I have an 11 year old son who was diagnosed w/ PDD-NOS (mild autism) when he was 6 years old. He's seen many professionals over the years and while they all agreed with the dx, they also all said that there just seemed to be something else that they couldn't put their finger on.
Anyhow, when he was younger it seemed as though he was perpetually angry. He no longer walks around with an angry expression, but he still has a quick temper. I know that tantrums aren't uncommon for kids on the spectrum, but he seems to believe that others are always angry with him or trying to manipulate him. He even believes this with his 3 year old sister. Innocent comments that aren't even always directed toward him will offend him and send him stomping off into another room. If someone walks in the room while he's speaking to someone, he'll stop speaking as he believes that the other person is just walking in the room to eavesdrop. He'll shut his schoolbooks if someone walks up to him while he's reading. If he's doing an activity, he also stops if someone approaches. He often believes that others have ulterior motives when doing everyday activities. Someone is loading the dishwasher just to distract him. Favorite foods are eaten so there won't be any left for him. People sneeze in the same room just to get him sick. He will lash out and hit, shove and kick his 13 year old sister when nobody is watching, but he doesn't lash out at others. For the most part, when he's upset, he will just try to seclude himself.
He isn't picked on at home. We don't use harsh language or shame him. He's not spanked, slapped or hit. He's not being bullied outside of the home as he attends an online school at home. I make sure that I greet him with a warm smile when he enters the room. (I'm the only one who he usually trusts isn't trying to upset him.) I gently explain why someone may be doing a certain behavior and let him know that it's not something directed toward him. He seems comforted immediately after my explanations, but 10 minutes later, something else happens and he's upset again.
Is this common in kids on the spectrum?