The schizophrenia spectrum anhedonia paradox

Emotional Experience of People With Schizophrenia and People at Risk for Psychosis: A Meta-Analysis

Importance

Psychotic symptoms are associated with subjective reports of aberrant emotion, such as excessive fear or anhedonia, but whether these aberrations reflect aberrant emotional experience of normative stimuli is uncertain both for individuals with schizophrenia and those at risk for psychosis.

Objective

To provide a meta-analysis of study samples of emotional experience in individuals with schizophrenia and those at risk for psychosis as assessed in laboratory-based emotion-induction studies.

Data Sources

MEDLINE and PsycINFO databases were searched for articles published from January 1986 and Google Scholar citations of a relevant earlier meta-analysis until August 2022. Reference lists were manually searched for additional studies.

Study Selection

Included studies measured positive or negative emotional experience in response to standardized emotionally evocative stimuli and compared participants diagnosed with schizophrenia or participants at risk for psychosis with healthy controls.

Data Extraction and Synthesis

The meta-analysis was registered with PROSPERO and followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines. Data were extracted by 2 independent coders, and random-effects analyses were conducted.

Main Outcomes and Measures

Outcomes were 3 scales of emotional experience (unipolar positive emotion, unipolar negative emotion, bipolar valence), analyzed separately for pleasant, neutral, and unpleasant stimuli. A meta-analysis was conducted for differences between the 2 clinical groups combined and controls. Subgroup differences (schizophrenia vs at risk) and the influence of several other variables were tested in moderator analyses.

Results

This systematic review and meta-analysis included data from 111 studies and 6913 participants (schizophrenia: 2848 [41.2%]; at risk: 877 [12.7%]; healthy controls: 3188 [46.1%]). Compared with controls, people with schizophrenia and those at risk for psychosis experienced pleasant stimuli as less positive (unipolar positive: standardized mean difference [SMD] Hedges g = -0.19; P =.001; bipolar valence: SMD Hedges g = -0.28; P <.001) and more negative (Hedges g = 0.52; P <.001), neutral stimuli as more negative (Hedges g = 0.55; P <.001), and unpleasant stimuli as both more positive (unipolar positive: SMD Hedges g = 0.23; P =.005; bipolar valence: Hedges g = 0.12; P =.01) and more negative (Hedges g = 0.22; P <.001). Moderator analyses indicated a less aberrant emotional experience for odors than for visual stimuli (unipolar negative, pleasant z score = -2.97; P =.003; unipolar negative, neutral z score = -2.70; P =.007), an association between higher negative symptoms and diminished positive emotion for pleasant stimuli in schizophrenia (z score = -2.98; P =.003), and that subgroup differences were limited to neutral stimuli.

Conclusions and Relevance

Results suggest a pattern of aberrant emotional experience of normative stimuli in schizophrenia and that this already was observable before disorder onset. In particular, the aberrant experience of pleasant stimuli needs to be considered as an intervention target.

Two and five-factor models of negative symptoms in schizophrenia are differentially associated with trait affect, defeatist performance beliefs, and psychosocial functioning

Recent factor analytic evidence supports both two-factor (motivation and pleasure, MAP; diminished expression, EXP) and five-factor (anhedonia, asociality, avolition, blunted affect, alogia) conceptualizations of negative symptoms. However, it is unclear whether these two conceptualizations of the latent structure of negative symptoms have differential associations with external correlates. The current study evaluated external correlates of the two- and five-factor structures by examining associations with variables known to have critical relations with negative symptoms: trait affect, defeatist performance beliefs, neurocognition, and community-based psychosocial functioning. Participants included a total of 245 outpatients diagnosed with schizophrenia who were rated on the Brief Negative Symptom Scale and completed a battery of additional measures during periods of clinical stability. These additional measures included the Positive and Negative Affect Schedule, Defeatist Performance Beliefs scale, MATRICS Consensus Cognitive Battery, and Level of Function Scale. Pearson correlations indicated differential patterns of associations between the BNSS scores and the external correlates. Support for the two-factor model was indicated by a stronger association of MAP with positive affect and psychosocial functioning, compared to EXP with neurocognition. Significance tests examining a differential magnitude of associations showed that the two-dimension negative symptom structure masked unique correlational relationships among the five negative symptom domains with neurocognition and social/vocational community functioning and captured unique patterns of correlation with trait affect. Support for the five-factor model was shown by a stronger association between Blunted Affect with Attention/Vigilance, and stronger associations between Avolition, Anhedonia, and Asociality with psychosocial functioning. Results offer support for both the two-dimension and five-domain model of negative symptoms as well as a hierarchical two-dimensions-five-domains model of negative symptoms. Findings may have implications for diagnostic criteria and descriptions of the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5), as well as possible treatment targets of negative symptoms.

Intact differentiation of responses to socially-relevant emotional stimuli across psychotic disorders: An event-related potential (ERP) study

Event-related potential (ERP) studies of motivated attention in schizophrenia typically show intact sensitivity to affective vs. non-affective images depicting diverse types of content. However, it is not known whether this ERP pattern: 1) extends to images that solely depict social content, (2) applies across a broad sample with diverse psychotic disorders, and (3) relates to self-reported trait social anhedonia. We examined late positive potential (LPP) amplitudes to images involving people that were normatively pleasant (affiliative), unpleasant (threatening), or neutral in 97 stable outpatients with various psychotic disorders and 38 healthy controls. Both groups showed enhanced LPP to pleasant and unpleasant vs. neutral images to a similar degree, despite lower overall LPP in patients. Within the patients, there were no significant LPP differences among subgroups (schizophrenia vs. other psychotic disorders; affective vs. non-affective psychosis) for the valence effect (pleasant/unpleasant vs. neutral). Higher social anhedonia showed a small, significant relation to lower LPP to pleasant images across all groups. These findings suggest intact motivated attention to social images extends across psychotic disorder subgroups. Dimensional transdiagnostic analyses revealed a modest association between self-reported trait social anhedonia and an LPP index of neural sensitivity to pleasant affiliative images.

Expanding the positivity offset theory of anhedonia to the psychosis continuum

People with schizophrenia and negative symptoms show diminished net positive emotion in low-arousing contexts (diminished positivity offset) and co-activate positive and negative emotion more frequently (increased ambivalence). Here, we investigated whether diminished positivity offset and increased ambivalence covary with negative symptoms along the continuum of psychotic symptoms. We conducted an online-study in an ad-hoc community sample (N = 261). Participants self-reported on psychotic symptoms (negative symptoms, depression, positive symptoms, anhedonia) and rated positivity, negativity, and arousal elicited by pleasant, unpleasant, and neutral stimuli. The data were analyzed with multilevel linear models. Increasing levels of all assessed symptom areas showed significant associations with diminished positivity offset. Increased ambivalence was related only to positive symptoms. Our results show that the diminished positivity offset is associated with psychotic symptoms in a community sample, including, but not limited to, negative symptoms. Ecological validity and symptom specificity require further investigation.

Sharing positive events: Ecological momentary assessment of emotion regulation via social capitalization in schizotypy

Emotional deficits are prominent in schizophrenia-spectrum psychopathology and linked with poorer outcomes. Schizotypy, an underlying personality organization that putatively confers vulnerability to developing schizophrenia, has been associated with increased negative affect, decreased positive affect, and some difficulty with emotion regulation. This study explored the role of social capitalization, the upregulation of positive emotion when positive life events are shared with others, in schizotypy. Social capitalization is relevant for schizotypy given its association with social functioning and social motivation abnormalities. Using mobile assessment methods, a sample of college students (N=73) completed daily surveys via a mobile application two times per day for seven days and made daily ratings of mood and answered questions regarding any capitalization attempt for a positive event. Results indicated that higher schizotypy and not sharing an event were independently associated with lower happiness and increased sadness and anxiety. When an event was shared, lower schizotypy and supportive/enthusiastic response perception were independently associated with increased happiness. No significant interactions were observed between schizotypy and social capitalization variables. Future research would benefit from exploring the role that other common schizotypy concomitants, e.g., social anxiety or social disconnection, play in social capitalization and the extent this is helped or hindered via mass personal technological mediums.

Anhedonia in Depression and Schizophrenia: Brain Reward and Aversion Circuits

Anhedonia, which is defined as markedly diminished interest or pleasure, is a prominent symptom of psychiatric disorders, most notably major depressive disorder (MDD) and schizophrenia. Anhedonia is considered a transdiagnostic symptom that is associated with deficits in neural reward and aversion functions. Here, we review the characteristics of anhedonia in depression and schizophrenia as well as shared or disorder-specific anhedonia-related alterations in reward and aversion pathways of the brain. In particular, we highlight that anhedonia is characterized by impairments in anticipatory pleasure and integration of reward-related information in MDD, whereas anhedonia in schizophrenia is associated with neurocognitive deficits in representing the value of rewards. Dysregulation of the frontostriatal circuit and mesocortical and mesolimbic circuit systems may be the transdiagnostic neurobiological basis of reward and aversion impairments underlying anhedonia in these two disorders. Blunted aversion processing in depression and relatively strong aversion in schizophrenia are primarily attributed to the dysfunction of the habenula, insula, amygdala, and anterior cingulate cortex. Furthermore, patients with schizophrenia appear to exhibit greater abnormal activation and extended functional coupling than those with depression. From a transdiagnostic perspective, understanding the neural mechanisms underlying anhedonia in patients with psychiatric disorders may help in the development of more targeted and efficacious treatment and intervention strategies.

Depressive Symptoms and PANSS Symptom Dimensions in Patients With Predominant Negative Symptom Schizophrenia: A Network Analysis

INTRODUCTION

Schizophrenia is a severe psychiatric disorder with a large symptomatic heterogeneity. Moreover, many patients with schizophrenia present with comorbid psychiatric symptoms or disorders. The relation between depressive symptoms and negative symptoms, such as blunted affect, alogia, anhedonia, asociality and avolition, is particularly intriguing. The negative symptoms can be primary or secondary of depression or overlapping with depressive symptoms. The aim of the present network analysis was to better understand the interactions between depressive symptoms and the different symptoms of schizophrenia and to investigate whether negative symptoms and depressive symptoms can be better delineated.

METHODS

A network analysis on the baseline item scores of the Positive and Negative Syndrome Scale (PANSS) and Calgary Depression Scale for Schizophrenia (CDSS) from the cariprazine-risperidone study in patients with predominant negative symptoms (PNS) was performed. The connections between all these symptoms (PANSS and CDSS) were investiged: node strength and network centrality were estimated and the Mohr 5-factor model of the PANSS was applied to test the validity of its different symptoms clusters.

RESULTS

Across 460 patients with schizophrenia and PNS, the most central symptom (largest node strength) was depression (PANSS) followed by depression (CDSS), anxiety, lack of judgment and insight and tension. The PANSS negative symptom cluster together and was only poorly connected with CDSS depresson symptoms. The Mohr 5 factor model was clearly recognized in the overall clustering of symptoms.

CONCLUSION

This network analysis suggests that depression and anxiety symptoms are the most central in this PNS patient population, despite the baseline low depression scores, and that negative symptoms are a clearly independent symptom cluster that can be delineated from depressive symptoms.

Alterations in Emotional Diversity Correspond With Increased Severity of Attenuated Positive and Negative Symptoms in the Clinical High-Risk Syndrome

Background: Alterations in emotional functioning are a key feature of psychosis and are present in individuals with a clinical high-risk (CHR) syndrome. However, little is known about alterations in emotional diversity (i.e., the variety and relative abundance of emotions that humans experience) and clinical correlates in this population. Methods: Individuals meeting criteria for a CHR syndrome (N = 47) and matched healthy controls (HC) (N = 58) completed the modified Differential Emotions Scale (used to derive scores of total, positive, and negative emotional diversity) and clinical interviews (i.e., Structured Interview for Psychosis-Risk Syndromes). Results: Findings showed that the CHR group experienced lower levels of positive emotional diversity compared to HCs. Among the CHR individuals, lower levels of positive and higher levels of negative emotional diversity were associated with more severe attenuated positive and negative symptoms. Analyses controlled for mean levels of emotion and current antipsychotic medication use. Discussion: Results demonstrate that altered emotional diversity (in particular lower levels of positive and higher levels of negative emotional diversity) is a clinically relevant marker in CHR individuals, above and beyond alterations in mean levels of emotional experiences. Future studies may probe sources, downstream consequences, and potential modifiability of decreased emotional diversity in individuals at CHR.

Neural Processing of Repeated Emotional Scenes in Schizophrenia, Schizoaffective Disorder, and Bipolar Disorder

Impaired emotional processing and cognitive functioning are common in schizophrenia, schizoaffective disorder, and bipolar disorders, causing significant socioemotional disability. While a large body of research demonstrates abnormal cognition/emotion interactions in these disorders, previous studies investigating abnormalities in the emotional scene response using event-related potentials (ERPs) have yielded mixed findings, and few studies compare findings across psychiatric diagnoses. The current study investigates the effects of emotion and repetition on ERPs in a large, well-characterized sample of participants with schizophrenia-bipolar syndromes. Two ERP components that are modulated by emotional content and scene repetition, the early posterior negativity (EPN) and late positive potential (LPP), were recorded in healthy controls and participants with schizophrenia, schizoaffective disorder, bipolar disorder with psychosis, and bipolar disorder without psychosis. Effects of emotion and repetition were compared across groups. Results displayed significant but small effects in schizophrenia and schizoaffective disorder, with diminished EPN amplitudes to neutral and novel scenes, reduced LPP amplitudes to emotional scenes, and attenuated effects of scene repetition. Despite significant findings, small effect sizes indicate that emotional scene processing is predominantly intact in these disorders. Multivariate analyses indicate that these mild ERP abnormalities are related to cognition, psychosocial functioning, and psychosis severity. This relationship suggests that impaired cognition, rather than diagnosis or mood disturbance, may underlie disrupted neural scene processing in schizophrenia-bipolar syndromes.

Remembering the past to live better in the future: A feasibility randomised controlled trial of memory specificity training for motivation in psychosis

BACKGROUND AND OBJECTIVES

People with a diagnosis of psychosis often experience low motivation and reduced activity levels. Autobiographical memory deficits have been identified in people with psychosis and this may limit the role of memory retrieval in supporting motivation. This pilot study adapted a recently developed protocol, Memflex, which aims to enhance autobiographical memory and has shown promise in depression. Our brief intervention targets experiential negative symptoms of psychosis using supported autobiographical memory retrieval.

METHOD

A sample of 31 participants with psychosis were recruited from inpatient and community settings and randomised in a 2:1 ratio to either a basic recall control or an enhanced recall intervention group. Participants were asked to generate positive autobiographical memories linked to activities they wish to repeat in the future. The enhanced recall condition received additional prompts from the Memflex protocol, and the basic recall condition received no additional support.

RESULTS

The intervention delivered was acceptable (rated >80%) and feasible (94% adherence) to those who took part. Participants were able to generate positive autobiographical memories linked to their goals and experienced appropriate emotions linked to these. The controlled preliminary effect sizes (0.2-0.34) showed encouraging signals for self-efficacy, motivation and a reduction in negative mood.

LIMITATIONS

As this was a pilot study with a small sample size between-group tests of statistical significance were not conducted, and therefore findings should be interpreted with caution.

CONCLUSIONS

These findings suggest that guided autobiographical memory retrieval may be an effective way tool for targeting motivation in people with psychosis.

Anhedonia in young people with first episode psychosis: a longitudinal study

Aim: Previous research observed deficits in pleasure experience in chronic schizophrenia, but little is known about anhedonia in early psychosis. Aim of this study is: (1) to examine anhedonia in distinct help-seeking subgroups of young people identified through the First Episode Psychosis (FEP) criteria, (2) to investigate its correlations with psychopathology in the FEP sample, and (3) to monitor longitudinally its stability in the FEP group along 1-year follow-up period.Materials and methods: All participants (137 FEP and 95 nonpsychotic psychiatric controls [i.e. non-FEP]), aged 13-35 years, completed the Comprehensive Assessment of At-Risk Mental States (CAARMS), the Schizotypal Personality Questionnaire - Brief version (SPQ-B), the Brief O-LIFE questionnaire (BOL), and the World Health Organization Quality of Life - Brief version (WHOQOL-BREF). We used two different indexes of anhedonia: CAARMS 'Anhedonia' item 4.3 and BOL 'Introvertive Anhedonia' subscale scores.Results: In comparison with non-FEP, FEP patients showed higher baseline anhedonia scores. After 1-year follow-up period, FEP individuals had a significant decrease in severity of anhedonia scores. In the FEP group, anhedonia showed significant, enduring (over time) correlations with impaired role functioning, negative symptoms, comorbid depression, poorer self-perceived quality of life and specific schizotypal personality traits (i.e. interpersonal deficits).Conclusions: Anhedonia is relevant in the early phase of psychosis and its severity is associated with functioning deterioration and a bad quality of life.

Anhedonia in adolescents at ultra-high risk (UHR) of psychosis: findings from a 1-year longitudinal study

Previous findings suggested deficits in pleasure experience in schizophrenia, but little is known in psychosis risk prodrome, especially in adolescence. Aim of this study was (1) to assess anhedonia in distinct help-seeking subgroups of adolescents identified through the ultra-high risk (UHR) criteria, (2) to explore any association of anhedonia with other psychopathological aspects in the UHR group, and (3) to monitor longitudinally the stability of anhedonia in UHR individuals across 1-year follow-up period. 123 participants (13-18 years) completed the Comprehensive Assessment of At-Risk Mental States (CAARMS), the Beck Depression Inventory-II, the Schizotypal Personality Questionnaire-Brief version, the Brief-O-LIFE questionnaire (BOL), and the Brief version of the World Health Organization Quality of Life scale (WHOQOL-BREF). Two different indexes of anhedonia were used: CAARMS "Anhedonia" item 4.3 and BOL "Introvertive Anhedonia" subscale scores. No difference in anhedonia levels between UHR and First Episode Psychosis (FEP) groups was found. UHR adolescents showed higher CAARMS and BOL anhedonia scores than non-UHR/FEP. After 1-year follow-up period, UHR adolescents had a significant decrease in severity only in CAARMS anhedonia subscores. In UHR subgroup, CAARMS anhedonia measures showed significant correlations with impaired role functioning and negative symptoms, while BOL anhedonia was significantly correlated with specific schizotypal personality traits concerning interpersonal deficits. Anhedonia is prominent in the psychosis prodrome, also in adolescence. Its severity is not statistically different from that of FEP adolescents and is related to more severe functioning impairment and a worse quality of life.

A meta-analysis of self-reported anticipatory and consummatory pleasure in the schizophrenia-spectrum

OBJECTIVE

Recent conceptual frameworks propose anhedonia reflects abnormalities in the temporal dynamics of positive emotion in schizophrenia, characterized by intact consummatory and impaired anticipatory pleasure. A comprehensive meta-analysis can directly test this theory using self-report data.

METHOD

A meta-analysis was performed on studies reporting Temporal Experience of Pleasure Scale (TEPS) data from healthy controls and schizophrenia or schizotypy groups. The TEPS was examined as it contains subscales to measure both consummatory and anticipatory pleasure separately. Statistical heterogeneity and study bias were examined. Meta-regressions evaluated moderators.

RESULTS

53 studies were retrieved (7,797 participants). Results revealed small effect sizes for comparisons of combined schizophrenia/schizotypy and control groups for both consummatory and anticipatory pleasure. Within-group comparisons of pleasure conditions were nonsignificant. The percentage of male schizophrenia/schizotypy participants significantly moderated anticipatory and consummatory pleasure for the combined sample and schizotypy alone; male participants were found to report reduced pleasure. There was only minor evidence of bias; sensitivity analysis confirmed result robustness. Exploratory outlier removal for schizophrenia within-group pleasure comparisons revealed a statistically significant difference between reported anticipatory and consummatory pleasure, with consummatory pleasure reduced relative to anticipatory (i.e., in the opposite direction of the majority of experimental research findings).

CONCLUSIONS

These findings provided only modest support for the temporal dynamics of positive emotion conceptualization because they revealed no evidence for: 1) specific anticipatory pleasure deficits in schizophrenia-spectrum participants compared to controls; 2) significant reductions in anticipatory pleasure relative to consummatory pleasure in schizophrenia-spectrum participants.

Network structure of anticipatory pleasure and risk features: Evidence from a large college sample

Investigating the relationship between anticipatory pleasure deficits and risk features of mental disorders not only theoretically benefits the understanding of anhedonia, but could also facilitate early detection and intervention of mental disorders. Using network analysis, the present study examined the pattern of relationship between anticipatory pleasure and risk features of schizophrenia spectrum, depressive, anxiety, autism spectrum, and obsessive-compulsive disorders in a large sample of college students (n = 2152). It was found that interpersonal features of schizotypal personality traits and poor social skills of autistic traits showed strong correlation with low social anticipatory pleasure. Depressive symptoms severity was weakly associated with reduced abstract anticipatory pleasure, while obsessive-compulsive traits were weakly associated with high contextual anticipatory pleasure. No significant correlation was found between anxiety symptoms severity and anticipatory pleasure. Social anticipatory pleasure had the highest strength centrality among all anticipatory pleasure components, while interpersonal features of schizotypal personality traits had the highest strength centrality in the whole network. Our findings suggest that impaired anticipatory pleasure, especially social anticipatory pleasure, is a particular feature of schizotypal personality traits and autistic traits. Our findings may have implications for intervention in that the social component may be a target to improve anhedonia in individuals with schizotypal and autistic traits, while interpersonal features may be a key treatment target given that it was central to the relationship between anticipatory pleasure and risk features.

The relationship between depressive symptoms and negative symptoms in people with non-affective psychosis: a meta-analysis

The negative symptoms of psychosis and depressive symptomatology share several features, e.g. low motivation, apathy and reduced activity. Understanding the associations between these two sets of symptoms will support improved assessment and the development of interventions targeting these difficulties in people with psychosis. This is the first large systematic review and meta-analysis to quantify the relationship between these two categories of symptoms, as measured in studies to date. PsycInfo, Embase and Medline were systematically searched to identify eligible studies. Inclusion criteria ensured the studies measured both depression and negative symptoms using validated measures in a sample of over 8000 participants with non-affective psychosis diagnoses. The search led to 2020 records being screened and 56 included in the meta-analysis and review. Both meta-analyses and meta-regressions were conducted to explore the main effect and potential moderating variables. A clear pattern emerges showing that higher ratings of negative symptoms are associated with higher levels of depressive symptoms, with a small effect [standardised effect size = 0.19, p < 0.05). This did not vary greatly with the measures used (SES = 0.19-0.26) and was not moderated by demographic variables or quality ratings. Interestingly, higher depressive symptoms predict a significant relationship with co-occurring negative symptoms. However, higher negative symptoms predict that it is less likely there will be a relationship with co-occurring depressive symptoms. Heterogeneity was high across these analyses. The findings support the adoption of a symptom-specific approach to understanding the interplay between negative and depressive symptoms in psychosis, to improve assessment and intervention.

Spanish validation of the self-evaluation of negative symptoms scale SNS in an adolescent population

BACKGROUND

Negative symptoms (NS) may be observed in the general population in an attenuated form and in high-risk mental states. However, they have been less studied in the general population than positive symptoms, in spite of their importance at the insidious onset of schizophrenia and their appearance before positive symptoms. This study aimed to analyze the empirical structure of the Spanish version of the Self-Evaluation of Negative Symptoms (SNS) Scale and find its psychometric properties and invariance of measurement across sex and age in a sample of adolescents.

METHODS

The sample consisted of 4521 adolescents (53.6% female) from 11 to 18 years of age.

RESULTS

Confirmatory Factor Analysis of the SNS confirmed an internal structure of five first-order factors by the characteristic dimensions of NS: avolition, social withdrawal, diminished emotional range, anhedonia, alogia, and one second-order factor which includes the total NS score. Multi-group confirmatory factor analysis showed that the scale was invariant across sex and age. Total scale reliability was adequate. A strong relationship was found between the SNS with depressive symptomatology, moderate with ideas of reference and low with aberrant salience.

CONCLUSION

The results back use of the Spanish version of the SNS scale for detection of NS in the general population of adolescents.

Anhedonia as a key clinical feature in the maintenance and treatment of opioid use disorder

There is a critical need for research on clinical features that may influence response to treatment for opioid use disorder (OUD). Given its neurobiology and relevance to opioid use, anhedonia may be one such promising clinical feature. We identified and reviewed 11 studies that measured anhedonia in humans with OUD to characterize the current state of evidence and highlight potential implications for treatment. The majority of studies were cross-sectional, indicating higher anhedonia scores in opioid-dependent samples compared to healthy controls. Rates of participants with clinically significant anhedonia ranged from 21% to 48%. Anhedonia scores were correlated with opioid craving and use, however there are significant knowledge gaps regarding its time course and impact on treatment adherence and outcomes. Repeated assessment of anhedonia early in treatment for OUD is recommended, as it may be a unique predictor of dropout or non-response, and a potential target for behavioral and/or pharmacological intervention.