"What, me worry?"

This question, which has been asked by many, is now usually attributed to Alfred E. Newman, the poster boy of Mad Magazine. His face tells it all — a composite of attractive merriment and troublesome mindlessness. Who doesn't want to feel like smiling all the time? But at what price?

Psychiatrists know that some people have pathological forms of worry. There are names for this such as obsessive-compulsive disorder and generalized anxiety disorder; and treatments, such as psychotherapy and Prozac. But what about the rest of us? What is the optimal balance between worry and contentment? Should we all be offered some kind of training to help us achieve this optimal balance? And how should we apply our growing understanding of the brain mechanisms that control these feelings?

Samuel Barondes is a professor and director of the Center for Neurobiology and Psychiatry at the UC-San Francisco and author of Mood Genes: Hunting for Origins of Mania and Depression.