Systemic delivery of mutant huntingtin lowering antisense oligonucleotides to the brain using apolipoprotein A-I nanodisks for Huntington disease.

Efficient delivery of therapeutics to the central nervous system (CNS) remains a major challenge for the treatment of neurological diseases. Huntington disease (HD) is a dominantly inherited neurodegenerative disorder caused by a CAG trinucleotide expansion mutation in the HTT gene which codes for a toxic mutant huntingtin (mHTT) protein. Pharmacological reduction of mHTT in the CNS using antisense oligonucleotides (ASO) ameliorates HD-like phenotypes in rodent models of HD, with such therapies being investigated in clinical trials for HD. In this study, we report the optimization of apolipoprotein A-I nanodisks (apoA-I NDs) as vehicles for delivery of a HTT-targeted ASO (HTT ASO) to the brain and peripheral organs for HD. We demonstrate that apoA-I wild type (WT) and the apoA-I K133C mutant incubated with a synthetic lipid, 1,2-dimyristoyl-sn-glycero-3-phosphocholine, can self-assemble into monodisperse discoidal particles with diameters <20 nm that transmigrate across an in vitro blood-brain barrier model of HD. We demonstrate that apoA-I NDs are well tolerated in vivo, and that apoA-I K133C NDs show enhanced distribution to the CNS and peripheral organs compared to apoA-I WT NDs following systemic administration. ApoA-I K133C conjugated with HTT ASO forms NDs (HTT ASO NDs) that induce significant mHTT lowering in the liver, skeletal muscle and heart as well as in the brain when delivered intravenously in the BACHD mouse model of HD. Furthermore, HTT ASO NDs increase the magnitude of mHTT lowering in the striatum and cortex compared to HTT ASO alone following intracerebroventricular administration. These findings demonstrate the potential utility of apoA-I NDs as biocompatible vehicles for enhancing delivery of mutant HTT lowering ASOs to the CNS and peripheral organs for HD.

A randomized, controlled pilot study of positive affect treatment adapted for anorexia nervosa.

OBJECTIVE: Novel treatments for adults with anorexia nervosa (AN) are sorely needed. Although psychological interventions have been developed for AN, none have been identified as superior to one another or nonspecific treatments. Common comorbidities (e.g., mood and anxiety disorders) are rarely targeted in AN treatments, possibly impairing long-term clinical improvement. AN is associated with reward processing dysfunctions paralleling those identified in affective disorders; however, few treatments directly target these processes. METHOD: We adapted Positive Affect Treatment, a neuroscience-informed behavioral treatment developed for affective disorders, to the treatment of AN (PAT-AN). Adults with AN (N = 20) were randomized to 20 weeks of PAT-AN or waitlist to investigate the feasibility, acceptability, preliminary efficacy, and target engagement (on reward mechanisms) of PAT-AN. RESULTS: PAT-AN demonstrated strong retention (100%) and acceptability ratings (M = 5.67-5.95 on a 7-point scale). BMI (p = .006) and eating disorder symptoms (p < .001) improved over PAT-AN sessions. The PAT-AN group showed medium to large pre-to-post-treatment improvements in BMI, eating disorder symptoms and impairment, depressive and anxiety symptoms, and some reward indices (ds = .56-.87); changes were largely sustained at 3-month follow-up. Waitlist showed negligible changes (ds < .20) on nearly all measures. DISCUSSION: PAT-AN holds promise as an innovative treatment with capability to simultaneously improve eating disorder symptoms, affective symptoms, and underlying reward mechanisms. Findings should be interpreted cautiously due to small sample size and permitted concurrent enrollment in other treatments. Future, larger-scale research is warranted to establish the efficacy of PAT-AN. PUBLIC SIGNIFICANCE: This study provided a preliminary evaluation of Positive Affect Treatment for anorexia nervosa (PAT-AN), a novel, neuroscience-informed treatment aimed at increasing rewarding life experiences outside of one's eating disorder. Initial results suggest that PAT-AN is considered acceptable and may alleviate eating disorder, depressive, and anxiety symptoms. Therefore, this study presents promising data on a treatment that may hold potential for improving the lives of individuals with this disorder.

Causal discovery analysis: A promising tool in advancing precision medicine for eating disorders.

OBJECTIVE: Precision medicine (i.e., individually tailored treatments) represents an optimal goal for treating complex psychiatric disorders, including eating disorders. Within the eating disorders field, most treatment development efforts have been limited in their ability to identify individual-level models of eating disorder psychopathology and to develop and apply an individually tailored treatment for a given individual's personalized model of psychopathology. In addition, research is still needed to identify causal relationships within a given individual's model of eating disorder psychopathology. Addressing this limitation of the current state of precision medicine-related research in the field will allow us to progress toward advancing research and practice for eating disorders treatment. METHOD: We present a novel set of analytic tools, causal discovery analysis (CDA) methods, which can facilitate increasingly fine-grained, person-specific models of causal relations among cognitive, behavioral, and affective symptoms. RESULTS: CDA can advance the identification of an individual's causal model that maintains that individuals' eating disorder psychopathology. DISCUSSION: In the current article, we (1) introduce CDA methods as a set of promising analytic tools for developing precision medicine methods for eating disorders including the potential strengths and weaknesses of CDA, (2) provide recommendations for future studies utilizing this approach, and (3) outline the potential clinical implications of using CDA to generate personalized models of eating disorder psychopathology. PUBLIC SIGNIFICANCE STATEMENT: CDA provides a novel statistical approach for identifying causal relationships among variables of interest for a given individual. Person-specific causal models may offer a promising approach to individualized treatment planning and inform future personalized treatment development efforts for eating disorders.

The impact of social media use on body image and disordered eating behaviors: Content matters more than duration of exposure.

Social media use is rapidly expanding in terms of frequency, duration, and the diversity of platforms available. Given evidence for associations between social media use, body image disturbances, and disordered eating it is important to identify potentially harmful aspects of social media use that could serve as intervention targets. This study surveyed two demographically diverse undergraduate student cohorts in 2015 and 2022 to compare patterns in social media use, body image, and disordered eating behaviors between samples, including as a function of the COVID-19 pandemic, and to test the hypothesized moderating role of specific content consumed in the association between social media use and maladaptive outcomes. Participants in 2022 reported greater body image disturbances, more frequent vomiting and laxative use, and more time spent on a greater number of social media accounts, with significantly greater use of image-based platforms such as Snapchat, TikTok, and YouTube. Moderated regression analyses suggest that type of content consumed, but not the amount of time spent on social media or diversity of platforms utilized, is associated with body image disturbances and disordered eating behaviors after controlling for gender and body mass index. Specifically, exposure to weight loss content was associated with lower body appreciation, greater fears of negative appearance evaluation, and more frequent binge eating. Contrary to initial hypotheses, exposure to body positivity/neutrality content did not have protective effects. Findings suggest that interventions targeting negative consequences of social media use should focus on addressing content consumed, rather than time spent on social media platforms.

Urine Residual Volume in Normal Dogs Determined by Direct Measurement and Comparison to Two-Dimensional Ultrasonographic Measurement.

Normal urine residual volume (URV) in dogs has not previously been established by direct measurement. Twenty-two client-owned normal healthy dogs (8 female spayed, 12 male castrated, 2 male intact) without history of urinary abnormalities were included. Dogs were walked outside for 5 min to allow for natural voiding, immediately followed by urinary bladder ultrasound and urinary catheterization. The URV was recorded, and the ultrasound images were used to estimate URV for each dog. There was no significant difference between male and female URV; therefore, all data were pooled. With a 90% confidence interval, URV was 0-0.47 mL/kg with a mean URV of 0.21 mL/kg and a median value of 0.175 mL/kg. There was no significant difference between the measured URV and the ultrasound-determined URV. This case series supports previously established normal URV in the dog; however, a reference interval based on a larger population of dogs with further evaluation of body size/weight, sex, and neuter status is recommended to be established for use in clinical setting to differentiate normal urination from urinary retention in patients.

Identifying transdiagnostically relevant risk and protective factors for internalizing psychopathology: An umbrella review of longitudinal meta-analyses.

Internalizing mental disorders are highly comorbid with one another, and evidence suggests that etiological processes contributing to these disorders often overlap. This systematic umbrella review aimed to synthesize meta-analytic evidence from observational longitudinal studies to provide a comprehensive overview of potentially modifiable risk and protective factors across the depressive, anxiety, and eating disorder psychopathology domains. Six databases were searched from inception to August 2022. Only meta-analyses of longitudinal studies that accounted for baseline psychopathology (either via exclusion of baseline cases or statistical adjustment for baseline symptoms) were included. Methodological quality of meta-analyses was evaluated using the AMSTAR 2, and quality of evidence for each analysis was rated using GRADE. Study selection, quality assessment, and data extraction were conducted in duplicate by independent reviewers. The protocol for this review was registered with PROSPERO (CRD42020185575). Sixty-one meta-analyses were included, corresponding to 137 meta-analytic estimates for unique risk/protective factor-psychopathology relationships. Most potential risk/protective factors, however, were examined only in relation to depressive psychopathology. Concern over mistakes and self-esteem were the only risk and protective factors, respectively, identified as statistically significant across depressive, anxiety, and eating disorder psychopathology domains. Eight risk factors and four protective factors also emerged as having transdiagnostic relevance across depressive and anxiety domains. Results suggest intervention targets that may be valuable for preventing/treating the spectrum of internalizing psychopathology and reducing comorbidity. However, few factors were identified as transdiagnostically relevant across all three internalizing domains, highlighting the need for more research investigating similar sets of potential risk/protective factors across internalizing domains.

Exploring the contributions of affective constructs and interoceptive awareness to feeling fat.

PURPOSE: Feeling fat, a subjective feeling of being overweight that does not always correspond to actual body weight, is commonly reported in patients with an eating disorder. Research suggests that feeling fat relates to deficits in interoceptive awareness, the perception and integration of signals related to body states. Relatedly, recent work has linked feeling fat to affective constructs, such as depressive symptoms and guilt. The current study explores the unique relationships between feeling fat, self-reported, and objective IA, guilt, alexithymia, and depressive symptoms. METHOD: Female undergraduates (N = 128) completed the 11th item of the Eating Disorder Examination Questionnaire, the Toronto Alexithymia Scale, the Guilt subscale of the Positive and Negative Affect Schedule, and the Beck Depression Inventory-II. Participants also completed two IA measures: a heartbeat perception task and the Multidimensional Assessment of Interoceptive Awareness. RESULTS: All collected measures explained 56% of the variability in feeling fat. Depressive symptoms, self-reported IA, and BMI accounted for significant variability in feeling fat. Relative weights analyses revealed that depressive symptoms accounted for the most variability in feeling fat (19%). This finding remained significant after controlling for BMI, which also accounted for significant variability in feeling fat (25%). CONCLUSIONS: Our results replicate previous findings that depressive symptoms relate significantly to feeling fat and extend this work by incorporating the role of interoceptive awareness, guilt, and alexithymia. Endorsement of feeling fat during an intake assessment may alert clinicians to assess for depressive symptoms, and focusing on depressive symptoms in treatment may improve feeling fat. LEVEL OF EVIDENCE: Level I Evidence obtained from an experimental study.

Eating Disorder Examination-Questionnaire and Clinical Impairment Assessment norms for intersectional identities using an MTurk sample.

OBJECTIVE: There are limited data to guide the interpretation of scores on measures of eating-disorder psychopathology among underrepresented individuals. We aimed to provide norms for the Eating Disorder Examination-Questionnaire (EDE-Q) and Clinical Impairment Assessment (CIA) across racial/ethnic, gender, and sexual identities, and sexual orientations and their intersections by recruiting a diverse sample of Amazon MTurk workers (MTurkers; N = 1782). METHOD: We created a comprehensive, quantitative assessment of racial/ethnic identification, gender identification, sex assigned at birth, current sexual identification, and sexual orientation called the Demographic Assessment of Racial, Sexual, and Gender Identities (DARSGI). We calculated normative data for each demographic category response option. RESULTS: Our sample was comprised of 68% underrepresented racial/ethnic identities, 42% underrepresented gender identities, 13% underrepresented sexes, and 49% underrepresented sexual orientations. We reported means and standard deviations for each demographic category response option and, where possible, mean estimates by percentile across intersectional groups. EDE-Q Global Score for a subset of identities and intersections in the current study were higher than previously reported norms for those identities/intersections. DISCUSSION: This is the most thorough reporting of norms for the EDE-Q and CIA among racial/ethnic, sexual, and gender identities, and sexual orientations and the first reporting on multiple intersections, filling some of the gaps for commonly used measures of eating-disorder psychopathology. These norms may be used to contextualize eating-disorder psychopathology reported by underrepresented individuals. The data from the current study may help inform research on the prevention and treatment of eating-disorder psychopathology in underrepresented groups. PUBLIC SIGNIFICANCE: We provide the most thorough reporting on racial/ethnic, sexual, and gender identities, and sexual orientations for the Eating Disorder Examination - Questionnaire and Clinical Impairment Assessment, and the first reporting on intersections, which fills some of the gaps for commonly used measures of eating-disorder psychopathology. These norms help inform research on the prevention and treatment of eating-disorder psychopathology in underrepresented groups.

"Feeling fat," disgust, guilt, and shame: Preliminary evaluation of a mediation model of binge-eating in adults with higher-weight bodies.

"Feeling fat" is a subjective state that theoretically contributes to the maintenance of binge eating (BE). However, feeling fat, and its relation to BE among individuals with higher-weight bodies, has been infrequently studied. This study proposes a momentary-level model in which negative moral emotion states (disgust, guilt, shame) mediate the association between feeling fat and binge eating. In this study, 50 adults with higher-weight bodies (MBMI=40.3 ± 8.5 kg/m2; 84% female) completed a two-week ecological momentary assessment protocol, which measured experiences of feeling fat, emotion states, and binge-eating behavior. Univariate generalized linear mixed models (GLMM) evaluated the momentary associations among levels of feeling fat at Time 1, emotion states at Time 2, and binge eating at Time 2, controlling for Time 1 emotion states. GLMM results suggest that increases in each emotion from Time 1 to Time 2 mediated the association between Time 1 feeling fat and Time 2 binge eating. When modeled simultaneously within one multivariate multilevel structured equation model, disgust appeared to drive the relation between feeling fat and binge eating, over and above guilt and shame. Although preliminary, findings suggest increases in negative moral emotions, particularly disgust, mediate the feeling fat-binge eating association in adults with higher-weight bodies.

Disgust and Self-Disgust in Eating Disorders: A Systematic Review and Meta-Analysis.

Disgust and self-disgust are aversive emotions which are often encountered in people with eating disorders. We conducted a systematic review and meta-analysis of disgust and self-disgust in people with eating disorders using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The systematic review of the literature revealed 52 original research papers. There was substantial heterogeneity regarding the research question and outcomes. However, we found 5 articles on disgust elicited by food images, 10 studies on generic disgust sensitivity, and 4 studies on self-disgust, and we proceeded to a meta-analytic approach on these studies. We found that women with eating disorders have significantly higher momentary disgust feelings in response to food images (1.32; 95% CI 1.05, 1.59), higher generic disgust sensitivity (0.49; 95% CI 0.24, 0.71), and higher self-disgust (1.90; 95% CI 1.51, 2.29) compared with healthy controls. These findings indicate the potential clinical relevance of disgust and self-disgust in the treatment of eating disorders.

Cerebrospinal fluid mutant huntingtin is a biomarker for huntingtin lowering in the striatum of Huntington disease mice.

Huntington disease (HD) is a neurodegenerative disease caused by a trinucleotide repeat expansion in the HTT gene encoding an elongated polyglutamine tract in the huntingtin (HTT) protein. Expanded mutant HTT (mHTT) is toxic and leads to regional atrophy and neuronal cell loss in the brain, which occurs earliest in the striatum. Therapeutic lowering of mHTT in the central nervous system (CNS) has shown promise in preclinical studies, with multiple approaches currently in clinical development for HD. Quantitation of mHTT in the cerebrospinal fluid (CSF) is being used as a clinical pharmacodynamic biomarker of target engagement in the CNS. We have previously shown that the CNS is a major source of mHTT in the CSF. However, little is known about the specific brain regions and cell types that contribute to CSF mHTT. Therefore, a better understanding of the origins of CSF mHTT and whether therapies targeting mHTT in the striatum would be expected to be associated with significant lowering of mHTT in the CSF is needed. Here, we use complementary pharmacological and genetic-based approaches to either restrict expression of mHTT to the striatum or selectively deplete mHTT in the striatum to evaluate the contribution of this brain region to mHTT in the CSF. We show that viral expression of a mHTT fragment restricted to the striatum leads to detectable mHTT in the CSF. We demonstrate that targeted lowering of mHTT selectively in the striatum using an antisense oligonucleotide leads to a significant reduction of mHTT in the CSF of HD mice. Furthermore, using a transgenic mouse model of HD that expresses full length human mHTT and wild type HTT, we show that genetic inactivation of mHTT selectively in the striatum results in a significant reduction of mHTT in the CSF. Taken together, our data supports the conclusion that the striatum contributes sufficiently to the pool of mHTT in the CSF that therapeutic levels of mHTT lowering in the striatum can be detected by this measure in HD mice. This suggests that CSF mHTT may represent a pharmacodynamic biomarker for therapies that lower mHTT in the striatum.

Transmission from vaccinated individuals in a large SARS-CoV-2 Delta variant outbreak.

An outbreak of over 1,000 COVID-19 cases in Provincetown, Massachusetts (MA), in July 2021-the first large outbreak mostly in vaccinated individuals in the US-prompted a comprehensive public health response, motivating changes to national masking recommendations and raising questions about infection and transmission among vaccinated individuals. To address these questions, we combined viral genomic and epidemiological data from 467 individuals, including 40% of outbreak-associated cases. The Delta variant accounted for 99% of cases in this dataset; it was introduced from at least 40 sources, but 83% of cases derived from a single source, likely through transmission across multiple settings over a short time rather than a single event. Genomic and epidemiological data supported multiple transmissions of Delta from and between fully vaccinated individuals. However, despite its magnitude, the outbreak had limited onward impact in MA and the US overall, likely due to high vaccination rates and a robust public health response.

Beyond Description and Deficits: How Computational Psychiatry Can Enhance an Understanding of Decision-Making in Anorexia Nervosa.

PURPOSE OF REVIEW: Despite decades of research, knowledge of the mechanisms maintaining anorexia nervosa (AN) remains incomplete and clearly effective treatments elusive. Novel theoretical frameworks are needed to advance mechanistic and treatment research for this disorder. Here, we argue the utility of engaging a novel lens that differs from existing perspectives in psychiatry. Specifically, we argue the necessity of expanding beyond two historically common perspectives: (1) the descriptive perspective: the tendency to define mechanisms on the basis of surface characteristics and (2) the deficit perspective: the tendency to search for mechanisms associated with under-functioning of decision-making abilities and related circuity, rather than problems of over-functioning, in psychiatric disorders. RECENT FINDINGS: Computational psychiatry can provide a novel framework for understanding AN because this approach emphasizes the role of computational misalignments (rather than absolute deficits or excesses) between decision-making strategies and environmental demands as the key factors promoting psychiatric illnesses. Informed by this approach, we argue that AN can be understood as a disorder of excess goal pursuit, maintained by over-engagement, rather than disengagement, of executive functioning strategies and circuits. Emerging evidence suggests that this same computational imbalance may constitute an under-investigated phenotype presenting transdiagnostically across psychiatric disorders. A variety of computational models can be used to further elucidate excess goal pursuit in AN. Most traditional psychiatric treatments do not target excess goal pursuit or associated neurocognitive mechanisms. Thus, targeting at the level of computational dysfunction may provide a new avenue for enhancing treatment for AN and related disorders.

Ethnic/racial and gender differences in disordered eating behavior prevalence trajectories among women and men from adolescence into adulthood.

BACKGROUND: Disordered eating behaviors (DEB) are highly prevalent and are associated with negative long-term health outcomes. Extant research on DEB prevalence trajectories has predominantly focused on white women, thereby lacking both gender and ethnic/racial diversity, which may lead to preventive interventions that are not optimally timed for socially minoritized groups. The purpose of this study was to identify patterns in DEB trajectories from adolescence to adulthood across intersecting gender and ethnic/racial identities. METHODS: Participants (n = 1314) were from Project EAT (Eating and Activity in Teens and Young Adults), a population-based sample in the United States. Unhealthy weight control behaviors and binge eating were assessed across four waves at 5-year intervals. Gender-stratified generalized estimating equations (GEE) analyses were applied to examine ethnic/racial and gender differences in the prevalence trajectories of two forms of DEB (unhealthy weight control behaviors and binge eating). RESULTS: Hispanic/Latina young women reported heightened prevalence of unhealthy weight control behaviors and binge eating during adolescence (82.4% and 31.1%) relative to women with other ethnic/racial identities (44-70.2% and 8.8-18.2%) at any other developmental time point. Black/African American women reported linear increases in unhealthy weight control behaviors from adolescence (46.6%) to adulthood (65.5%), with nearly 20% greater prevalence relative to white women (44.6%) during adulthood. Among men, prevalence of unhealthy weight control behaviors was higher among Hispanic/Latinos (60.7-68.0%) and Asian Americans (41.9-56.7%) relative to Black/African American (24.6-36.9%) and white men (25.7-34.9%). Similarly, Hispanic/Latino young men reported up to ten or more times higher prevalence of binge eating during adolescence (22.8%) and adulthood (26.8%) relative to men from other ethnic/racial identities at any other time point (1.7-12.3%). CONCLUSIONS: Ethnic/racial disparities in DEB prevalence vary across development, DEB subtype, and by gender. Targeted preventive interventions, or interventions that address these different trajectories, that are optimally timed may reduce these disparities.

Gastrointestinal Interoception in Eating Disorders: Charting a New Path.

PURPOSE OF REVIEW: Abnormal interoception has been consistently observed across eating disorders despite limited inclusion in diagnostic conceptualization. Using the alimentary tract as well as recent developments in interoceptive neuroscience and predictive processing as a guide, the current review summarizes evidence of gastrointestinal interoceptive dysfunction in eating disorders. RECENT FINDINGS: Eating is a complex process that begins well before and ends well after food consumption. Abnormal prediction and prediction-error signals may occur at any stage, resulting in aberrant gastrointestinal interoception and dysregulated gut sensations in eating disorders. Several interoceptive technologies have recently become available that can be paired with computational modeling and clinical interventions to yield new insights into eating disorder pathophysiology. Illuminating the neurobiology of gastrointestinal interoception in eating disorders requires a new generation of studies combining experimental probes of gut physiology with computational modeling. The application of such techniques within clinical trials frameworks may yield new tools and treatments with transdiagnostic relevance.

Micro-level de-coupling of negative affect and binge eating in relationship to macro-level outcomes in binge eating disorder treatment.

BACKGROUND: While negative affect reliably predicts binge eating, it is unknown how this association may decrease or 'de-couple' during treatment for binge eating disorder (BED), whether such change is greater in treatments targeting emotion regulation, or how such change predicts outcome. This study utilized multi-wave ecological momentary assessment (EMA) to assess changes in the momentary association between negative affect and subsequent binge-eating symptoms during Integrative Cognitive Affective Therapy (ICAT-BED) and Cognitive Behavior Therapy Guided Self-Help (CBTgsh). It was predicted that there would be stronger de-coupling effects in ICAT-BED compared to CBTgsh given the focus on emotion regulation skills in ICAT-BED and that greater de-coupling would predict outcomes. METHODS: Adults with BED were randomized to ICAT-BED or CBTgsh and completed 1-week EMA protocols and the Eating Disorder Examination (EDE) at pre-treatment, end-of-treatment, and 6-month follow-up (final N = 78). De-coupling was operationalized as a change in momentary associations between negative affect and binge-eating symptoms from pre-treatment to end-of-treatment. RESULTS: There was a significant de-coupling effect at follow-up but not end-of-treatment, and de-coupling did not differ between ICAT-BED and CBTgsh. Less de-coupling was associated with higher end-of-treatment EDE global scores at end-of-treatment and higher binge frequency at follow-up. CONCLUSIONS: Both ICAT-BED and CBTgsh were associated with de-coupling of momentary negative affect and binge-eating symptoms, which in turn relate to cognitive and behavioral treatment outcomes. Future research is warranted to identify differential mechanisms of change across ICAT-BED and CBTgsh. Results also highlight the importance of developing momentary interventions to more effectively de-couple negative affect and binge eating.

Naturalistically assessed associations between physical activity, affective functioning, and binge eating among adults with binge-eating disorder.

Binge-eating disorder (BED) is associated with overweight/obesity, physical inactivity, and disturbances in affective functioning. While research suggests that physical activity (PA) may have beneficial effects on BED symptoms, little is known about the daily correlates of PA. As a first step in understanding the processes linking PA and binge eating, this study examined associations between PA (i.e., self-reported time engaged in moderate-to-vigorous PA), affective functioning (i.e., positive and negative affect, body satisfaction, emotion regulation), and eating-related cognitions and behaviors (i.e., craving, overeating, loss of control eating) measured via ecological momentary assessment (EMA). Adults with BED (N = 91) completed a seven-day EMA protocol during which they completed repeated measures of these variables. Results indicated individuals who reported greater time engaged in PA over the EMA protocol evidenced higher positive affect and body satisfaction, and lower overeating (between-subjects effects). No significant within-subjects effects were observed. Findings demonstrate that individual differences in PA levels were related to more adaptive affective functioning and eating regulation in daily life. Results highlight the relevance of PA in BED, and the need for future studies to identify the timescale of these relationships using objective measurements of PA.

The role of rumination and positive beliefs about rumination in eating pathology.

PURPOSE: General and eating disorder (ED)-specific ruminations have been identified as key factors that may contribute to eating pathology. Positive beliefs about rumination (e.g., "Ruminating helps me to prevent future mistakes") may impact this association. However, the effect of positive beliefs about rumination on the links between rumination and ED symptom severity has not been investigated. This study sought to clarify relations between rumination and ED symptom severity and to evaluate the potential moderating effect of positive beliefs about rumination on these associations. METHODS: During a laboratory visit, undergraduate participants (N = 473, MAge = 18.90 ± 2.27, MBMI = 23.45 kg/m2 ± 4.31, 54.8% female) completed an online battery of questionnaires assessing general and ED-specific ruminative processes (e.g., brooding, reflection), positive beliefs about rumination, and global ED symptoms. Hierarchical multiple regression analyses assessed the unique contributions of specific ruminative processes, and the moderating effect of positive beliefs on associations between ruminative processes and ED symptom severity. RESULTS: Hierarchical multiple regression results suggest that, after controlling for gender and BMI, ED-specific brooding, b = 1.32, SE = 0.13, ß = 0.46, p < 0.0001, and reflection, b = 1.44, SE = 0.33, ß = 0.19, p < 0.0001, accounted for unique variance in ED symptom severity. Moderation model results indicate that, at low levels of general reflection, b = - 0.06, SE = 0.02, ß = - 0.51, p = 0.003, and ED-specific reflection, b = - 0.15, SE = 0.03, ß = - 0.59, p < 0.0001, increased positive beliefs about rumination were associated with greater ED symptom severity. CONCLUSION: Findings suggest ED-specific rumination accounts for ED symptom severity above and beyond general rumination, and that rumination-related expectancies influence the association between reflection and ED symptom severity. LEVEL OF EVIDENCE: Level III, evidence obtained from a well-designed cohort study.

Eating disorders during the COVID-19 pandemic and quarantine: an overview of risks and recommendations for treatment and early intervention.

Individuals with eating disorders (EDs) are at significant risk for increases in symptomatology and diminished treatment access during the COVID-19 pandemic. Environmental precautions to limit coronavirus spread have affected food availability and access to healthy coping mechanisms, and have contributed to weight-stigmatizing social media messages that may be uniquely harmful to those experiencing EDs. Additionally, changes in socialization and routine, stress, and experiences of trauma that are being experienced globally may be particularly deleterious to ED risk and recovery. This paper presents a brief review of the pertinent literature related to the risk of EDs in the context of COVID-19 and offers suggestions for modifying intervention efforts to accommodate the unique challenges individuals with EDs and providers may be experiencing in light of the ongoing public health crisis.

Computational validity: using computation to translate behaviours across species.

We propose a new conceptual framework (computational validity) for translation across species and populations based on the computational similarity between the information processing underlying parallel tasks. Translating between species depends not on the superficial similarity of the tasks presented, but rather on the computational similarity of the strategies and mechanisms that underlie those behaviours. Computational validity goes beyond construct validity by directly addressing questions of information processing. Computational validity interacts with circuit validity as computation depends on circuits, but similar computations could be accomplished by different circuits. Because different individuals may use different computations to accomplish a given task, computational validity suggests that behaviour should be understood through the subject's point of view; thus, behaviour should be characterized on an individual level rather than a task level. Tasks can constrain the computational algorithms available to a subject and the observed subtleties of that behaviour can provide information about the computations used by each individual. Computational validity has especially high relevance for the study of psychiatric disorders, given the new views of psychiatry as identifying and mediating information processing dysfunctions that may show high inter-individual variability, as well as for animal models investigating aspects of human psychiatric disorders. This article is part of the theme issue 'Systems neuroscience through the lens of evolutionary theory'.