Divergent trajectories of positive affect following maladaptive and non-maladaptive exercise among individuals with binge-spectrum eating disorders

Subtypes of exercise are differentially associated with baseline eating disorder pathology and treatment outcome among individuals with bulimia nervosa

OBJECTIVE

Individuals with bulimia nervosa (BN) engage in both maladaptive (i.e., compulsive and/or compensatory) and adaptive exercise (e.g., for enjoyment). No research has examined whether those who engage in adaptive, compulsive, and/or compensatory exercise exhibit differences in BN pathology or treatment outcome compared to those not engaging in exercise, limiting intervention efficacy.

METHOD

We examined associations of baseline exercise engagement with baseline and posttreatment BN pathology among 106 treatment-seeking adults (Mage  = 37.4, SDage  = 12.95, 87.74% female, 68.87% White) enrolled across four clinical trials of outpatient enhanced cognitive behavioral therapy for BN (range: 12-16 sessions). Analysis of covariances examined associations between baseline exercise type and baseline/posttreatment global eating pathology, dietary restraint, loss-of-control (LOC) eating, and purging frequency.

RESULTS

Those engaging in only adaptive exercise reported lower global eating pathology compared to those engaging in compulsive-only exercise (Est = -1.493, p = .014, Mdiff  = -.97) while those engaging in baseline compulsive exercise reported less LOC eating compared to those not engaging in exercise (Est = -22.42, p = .012, Mdiff  = -12.50). Baseline engagement in compulsive-only exercise was associated with lower posttreatment global eating pathology compared to baseline engagement in no exercise (Est = -.856, p = .023, Mdiff  = -.64) and both compulsive and compensatory exercise (Est = .895, p = .026, Mdiff  = -1.08).

DISCUSSION

Those engaging in compulsive, compensatory, adaptive, and no exercise exhibit different patterns and severity of BN pathology. Future research is needed to position treatments to intervene on maladaptive, while still promoting adaptive, exercise.

PUBLIC SIGNIFICANCE STATEMENT

No research to date has examined whether those who engage in adaptive, compulsive, and/or compensatory exercise exhibit differences in BN pathology or treatment outcome compared to those not engaging in exercise, limiting targeted intervention efforts. We found that those engaging in compulsive, compensatory, and adaptive exercise exhibit different patterns of BN pathology and that adaptive exercise engagement was related to lower cognitive eating disorder symptoms at baseline.

A transdiagnostic and translational framework for delineating the neuronal mechanisms of compulsive exercise in anorexia nervosa

OBJECTIVE

The development of novel treatments for anorexia nervosa (AN) requires a detailed understanding of the biological underpinnings of specific, commonly occurring symptoms, including compulsive exercise. There is considerable bio-behavioral overlap between AN and obsessive-compulsive disorder (OCD), therefore it is plausible that similar mechanisms underlie compulsive behavior in both populations. While the association between these conditions is widely acknowledged, defining the shared mechanisms for compulsive behavior in AN and OCD requires a novel approach.

METHODS

We present an argument that a better understanding of the neurobiological mechanisms that underpin compulsive exercise in AN can be achieved in two critical ways. First, by applying a framework of the neuronal control of OCD to exercise behavior in AN, and second, by taking better advantage of the activity-based anorexia (ABA) rodent model to directly test this framework in the context of feeding pathology.

RESULTS

A cross-disciplinary approach that spans preclinical, neuroimaging, and clinical research as well as compulsive neurocircuitry and behavior can advance our understanding of when, why, and how compulsive exercise develops in the context of AN and provide targets for novel treatment strategies.

DISCUSSION

In this article, we (i) link the expression of compulsive behavior in AN and OCD via a transition between goal-directed and habitual behavior, (ii) present disrupted cortico-striatal circuitry as a key substrate for the development of compulsive behavior in both conditions, and (iii) highlight the utility of the ABA rodent model to better understand the mechanisms of compulsive behavior relevant to AN.

PUBLIC SIGNIFICANCE

Individuals with AN who exercise compulsively are at risk of worse health outcomes and have poorer responses to standard treatments. However, when, why, and how compulsive exercise develops in AN remains inadequately understood. Identifying whether the neural circuitry underlying compulsive behavior in OCD also controls hyperactivity in the activity-based anorexia model will aid in the development of novel eating disorder treatment strategies for this high-risk population.

Affective profiles of exercise episodes are associated with maladaptive and adaptive motivations for exercise

OBJECTIVE

Maladaptive exercise (i.e., driven and/or compensatory exercise) is common in binge-spectrum eating disorders (EDs; e.g., bulimia nervosa, binge ED) and associated with adverse treatment outcomes. Alternatively, individuals with EDs are often also engaging in adaptive exercise (e.g., for enjoyment or health improvement), and increasing adaptive exercise may decrease ED symptoms. The current study aimed to understand which exercise episodes are likely to be maladaptive/adaptive so that interventions can appropriately decrease/increase maladaptive and adaptive exercise.

METHOD

We used latent profile analysis (LPA) to identify pre-exercise affective profiles of 661 exercise episodes among 84 individuals with binge-spectrum EDs and examined associations between LPA-identified profiles and subsequent exercise motivations using ecological momentary assessment.

RESULTS

A two-profile solution best fit our data: Profile 1 (n = 174), 'positive affectivity,' and Profile 2 (n = 487), 'negative affectivity.' Episodes in the 'negative affectivity' profile were more likely to be endorsed as both driven and intended to influence body shape/weight. Episodes in the 'positive affectivity' profile were more likely to be endorsed as exercising for enjoyment.

CONCLUSIONS

Results support two phenotypes of exercise episodes, and differential associations of these phenotypes with adaptive and maladaptive motivations for exercise.