For more than two decades, Dr. David Kessler, a former Food and Drug Administration commissioner, has researched the ways tobacco and food control our actions. What fascinates him most is how these substances can override both reason and will, directing our behavior. He says the latest brain research indicates that the same neurological process that drives us to chain-smoke or over-eat is responsible for many mental illnesses. Diane talks with Dr. Kessler about how our minds become taken hold by certain triggers and thoughts and what we can do about it.