Indicated, Internet-based Prevention for Women With Anorexia Nervosa Symptoms: A Randomised Controlled Efficacy Trial (Preprint)

Abstract

While preventive interventions for eating disorders in general have shown promise, interventions specifically targeting individuals at risk for anorexia nervosa have not been evaluated.

To determine the efficacy of a guided, indicated, Internet-based prevention program for women at risk for anorexia nervosa (AN).

Randomized, controlled efficacy trial for women at risk for AN. Assessments at baseline (pre), post-intervention (10 weeks after baseline), 6-, and 12-month follow-up (FU). 168 women with low body weight (17.5≤BMI≤19) and high weight concerns, or with normal body weight 19<BMI≤25, high weight concerns and high restrained eating were recruited from three German universities as well as online, and randomized to Student Bodies-AN (SB-AN) or a waiting list control group (CG). Exclusion criteria were current DSM-IV full-syndrome AN, bulimia nervosa or binge eating disorder, serious medical or mental problems, such as current substance abuse, acute or chronic organic or schizophrenic psychosis, severe suicidal ideation or behaviour, no Internet access. Interventions: 1. Cognitive-behavioural, guided, Internet-based prevention program (SB-AN) over 10 weeks (IG); 2. Waiting list control condition (CG). Primary outcomes were clinically significant changes in attitudes and behaviours of disordered eating, and change in BMI in the underweight group of participants at 12-month follow-up. Secondary outcomes are new onset of eating disorders, symptoms of disordered eating, and associated psychopathology.

Data were available at post-intervention for N=137 women, and for N=116 women at 12-month FU. At 12-month FU, IGs participants showed larger decreases in EDE Total scores (79% vs. 57%) compared to the CG, and underweight IG participants also showed larger clinically relevant increases in BMI (49% vs. 32%) compared with underweight CG participants, but these differences were not significant. In addition, at post-intervention and 12-month follow-up, we found a significant increase in continuously measured BMI for underweight participants and significant improvements in attitudes and behaviours of disordered eating (e.g., restrained eating, weight and shape concerns). At all time points, rates of newly emerging ED onset cases were (non-significantly) lower in the IG compared with the CG and reductions in DSM-5-based ED syndromes were (non-significantly) higher in the IG compared with the CG.

SB-AN is the first preventive intervention shown to significantly reduce specific risk factors and symptoms for AN and shows promise for reducing full-syndrome AN onset.

ISRCTN70380261