Reward responsivity and habit formation in the co-occurrence of restrictive eating and nonsuicidal self-injury.

Dysfunctions in reward and/or habit formation have been proposed as factors contributing individually to the maintenance of restrictive eating and nonsuicidal self-injury (NSSI). However, despite the high comorbidity between these behaviors, the associations between reward and habit formation in their co-occurrence remains unclear. This study examined self-reported reward responsivity and habit strength among individuals with co-occurring restrictive eating and NSSI (Comorbid group; n = 108) and those with one behavior only (One-behavior group; n = 113). Hierarchical logistic regression analyses assessed the association between reward and habit features and the co-occurrence of restrictive eating and NSSI, accounting for the effects of impulsivity (a characteristic commonly considered to underlie co-occurring disordered eating and NSSI). Partial correlations examined the relationships between these features and the severity of eating disorder and NSSI symptoms, also controlling for impulsivity. Lower reward responsivity was associated with the co-occurrence of restrictive eating and NSSI, even after accounting for impulsivity (p = 0.017). In exploratory analyses, this relationship was no longer significant after accounting for self-reported depression. No significant associations were found regarding habit formation and restrictive eating and NSSI co-occurrence. Lower reward responsivity was linked to increased NSSI frequency and versatility in both groups and associated with severity of eating pathology in the Comorbid group (ps < 0.05). Our findings suggest that blunted reward responsivity may relate to the co-occurrence of restrictive eating, NSSI, and depressive symptoms, as well as the severity of restrictive eating and NSSI. Reward disturbances may serve as a crucial target in the treatment of multiple self-destructive behaviors.

Naturalistic symptom trajectories of atypical anorexia nervosa, anorexia nervosa, and bulimia nervosa in a prospective cohort study of United States college students.

OBJECTIVE: Research on the natural course of symptoms of atypical anorexia nervosa (AN) relative to AN and bulimia nervosa (BN) is limited yet needed to inform nosology and improve understanding of atypical AN. This study aimed to 1) characterize trajectories of eating disorder and internalizing (anxiety, depression) symptoms in college students with and without a history of atypical AN, AN, and BN; and 2) compare sex and race/ethnicity distributions across groups. METHOD: United States college students who participated in Spit for Science™, a prospective cohort study, were classified as having a history of atypical AN (n = 125), AN (n = 160), BN (n = 617), or as non-eating-disorder controls (NCs, n = 5876). Generalized and linear mixed-effects models assessed group differences in eating and internalizing symptom trajectories, and logistic regression compared groups on sex and race/ethnicity distributions. RESULTS: Atypical AN participants demonstrated elevated eating disorder and internalizing symptoms compared to NCs during college, but less severe symptoms than AN and BN participants. Although all eating disorder groups showed signs of improvement in fasting and driven exercise, purging and depression remained elevated. Atypical AN participants showed increasing anxiety and stable binge-eating trajectories compared to AN and/or BN participants. The atypical AN group comprised significantly more people of color than the AN group. DISCUSSION: Findings underscore that atypical AN is a severe psychiatric disorder. As atypical AN may present as less severe than AN and BN and disproportionately affects people of color, clinicians should be mindful of biases that could delay diagnosis and care. PUBLIC SIGNIFICANCE: College students with histories of atypical AN, AN, and BN demonstrated improvements in fasting and driven exercise and stable purging and depression levels. Atypical AN students showed worsening anxiety and stable binge-eating trajectories compared to favorable changes among AN and BN students. A higher percentage of atypical AN (vs. AN) students were people of color. Findings may improve the detection of atypical AN in college students.

The explore/exploit trade-off: An ecologically valid and translational framework that can advance mechanistic understanding of eating disorders.

The explore/exploit trade-off is a decision-making process that is conserved across species and balances exploring unfamiliar choices of unknown value with choosing familiar options of known value to maximize reward. This framework is rooted in behavioral ecology and has traditionally been used to study maladaptive versus adaptive non-human animal foraging behavior. Researchers have begun to recognize the potential utility of understanding human decision-making and psychopathology through the explore/exploit trade-off. In this article, we propose that explore/exploit trade-off holds promise for advancing our mechanistic understanding of decision-making processes that confer vulnerability for and maintain eating pathology due to its neurodevelopmental bases, conservation across species, and ability to be mathematically modeled. We present a model for how suboptimal explore/exploit decision-making can promote disordered eating and present recommendations for future research applying this framework to eating pathology. Taken together, the explore/exploit trade-off provides a translational framework for expanding etiologic and maintenance models of eating pathology, given developmental changes in explore/exploit decision-making that coincide in time with the emergence of eating pathology and evidence of biased explore/exploit decision-making in psychopathology. Additionally, understanding explore/exploit decision-making in eating disorders may improve knowledge of their underlying pathophysiology, informing targeted clinical interventions such as neuromodulation and pharmacotherapy. PUBLIC SIGNIFICANCE STATEMENT: The explore/exploit trade-off is a cross-species decision-making process whereby organisms choose between a known option with a known reward or sampling unfamiliar options. We hypothesize that imbalanced explore/exploit decision-making can promote disordered eating and present preliminary data. We propose that explore/exploit trade-off has significant potential to advance understanding of the neurocognitive and neurodevelopmental mechanisms of eating pathology, which could ultimately guide revisions of etiologic models and inform novel interventions.

El balance entre explorar y explotar es un proceso de toma de decisiones que se conserva a través de las especies y equilibra la exploración de opciones desconocidas de valor desconocido con la elección de opciones familiares de valor conocido para maximizar la recompensa. Este marco está arraigado en la ecología del comportamiento y tradicionalmente se ha utilizado para estudiar el comportamiento de forrajeo no adaptativo versus adaptativo en animales no humanos. Los investigadores han comenzado a reconocer la utilidad potencial de entender la toma de decisiones humanas y la psicopatología a través del balance entre explorar y explotar. En este artículo, proponemos que el balance entre explorar y explotar ofrece promesas para avanzar en nuestra comprensión mecanicista de los procesos de toma de decisiones que confieren vulnerabilidad y mantienen la patología alimentaria debido a sus bases neurodesarrolladoras, su conservación a través de las especies y su capacidad de ser modelado matemáticamente. Presentamos un modelo de cómo la toma de decisiones subóptima entre explorar y explotar puede promover la alimentación disfuncional y presentamos recomendaciones para futuras investigaciones que apliquen este marco a la patología alimentaria. En conjunto, el balance entre explorar y explotar proporciona un marco translacional para expandir los modelos etiológicos y de mantenimiento de la patología alimentaria, dadas los cambios en el desarrollo de la toma de decisiones entre explorar y explotar que coinciden en el tiempo con la aparición de la patología alimentaria y la evidencia de una toma de decisiones entre explorar y explotar sesgada en la psicopatología. Además, comprender la toma de decisiones entre explorar y explotar en los trastornos alimentarios puede mejorar el conocimiento de su fisiopatología subyacente, informando intervenciones clínicas dirigidas como la neuromodulación y la farmacoterapia.

Not niche: eating disorders as an example in the dangers of overspecialisation.

Labelling specific psychiatric concerns as 'niche' topics relegated to specialty journals obstructs high-quality research and clinical care for these issues. Despite their severity, eating disorders are under-represented in high-impact journals, underfunded, and under-addressed in psychiatric training. We provide recommendations to stimulate broad knowledge dissemination for under-acknowledged, yet severe, psychiatric disorders.