What is inbalanced in the brain when a person has Avoidant Personality Disorder?
I do not know of any research that has led the mental health profession to hold that avoidant personality disorder has to do with the brain. Personality disorders, in general, are not tied to organic issues of the brain, chemical imbalances or otherwise. This is why, for the most part, there are no prescription medicines for personality disorders. They are even difficult to treat with therapy, although it is possible to do so. Usually, some form of cognitive therapy – dealing with how people think – is how this is done.