Psychiatric Comorbidity and Severity in Anorexia Nervosa: A Comparative Study of the DSM-5, the ICD-11, and Overvaluation of Weight/Shape Severity Ratings

Objective: This study assessed the rate of a.) the total and b.) specific psychiatric comorbidities among three severity ratings for Anorexia Nervosa (AN): DSM-5, ICD-11 and overvaluation of weight and shape (OWS). Method: The sample comprised 312 treatment-seeking patients with AN (mean age = 26.9). Weight and height were taken at intake to calculate BMI, the foundation for the DSM-5 and ICD-11 severity indices. The EDE-Q was used to assess OWS and the Mini International Neuropsychiatric Interview was conducted to assess psychiatric comorbidities Result: For the DSM-5, the mild severity group showed a higher total number of psychiatric comorbidity, especially for panic, social anxiety, generalised anxiety, and post-traumatic stress disorders compared to the severe and extremely severe groups. ICD-11 and OWS severity groups did not significantly differ in total comorbidities, except for major depressive disorder and obsessive-compulsive disorders being more prevalent in the "significantly low BMI" ICD-11 group. The high OWS group displayed a notably higher rate of major depressive disorder than the low OWS group. Discussion: The study underscores inconsistent patterns across the three severity systems, emphasising the need to recognise the current limitations of the assessed severity classification systems in AN assessment and guiding treatment.