Key features of illness and treatment experiences in longstanding anorexia nervosa: qualitative descriptive study

Studies have consistently found that up to 20% of people with anorexia nervosa experience a persistent illness, resulting in considerable psychosocial impairment, morbidity and mortality. This has been variously termed severe and enduring anorexia nervosa or longstanding anorexia nervosa (L-AN). Conflicting findings have hindered progress in distinguishing the nosological features of individuals with persistent illness.

This study aims to investigate the putative defining features of individuals reporting symptoms of L-AN, including consideration of their treatment trajectory.

This cross-sectional study, drawing from a mixed-methods design, utilised a sample of symptomatic individuals who reported experiencing eating disorder treatment (n = 208). Several qualitative and quantitative data strands (a-c) were embedded within a single, self-report questionnaire measuring eating disorder severity and treatment experiences. Between-group comparisons were used to compare those of shorter (<3 years) and longer (>7 years) duration of illness.

No between-group differences were found in measures of severity, including body mass index (kg/m²), eating disorder symptom scores, psychological distress or perceived health-related quality of life. However, those with L-AN had a significantly higher number of mental and physical health comorbidities, longer treatment delay, greater number of episodes of treatment and poorer subjective ratings of their treatment experiences.

Delineating L-AN by severity may be inappropriate; anorexia nervosa of any duration is a severe illness. This study suggests that treatments, or lack thereof, may have an inadvertent impact on duration of illness. Future focus needs to be on reconceptualising L-AN and its treatments. Treatment refinements informed by lived experience are proposed.