I haven't read the book, but it sounds like a very simplistic view of depression.
As others have said, there are several types, some in my own family.
I don't think bipolar - or manic depression - has been mentioned.
Or a type of depression in old age which could be chemically based (an aunt and an old male friend had this.)
Please hold my dear GD in your heart for a few days.
How can we thank the Fire Service?


