A Socially Assistive Robot for Outpatient Eating Disorder Waiting-List Support: A Mixed-Methods Feasibility Randomised Controlled Trial

Abstract

Objective

This feasibility randomised controlled trial (RCT) evaluated Purrble, a socially assistive robot for emotion regulation, as a low-intensity adjunct during waitlist periods in adult eating disorder services.

Method

Adults waiting for outpatient eating disorder treatment were randomised to four weeks of Purrble use or waitlist-as-usual. The primary outcome was emotion regulation, assessed with the Difficulties in Emotion Regulation Scale; secondary outcomes included sensory sensitivity, anxiety, depression, and motivation for change. Analyses were conducted using paired t-tests and linear mixed-effects models. Acceptability was explored via a qualitative survey.

Results

39 participants were enrolled in the trial and 37 participants were retained (19 Purrble, 18 control). A significant group × time interaction emerged for depression, with greater reductions in symptoms among Purrble participants. No significant interactions were found for emotion regulation, sensory sensitivity, motivation, or anxiety, though the Purrble group showed small-to-moderate improvements in emotion regulation, sensory sensitivity, and anxiety, and a significant within-group increase in motivation. Qualitative findings identified four categories: situational use during distress, sensory comfort and emotional connection, design limitations/barriers, and continued use with integration into self-care.

Conclusions

Purrble proved acceptable and feasible as a waitlist adjunct in adult eating disorder outpatient services. A significant between-group effect on depression and a within-group improvement in motivation provide preliminary support for a fully powered trial.