[JohnMakin]

Mental illness is a testable set of clearly-defined symptoms that are diagnosed by a mental health professional. You are contributing to the stigma around mental illness when you toss that word around to describe something like a stupid/delusional belief. They aren't remotely the same.

[dragonwriter]

> Mental illness is a testable set of clearly-defined symptoms that are diagnosed by a mental health professional

For many mental illnesses, this is true only with a meaninglessly broad definition of “testable” and/or “clearly defined”.