In any given 1-year period, 9.5 percent of the population, or about 18.8 million American adults, suffer from a depressive illness. The economic cost for this disorder is high, but the cost in human suffering cannot be estimated. Depressive illnesses often interfere with normal functioning and cause pain and suffering not only to those who have a disorder, but also to those who care about them. Serious depression can destroy family life as well as the life of the ill person. But much of this suffering is unnecessary.