Dysthymia (also known as neurotic depression, is a mood disorder consisting of chronic depression, with less severe but longer lasting symptoms than major depressive disorder. The concept was coined by Dr Robert Spitzer (an editor of the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM-III)) as a replacement for the term "depressive personality" in the late 1970s.
According to the DSM's definition of dysthymia, it is a serious state of chronic depression, which persists for at least 2 years; it is less acute and severe than major depressive disorder. 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.