Interpersonal, affective and compulsive features of driven exercise in anorexia nervosa

This preregistered (https://osf.io/g9ajb) analysis sought to integrate the current literature on trait compulsivity into maintenance models of driven exercise in anorexia nervosa (AN). We tested whether compulsivity increases the likelihood of driven exercise via interpersonal and affect-regulatory pathways.

We used multilevel structural equation modeling to test the hypothesis that trait compulsivity predicts a stronger within-person link between affect-regulatory difficulties or interpersonal sensitivity and driven exercise in female adolescents and adults with AN. We used data from five assessments across inpatient treatment and 6-months follow-up of 207 adult and adolescent patients with AN (1035 datapoints).

In line with our hypotheses, patients who generally experienced more affect-regulatory difficulties or stronger interpersonal sensitivity tended to engage in driven exercise more strongly. Moreover, high levels of trait compulsivity amplified the effect of interpersonal sensitivity on driven exercise across time. Contrary to our hypotheses, the link between affect regulation and driven exercise was not moderated by compulsivity. Similar effects on general eating disorder psychopathology were found, but no cross-level moderation effect of compulsivity.

Due to sample size, potential AN subtype-dependent effects were not analyzed.

Our results suggest that driven exercise coincides with self-reported experiences of interpersonal sensitivity and that this link varies as a function of compulsivity such that the within-person coupling is stronger among those scoring high on compulsivity. To derive clinically useful functional models of driven exercise, future studies might use intensive longitudinal data to investigate its momentary associations with affect and interpersonal sensitivity in the context of compulsive traits.