The American Psychiatric Association have published their new diagnostic guide (DSM 5) and according to quite a lot of people (just google it) they have classed grief as a type of depression. As far as I can tell (without actually buying a copy) this isn't actually true. What has happened is that they have removed the so-called 'bereavement exclusion' which said that major depressive disorder (aka depression) should not be diagnosed following a significant bereavement. They have also listed something called 'Persistent Complex Bereavement Disorder' as requiring further study.
Why does it make sense to remove this bereavement exclusion clause? Well, suppose you had got depression already and then a loved one died and you then sought medical help for your depression. You might not be able to get the treatment you needed because DSM-IV said you shouldn't be diagnosed with it and therefore your insurance company would not pay for your treatment. Maybe you didn't have depression before this event. Maybe you just had a tendency, or a past episode, or were just starting mild depression. Given that the causes of depression are not well understood, maybe you didn't have depression at all. The result would be the same. No DSM number, no drugs. As there don't seem to have been any other exclusions (such as job loss, divorce, or other severe stress) it makes sense (to me, at least) to remove this exclusion which might be preventing people who really need help from getting that help.
On the other hand, as there does seem to be a trend for doctors to overprescribe anti-depressants anyway, it does mean that there is now further potential to misdiagnose depressive disorders. Furthermore, evidence shows that many doctors end up prescribing as a way of ending consultations. Also, as all of this is taking place in the USA where prescription medicines can be advertised to the public (not allowed in the UK), there is a possibility that drug companies could target the recently bereaved, who will then go to their doctors demanding anti-depressants which they will be prescribed and which will not help them because they do not have depression, they are grieving. Due to the stigma attached to mental illness it might also mean that some people don't seek the support (by which I don't mean treatment) they need in their grief because they're afraid of the potential diagnosis. All of which begs the question: when did it stop being OK to be sad?
Or perhaps we are sadder than we used to be. With the loss of God from our culture, we have also lost the resurrection and life after death. Funerals are now termed 'celebrations of life' and even mentioning the deceased can be something of a taboo. Deciding whether to tell a friend or acquaintance that you are praying for them and their loved one presents itself as a dilemma (even if praying for them is the first thing you would do). A friend of mine told me recently that after agonising for some time, she decided to offer her condolences (and prayers) to a colleague whose father had died, with the awkwardness of trying to broach the subject with someone she didn't know that well compounded by the fact that everyone else in the department would fall silent as soon as he came into the room. Some time afterwards, he told her that she was the only person at work who had said anything at all to him.
We no longer seem to know that it's OK to be sad. It is wrong, and therefore pathological, an illness. And in a way, there is something 'wrong' in that sadness wasn't part of the original plan: sadness and grief, like death, are a consequence of moral and physical evil. We have no idea how to talk about death. We worry about exacerbating grief, making someone sadder, or causing offence or embarrassment (as if brief embarrassment on either side could really be worse than the death of a loved one?!). So here it is (for what it's worth), my opinion about being sad: it's OK to be sad. And this may be the key to telling the difference between grief and depression. Grief is not an illness, it is part of life, just as death is.