Effects of an Internet-based intervention for subthreshold eating disorders: a randomized controlled trial.

Background: Women reporting initial eating disorder (ED) symptoms are at highest risk for the development of an eating disorder. Preventive interventions should, therefore, be specifically tailored for this subgroup.

Aims: To adapt and evaluate the effects of the Internet-based prevention program "Student Bodies™" for women with symptoms of disordered eating and/or subthreshold eating disorder (ED) syndromes.

Method: 126 women, reporting subthreshold ED symptoms (high weight and shape concerns and below threshold bingeing, purging, chronic dieting or several of these symptoms) were randomly assigned to a Student Bodies™+ (SB+) intervention or a wait-list control group and assessed at pre-intervention, post-intervention, and 6-month follow-up. "Student Bodies™" was adapted to be suitable for subthreshold EDs. Main outcome measures were attitudes and symptoms of disordered eating. Pre-follow-up data were analyzed by ANCOVAS with mixed effects.

Results: At 6-month follow-up, compared to participants in the control group, participants in the intervention group showed significantly greater improvements on ED-related attitudes. Intervention participants also showed 67% (95% CI = 20-87%) greater reductions in combined rates of subjective and objective binges, and 86% (95% CI = 63-95%) greater reduction in purging episodes. Also, the rates of participants abstinent from all symptoms of disordered eating (restrictive eating, binge eating and any compensatory behavior) were significantly higher in the intervention group (45.1% vs. 26.9%). Post-hoc subgroup analyses revealed that for participants with binge eating the effect on EDE-Q scores was larger than in the pure restricting subgroup.

Conclusion: The adapted "SB+" program represents an effective intervention for women with subthreshold EDs of the binge eating subtype.