In DSM-III, this category is called Atypical Depression
This is a residual category for individuals with depressive symptoms who cannot be diagnosed as having a Major or Other Specific Affective Disorder or Adjustment Disorder. Examples include the following:
- A distinct and sustained episode of the full depressive syndrome in an individual with Schizophrenia, Residual Type, that develops without an activation of the psychotic symptoms.
- A disorder that fulfills the criteria for Dysthymic Disorder; however, there have been intermittent periods of normal mood lasting more than a few months.
- A brief episode of depression that does not meet criteria for a Major Affective Disorder and that is apparently not reactive to psychosocial stress, so that it cannot be classified as an Adjustment Disorder.
In DSM-IV, this category is called Depressive Disorder Not Otherwise Specified
The Depressive Disorder Not Otherwise Specified category includes disorders with depressive features that do not meet the criteria for Major Depressive Disorder, Dysthymic Disorder, Adjustment Disorder With Depressed Mood, or Adjustment Disorder With Mixed Anxiety and Depressed Mood. Sometimes depressive symptoms can present as part of an Anxiety Disorder Not Otherwise Specified. Examples of Depressive Disorder Not Otherwise Specified include
- Premenstrual dysphoric disorder: in most menstrual cycles during the past year, symptoms (e.g., markedly depressed mood, marked anxiety, marked affective lability, decreased interest in activities) regularly occurred during the last week of the luteal phase (and remitted within a few days on the onset of menses). These symptoms must be severe enough to markedly interfere with work, school, or usual activities and be entirely absent for at least 1 week postmenses.
- Minor depressive disorder: episodes of at least 2 weeks of depressive symptoms but with fewer than the five items required for Major Depressive Disorder.
- Recurrent brief depressive disorder: depressive episodes lasting from 2 days up to 2 weeks, occurring at least once a month for 12 months (not associated with the menstrual cycle).
- Postpsychotic depressive disorder of Schizophrenia: a Major Depressive Episode that occurs during the residual phase of Schizophrenia.
- A Major Depressive Episode superimposed on Delusional Disorder, Psychotic Disorder Not Otherwise Specified, or the active phase of Schizophrenia.
- Situations in which the clinician has concluded that a depressive disorder is present but is unable to determine whether it is primary, due to a general medical condition, or substance induced.
This category applies to presentations in which symptoms characteristic of a depressive disorder that cause clinically significant distress or impairment in social, occupational, or other important areas of functioning predominate but do not meet the full criteria for any of the disorders in the depressive disorders diagnostic class. The unspecified depressive disorder category is used in situations in which the clinician chooses not to specify the reason that the criteria are not met for a specific depressive disorder, and includes presentations for which there is insufficient information to make a more specific diagnosis (e.g., in emergency room settings).