Why are eating disorders the most deadly psychological illness?

Anything that under-: mines the physical body compromises the brain, which is directly connected (and forms a two-way communication with the body). The more something impacts the very mechanism that regulates survival, the more risk of death. Mental illness like anxiety, phobias don't have this impact as much. Major depression does, as does schizophrenia, and these death rates are higher, but not like ED's.