Are there any existing cases where a person changes in behavior drastically after receiving a head injury? Like as big as a violent person becoming peaceful or as small as eating only when around people.
Typically head injuries make people more violent/agitated, not less. But yes, personality changes are a very common effect of a head injury.
The frontal lobe of the brain is the place that controls behavior, social concepts, etc. When that gets damaged, people tend to have less patience, and may not comprehend social rules or roles as well. They can get frustrated very easily, which can lead to lashing out. The injury doesn’t even have to be directly to the front of the head; if there’s bleeding inside the skull, it can put pressure on the frontal lobe and cause the changes.
I will say this…. docile or calmer behavior is almost never seen as a “bad thing,” so there’s definitely not as much written about how to “cope” with someone being calm.
I hope these references are helpful and help you make good stories!