[heurist]

Depression (and other forms mental illness) isn't as fatal as diabetes or cancer but it is fatal for many people and ruins the lives of even more.

[EvanKelly]

Depression (specifically Bipolar disorder, since it's the disorder I'm most educated on) is almost certainly as fatal as diabetes and more fatal than many forms of cancer.

1 in 3 sufferers of Bipolar disorder attempt suicide and 1 in 5 eventually die from suicide. Clinical depression is a very fatal disease.