Sky what you just said here is so true, most people who are mentally unwell don't know it as those around them notice somethings not right, some do recognize it. Golly, there's people like my hubby who denies he has depression,anger, and a need to control, 3 therapists and one pdoc, told me he really needs some therapy, but he claims he's just fine, and never persued therapy.
Mental issues in a home can be devasting, I know I grew up in a home like that, my brother had many violent episodes,deep depressions,my parents fought, but my brother had no control, no way could he be responsible for this, he was mentally unwell, and back in the 60's there weren't good meds like today, just Lithium had been released in the US, and he's been with it for 30 plus years and then became responsible, keeping stable, etc. People need to understand some may be responsible and recognize their illness, while that is not always true for others, nothings black or white. And those suffering do not like all of this and are devastated just as much or more, than the so called "normal/stable" spouse,child, or friend. I agree with what Sky has posted in her reply.
Just my 2 cents