https://www.nature.com/articles/s41467-026-69218-1#Fig1

Shared Genetic Liability across Systems of Psychiatric and Physical Illness

ie, if you’ve got a brain disorder like depression or bipolar, you’re likely to also have a physical disorder like cardiovascular or IBS.

It’s already known that ASD/ADHD often co-occurs with gastrointestinal issues like reflux, coeliac and whatnot.