Introduction

Depressive disorders are categorized by the ways in which they exhibit criteria set down in the DSM-IV. These criteria refer to severity, associated symptoms and signs, duration, and identifiable stressors. It is important to recognize that, like many psychiatric diagnoses, the diagnoses of major depression, dysthymic disorder, and adjustment disorder with depressed mood are constructs that refer to signs and symptoms; they cannot (at present) be reliably correlated with an underlying pathophysiology. Despite this fact, effective treatments exist for depressive disorders, and a careful diagnostic assessment remains of primary importance for guiding treatment.