Depressed mood is a normal reaction to certain life events, a symptom of some medical conditions (e.g., Addison's disease, hypothyroidism), various medical treatments (e.g., hepatitis C drug therapy), and a feature of certain psychiatric syndromes.
Dysthymia, sometimes also called neurotic depression,dysthymic disorder, or chronic depression, is a mood disorder consisting of the same cognitive and physical problems as in depression, with less severe but longer-lasting symptoms.[1][2] The concept was coined by Dr. Robert Spitzer as a replacement for the term "depressive personality" in the late 1970s.[3]
According to the diagnosis manual DSM-IV of 1994, dysthymia is a serious state of chronic depression, which persists for at least 2 years (1 year for children and adolescents); it is less acute and severe than major depressive disorder.[4] As dysthymia is a chronic disorder, sufferers may experience symptoms for many years before it is diagnosed, if diagnosis occurs at all. As a result, they may believe that depression is a part of their character, so they may not even discuss their symptoms with doctors, family members, or friends.
Dysthymia often co-occurs with other mental disorders. A "double depression" is the occurrence of episodes of major depression in addition to dysthymia. Switching between periods of dysthymic moods and periods of hypomanic moods is indicative of cyclothymia, which is a mild variant of bipolar disorder.
The DSM-5, the 5th edition of the DSM, was released in May 2013 and includes a number of changes. In this edition, dysthymia is replaced by persistent depressive disorder. This new condition includes both chronic major depressive disorder and the previous dysthymic disorder. The reason for this change is that there was no evidence for meaningful differences between these two conditions.[5]