Epidemiology of Depression

Abstract

Investigations of abnormal behavior depend on various levels of observation. The description of actions and classes of actions results in the description of symptoms and syndromes that clinicians use for the characterization of a mental illness and the evaluation of the therapeutic action of drugs. To study neurophysiological mechanisms and relations between brain and behavior, it is necessary to shift to a finer level of observation and to observe processes which underlie actions (memory, attention, arousal, etc.). But, like any human behavior, abnormal behavior must also be considered from a higher-level viewpoint. Like economics and sociology, psychiatric epidemiology deals with large scale patterns of human activity.