Mania is as bad as it gets. If not treated, it will become worse, more frequent, and harder to treat.
'An Unquiet Mind' wasn't hard to write in terms of the actual writing of it.
People respond differently to people who are grieving. They reach out. But depression is so very isolating. It's hard to explain to anyone who has never been depressed how isolating it is. Grief comes and goes, but depression is unremitting.