Add-on effect of a brief internet-delivered emotion regulation intervention for eating disorders: a replicated single-case experimental design.

Emotion dysregulation is a potentially important process to target in eating disorder treatment. This study aimed to investigate whether emotion dysregulation may be improved in individuals with eating disorders using a brief online treatment designed specifically to increase emotion regulation skills. A replicated single-case experimental randomized AB-design was used to investigate the added effect of emotion regulation interventions (B phase), beyond the effects of eating disorder treatment focusing on normalization of eating and refrainment from compensatory behaviors (A phase). Twelve individuals with eating disorders were recruited from psychiatric outpatient services, and eight received an 8-week online treatment. The start of B phase in treatment (i.e. emotion regulation interventions) was randomized for each participant. Emotion dysregulation and negative affect were assessed every third day in both phases (20 assessments in total). Visual and baseline-corrected Tau analyses revealed short-term positive experimental effects on negative affect and emotion regulation for four participants, suggesting that emotion regulation interventions may be beneficial for some individuals. The study also demonstrated the feasibility and acceptability of delivering and evaluating treatment in this intensified online format, allowing for future detailed investigation of treatment processes and components at the intraindividual level.