Maternal stress disorders and depression

It would be untrue to say that mothers do not love their children. But if you watch this video, it will make you wonder, what really happened to mothers as the world turns. Mothers have become killers.
http://www.youtube.com/watch?v=hmBlYhjdRyg&feature=related
The text below is from the video.


More than 600 mothers kill their children each year.

There are six major personality profiles of mothers who kill their children:-

1. The mentally ill mother
2. The retaliating mother
3. The depressed mother
4. The unwanted or unexpected mother
5. The merciful mother
6. The battering mother

What drove them to the breaking point?
Was it unintentional?
Was it done out of anger or frustration?
Are these mothers suffering with depression?
Or maternal stress disorders?

Are young mothers becoming so detached from their emotions and becoming unable to bond with their babies?