It's a curious title, but this is the exact phrasing used in the Diagnostic and Statistical Manual of Mental Disorders; an agreed set of guidelines for diagnosis, for one of the three forms of unipolar depression. Within the DSM manual, unipolar depression is categorized as a major depressive episode, dysthymic disorder or "depression not otherwise specified." So, in this post I'd like to reveal just what's beneath this intriguing category.
The presence of depressive features can occur in a number of conditions. When the symptoms don't fall neatly into those seen in major depression or dysthymic disorder, it is quite likely they will fit with one of several other sub-categories. An example of this is premenstrual dysphoric disorder (PMDD), which is the presence, during most menstrual cycles in the last year, of five or more of the symptoms of depression. PMDD is considered to occur in as much as 8 percent of women. Symptoms of depression tend to recede a few days after menstruation. The current classification of PMDD is under scrutiny. There is some debate as to whether it is a mood disorder at all, or whether it is more appropriately considered an anxiety disorder. Some suggest that it is neither, and should be considered an entity in its own right.
Minor Depressive Disorder, or minor depression, includes at least two weeks of depressive symptoms but with fewer than the five required for major depressive disorder. According to current classification guidelines, one of the symptoms must be depressed mood or loss of interest or pleasure. People with minor depression tend to have more subjective symptoms such as self-blame, lethargy and irritability, and fewer physical or behavioral changes such as sleep disturbances or changes in appetite.
Recurrent Brief Depression, or Recurrent Depressive Disorder (RBD) refers to depressive episodes that can last anywhere from two days to two weeks, but which occurs at least one month in every 12. RBD has the same symptoms as Major Depressive Disorder (MDD) but is distinguished both by the duration of episodes (less than 14 days) and the frequency (approximately one episode per month). The episodes of depression should not fall at the same time as the menstrual cycle.
American Psychiatric Association. (2000). Diagnostic and statistical manual of mental disorders (4th ed., text rev.). Washington, DC: Author.