For us we definitely saw a correlation with acting out and timing of him becoming a big brother. He was already going through a phase of acting out and testing limits but when he found out he was going to be a big brother all that behavior escalated a bit and was more frequent.

At this age they are too young to know how to deal with emotions of not being the center of attention. You almost can't reason with them because they don't act rationally and they just don't know how to deal with their emotions. I've been able to break through with him quite a bit by removing him from the escalating situations and talking to him and convincing him I'm trying to help. It's hard, and doesn't always work but when it does he actually calms down and will tell the truth about his feelings - much of which is related to his brother and some of it is us just not understanding his intent on his actions and reacting to something we think is bad.

In my son's case he's already a bit weird and my wife has on more that one occasion suggested he has autism because he won't eat certain foods, doesn't like loud noises, etc. I think he's unique and creative and has a big imagination like all kids do. I'm not interested in diagnosing him and making him a robot. It's tough at times but we take it day by day.