Anticipatory and consummatory components of the experience of pleasure: A scale development study

Association of anhedonia and suicidal ideation in patients with treatment-refractory depression after intravenous ketamine infusions

OBJECTIVES

Accumulating evidence suggests that the effects of ketamine administered intravenously at subanaesthetic doses on both anhedonic symptoms and suicidal ideation occur independently of depressive symptoms in major depressive disorder (MDD) and bipolar disorder (BD). This study sought to determine the relationship between anhedonia and suicidal ideation after serial ketamine infusions.

METHODS

A total of 79 subjects with either treatment-refractory MDD (n = 60) or BD (n = 19) were included in a clinical ketamine study. The Montgomery-Åsberg Depression Rating Scale (MADRS) anhedonia factor and the first five items of the Scale for Suicidal Ideations (SSI-Part I) were used to assess anhedonia symptoms and suicidal ideation, respectively.

RESULTS

At baseline, anhedonia, as measured by the MADRS, was not significantly associated with suicidal ideation or specific suicide-related ideation as measured by SSI-Part I (all p's > 0.05). Only the 'wish to die' and 'desire to make a suicide attempt' items were positively associated with anhedonia at two weeks after the sixth ketamine infusion, which was independent of the reductions in depressive symptoms (all p's < 0.05).

CONCLUSION

Anhedonia as measured by the MADRS appeared to not be positively related to suicidal ideation after serial ketamine infusions.KEY POINTSSerial ketamine (0.5 mg/kg) infusions have shown quick and dramatic antisuicidal and antianhedonic effects in patients with depression.The association between anhedonia and suicidal ideation after serial ketamine infusions is unclear.Anhedonia appeared to not be positively related to suicidal ideation after serial ketamine infusions.

Behavioural phenotypes of intrinsic motivation in schizophrenia determined by cluster analysis of objectively quantified real-world performance

Intrinsic motivation deficits are a prominent feature of schizophrenia that substantially impacts functional outcome. This study used cluster analysis of innate real-world behaviours captured during two open-field tasks to dimensionally examine heterogeneity in intrinsic motivation in schizophrenia patients (SZ) and healthy controls (HC). Wireless motion capture quantified participants' behaviours aligning with distinct aspects of intrinsic motivation: exploratory behaviour and effortful activity in the absence of external incentive. Cluster analysis of task-derived measures identified behaviourally differentiable subgroups, which were compared across standard clinical measures of general amotivation, cognition, and community functioning. Among 45 SZ and 47 HC participants, three clusters with characteristically different behavioural phenotypes emerged: low exploration (20 SZ, 19 HC), low activity (15 SZ, 8 HC), and high exploration/activity (10 SZ, 20 HC). Low performance in either dimension corresponded with similar increased amotivation. Within-cluster discrepancies emerged for amotivation (SZ > HC) within the low exploration and high performance clusters, and for functioning (SZ < HC) within all clusters, increasing from high performance to low activity to low exploration. Objective multidimensional characterization thus revealed divergent behavioural expression of intrinsic motivation deficits that may be conflated by summary clinical measures of motivation and overlooked by unidimensional evaluation. Deficits in either aspect may hinder general motivation and functioning particularly in SZ. Multidimensional phenotyping may help guide personalized remediation by discriminating between intrinsic motivation impairments that require amelioration versus unimpaired tendencies that may facilitate remediation.

Overlapping and segregated changes of functional hubs in melancholic depression and non-melancholic depression

BACKGROUND

Previous research found associations between neuropsychiatric disorders and patterns of highly connected "hub" nodes, which are crucial in coordinating brain functions. Melancholic depression is considered a relatively distinct and homogenous subtype of major depressive disorder (MDD), which responds better to pharmacological treatments than placebos or psychotherapies. Accordingly, melancholic depression probably has distinct neuropathological underpinnings. This study aims to examine the overlapping and segregated changes of functional hubs in melancholic and non-melancholic MDD.

METHODS

Thirty-one melancholic patients, 28 non-melancholic patients, and 32 healthy controls were included. Resting-state functional imaging data were analyzed using global functional connectivity.

RESULTS

Both melancholic and non-melancholic patients had increased GFC in the bilateral insula and decreased GFC in the PCC/precuneus compared to HCs. The distinction was that melancholic patients showed increased GFC in the bilateral thalamus, right inferior parietal lobule (IPL), and left cerebellum Crus I and decreased GFC in the left temporal lobe, whereas non-melancholic patients showed increased GFC in the left superior parietal lobe. Additionally, compared with non-melancholic patients, melancholic individuals displayed significant increases of GFC in the left IPL and cerebellum.

CONCLUSION

Increased GFC of the insula and decreased GFC of the PCC and precuneus are the common abnormalities of melancholic and non-melancholic MDD. Hyperconnectivity of the IPL and cerebellum might be distinctive neuropathological features of melancholic MDD.

Sucrose Preference Test as a Measure of Anhedonic Behavior in a Chronic Unpredictable Mild Stress Model of Depression: Outstanding Issues

Despite numerous studies on the neurobiology of depression, the etiological and pathophysiological mechanisms of this disorder remain poorly understood. A large number of animal models and tests to evaluate depressive-like behavior have been developed. Chronic unpredictable mild stress (CUMS) is the most common and frequently used model of depression, and the sucrose preference test (SPT) is one of the most common tests for assessing anhedonia. However, not all laboratories can reproduce the main effects of CUMS, especially when this refers to a decrease in sucrose preference. It is also unknown how the state of anhedonia, assessed by the SPT, relates to the state of anhedonia in patients with depression. We analyzed the literature available in the PubMed database using keywords relevant to the topic of this narrative review. We hypothesize that the poor reproducibility of the CUMS model may be due to differences in sucrose consumption, which may be influenced by such factors as differences in sucrose preference concentration threshold, water and food deprivation, and differences in animals’ susceptibility to stress. We also believe that comparisons between animal and human states of anhedonia should be made with caution because there are many inconsistencies between the two, including in assessment methods. We also tried to offer some recommendations that should improve the reproducibility of the CUMS model and provide a framework for future research.

Define and characterize the anhedonia in major depressive disorder: An explorative study

BACKGROUND

Although anhedonia is a key symptom of major depressive disorder (MDD), there is neither a concise nor effective method to distinguish and define anhedonia in MDD. The current study attempts to answer two questions based on validating the Dimensional Anhedonia Rating Scale (DARS) in Chinese MDD patients: 1) whether anhedonia subgroup can be identified? 2) whether patients with anhedonia display unique psychosocial and clinical features?

METHODS

In the discovery sample, 533 MDD patients and 124 healthy controls were recruited into a multicenter study. For replication, a further 112 first-episode, drug-naïve MDD patients were recruited. Latent profile analysis (LPA) was used to identify the latent subgroups based on their hedonic function measured by the DARS. According to the categorization, ROC curves were applied to find the cut-off value. Lasso regression was performed to characterize psychological and clinical features linked to anhedonia.

RESULTS

The data-driven approach identified and validated the anhedonia subgroup, and proposed that the cut-off value for distinguishing anhedonia was 28.5 based on the total score of DARS. Lasso regression demonstrated that melancholia, lower levels of positive affect and education, more severe depressive symptoms, older age were associated with anhedonia in MDD patients.

CONCLUSION

This study used a data-driven approach to propose a new and convenient method for distinguishing the anhedonia of MDD patients with unique psychological and clinical features. Identifying the subtype may contribute to pinpointing more specific biomarkers in shedding light on the mechanisms of anhedonia in MDD.

TRIAL REGISTRATION

TNDTAD study, NCT03294525; TOSD study, NCT03148522.

Electroconvulsive therapy effects on anhedonia and reward circuitry anatomy: A dimensional structural neuroimaging approach

BACKGROUND

Anhedonia is a core symptom of major depressive disorder (MDD) resulting from maladaptive reward processing. Electroconvulsive therapy (ECT) is an effective treatment for patients with MDD. No previous neuroimaging studies have taken a dimensional approach to assess whether ECT-induced volume changes are specifically related to improvements in anhedonia and positive valence emotional constructs. We aimed to assess the relationship between ECT-induced brain volumetric changes and improvement in anhedonia and reward processing in patients with MDD.

METHODS

We evaluated 15 patients with MDD before and after ECT. We used magnetic resonance imaging, clinical scales (i.e., Quick Inventory of Depressive Symptomatology for syndromal depression severity and Snaith-Hamilton Pleasure Scale for anhedonia) and the Temporal Experience of Pleasure Scale for anticipatory and consummatory experiences of pleasure. We identified 5 regions of interest within the reward circuit and a 6th control region relevant for MDD but not core to the reward system (Brodmann Area 25).

RESULTS

Anhedonia, anticipatory and consummatory reward processing improved after ECT. Volume increases within the right reward system separated anhedonia responders and non-responders. Improvement in anticipatory (but not consummatory) reward correlated with increases in volume in hippocampus, amygdala, ventral tegmental area and nucleus accumbens.

LIMITATIONS

We evaluated a modest sample size of patients with concurrent pharmacological treatment using a subjective psychometric assessment.

CONCLUSIONS

We highlight the importance of a dimensional and circuit-based approach to understanding target engagement and the mechanism of action of ECT, with the goal to define symptom- and circuit-specific response biomarkers for device neuromodulation therapies.

Correcting the reward imbalance in binge eating: A pilot randomized trial of reward re-training treatment

Behavioral treatments for psychological disorders characterized by reward-driven maladaptive behaviors (e.g., substance use disorder, eating disorders, behavioral addictions) primarily seek to reduce hyper-reward response to disorder-specific stimuli. Suboptimal outcomes for these treatments highlight the need to also target hypo-reward response to day-to-day life activities. The present study sought to conduct an initial test of a novel behavioral treatment, Reward Re-Training (RRT) to target hyper- and hypo-reward response in individuals with binge eating. Individuals with binge eating (N = 23) were randomly assigned to either 10 weeks of outpatient, group-based RRT treatment or a waitlist control. RRT was found to be feasible and acceptable, demonstrated large impacts on both hypo- and hyper-reward response (measured by self-report (pre-to post-treatment ηp2 range 0.38-0.58) and neural activation via fMRI), and was efficacious in reducing eating disorder pathology (ηp2 range 0.40-0.64, including binge eating, ηp2 = 0.64) compared to waitlist control (ηp2 range 0.00-0.04). This pilot data provides preliminary support for the feasibility, acceptability, and effectiveness of a novel treatment targeting reward imbalance for individuals with binge eating. Future evaluations of RRT may benefit from an active treatment comparison condition and a follow-up assessment to examine persistence of positive outcomes.

Clinical and Preclinical Assessments of Anhedonia in Psychiatric Disorders

Anhedonia is a prevalent symptom across many psychiatric disorders. The contemporary scope of anhedonia across various models includes interest, reward anticipation, motivation, effort expenditure, reward valuation, expectation, pleasure, satiation, and learning. In order to further elucidate the impact of anhedonia on treatment outcomes, quality of life, as well as brain function, validated tools to probe the various facets of anhedonia are necessary. This chapter evaluates assessment tools for anhedonia in clinical populations and in animals. Subjective clinical scales have been in use for decades, and as the construct of anhedonia evolved, contemporary scales were developed to integrate these new concepts. Clinical scales are useful for understanding the subjective experience of anhedonia but do not account for objective aspects of anhedonia, including implicit learning. Behavioral tasks that probe responses to rewarding stimuli have been useful to fill this gap and to delineate the specific brain processes underlying facets of anhedonia. Although there have been translational challenges in the assessments of anhedonia and reward deficits from preclinical to clinical (and vice versa), the multifaceted clinical scales and reward tasks provide valuable insights into the conceptualization of anhedonia and its neural basis across psychiatric disorders.

Mental Activity as the Bridge between Neural Biomarkers and Symptoms of Psychiatric Illness

The Research Domain Criteria (RDoC) initiative challenges researchers to build neurobehavioral models of psychiatric illness with the hope that such models identify better targets that will yield more effective treatment. However, a guide for building such models was not provided and symptom heterogeneity within Diagnostic Statistical Manual categories has hampered progress in identifying endophenotypes that underlie mental illness. We propose that the best chance to discover viable biomarkers and treatment targets for psychiatric illness is to investigate a triangle of relationships: severity of a specific psychiatric symptom that correlates to mental activity that correlates to a neural activity signature. We propose that this is the minimal model complexity required to advance the field of psychiatry. With an understanding of how neural activity relates to the experience of the patient, a genuine understanding for how treatment imparts its therapeutic effect is possible. After the discovery of this three-fold relationship, causal testing is required in which the neural activity pattern is directly enhanced or suppressed to provide causal, instead of just correlational, evidence for the biomarker. We suggest using non-invasive brain stimulation (NIBS) as these techniques provide tools to precisely manipulate spatial and temporal activity patterns. We detail how this approach enabled the discovery of two orthogonal electroencephalography (EEG) activity patterns associated with anhedonia and anxiosomatic symptoms in depression that can serve as future treatment targets. Altogether, we propose a systematic approach for building neurobehavioral models for dimensional psychiatry.

State-independent and -dependent behavioral and neuroelectrophysiological characteristics during dynamic decision-making in patients with current and remitted depression

BACKGROUND

It is unclear whether the altered decision-making (DM) observed in patients with major depressive disorder (MDD) is neurophysiological and whether it improves with remission of depressive symptoms. The aim of this study was to identify developmental patterns of DM behavior, related cognitive characteristics, and electrophysiological abnormalities in patients with MDD across clinical stages.

METHODS

A sample of 48 first-episode MDD patients (FD group), 41 remitted MDD patients (RD group), and 43 healthy controls (HCs) completed psychometric assessments and performed the balloon analogue risk task (BART) while event-related potentials (ERPs) were recorded.

RESULTS

The RD group had lower depressiveness, self-blame, rumination, and catastrophizing tendencies, and higher mental resilience scores than the FD group, but retained significant differences from HCs. MDD patients showed a more conservative DM strategy than HCs, with no significant difference between the FD and RD groups. Compared to the FD group, the RD group had a smaller FRN for negative feedback and a trend toward a smaller P3 for positive feedback. Compared with HCs, the RD group had a smaller P3 during the positive feedback phase. FRN amplitude correlated positively with depression level and negatively with mental resilience.

LIMITATIONS

Because a comparative cross-section design was employed, longitudinal studies are needed to make causal inferences.

CONCLUSION

MDD patients presented a stable risk-avoidance bias in actively depressed and remission periods, consistent with a state-independent impairment pattern. Significantly reduced FRN amplitudes during remission indicated a state-dependent impairment pattern, and FRN amplitudes correlated with depression level. An abnormal feedback P3 component may be a state-independent characteristic that may become more pronounced with MDD progression.

Is Stress Taking the Pleasure out of Food?—A Characterization of the Food Pleasure Profiles, Appetite, and Eating Behaviors of People with Chronic Stress

Psychological stressors frequently occur in modern society, and are associated with general anhedonic traits (inability to experience pleasure) and altered eating behavior. As eating behavior is largely motivated by a desire for pleasure, the Food Pleasure Scale (FPS) was introduced as a new research tool for investigating aspects of pleasure from food-related experiences. Thereby, insights on whether some aspects of pleasure are more affected by stress than others can be investigated, and can help explain why changes in eating behavior are seen when under the influence of stress. A consumer survey including n = 190 Danish consumers all with moderate or high levels of perceived stress was conducted to explore the perception of pleasure from food, general appetite, meal patterns, as well as specific food preferences. The study showed that the majority found pleasure in the sensory modalities of food, as well as in the ‘comforting’ aspects of food pleasure. Furthermore, the moderately stressed respondents had fewer main meals and more post-dinner snacks and night meals, as compared to before falling ill, whereas the highly stressed group showed signs of anhedonic traits and losing appetite altogether. The present study contributes to our understanding of how a common condition, such as chronic stress, can affect individual, as well as public, health.

Toward a Better Understanding of the Mechanisms and Pathophysiology of Anhedonia: Are We Ready for Translation?

Anhedonia-the loss of pleasure or lack of reactivity to pleasurable stimuli-remains a formidable treatment challenge across neuropsychiatric disorders. In major depressive disorder, anhedonia has been linked to poor disease course, worse response to psychological, pharmacological, and neurostimulation treatments, and increased suicide risk. Moreover, although some neural abnormalities linked to anhedonia normalize after successful treatment, several persist-for example, blunted activation of the ventral striatum to reward-related cues and reduced functional connectivity involving the ventral striatum. Critically, some of these abnormalities have also been identified in unaffected, never-depressed children of parents with major depressive disorder and have been found to prospectively predict the first onset of major depression. Thus, neural abnormalities linked to anhedonia may be promising targets for prevention. Despite increased appreciation of the clinical importance of anhedonia and its underlying neural mechanisms, important gaps remain. In this overview, the author first summarizes the extant knowledge about the pathophysiology of anhedonia, which may provide a road map toward novel treatment and prevention strategies, and then highlights several priorities to facilitate clinically meaningful breakthroughs. These include a need for 1) appropriately controlled clinical trials, especially those embracing an experimental therapeutics approach to probe target engagement; 2) novel preclinical models relevant to anhedonia, with stronger translational value; and 3) clinical scales that incorporate neuroscientific advances in our understanding of anhedonia. The author concludes by highlighting important future directions, emphasizing the need for an integrated, collaborative, cross-species, and multilevel approach to tackling anhedonic phenotypes.

Startle-elicited Event-Related Potentials to Affective Stimuli are Associated with Recent Illicit Opioid use among Patients Receiving Opioid Agonist Treatment

Opioid use disorder (OUD) has been linked to exaggerated attentional, affective, and arousal responses to opioid-related stimuli, as well as altered responses to other affective (eg, naturally rewarding or aversive) stimuli, particularly blunted responses to pleasant/rewarding stimuli. Both exaggerated responses to drug-related stimuli and reduced response to pleasant stimuli may influence the course of OUD and its treatment, however interpretation of studies thus far is limited by methodological issues. In the present study, we examined subjective ratings, and attenuation of the P3 component of the acoustic startle-evoked event-related potential (as a measure of attention), while viewing neutral, pleasant, unpleasant, and drug-related images. Participants prescribed opioid agonist treatment (OAT) for OUD (n = 82) were compared to a carefully-matched control group (n = 33) and to recently-abstinent participants with OUD (n = 22). Relative to controls, participants prescribed OAT gave higher positive valence ratings of drug images, and blunted valence responses to other affective images, but groups did not differ in terms of arousal ratings or P3 amplitude. Within the OAT group, linear modeling of associations between frequency of recent illicit opioid use and startle P3 amplitude found an association between increased recent illicit opioid use and reduced attention to pleasant, relative to unpleasant, images. The latter finding may have implications for interventions targeting cognitive biases in people with substance use disorder. In particular, they suggest that enhancing attention to pleasant stimuli may be as, if not more important, than the typical approach of trying to reduce attentional bias to drug-related stimuli.

The Effect of Electroconvulsive Therapy on Positive Affect and Hedonism in Patients With Depression: A Prospective Study

OBJECTIVES

The outcome of antidepressant treatments is generally assessed with standardized symptom scales such as the Quick Inventory of Depressive Symptomatology-Clinician Rating (QIDS-C). These scales, however, might not reflect patients' expectations for treatment, including a recovery of positive affect (PA) and hedonism. The Leuven Affect and Pleasure Scale (LAPS) was developed to better reflect patients' expectations for treatment. We used the LAPS to investigate changes in PA and hedonism alongside depressive symptoms during electroconvulsive therapy (ECT) and over 12 weeks after treatment.

METHODS

Fifty-three patients with a Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, depressive episode, referred for ECT, were included in this prospective study. The LAPS and QIDS-C were administered before and 1 and 12 weeks after the ECT course. LAPS normative levels were obtained in 149 healthy controls.

RESULTS

Pearson correlations revealed only moderate overlap of the QIDS-C with PA and hedonism. Piecewise linear mixed models indicated significant improvements in depressive symptoms (QIDS-C and LAPS negative affect), PA, and hedonism during ECT. In the 12 weeks after ECT treatment, negative affect and QIDS-C further improved, but PA and hedonism plateaued. Exploratory analyses indicated that only fully remitted patients (QIDS-C) attained normative levels on PA and hedonism at 12 weeks after ECT.

CONCLUSIONS

Standardized symptom scales (QIDS-C) may incompletely reflect clinical change in ECT treatment for depression. Although ECT improved depressive symptoms, PA, and hedonism in patients with depression, only fully remitted patients attained normative levels of PA and hedonism, due to plateaus in improvement. These plateaus were not observed for depressive symptoms, which further improved after ECT discontinuation.

Gender differences in pleasure: the mediating roles of cognitive flexibility and emotional expressivity

BACKGROUND

Gender differences have been found to be associated with individuals' pleasure. Cognitive flexibility and emotional expressivity might play an important role between gender differences and pleasure. This current study is to explore the mediating role of cognitive flexibility and emotional expressivity in the relationship between gender differences and pleasure.

METHOD

In this cross-sectional study, a sample of 1107 full-time university students from five colleges in Tianjin, Chinese mainland was investigated by questionnaire. All participants completed the Temporal Experience of Pleasure Scale (TEPs), the Cognitive Flexibility Inventory (CFI), and the Berkeley Expressivity Questionnaire (BEQ).

RESULTS

The results of independent T-test suggested that females reported better emotional expressivity, anticipatory pleasure and consummatory pleasure than males, whereas males had better cognitive flexibility than females. Using bootstrapping approach revealed that the partially mediation effects of cognitive flexibility on gender differences in anticipatory and consummatory pleasure, and that of emotional expressivity on gender differences in anticipatory and consummatory pleasure. Results of this present study stated that cognitive flexibility and emotional expressivity play a partial mediating role in explaining gender differences in anticipatory and consummatory pleasure.

CONCLUSION

Females had higher anticipatory and consummatory pleasure because they tend to use emotional regulation strategy to express their emotion.

Imagine How Good That Feels: The Impact of Anticipated Positive Emotions on Motivation for Reward Activities

Background

Disease burden and unsatisfactory treatment outcomes call for innovation in treatments of depression. Prospective mental imagery, i.e. future-directed voluntary imagery-based thought, about potentially-rewarding activities may offer a mechanistically-informed intervention that targets deficits in reward processing, a core clinical feature of depression. We propose that the previously described impact of prospective mental imagery on motivation for everyday activities is facilitated by affective forecasting, i.e. predictions about an individual’s emotional response to the imagined activities.

Methods

Participants (N = 120) self-nominated six activities to engage in over the following week and were randomized to either: (1) an affective forecasting imagery condition (n = 40); (2) a neutral process imagery condition (n = 40); or (3) a no-imagery control condition (n = 40).

Results

As predicted, increases in motivation ratings from pre to post experimental manipulation were significantly higher following affective forecasting imagery compared to both neutral process imagery (d = 0.62) and no-imagery (d = 0.91). Contrary to predictions, the number of activities participants engaged in did not differ between conditions.

Conclusions

Results provide initial evidence for a potentially important role of affective forecasting in prospective mental imagery. We discuss how these findings can inform future research aiming to harness prospective mental imagery’s potential for clinical applications.

Childhood Maltreatment and Anhedonic Symptoms: Test of a Dual-risk Model in Emerging Adults

Anhedonia, defined as deficits in positive affect and approach related behaviors, remains an understudied trauma response. As anhedonic responses to interpersonal violence are associated with a more severe course of psychopathology that is more difficult to treat, an increased focus on risk factors for anhedonia is necessary. The present study sought to address this gap in the literature by testing a theoretical model that highlights two transdiagnostic pathways leading to anhedonic responses in emerging adults attending college. Specifically, our study examined how childhood maltreatment subtypes (a) uniquely associate with depressive and post-traumatic stress (PTS) manifestations of anhedonia and (b) how temperament (i.e., anticipatory positive affect) and distress (i.e., negative mood) explain these relations. At baseline, a racially diverse sample of 462 emerging adults (Age_Mean = 19.45; 75.5% female; 45.5% White) completed self-report forms on childhood abuse and neglect, anticipatory positive affect, negative mood, and anhedonia. Individuals completed measures of temperament and psychological distress again 6-weeks, and 12-weeks later. Latent growth curve models were utilized to test our model. Consistent with hypotheses, deficits in anticipatory positive affect uniquely explained the relation between neglect and depressive/PTS anhedonic symptoms. Meanwhile, negative mood mediated the relation between abuse and both forms of anhedonia. These findings support the theory that two separate risk pathways lead to anhedonia. Support for our model suggests that distinguishing between pathways for anhedonic responses may be the key to a more targeted, transdiagnostic, trauma-informed approach for treating and preventing these deleterious, treatment-resistant, internalizing symptoms.

GENETIC AND ENVIRONMENTAL CONTRIBUTIONS TO POSITIVE AFFECT: INSIGHTS FROM ADOLESCENT TWINS

Disturbances in positive affect and reductions in social reward/interpersonal pleasure are common across a range of clinical disorders and are often related. We examined the relationship between the Anticipatory and Consummatory Interpersonal Pleasure Scale (ACIPS-A), and other measures of positive affect in adolescents in a genetically informative research design. The sample consisted of 177 MZ and 136 same sex DZ twins drawn from a study of adolescent twins (M = 16.4 ± .97 years) who were part of the Wisconsin Twin Project. The self-report questionnaires included the Behavioral Activation Scale (BAS), Psychological Well-Being Scale, revised Early Adolescent Temperament Questionnaire (EATQR) and the adolescent version of the ACIPS (ACIPS-A). Structural equation modeling estimated the relative contribution of genetic and environmental factors to the phenotypic variance in each of the measures. Follow-up bivariate analyses parsed the genetic and environmental contributions to the phenotypic covariances between the ACIPS-A and each of the other measures of positive affect. We found evidence of moderate heritability for the ACIPS-A scale scores. Overall, models specifying additive genetic and unique environmental effects (AE models) were the most parsimonious models for each of the measures. Several of the measures showed moderate positive phenotypic intercorrelations, and all but one of these intercorrelations showed significant partial genetic underpinnings. Moreover, the bivariate biometric analyses indicated that the ACIPS-A also captures unique heritable variation. Thus, the ACIPS-A captures unique heritable contributions to social/interpersonal pleasure, as well as shared genetic variance with other measures of positive affectivity.

Evaluating the item-level factor structure of anhedonia

BACKGROUND

Anhedonia has long been theorized to be a multidimensional construct, focusing on domains of reward stimuli and temporal relationship to reward. However, little empirical work has directly examined whether there is support for this assertion.

METHODS

The study used data from young adults from four independent samples (n = 2098). Participants completed multiple measures of anhedonia.

RESULTS

We used rigorous conducted exploratory and confirmatory factor analyses on items from six commonly used anhedonia measures to examine dimensions underlying anhedonia. Results suggested a four-factor solution with factors reflecting social reward, social disinterest, status/achievement, and physical/natural reward. The identified factors reflected broad content domains of pleasure, but not specific reward processes. The four factors were modestly associated with one another, suggesting a weak common underlying anhedonia trait that manifests across multiple dimensions. Factor scores were associated with personality measures, reward-related indices, and depression symptoms, supporting the validity of the factors.

LIMITATIONS

Participants were all young adults and we assessed anhedonia only at the level of self-report.

CONCLUSION

Anhedonia is a multidimensional construct. However, the dimensions of anhedonia only distinguish domains of, but not temporal processes of anhedonia. Future work should continue to refine the structures underlying the construct of anhedonia through iterative theory- and data-driven research and examine associations between anhedonia and clinical outcomes.

Cognitive Effort Exertion Enhances Electrophysiological Responses to Rewarding Outcomes

Recent work has highlighted neural mechanisms underlying cognitive effort-related discounting of anticipated rewards. However, findings on whether effort exertion alters the subjective value of obtained rewards are inconsistent. Here, we provide a more nuanced account of how cognitive effort affects subsequent reward processing in a novel task designed to assess effort-induced modulations of the Reward Positivity, an event-related potential indexing reward-related neural activity. We found that neural responses to both gains and losses were significantly elevated in trials requiring more versus less cognitive effort. Moreover, time-frequency analysis revealed that these effects were mirrored in gain-related delta, but not in loss-related theta band activity, suggesting that people ascribed more value to high-effort outcomes. In addition, we also explored whether individual differences in behavioral effort discounting rates and reward sensitivity in the absence of effort may affect the relationship between effort exertion and subsequent reward processing. Together, our findings provide evidence that cognitive effort exertion can increase the subjective value of subsequent outcomes and that this effect may primarily rely on modulations of delta band activity.

Social Isolation-Mediated Exacerbation of Negative Affect in Young Drinkers during the COVID-19 Pandemic

Emerging research on psychological adjustment during the COVID-19 outbreak has suggested that young people may be particularly vulnerable to increases in negative affect during the pandemic. However, the association between alcohol use in youth and change in negative affect during this unprecedented time is not clear. Using an online survey, this study obtained scores on negative affect (before and during the COVID-19 pandemic), pandemic-related stress, change in drinking frequency, and traits including resilience, impulsivity and anhedonia, from a sample of drinkers and non-drinkers, up to the age of 21. Young drinkers experienced a greater increase in negative affect during the pandemic compared to non-drinkers, and this differential rise in negative affect was mediated by the pandemic-related stress of social isolation. Young drinkers also experienced a decrease in alcohol use during the pandemic, but this was not associated with a change in negative affect. Interestingly, young drinkers with greater resilience and lower anhedonia reported less increase in negative affect during the COVID-19 pandemic. Taken together, these results show that the greater increase in negative affect that young drinkers experienced during the COVID-19 pandemic, compared to their non-drinking counterparts, was mediated by pandemic-related social isolation. Moreover, greater resilience and lower anhedonia may have served as protective factors for mitigating the social isolation-induced worsening of negative affect in young drinkers during the pandemic. These findings may inform future studies investigating potential indicators of maladaptive affective responses to public health crises in vulnerable adolescent populations.

The Cognitive, Affective and Somatic Empathy Scales for Adults

The Cognitive, Affective and Somatic Empathy Scales (CASES) assess three forms of empathy, each with subscales for positive and negative empathy. The present study extends this child instrument to adults and examines its factor structure and construct validity. A secondary aim is to investigate the under-researched area of positive empathy. Community samples totaling 2,604 adults completed the CASES for adults, together with scales assessing construct validity. Confirmatory factor analysis supported the three-factor cognitive-affective-somatic model and a two-factor positive-negative empathy model. Findings were replicated in a second independent sample. Internal reliabilities ranged from .80 to .92. Individuals with higher psychopathy and stimulation-seeking scores were less impaired in their empathic reactions to positive relative to negative valence events, suggesting that they are relatively capable of responding emotionally to rewarding events. Somatic empathy was most strongly associated with pleasure in affective touch and with female > male gender differences. While proactive aggression was associated with reduced cognitive and affective empathy, reactive aggression was associated with increased empathy. Findings provide initial support for the utility of CASES for assessing different forms of empathy and suggest that the balance between positive and negative empathy could provide new insights into psychological traits.

Examining the reliability and validity of two versions of the Effort-Expenditure for Rewards Task (EEfRT)

The Effort-Expenditure for Rewards Task (EEfRT) has gained validity evidence from several studies. However, various modifications have been applied to the original version, which have never been compared systematically. In Study 1, we tested 120 healthy participants to directly compare two versions of the EEfRT. In Study 2, we tested a larger sample of 394 healthy participants to further examine the original EEfRT. We replicated the split-half reliability of both task versions. However, self-reported personality traits (e.g., trait BAS) correlated with only some task performance parameters in Study 1, which did not replicate for the original EEfRT in Study 2. Our results indicate complex and sometimes inconsistent relations between different personality traits, task properties, and reward attributes.

Neural mapping of anhedonia across psychiatric diagnoses: A transdiagnostic neuroimaging analysis

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Anhedonia is present in many different psychiatric disorders.

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Anhedonia has been associated with abnormal reward-related striatal dopamine functioning.

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This study tested whether transdiagnostic anhedonia expression mapped onto striatal volume.

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Our findings suggest volumetric abnormalities in the putamen and cerebellum as a common neural substrate of anhedonia severity that cut across psychiatric entities.

Anhedonia has been associated with abnormal reward-related striatal dopamine functioning in patients with different psychiatric disorders. Here, we tested whether anhedonia expression mapped onto striatal volume across several psychiatric diagnoses.

T1-weighted images from 313 participants including 89 healthy controls (HC), 22 patients with opioid use disorder (OUD), 50 patients with major depressive disorder (MDD), 45 patients with borderline personality disorder (BPD), 49 patients with first-episode psychosis (FEP), 43 patients with cocaine use disorder (CUD) and 15 patients with schizophrenia (SZ) were included. Anhedonia was assessed with subscores of the Beck Depression Inventory (BDI) and/or the Scale for the Assessment of Negative Symptoms (SANS). Voxel-based morphometry (VBM) was conducted for identifying dimensional symptom-structure associations using region of interest (ROI, dorsal and ventral striatum) and whole-brain analyses, as well as for group comparisons of striatal volume.

ROI analyses revealed significant negative relationships between putamen volume and BDI and SANS anhedonia scores across OUD, MDD, BPD, CUD and SZ patients (n = 175) and MDD, FEP and SZ patients (n = 114), respectively. Whole-brain VBM analyses confirmed these associations and further showed negative relationships between anhedonia severity and volume of the bilateral cerebellum. There were group differences in right accumbens volume, which however were not related to anhedonia expression across the different diagnoses.

Our findings indicate volumetric abnormalities in the putamen and cerebellum as a common neural substrate of anhedonia severity that cut across psychiatric entities.

Psychometric properties of the Dimensional Anhedonia Rating Scale in Chinese typical, subthreshold, and clinically depressed adolescents

The Dimensional Anhedonia Rating Scale measures state anhedonia in multiple domains, such as hobbies, food and drink, social activities, and sensory experience, and it has good reliability and validity in adult samples. However, no study has examined the psychometrical properties of this scale in adolescents. The present study examined its reliability and validity in adolescents with and without depression. In Study 1, 988 high-school students completed the Dimensional Anhedonia Rating Scale; 915 completed the second-round survey 3 months later. Confirmatory factor analysis was used to determine the factor structure. Additionally, internal consistency and test-retest reliability, and concurrent, convergent, and divergent validity were assessed in typical adolescents. In Study 2, the Dimensional Anhedonia Rating Scale was administrated to 108 patients with major depressive disorder, 108 adolescents with subthreshold depression, and 108 healthy controls. Factor structure and convergent validity were assessed in the clinical and subclinical groups. Finally, a one-way analysis of variance (ANOVA) was applied to examine the effect of depression severity on the scale scores. The results of Study 1 indicated that a four-factor model (i.e., hobbies, food and drink, social activities, and sensory experience) best fit the data. Meanwhile, the scale also yielded good concurrent, convergent, and divergent validity, as well as high internal consistency and test-retest reliability, in typical adolescents. In Study 2, goodness-of-fit statistics also suggested a good fit for the four-factor model in the two depressed groups. The one-way ANOVA revealed significant group differences in the total and factor scores, whereby the major depressive disorder group had lower scores than the subthreshold depression group, whose scores were lower than the healthy controls, indicating excellent eligibility of the scale in depressed adolescents. The Chinese version of the Dimensional Anhedonia Rating Scale is a reliable and valid instrument to comprehensively measure state anhedonia in Chinese typical and depressed adolescents.

Pleasure, Reward Value, Prediction Error and Anhedonia

In order to develop effective treatments for anhedonia we need to understand its underlying neurobiological mechanisms. Anhedonia is conceptually strongly linked to reward processing, which involves a variety of cognitive and neural operations. This chapter reviews the evidence for impairments in experiencing hedonic response (pleasure), reward valuation and reward learning based on outcomes (commonly conceptualised in terms of "reward prediction error"). Synthesising behavioural and neuroimaging findings, we examine case-control studies of patients with depression and schizophrenia, including those focusing specifically on anhedonia. Overall, there is reliable evidence that depression and schizophrenia are associated with disrupted reward processing. In contrast to the historical definition of anhedonia, there is surprisingly limited evidence for impairment in the ability to experience pleasure in depression and schizophrenia. There is some evidence that learning about reward and reward prediction error signals are impaired in depression and schizophrenia, but the literature is inconsistent. The strongest evidence is for impairments in the representation of reward value and how this is used to guide action. Future studies would benefit from focusing on impairments in reward processing specifically in anhedonic samples, including transdiagnostically, and from using designs separating different components of reward processing, formulating them in computational terms, and moving beyond cross-sectional designs to provide an assessment of causality.

Anhedonia in Nicotine Dependence

Prior findings indicate that trait anhedonia enhances the likelihood of becoming a tobacco smoker, and preliminary evidence suggests that smoking abstinence leads to anhedonic states in some individuals and situations, and nicotine administration reduces anhedonic states. Nevertheless, many vital questions exist concerning relationships between anhedonia and nicotine dependence, including situational and individual difference factors that may moderate the strength of these associations. This chapter provides a critical review of the literature assessing relationships of anhedonia to nicotine dependence and the effects of acute nicotine through the lenses of the Research Domain Criteria's (RDoC) Positive Valence Systems (NIMH, RDoC changes to the matrix (CMAT) workgroup update: proposed positive valence domain revisions. A report by the national advisory mental health council workgroup on changes to the research domain criteria matrix, 2018) and the Situation x Trait Affective Response (STAR) model of nicotine's effects and nicotine dependence (Gilbert, Smoking individual differences, psychopathology, and emotion. Taylor and Francis, Washington, DC, 1995; Gilbert, Hum Psychopharmacol Clin Exp 12:S89-S102, 1997). The effects of nicotine and nicotine withdrawal on subjective, behavioral, and brain indices vary across the three RDoC Positive Valences Systems (Reward Responsiveness, Reward Learning, and Reward Valuation) in a manner that supports the research and potential clinical utility of using RDoC criteria and the STAR model to guide research and clinical innovation. We provide a revision of the STAR model that incorporates the three RDoC Positive Valence Systems with evidence that nicotine's effects on hedonic and affective processes vary as a function of the dominance/salience of (1) situational hedonic and affective cues and task/active coping cues, and (2) state executive functioning level/capacity and state reward sensitivity such that these effects of nicotine are maximal during states of suboptimal cognitive functioning and reward sensitivity, combined with low situational stimulus salience and low task-related cues/demands.

Negative symptoms in alcohol use disorder: A pilot study applying the two-factor model of negative symptoms to patients with alcohol use disorder

BACKGROUND AND AIMS

Alcohol Use Disorder (AUD) is characterized by a reduction in goal-directed behavior, with alcohol use taking precedence over other areas of life. These features in AUD resemble negative symptoms in schizophrenia, especially the reduction in motivation and pleasure (MAP). Given the clinical similarities of negative symptoms across diagnostic categories, it comes as a surprise that there are few investigations on negative symptoms in alcohol and other substance use disorders. To our knowledge, our study is the first to assess negative symptoms in AUD based on a two-factorial approach, and to investigate the interrelation of these dimensions with the severity of AUD, and alcohol craving.

MATERIALS AND METHODS

We examined a sample of 42 patients with AUD at the Psychiatric University Hospital in Zurich. Participants provided self-report and interview-based measures of the severity of AUD, negative symptoms, and alcohol craving. Finally, we used data from the electronic health records of the patients.

RESULTS

Patients with AUD show negative symptoms to a similar extent as patients with schizophrenia or bipolar disorder. We found a positive correlation between the extent of impairment within the MAP factor and overall severity of AUD. Furthermore, MAP negative symptoms were correlated with alcohol craving. In a linear regression, negative symptoms predicted alcohol craving whereas depression did not.

SUMMARY

Negative symptoms as conceptualized for schizophrenia are prevalent in patients with AUD and associated with the severity of AUD. More specifically, severity of AUD correlates with diminished motivation and pleasure, highlighting the importance of disturbances in motivational functions in AUD. This is further supported by the correlation between negative symptoms and craving, a hallmark of AUD. Taken together, our findings suggest that negative symptoms might be a highly relevant but hitherto often neglected therapeutic target in AUD.

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.

Dysfunctional Attitudes Mediate the Relationship Between Childhood Emotional Neglect and Anhedonia in Young Adult Major Depression Patients

BACKGROUND

Childhood traumas are well-established risk factors for major depressive disorder (MDD). However, the relationship between childhood traumas types and MDD symptoms is unclear. The present study tested the hypothesis that childhood traumas affect specific types of anhedonia in depression and the mediating role of dysfunctional attitude.

METHODS

Within this cross-sectional study, 310 young adult patients with MDD completed the PHQ-9, CTQ-SF, DAS, and SHAPS. The statistical analyses used the Mann-Whitney U test, Spearman's rank correlation, and multiple regression analysis. Mediation analyses were tested by the structural equation model (SEM).

RESULTS

Spearman's rank correlation analysis showed positive correlations between the SHAPS, CTQ-SF, and DAS total score (p < 0.05). The EA, EN, PN, and SHAPS scores were positively correlated (p < 0.05). Among the four factors of anhedonia, social interaction and interest/pastimes were positively correlated with EA, EN, and PN (p < 0.05), the sensory experience was positively correlated with EN (p < 0.01), and diet did not correlate with childhood traumas. Stepwise regression analysis showed that dysfunctional attitude and emotional neglect were the main influencing factors of sensory experience (p < 0.001) and social interaction (p < 0.001). Dysfunctional attitude and physical neglect were the main factors influencing interest/pastimes (p < 0.001). SEM analysis found that dysfunctional mediated between childhood traumas and anhedonia.

CONCLUSIONS

The degree of anhedonia was related to dysfunctional attitudes and childhood traumas. The childhood emotional neglect experience was the most important and was related to sensory and social anhedonia. Dysfunctional attitudes played a mediating role between childhood neglect and anhedonia. Early psychotherapy targeting young adult MDD patients with childhood emotional neglect may help decrease symptoms of anhedonia.

Anhedonia in Eating Disorders

Anhedonia is frequently observed among individuals with eating disorders (ED), though its relevance to ED pathology and clinical outcomes remain poorly understood. This chapter will present the latest findings regarding anhedonia in ED, with the majority of data available for anorexia nervosa (AN) and bulimia nervosa (BN). We consider anhedonia from the mechanistic lens of altered reward processing, with attention given to subjective experience, neurotransmitter function, neural correlates, and cognitive performance corresponding to distinct components of reward (i.e., liking, wanting, and learning). Findings from animal models are also highlighted. The chapter concludes with a discussion of implications for treatment and future directions aimed at better understanding anhedonia in ED.

Learning it the hard way - how enjoying life and positive appraisal buffer the negative effects of stressors on mental health in the COVID-19 pandemic

Background

Higher levels of stress and negative emotions such as anxiety and depression have been reported since the beginning of the COVID-19 pandemic, but it remains less clear how positive emotions, such as hedonic capacity, may be affected. Further, during lockdowns, the ability to learn new pleasurable activities (hedonic learning) may be particularly relevant. Here, we investigated if state hedonia and/or hedonic learning mediated the relationship between COVID-19 stress and mental health. Moreover, we explored whether positive appraisal style (PAS), a major resilience factor, influenced these relationships.

Methods

Using a cross-sectional design, 5000 German-speaking participants filled out online questionnaires targeting stressors, mental health, state hedonia, hedonic learning, and PAS between April 9 and May 15, 2020. After confirming the factor structure of our constructs, we applied latent structural equation modeling to test mediation as well as moderated mediation models.

Results

Stress showed a positive association with mental health symptoms, which was buffered by both state hedonia and hedonic learning. While higher stress was related to lower state hedonia, participants reported more hedonic learning with greater stressor load. The latter effect was greater for individuals with high PAS.

Limitations

The present results should be replicated in longitudinal designs with representative samples to confirm the directionality and generalizability of effects.

Conclusions

Both state hedonia and hedonic learning buffered the effect of stress on mental health in an early phase of the COVID-19 pandemic. Learning new rewarding activities in combination with a PAS may be especially relevant for maintaining mental health during lockdowns.

Psychological Treatments for Anhedonia

Anhedonia, a loss of interest or pleasure in activities, is a transdiagnostic symptom that characterizes many individuals suffering from depression and anxiety. Most psychological interventions are designed to decrease negative affect rather than increase positive affect, and are largely ineffective for reducing anhedonia. More recently, affective neuroscience has been leveraged to inform treatments for anhedonia by targeting aspects of the Positive Valence Systems, including impairments in reward anticipation, reward responsiveness, and reward learning. In this chapter, we review the efficacy of treatments and, when possible, highlight links to reward constructs. Augmented behavioral approaches and targeted cognitive interventions designed to target reward anticipation, responsiveness, and learning show preliminary efficacy in reducing anhedonia, while there is a relative lack of treatments that target positive emotion regulation and reward devaluation. In addition to developing treatments that address these targets, the field will benefit from establishing standardized measurement of anhedonia across units of analysis, mapping mechanisms of change onto aspects of reward processing, and examining anhedonia outcomes in the long-term.

Trait Anhedonia in Schizophrenia: A Systematic Review and Comparative Meta-analysis

Anhedonia, the reduced capacity to experience pleasure, has long been considered a prominent feature of schizophrenia spectrum disorders. Many domain-specific conceptualizations of anhedonia and pleasure capacity have been developed, and there currently exist a variety of self-report assessment tools that purport to assess these various domains. The current systematic review and meta-analysis (PROSPERO: CRD42020156169) aimed to quantify overall and domain-specific self-reported anhedonia in people with schizophrenia compared to nonpsychiatric controls. We performed a literature search of PsycINFO, MEDLINE, and Embase databases for dissertations and peer-reviewed articles published in English prior to June 2021. Studies employing a psychometrically validated self-report measure of anhedonia, pleasure experience or affect in people with schizophrenia, schizoaffective, or schizophreniform disorders; studies utilizing at least one clearly defined healthy or community control group for comparison; and studies providing sufficient data to calculate effect sizes were included in this review. Random and mixed effects meta-analyses, meta-regressions, and subgroup comparisons were run across domains of anhedonia to explore weighted mean effect sizes and their associated moderators. In total, 146 studies met inclusion criteria, yielding 390 Hedges' g effect sizes from the included comparisons. People with schizophrenia reported moderate-to-large elevations in overall and domain-specific anhedonia. A sensitivity analysis accounting for high risk of bias studies did not significantly impact results. Lastly, patient sex, education, negative symptom severity, antipsychotic class, and trait negative affect differentially moderated effect sizes across domains of anhedonia. Despite the heterogeneity inherent in schizophrenia spectrum disorders, self-reported anhedonia is ubiquitously reported across self-report measures in this population.

Understanding and restoring dopaminergic function in fibromyalgia patients using a mindfulness-based psychological intervention: a [18F]-DOPA PET study. Study protocol for the FIBRODOPA study—a randomized controlled trial

Background

Fibromyalgia (FM) is a very prevalent and debilitating chronic pain disorder that is difficult to treat. Mindfulness-based techniques are regarded as a very promising approach for the treatment of chronic pain and in particular FM. The Mindfulness-Oriented Recovery Enhancement (MORE) intervention, a mindfulness-based group intervention, has shown beneficial effects in opioid-treated chronic pain patients, including reduced pain severity, functional interference, and opioid dosing, by restoring neurophysiological and behavioral responses to reward. The first evidence for a hypodopaminergic state and impaired reward processing in FM has been reported. However, little is known about its impact on dopamine (DA) function and in particular with regard to DA responses to monetary reward in FM. The aim of the present study protocol is to evaluate if MORE is able to restore the DA function in FM patients, in particular with regard to the DA responses to reward, and to reduce pain and mood complaints in FM.

Methods

The present study is a multi-center interventional RCT with 3 time points: before the intervention, after completion of the intervention, and 3 months after completion of the intervention. Sixty-four FM patients will be randomly assigned to either the MORE intervention (N = 32) or a non-intervention control group (N = 32). Additionally, a comparison group of healthy women (N = 20) for PET measures will be enrolled and another group of healthy women (N = 15) will do the ambulatory assessments only. The MORE intervention consists of eight 2-h-long group sessions administered weekly over a period of 8 weeks. Before and after the intervention, FM participants will undergo [18F] DOPA positron emission tomography (PET) and functional MR imaging while performing a reward task. The primary outcome will be endogeneous DA changes measured with [18F] DOPA PET at baseline, after the intervention (after 8 weeks for the non-intervention control group), and at 3 months’ follow-up. Secondary outcomes will be (1) clinical pain measures and FM symptoms using standardized clinical scales; (2) functional brain changes; (3) measures of negative and positive affect, stress, and reward experience in daily life using the ambulatory assessment method (AA); and (4) biological measures of stress including cortisol and alpha-amylase.

Discussion

If the findings of this study confirm the effectiveness of MORE in restoring DA function, reducing pain, and improving mood symptoms, MORE can be judged to be a promising means to improve the quality of life in FM patients. The findings of this trial may inform health care providers about the potential use of the MORE intervention as a possible non-pharmacological intervention for FM.

Trial registration

ClinicalTrials.govNCT 04451564. Registered on 3 July 2020. The trial was prospectively registered.

Endogenous opioids contribute to the feeling of pain relief in humans

Endogenous opioids mediate the pleasurable responses to positively reinforcing stimuli such as palatable food. Yet, the reduction or omission of a negative experience can also be rewarding (negative reinforcement). As such, pain relief leads to negative reinforcement and evokes a pleasant feeling in humans. Although it has been shown that the feeling of pleasure associated with positive reinforcement is at least partly mediated through endogenous opioids, it is currently unknown whether similar neurochemical mechanisms are involved in the pleasant feeling evoked by pain relief. In this study, 27 healthy participants completed 2 identical experimental sessions, 1 with placebo and 1 with naltrexone, an endogenous opioid antagonist. Pain relief was induced by superficial cooling after heat stimulation of capsaicin-sensitized skin. Participants rated the relief and pleasantness in response to the cooling. Endogenous opioid blockade by naltrexone decreased relief and pleasantness ratings compared with placebo (P = 0.0027). This study provides evidence that endogenous opioids play a role in mediating the pleasant feeling of pain relief in humans. Clinically, the rewarding nature of pain relief and its underlying mechanisms require consideration because of their potential reinforcing effects on behaviors that might be beneficial short-term but maladaptive long-term.

Wisket rat model of schizophrenia: Impaired motivation and, altered brain structure, but no anhedonia

It is well-known that the poor cognition in schizophrenia is strongly linked to negative symptoms, including motivational deficit, which due to, at least partially, anhedonia. The goal of this study was to explore whether the schizophrenia-like Wisket animals with impaired motivation (obtained in the reward-based hole-board test), also show decreased hedonic behavior (investigated with the sucrose preference test). While neurochemical alterations of different neurotransmitter systems have been detected in the Wisket rats, no research has been performed on structural changes. Therefore, our additional aim was to reveal potential neuroanatomical and structural alterations in different brain regions in these rats. The rats showed decreased general motor activity (locomotion, rearing and exploration) and impaired task performance in the hole-board test compared to the controls, whereas no significant difference was observed in the sucrose preference test between the groups. The Wisket rats exhibited a significant decrease in the frontal cortical thickness and the hippocampal area, and moderate increases in the lateral ventricles and cell disarray in the CA3 subfield of hippocampus. To our knowledge, this is the first study to investigate the hedonic behavior and neuroanatomical alterations in a multi-hit animal model of schizophrenia. The results obtained in the sucrose preference test suggest that anhedonic behavior might not be involved in the impaired motivation obtained in the hole-board test. The neuropathological changes agree with findings obtained in patients with schizophrenia, which refine the high face validity of the Wisket model.

The psychosis human connectome project: An overview

Investigations within the Human Connectome Project have expanded to include studies focusing on brain disorders. This paper describes one of the investigations focused on psychotic psychopathology: The psychosis Human Connectome Project (P-HCP). The data collected as part of this project were multimodal and derived from clinical assessments of psychopathology, cognitive assessments, instrument-based motor assessments, blood specimens, and magnetic resonance imaging (MRI) data. The dataset will be made publicly available through the NIMH Data Archive. In this report we provide specific information on how the sample of participants was obtained and characterized and describe the experimental tasks and procedures used to probe neural functions involved in psychotic disorders that may also mark genetic liability for psychotic psychopathology. Our goal in this paper is to outline the data acquisition process so that researchers intending to use these publicly available data can plan their analyses. MRI data described in this paper are limited to data acquired at 3 Tesla. A companion paper describes the study's 7 Tesla image acquisition protocol in detail, which is focused on visual perceptual functions in psychotic psychopathology.

Emotion prediction errors guide socially adaptive behaviour

People make decisions based on deviations from expected outcomes, known as prediction errors. Past work has focused on reward prediction errors, largely ignoring violations of expected emotional experiences—emotion prediction errors. We leverage a method to measure real-time fluctuations in emotion as people decide to punish or forgive others. Across four studies (N=1,016), we reveal that emotion and reward prediction errors have distinguishable contributions to choice, such that emotion prediction errors exert the strongest impact during decision-making. We additionally find that a choice to punish or forgive can be decoded in less than a second from an evolving emotional response, suggesting emotions swiftly influence choice. Finally, individuals reporting significant levels of depression exhibit selective impairments in using emotion—but not reward—prediction errors. Evidence for emotion prediction errors potently guiding social behaviors challenge standard decision-making models that have focused solely on reward.

Addressing anhedonia to increase depression treatment engagement

Anhedonia, or reward system dysfunction, is associated with poorer treatment outcomes among depressed individuals. The role of anhedonia in treatment engagement, however, has not yet been explored. We review research on components of reward functioning impaired in depression, including effort valuation, reward anticipation, initial responsiveness, reward learning, reward probability, and reward delay, highlighting potential barriers to treatment engagement associated with these components. We then propose interventions to improve treatment initiation and continuation by addressing deficits in each component of reward functioning, focusing on modifications of existing evidence-based interventions to meet the needs of individuals with heightened anhedonia. We describe potential settings for these interventions and times at which they can be delivered during the process of referring individuals to mental health treatment, conducting intakes or assessments, and providing treatment. Additionally, we note the advantages of using screening processes already in place in primary care, workplace, school, and online settings to identify individuals with heightened anhedonia who may benefit from these interventions. We conclude with suggestions for future research on the impact of anhedonia on treatment engagement and the efficacy of interventions to address it. PRACTITIONER POINTS: Many depressed individuals who might benefit from treatment do not initiate it or discontinue early. One barrier to treatment engagement may be anhedonia, a core symptom of depression characterized by loss of interest or pleasure in usual activities. We describe brief interventions to improve treatment engagement in individuals with anhedonia that can be implemented during the referral process or early in treatment. We argue that interventions aiming to improve treatment engagement in depressed individuals that target anhedonia may be particularly effective.

Neural signatures of saliency-mapping in anhedonia: A narrative review

Anhedonia is the loss of pleasure or motivation to engage in previously enjoyable activities, and is a transdiagnostic symptom associated with significant clinical impairment. Anhedonia is implicated in several different psychiatric disorders, presenting a promising opportunity for transdiagnostic treatment. Thus, developing targeted treatments for anhedonia is of critical importance for population mental health. An important first step in doing so is establishing a thorough understanding of the neural correlates of anhedonia. The Triple Network Model of Psychopathology provides a frame for how brain activity may go awry in anhedonia, specifically in the context of Salience Network (SN) function (i.e., saliency-mapping). We present a narrative review examining saliency-mapping as it relates to anhedonia severity in depressed and transdiagnostic adult samples. Results revealed increased anhedonia to be associated with hyperactivity of the SN at rest and in the context of negative stimuli, as well as a global lack of SN engagement in the context of positive stimuli. Potential treatments for anhedonia are placed within this model, and future directions for research are discussed.

Radically open dialectical behaviour therapy adapted for adolescents: a case series

BACKGROUND

Overcontrol is a transdiagnostic cluster of traits associated with excessive psychological, behavioural and social inhibitory control. It is associated with psychiatric diagnoses of depression, restrictive eating disorders and/or obsessive-compulsive personality disorder. Radically Open Dialectical Behaviour Therapy is a transdiagnostic treatment for maladaptive overcontrol. This case series evaluates an adolescent adaption (RO-A) for a transdiagnostic group of adolescents identified as overcontrolled.

METHODS

Twenty-eight adolescents were consecutively referred for RO-A from two different National and Specialist Child and Adolescent Mental Health Services between June 2017 and February 2020. Baseline self-report measures assessed overcontrol characteristics, relationship and attachment quality and mental health symptoms of depression and eating disorders, which were repeated at discharge.

RESULTS

Adolescents in this case series reported high rates of depression (78.6%), self-harm (64.3%) and eating disorders (78.6%). Most (85.7%) had two or more mental health diagnoses and all had previous mental health treatments before starting RO-A. The mean number of RO-A sessions attended was 18 group-based skills classes and 21 individual sessions over a mean period of 34 weeks. Significant improvements with medium and large effect sizes were reported in cognitive flexibility (d = 1.63), risk aversion (d = 1.17), increased reward processing (d = .79) and reduced suppression of emotional expression (d = .72). Adolescents also reported feeling less socially withdrawn (d = .97), more connected to others (d = 1.03), as well as more confident (d = 1.10) and comfortable (d = .85) in attachment relationships. Symptoms of depression (d = .71), eating disorders (d = 1.06) and rates of self-harm (V = .39) also significantly improved. Exploratory correlation analyses suggest improvements in overcontrol are moderately to strongly correlated with improvements in symptoms of depression and eating disorders.

CONCLUSIONS

This case series provides preliminary data that RO-A may be an effective new treatment for adolescents with overcontrol and moderate to severe mental health disorders like depression and eating disorders. RO-A led to improved management of overcontrol, improved relationship quality and reduced mental health symptoms. Further evaluation is indicated by this case series, particularly for underweight young people with eating disorders. More rigorous testing of the model is required as conclusions are only tentative due to the small sample size and methodological limitations.

Highlighting psychological pain avoidance and decision-making bias as key predictors of suicide attempt in major depressive disorder-A novel investigative approach using machine learning

OBJECTIVE

Predicting suicide is notoriously difficult and complex, but a serious public health issue. An innovative approach utilizing machine learning (ML) that incorporates features of psychological mechanisms and decision-making characteristics related to suicidality could create an improved model for identifying suicide risk in patients with major depressive disorder (MDD).

METHOD

Forty-four patients with MDD and past suicide attempts (MDD_SA, N = 44); 48 patients with MDD but without past suicide attempts (MDD_NS, N = 48-42 of whom with suicide ideation [MDD_SI, N = 42]), and healthy controls (HCs, N = 51) completed seven psychometric assessments including the Three-dimensional Psychological Pain Scale (TDPPS), and one behavioral assessment, the Balloon Analogue Risk Task (BART). Descriptive statistics, group comparisons, logistic regressions, and ML were used to explore and compare the groups and generate predictors of suicidal acts.

RESULTS

MDD_SA and MDD_NS differed in TDPPS total score, pain arousal and avoidance subscale scores, suicidal ideation scores, and relevant decision-making indicators in BART. Logistic regression tests linked suicide attempts to psychological pain avoidance and a risk decision-making indicator. The resultant key ML model distinguished MDD_SA/MDD_NS with 88.2% accuracy. The model could also distinguish MDD_SA/MDD_SI with 81.25% accuracy. The ML model using hopelessness could classify MDD_SI/HC with 94.4% accuracy.

CONCLUSION

ML analyses showed that motivation to avoid intolerable psychological pain, coupled with impaired decision-making bias toward under-valuing life's worth are highly predictive of suicide attempts. Analyses also demonstrated that suicidal ideation and attempts differed in potential mechanisms, as suicidal ideation was more related to hopelessness. ML algorithms show useful promises as a predictive instrument.

The effect of physical activity on anhedonia in individuals with depressive symptoms

The therapeutic effect of antidepressants has been demonstrated for anhedonia in patients with depression. However, antidepressants may cause side-effects, such as cardiovascular dysfunction. Although physical activity has minor side-effects, it may serve as an alternative for improving anhedonia and depression. We sought to investigate whether physical activity reduces the level of anhedonia in individuals with depression. Fifty-six university students with moderate depressive symptoms (Beck Depression Inventory total score > 16) were divided into three training groups: the Running Group (RG, n = 19), the Stretching Group (SG, n = 19), and the Control Group (n = 18). We employed the Monetary Incentive Delay (MID) task and the Temporal Experience of Pleasure Scale (TEPS) to evaluate hedonic capacity. All participants in the RG and SG received 8 weeks of jogging and stretching training, respectively. The RG experienced an increase in the level of arousal during anticipation of a future reward and recalled less negativity towards the loss condition. The SG exhibited enhanced scores on the Anticipatory and Consummatory Pleasure subscales of the TEPS after training. Moreover, in the RG, greater improvements in anticipatory arousal ratings for pleasure and remembered valence ratings for negative affect were associated with longer training duration, lower maximum heart rate, and higher consumed calories during training. To conclude, physical activity is effective in improving anticipatory anhedonia in individuals with depressive symptoms.

Reward mechanism of depressive episodes in bipolar disorder: Enhanced theta power in feedback-related negativity

INTRODUCTION

This study aimed to explore the reward-related neural mechanism in patients with depressive mood in bipolar disorder (BD) using event-related potentials. It remains unknown whether or not different neurobiological markers underlying depression symptoms in BD depression and major depression disorder (MDD).

METHODS

24 patients with BD depression and 20 healthy controls were included. Participants underwent evaluation with the Temporal Experience of Pleasure Scale (TEPS), followed by the classical gambling paradigm, while undergoing 64-channel electroencephalography. The waveform of feedback-related negativity (FRN) was extracted from the 250-350 ms time-window after participants received feedback regarding loss or gain. Event-related potential datasets were obtained using time-frequency analysis.

RESULTS

(1) The TEPS scores of the patients were significantly lower than those of the controls [t₍₄₂₎ = 5.16, p < 0.01]. (2) The event of loss elicited a deeper FRN in patients than that in controls [t₍₄₂₎ = 2.19, p < 0.05], while no difference was observed in the event of gains (t₍₄₂₎ = 1.12, p > 0.05). (3) Theta power rooted in FRN in patients was significantly higher in loss than in gain [F_(1,42) = 30.32, p < 0.01]. (4) Analysis of Variance (ANOVA) illustrated the interaction effect of theta power in gain/loss between two groups [F_(1,42) = 3.59, p = 0.06].

LIMITATION

Our study did not analyze the effect of different drugs which might affect our results.

CONCLUSION

The enhanced reflection of negative feedback was consistent with the negative bias, impulse control impairment, and emotional dysregulation observed in the bipolar disorder spectrum. We suggested that the extreme theta power generated from the anterior cingulate gyrus (ACC) might be the main component of abnormal FRN.

A Conceptual Framework for Multi-Dimensional Measurements of Food Related Pleasure-The Food Pleasure Scale

In modern times, the majority of food intake is believed to be driven by hedonic processes, rather than homeostatic ones. Various factors have been found to influence the hedonic eating experience and thereby influence eating behaviour, and each factor can be regarded a piece that contributes to parts of the total picture of the hedonic response to food. As a result, the literature on the hedonic response to food-related experiences is comprehensive, but at the same time rather fragmented; and importantly, it is not clear how individuals/segments differ in key drivers of their hedonic experience and the extent to which food pleasure is perceived. In this paper, we present a conceptual framework for the development of a scale (self-report questionnaire) to measure the qualitative and quantitative aspects of food-related pleasure, the Food Pleasure Scale. We introduce the concept of (an)hedonia and scales developed in the past for its measurement, identify the spectrum of characteristics influencing food-related pleasure and explain the relevance of developing such a scale. Based on this theoretical framework, a strategy for the development of the Food Pleasure Scale is proposed.