A: Kids love consistency and predictability. When things are more or less the same day in and day out it is just fine by them. So when changes happen in their lives it is common to see regression. This regression can take many forms, and angry and aggressive behavior, although common, is always challenging to deal with. Unfortunately, when young children experience multiple changes simultaneously, the effect can be even more intense. The remedy to this starts with doing the best you can to implement a daily routine that you can stick with now that the changes are behind you. The more consistent and predictable his life is from morning until night, the easier it will be for him to return to his previous level of behavior. Part of this process should include creating a structured reward system that you can use to frequently and consistently recognize, praise and reinforce desired behaviors. When a child is acting out frequently, this can be challenging to accomplish, but the single most effective way to increase positive behaviors is positive reinforcement. Of course, when you are seeing behaviors that are unacceptable, a system of consequences is also necessary. However, it is very important the consequences be proportional and instructive (rather than excessive and punitive). For an easy-to-implement and age appropriate parenting system, I strongly recommend 1, 2, 3 Magic, by Thomas Phelan. This book will provide insight into your son's experience of the world, how he learns, and how you can use both positive reinforcement and consequences to get your son back on track.