Outpatient interventions for adult anorexia nervosa typically have a modest impact on weight and eating disorder symptomatology. This study examined whether adding a brief online intervention focused on enhancing motivation to change and the development of a recovery identity (RecoveryMANTRA) would improve outcomes in adults with anorexia nervosa.

Participants with anorexia nervosa (n = 187) were recruited from 22 eating disorder outpatient services throughout the UK. They were randomised to receiving RecoveryMANTRA in addition to treatment as usual (TAU) (n = 99; experimental group) or TAU only (n = 88; control group). Outcomes were measured at end-of-intervention (6 weeks), 6 and 12 months.

Adherence rates to RecoveryMANTRA were 83% for the online guidance sessions and 77% for the use of self-help materials (workbook and/or short video clips). Group differences in body mass index at 6 weeks (primary outcome) were not significant. Group differences in eating disorder symptoms, psychological wellbeing and work and social adjustment (at 6 weeks and at follow-up) were not significant, except for a trend-level greater reduction in anxiety at 6 weeks in the RecoveryMANTRA group (p = 0.06). However, the RecoveryMANTRA group had significantly higher levels of confidence in own ability to change (p = 0.02) and alliance with the therapist at the outpatient service (p = 0.005) compared to the control group at 6 weeks.

Augmenting outpatient treatment for adult anorexia nervosa with a focus on recovery and motivation produced short-term reductions in anxiety and increased confidence to change and therapeutic alliance.