An opinion is made based on a series of questions basically.
When I was seriously, deeply, clinically depressed, I was told by the examining Psychiatrist that I was "as sane as he was".
I still don't know whether that was a compliment.
And yes, at some stage I was about to commit suicide - but that is no longer a possibility.
And for those who doubt my intentions, I had written notes, rigged the rope, and was standing on the branch of the tree . . .
There were reasons for my contemplation, the depression was part of the result of those reasons - but not the whole cause.