Illness severity, treatment motivation and personality as predictors for the treatment outcome in adolescents and young adults with anorexia nervosa.

backgroundAnorexia nervosa (AN) is a severe psychiatric disorder with high chronicity, particularly affecting adolescents. Existing treatments for adolescents do not always lead to full recovery. Recently, the developmentally adapted Maudsley Model of Anorexia Nervosa Treatment for Adolescents (MANTRa) has emerged as a promising alternative, warranting investigation into its outcome predictors.

methodsThis secondary analysis is based on data from a multi-center cohort study conducted in several Austrian clinical settings. The study included 92 participants aged 13-21 years diagnosed with AN who received MANTRa (n = 45) or treatment-as-usual (TAU, n = 47). Statistical analyses focused on identifying baseline predictors and moderators of treatment success (change in eating disorder symptomatology) for the MANTRa and TAU groups at end-of-treatment and 18-month-follow-up. In addition to univariate linear regression models associating various predictor variables (BMI, eating disorder severity, depressive symptoms, weight suppression, illness duration, age of onset, motivation for change, and personality traits) with the long-term eating disorder outcome, we used a cluster analysis approach to categorize patients into high vs. low illness severity and "favorable" vs. "unfavorable" treatment motivation/personality profiles. Differences between clusters regarding treatment outcome were explored further.

resultsIn the MANTRa group, none of the examined baseline variables significantly predicted outcomes at 18-month follow-up in univariate models. In contrast, in the TAU group, higher initial eating-disorder psychopathology and lower motivation were associated with poorer outcomes. In MANTRa, there was a trend suggesting that patients with both high and low baseline illness severity, as well as those with unfavorable and favorable motivation/personality profiles, demonstrated sustained symptom reduction. By contrast, in the TAU group, sustained improvements were observed primarily among patients with low baseline illness severity and a favorable motivation/personality profile, whereas those with high illness severity and an unfavorable profile tended to show less benefit.

conclusionsThese results provide preliminary evidence for MANTRa as an effective, individualized treatment for adolescents with AN, including those exhibiting severe pathology, low baseline motivation and personality traits, e.g. low self-directedness, high harm avoidance and low cooperativeness. Future randomized controlled trials comparing MANTRa with established treatments are warranted to validate these findings and refine patient selection criteria.

trial registrationThe original trial was registered at clinicaltrials.gov (Identifier NCT03535714).