The impact of duration of illness on treatment nonresponse and drop-out: Exploring the relevance of enduring eating disorder concept.

OBJECTIVE There are no generally accepted definitions or markers of treatment nonresponse in eating disorders (EDs). The aim of this paper was to examine how the duration of illness and other potential prognostic markers impacted on nonresponse and drop-out from treatment across different EDs subtypes. METHODS A total sample of 1199 consecutively treated patients with EDs, according to Diagnostic and Statistical Manual of Mental Disorders, fifth edition criteria, participated in this study. Kaplan-Meier curves were calculated for each ED diagnosis in which the probability of recovery was plotted against the duration of illness. RESULTS Full remission was more likely for people with binge eating disorder (BED; 47.4%) and anorexia nervosa (AN; 43.9%) compared to bulimia nervosa (BN; 25.2%) and other specified feeding and EDs (OSFED; 23.2%). The cut-off points for the duration of the illness related with high likelihoods of poor response was 6-8 years among OSFED, 12-14 years among AN and BN and 20-21 years among BED. Other variables predicting nonresponse included dysfunctional personality traits. CONCLUSIONS Nonresponse to treatment is associated with duration of illness which is in turn associated with poor response to previous treatment. However, there was no evidence for staging the illness using specific duration of illness criteria. Nevertheless, the shorter temporal trajectory for OSFED suggests that early interventions may be of importance for this group.