ABSTRACT
This chapter is concerned with a theory of stable mental illness. It discusses a decision-making problem that psychiatry shares with general medicine. The chapter describes one important norm for handling uncertainty in medical diagnosis, that judging a sick person well is more to be avoided than judging a well person sick, and suggests some of the consequences of the application of this norm in medical practice. Decision rules in law, statistics, and medicine are compared to indicate the types of error are thought to be the more important to avoid and the assumptions underlying this preference. The chapter suggests that psychiatric diagnosis and treatment are influenced by the payoff for the psychiatrist as well as for the patient. In any type of medical decision, the use of the expected value equation may show the extent of the conflict of interest between the physician and patient and thereby shed light on the complex process of medical decision-making.
