Orthorexic tendencies in inpatients with mental disorders

Most research on orthorexia nervosa (ON)-the tendency to only eat foods that are perceived as healthy-has been based on non-clinical samples. Thus, we examined prevalence of and changes in orthorexic tendencies in a large sample of inpatients with mental disorders. Cross-sectional and longitudinal associations with body weight and eating disorder (ED) symptoms were tested in subgroups of inpatients with anorexia nervosa (AN) and bulimia nervosa (BN).

Inpatients (N = 1167) receiving disorder-specific treatment for disorders classified in the ICD-10 in F3, F4, or F5 completed the Düsseldorf Orthorexia Scale (DOS) at admission and a subset (N = 647) at discharge. ED patients completed the Eating Disorder Inventory-2 and their body weight and height was measured.

Prevalence of ON was higher in ED patients than in all other groups, in which prevalence rates were similar to findings from the general population. Across ED groups, DOS scores decreased from admission to discharge, while there was no change in the other groups. In patients with BN, higher DOS scores related to lower BMI and predicted larger decreases in body dissatisfaction. Across ED groups, higher DOS scores related to higher body dissatisfaction and drive for thinness and predicted larger decreases in drive for thinness.

Our results highlight that ON is part of the ED spectrum. Associations with core ED symptoms question the suggested exclusive health focus on eating in ON and its potential as a distinct diagnosis. Rather, ON may represent a phenomenological subtype of restrictive EDs.