Hi, My book on defiance looks at various causes of defiant behavior in children. The book helps parents identify the cause and then suggests strategies for each cause. My book on anger overload is a parent's manual focusing on children who have severe meltdowns--tantrums that can last for minutes or hours--but who otherwise behave well. The anger overload manual outlines specific strategies for you to try. For four year olds, I recommend parents focus on the first half of the book: the first two sections are "what is anger overload?" and "parents as the agent of change." The defiance book discusses anger overload but also other behavioral and personality issues. There is a section on bipolar disorder in children, which you may find helpful, for example. Yes, doctors do not usually diagnose and treat bipolar disorder in four year olds, because the brains of these children are still developing, and the children may develop better self control in the years to come. Also the medications for bipolar disorder can have significant side effects, and most are not approved yet for young children.
In the anger overload manual, I encourage parents to first observe the patterns, and if there are some situations that are more likely to trigger outbursts, I explain how to approach your child before he has an outburst. You can change the sequence of events, lower your child's expectations in advance, use "emotional" distraction (I explain in the book that the distraction technique must grab your child emotionally in order for it to work.), or sometimes calming techniques can help. Once your child is in overload, he is not thinking rationally and it is usually better not to say or do anything at that time, unless someone is being hurt. Sometimes consequences can help later in the day when he is calmer, particularly if he uses some words that are not acceptable in your house, or if he broke something. The consequence is not for anger overload per se, but for certain behaviors that you want to try to extinguish. I explain more about these topics in the book.
The last part of the anger overload book "teaching your child new skills" works better with older children--preteens and teens--however some young children benefit from using labels for the level of their anger. The idea of the labels is to help children begin to be aware they are angry before they lose it. Then they can be guided to use a calming technique before they explode. Sometimes a fun activity works better than a relaxation technique to help a child calm down, but neither usually works well once a child is already in overload. So you can see that the key is early intervention, when possible. Otherwise you wait out the storm and try to not respond to mean or hurtful comments a child typically makes during overload.
All the best, Dr. Dave Gottlieb