Leeat Granek and Meghan O’Rourke argue against reclassifying it as such in the new Diagnostic and Statistical Manual of Mental Disorders (DSM):
A group of psychiatrists have spearheaded a movement to include ongoing grief as a disorder, to be labeled “complicated” or “prolonged grief.” Others have proposed, separately, that a mourner can be labeled clinically depressed only two weeks after the loss of a loved one. The problem with both potential changes is that more people’s grief will be diagnosed as abnormal or extreme, in a culture that already leads mourners to feel they need to just “get over it” and “heal.”
We seem to be further and further away from the Victorian fetish of intense and long grief. Some kind of new balance is obviously desirable: grief is no more a disease than life itself. It requires living, not curing.