““Virtually all the authors of popular books on the subject assert that ADD is a heritable genetic disorder. With some notable exceptions, the genetic view also dominates much of the discussion within professional circles, a view I do not agree with. I believe that ADD can be better understood if we examine people’s lives, not only bits of DNA. Heredity does make an important contribution, but far less than usually assumed. At the same time, it would serve no purpose to set up the false opposition of environment to genetic inheritance. No such split exists in nature, or in the mind of any serious scientist. There are many biological events involving body and brain that are not directly programmed by heredity, and so to say that ADD is not primarily genetic is not in any sense to deny its biological features — either those that are inherited or those that are acquired as a result of experience. The genetic blueprints for the architecture and the workings of the human brain develop in a process of interaction with the environment. ADD does reflect biological malfunctions in certain brain centers, but many of its features — including the underlying biology itself — are also inextricably connected to a person’s physical and emotional experiences in the world. There is in ADD an inherited predisposition, but that’s very far from saying there is a genetic predetermination. A predetermination dictates that something will inevitably happen. A predisposition only makes it more likely that it may happen, depending on circumstances. The actual outcome is influenced by many other factors.””
