CONCLUSIONS AND RELEVANCE: In this population-based cohort study including 392 098 mothers and 649 956 offspring, offspring from mothers with an eating disorder history or prepregnancy BMI outside normal weight were at higher risk of psychiatric disorders. The results differed somewhat between the 2 exposures with regard to which offspring diagnoses had associations, and effect sizes were typically larger for maternal eating disorders vs BMI. These findings suggest a need to consider these 2…