So to the question, is it hereditary? First and foremost, I am not a geneticist, by any stretch of the imagination. However, due to my work as a psychotherapist, I have studied a lot of research about neuroscience and and the role of genes in human behavior. The most important takeaway is that genes do not operate in isolation (Rutter M. 2006.) Another way to put it is that there is always an interaction between the genes of a person and the person’s experience. So while personalities are certainly inherited, the behavior of a child or teen is a result of how the child’s personality interacts with his or her daily experiences.