An individual with one or more specific genetic variants may have the potential to develop ADHD. But that potential may only be activated when conditions are ripe inside body cells, where genetic information is put to work. Gene expression is the technical term for the process by which the information encoded in one of these genes is used to direct the production of a protein in a cell. Proteins are needed for the structure and regulation of every tissue and organ in the body, including the brain. So the expression of certain genes affects the brain, and the brain influences behavior.
