further effort (change button press) to obtain the desired outcome. All participants preferentially avoided anger on their first choice. Yet, depressed patients less often chose to approach happy individuals, as a function of anhedonia severity. Depressed patients were also less inclined than controls to change their response when the anticipated outcome of their first choice was undesirable (approach angry and avoid happy). Again, such effect correlated with anhedonia severity. Our results support that both altered valuation and willingness to exert effort impact approach-avoidance decisions in social contexts in depression. On this basis, we propose a new integrating framework for reconciling different hypotheses on the effect of depression and anhedonia on motivational responses to emotional stimuli.

Anhedonia in Relation to Reward and Effort Learning in Young People with Depression Symptoms

Anhedonia, a central depression symptom, is associated with impairments in reward processing. However, it is not well understood which sub-components of reward processing (anticipation, motivation, consummation, and learning) are impaired in association with anhedonia in depression. In particular, it is unclear how learning about different rewards and the effort needed to obtain them might be associated with anhedonia and depression symptoms. Therefore, we examined learning in young people (N = 132, mean age 20, range 17-25 yrs.) with a range of depression and anhedonia symptoms using a probabilistic instrumental learning task. The task required participants to learn which options to choose to maximize their reward outcomes across three conditions (chocolate taste, puppy images, or money) and to minimize the physical effort required to obtain the rewards. Additionally, we collected questionnaire measures of anticipatory and consummatory anhedonia, as well as subjective reports of "liking", "wanting" and "willingness to exert effort" for the rewards used in the task. We found that as anticipatory anhedonia increased, subjective liking and wanting of rewards decreased. Moreover, higher anticipatory anhedonia was significantly associated with lower reward learning accuracy, and participants demonstrated significantly higher reward learning than effort learning accuracy. To our knowledge, this is the first study observing an association of anhedonia with reward liking, wanting, and learning when reward and effort learning are measured simultaneously. Our findings suggest an impaired ability to learn from rewarding outcomes could contribute to anhedonia in young people. Future longitudinal research is needed to confirm this and reveal the specific aspects of reward learning that predict anhedonia. These aspects could then be targeted by novel anhedonia interventions.

Neural function underlying reward expectancy and attainment in adolescents with diverse psychiatric symptoms

Reward dysfunction has been hypothesized to play a key role in the development of psychiatric conditions during adolescence. To help capture the complexity of reward function in youth, we used the Reward Flanker fMRI Task, which enabled us to examine neural activity during expectancy and attainment of both certain and uncertain rewards. Participants were 84 psychotropic-medication-free adolescents, including 67 with diverse psychiatric conditions and 17 healthy controls. Functional MRI used high-resolution acquisition and high-fidelity processing techniques modeled after the Human Connectome Project. Analyses examined neural activation during reward expectancy and attainment, and their associations with clinical measures of depression, anxiety, and anhedonia severity, with results controlled for family-wise errors using non-parametric permutation tests. As anticipated, reward expectancy activated regions within the fronto-striatal reward network, thalamus, occipital lobe, superior parietal lobule, temporoparietal junction, and cerebellum. Unexpectedly, however, reward attainment was marked by widespread deactivation in many of these same regions, which we further explored using cosine similarity analysis. Across all subjects, striatum and thalamus activation during reward expectancy negatively correlated with anxiety severity, while activation in numerous cortical and subcortical regions during reward attainment positively correlated with both anxiety and depression severity. These findings highlight the complexity and dynamic nature of neural reward processing in youth.

The role of anhedonia in predicting risk-taking behavior in university students

There is a growing interest in understanding symptoms of psychological distress, such as anhedonia, not just as related to individual psychological disorders, but transdiagnostically. This broader focus allows for the investigation of the effects of symptoms across disorders, or in non-clinical samples. Previous work has linked anhedonia and risk-taking behavior in clinical samples, though the exploration of this relationship in healthy adolescents and early adults is still a relatively new area of research. The current study explored the relationship between variability in anhedonia and risk-taking behavior by breaking each into separable parts (i.e. anhedonia into deficits in anticipatory and consummatory pleasure; risk-taking into risk propensity, sub-optimal risky behavior, and response to punishment). A sample of 81 university students completed two Chapman scales of anhedonia, the Temporal Experience of Pleasure Scale (TEPS), and the Balloon Analogue Risk Task (BART). Hierarchical linear regression analyses were completed to assess the predictive power of each anhedonia measure on each outcome measure on the BART. TEPS score significantly negatively predicted all three outcome measures, with anticipatory pleasure having more predictive power than consummatory pleasure. Physical anhedonia was also a significant predictor of sub-optimal risky behavior and response to punishment. These findings present a broader and more complex view of the associations between anhedonia and risk than have previously been reported, and merit further study to continue to elucidate how they are related to one another.

Altered motivation of effortful decision-making for self and others in subthreshold depression

BACKGROUND

Amotivation is a typical feature in major depressive disorders and refers to individuals exhibiting reduced willingness to exert effort for rewards. However, the motivation pattern when deciding whether to exert effort for self versus others in people with depression remains unclear.

METHODS

We conducted a functional magnetic resonance imaging study and employed an adapted Effort-Expenditure for Rewards Task in subthreshold depressive (SD) participants (n = 33) and healthy controls (HC) (n = 32). This required participants to choose between a fixed low-effort/low-reward and a variable high-effort/high-reward option, and then immediately exert effort to obtain corresponding rewards for themselves or for unfamiliar people.

RESULTS

Compared with the HC group, the SD group showed blunted activity in the left dorsal anterior cingulate cortex/dorsomedial prefrontal cortex, bilateral anterior insula (AI), and right putamen-left dorsolateral prefrontal cortex functional connectivity when choosing to exert effort for themselves. Additionally, the SD group exhibited increased willingness and greater activation in the bilateral AI when choosing to exert effort for others. Furthermore, these brain activations and functional connectivity were positively related to self-reported motivation.

CONCLUSIONS

These findings show altered motivation during effort-based decision-making in individuals with the mild depressive state, particularly with higher motivation for others. Thus, this suggests that motivational behaviors and prefrontal-striatal circuitry are altered in individuals with SD, which can be utilized to discover treatment targets and develop strategies to address mental illness caused by motivation disorders.

State Anhedonia and Suicidal Ideation in Adolescents

Abstract. Background: Recent work suggests that state anhedonia and its social aspect of loss of interest in people was an important predictor of suicidal ideation in adults. Aim: The current study investigated the relationship between state anhedonia, trait anhedonia, suicidal ideation, and suicide attempts in adolescents. Method: State anhedonia was assessed using the anhedonia subscale from the Child Mood and Feelings Questionnaire, while trait social anhedonia was assessed using the Adolescent Anticipatory and Consummatory Interpersonal Pleasure Scale and the Temporal Experience of Pleasure Scale. Results: Results indicated that state anhedonia was associated with suicidal ideation but not associated with past suicide attempts after controlling for depressive symptoms. Academic stressful events moderated the relationship between state anhedonia and suicidal ideation. Symptom-level analyses revealed that loss of interest in friends was most highly predictive of suicidal ideation compared with the other anhedonia components. Limitations: The current investigation was limited by its reliance on student samples and data from a single time point. Conclusion: The current study indicated that state anhedonia and its social component may be more informative of near-term suicidal ideation than trait anhedonia in adolescents.

Great Expectations: A Critical Review of and Suggestions for the Study of Reward Processing as a Cause and Predictor of Depression

Both human and animal studies support the relationship between depression and reward processing abnormalities, giving rise to the expectation that neural signals of these processes may serve as biomarkers or mechanistic treatment targets. Given the great promise of this research line, we scrutinized those findings and the theoretical claims that underlie them. To achieve this, we applied the framework provided by classical work on causality as well as contemporary approaches to prediction. We identified a number of conceptual, practical, and analytical challenges to this line of research and used a preregistered meta-analysis to quantify the longitudinal associations between reward processing abnormalities and depression. We also investigated the impact of measurement error on reported data. We found that reward processing abnormalities do not reach levels that would be useful for clinical prediction, yet the available evidence does not preclude a possible causal role in depression.

Red wine polyphenols reverse depressive-like behaviors in mice induced by repeated corticosterone treatment

The aim of this study was to investigate the antidepressant-like effect of red wine phenolic extracts in mouse model exposed to exogenous corticosterone. The results showed that 3-week corticosterone injections caused depression-like behavior in mice, as indicated by the significant decrease in sucrose consumption and increase immobility time in the forced swimming test (FST). Red wine phenolic extracts treatment significantly reduced serum corticosterone levels. Moreover, it was found that red wine phenolic extract increased the brain-derived neurotrophic factor protein (BNDF) and tropomyosin-related kinase B (TrkB) phosphorylation and cAMP-responsive element binding protein (CREB) phosphorylation levels in the hippocampus and prefrontal cortex. However, K252a, an inhibitor of TrkB, completely abolished those antidepressant-like effects. These results suggested that the red wine phenolic extracts produce an antidepressant-like effect in corticosteronetreated mice, at least in part, which is possibly mediated by modulating hypothalamic-pituitary-adrenal (HPA) axis, BDNF, TrkB and CREB phosphorylation levels in the brain region of mice.