I've noticed that there are several posters here who also take thyroid medication. I've read where thyroid (hyper or hypo) are usually linked to mental illness. Does anyone know why?

My 19 yo daughter was diagnosed with hypothyroidism after she attempted suicide and I had her committed. All her life she was overweight and they kept checking her for diabetes, but never thyroid testing. Turns out that thyroid issues are very common on her dad's side of the family.

Can anyone tell me their experiences with mental illness/weight issues/thyroid issues? Thanks so much