My 19 month ds has recently started hitting myself, dh and ds (8 years old). To begin with, he would do it without warning - if I was sitting down, he would walk up and smack my leg. More recently, he is doing it because he isn't getting the result he wants or we are invading his space a bit. I've noticed that he does it to me more than to his father and it's starting to get me down a bit. I had postnatal depression for the first few months so I can't help thinking that this is somehow linked to that. At other times, he a really sweet little boy, but once he gets in a grump, it's hard to do anything with him. At the moment I am telling him no firmly, but more often than not, he will do the same thing again He has managed to hurt our other ds by thwacking him with a toy.