I just found a great blog by Beyond Blue reader Lisa, “We Must Not Think Too Much” (which you can get to by clicking here) that covers a plethora of topics related to mental illness.
On her site was posted some excerpts from an article by sciencealert.com, on the controversy in psychiatric circles on when to classify grief that has gone on too long as a mental illness. The controversy is much like the debates that went on in the comments of my J.K. Rowling piece.
According to the article, which you can get to by clicking here:

Strong feelings of grief are normal and healthy after the death of someone you love but recent research from UNSW suggests that some people grieve for so long that it becomes a significant mental illness.
Estimates are that between 10 and 15 per cent of bereaved people experience an intense, prolonged sadness arising from longing or yearning for the deceased – so much so that their overall health is impaired, they withdraw socially, become depressed and even suicidal. As well, there’s growing recognition that traditional grief counselling may not help.
Happily, other recent findings suggest that such people can recover with treatment using Cognitive Behaviour Therapy, an approach already shown to be more effective than medication for a range of psychological problems, including anxiety and traumatic stress.
Now a team of Sydney researchers and counsellors is conducting further studies to evaluate the treatment more fully.