14.6 Mood Disorders: Clinical Features

Terminology Mood disorders are characterized by pervasive dysregulation of mood and psychomotor activity and by related biorhythmic and cognitive disturbances. The rubric of “affective disorder,” which in some European classifications also subsumes morbid anxiety states, is increasingly being replaced by the nosologically more delimited concept of “mood disorder.” Thus mood disorder is now the preferred term in both the World Health Organization's (WHO's) 10th revision of International Statistical Classification of Diseases and Related Health Problems (ICD-10) and the American Psychiatric Association's (APA's) fourth edition of Diagnostic and Statistical Manual of Mental Disorders (DSMIV). Official mood disorder categories in current use include bipolar disorders (with manic or hypomanic, depressive, or mixed episodes) and major depressive disorders and their respective attenuated variants known as cyclothymic and dysthymic disorders. Conditions that in earlier editions of these manuals were categorized as “endogenous depression,” “involutional melancholia,” and “psychotic depressive reaction” have been incorporated into major depressive disorder, whereas “depressive neurosis” has been largely absorbed by dysthymic disorder. Although the neuroticendogenous distinction has been officially deleted, the term “melancholic features” is now used to qualify major depressive disorders in which biological concomitants predominate. While both the American and international classifications recognize the common occurrence of mixed anxietydepressions, whether they should be classified with mood disorders or with anxiety disorders remains unresolved. It is equally uncertain how to classify the classic neurasthenic conditions, which have recently reemerged and overlap to some extent with the so-called chronic fatigue syndrome.