Comorbidity between eating disorders and psychiatric disorders

Previous literature has established an increased risk of eating disorders among individuals with other psychiatric disorders and vice versa. However, often studies have focused on eating disorders as a single diagnostic entity and/or investigated selected psychiatric comorbidities. We conducted a comprehensive study, exploring bidirectional associations between different types of eating disorders and broad groups of all other psychiatric disorders, to identify patterns of comorbidity.

We included all people born in Denmark 1963-2010. We collected information on eating disorders and considered the risk of subsequent psychiatric disorders using Cox-proportional hazards regression. Absolute risks were calculated using competing risks survival analyses. We also considered prior psychiatric disorders and subsequent eating disorders.

An increased risk was seen for almost all disorder pairs of diagnoses evaluated. Following an anorexia nervosa (AN) diagnosis, the median hazard ratio for the different subsequent psychiatric disorders was 3.80 (range 2.48-6.15); following an other eating disorder (OED) diagnosis, it was 3.16 (range 2.05-5.14). After different psychiatric disorder diagnoses, the median hazard ratio was 2.66 for later AN (range 1.21-5.31), and 2.51 for later OED (range 1.25-4.10). Absolute risk of eating disorders was also higher among those with other psychiatric disorders than those without.

In this broad examination, we identified bidirectional increases in risk of comorbidity for those with both eating disorder diagnoses and psychiatric disorder diagnoses. Although our findings indicate different patterns of comorbidity between eating disorders, these variations were generally small.