Our results help us understand processes that underlie the common clinical observation of MDD and suicide in individuals with AN. They show that the comorbidity of AN and SA that require clinical care is largely due to genetic factors. This is in contrast to AN and MDD, where the unique environmental correlation is substantial. Second, our results are meaningful for clinical practice. Although caution must be engaged when transferring knowledge from the population to individuals, our results encourage clinicians to consider that shared biology could underlie the frequency with which suicide attempts occur in individuals with AN. As such, clinicians should screen for a family history of SA in individuals with AN, regardless of lifetime MDD status. These findings further underscore the seriousness of AN and alert clinicians to be vigilant for signs of suicide. Third, quantifying the contribution of genetic and environmental factors to AN, MDD, and SA lends evidence to explanatory models that account for their co-occurrence. Our models provide valuable insight into the association among these traits and to factors that contribute to the lethality of AN.
