* I am indebted to Larry Amsel of Columbia University for our discussions on this topic.

^A The Diagnostic and Statistical Manual of Mental Disorders is the go-to guide for identifying psychiatric illness. The current edition is the DSM-IV-TR (“TR” stands for “text revision”), and the DSM-V is in the works. The other major manual used by clinicians for the identification of psychiatric disorders is the International Classification of Diseases, known as the ICD-10.¹

^B In actuality, it can be difficult to differentiate the chest pain of a heart attack from the chest pain of indigestion without an EKG,⁵ which is why one should not try to diagnose oneself at home. Of course, this just underscores the issue of understanding the causes and mechanisms, rather than just the symptoms, and having clinical tests that can reliably differentiate those causes.

^C Except perhaps in Twin Peaks, where the owls are not what they seem.¹⁷