I listened to a radio program yesterday ,BBC world radio and it had an hour long talk about psychedelic drugs being trialled for mental illness particularly but not solely depression .The main subject was a man who had lost his mother and never managed to grieve and went into depression .I was travelling and could listen to nearly all of it and found it enlightening .
I found this link :-
Can psychedelic drugs and psychological support help tackle depression?
www.bbc.co.uk
Not what I listened to but probably better.