I was "gifted" with the same kind of brain as Macaydia's, and years of "living with" and therapy, as well as having worked in the field have led me to understand its a mixture of genetic and circumstance.
I do agree with the awfulness of being told "look on the bright side" "you ought to try and do this or that". I have told helpers eventually with some success, "^stop suggesting/piling on this or that^ - please just "walk with me". It comes out of people's desperate desiring to stop your pain, or is it theirs?
(Although just sometimes "suggestions" do help, but it has to be got right - like someone who is not aware of a support group or whatever that they might chose to take advantage of or not).
Some things have sunk in over the years for example
its not just me
- which is that many many people at some time in their lives have experienced a moment where you "could" self harm, be it anger or helplessness or despair, or utter exhaustion - or you experience feelings that life is pointless, "what is the point". (Unless you are very v. robust as a personality)
Its just not talked about, and this thread is very valuable as it's owning "that which we are not supposed to say".