If you have a question then it's your unique question arising out of your own unique set of experiences. How can anyone else answer it? Even if one answers it it will not fully satisfy you because it's not 'your' answer.
It is neither a "brain" disorder or "mental" illness or even "psych" affliction. These all are just words. And the words prescribed by some "Doctors" can not define who you are.
We are a soul. And until we reach a place where we belong we will be beset with this sickening soul sickness.
But we always need a mortifying reminder to feel grateful for everything and everyone, WHY?
Why not be grateful and in awe despite the fact that we are mortals?