A nationwide Danish register study derived a severity index for 9,534 people diagnosed with anorexia nervosa and modelled its course, with polygenic scores available for 5,126. Three trajectories emerged, low and stable (32.6%), medium and stable (53.5%) and high increasing (14.0%), with each standard deviation of anorexia polygenic score corresponding to 13% greater odds of the high-increasing group. Pre-diagnosis psychiatric and somatic diagnoses did not distinguish the groups, while post-diagnosis morbidity did, with odds ratios of 1.73 to 3.81 for psychiatric and 1.61 to 5.38 for somatic conditions, and 0.27 for obesity.
Why it is interesting: It separates the course of a high-mortality psychiatric disorder into distinct groups, and finds the morbidity divergence only after diagnosis rather than before it.