Depressive Disorder NOS
The classification of Depressive Disorder Not Otherwise Specified (or NOS) is applied to people whose depressive symptoms do not adequately fit all the necessary criteria for diagnosing any of the other DSM depressive disorders. For example, someone who has 4 or fewer depressive symptoms (including either depressed mood or loss of interest or pleasure) during a 2-week period could be diagnosed with Depressive Disorder NOS. At least 5 depressive symptoms must be present during that 2-week period before a major depressive episode or a Major Depression can be diagnosed.
Often, the diagnosis of Depressive Disorder NOS is used by clinicians as a preliminary label when they don't have much information about a person's history. As time passes and the pattern of mood episodes becomes clearer, the NOS diagnosis is usually discarded for a better fitting and more specific diagnosis such as Major Depressive Disorder or Dysthymia.
Someone who has a mood disorder superimposed on another disorder such as a delusional or psychotic disorder may also be classified as having Depressive Disorder, NOS. In other words, if someone has a delusional or psychotic disorder such as Schizophrenia, but also exhibits some signs of depression, they may receive two diagnoses at the same time: Schizophrenia, and Depressive Disorder, NOS.
Readers who are paying attention may recall that psychotic symptoms can also be associated with a Major Depression diagnosis, and wonder why it would be necessary to diagnose Schizophrenia separately, if this is the case. The answer to this apparent paradox has to do with whether or not psychotic symptoms are present only during a depressive episode or whether they occur independently of a depressive episode. Hallucinations and delusions that occur only in the context of a mood disorder can be summarized with the single diagnosis of Major Depression (or Depressive Disorder, NOS). Hallucinations and delusions that occur independently (in time) from depressive symptoms require a separate explanation; namely an appropriate diagnosis of a psychotic disorder, such as Schizophrenia. This rather complicated, we know, but we think it is also an important idea to communicate.
The diagnosis of Major Depression with psychotic features (e.g., hallucinations) is not necessarily the same thing as separate but independent diagnoses of both Major Depression and Schizophrenia. It can be difficult for clinicians to tease out the difference between these two cases because it takes some time to determine whether psychotic symptoms are independent from or dependent upon depressive symptoms. During the period of time when this information is unavailable, clinicians may use the diagnosis of Depressive Disorder NOS to suggest that there is some sort of depressive condition occurring, but they don't really understand the details yet.
Mood Disorder NOS
This category is used to describe situations where it is clear that some sort of mood disorder is occurring, but which specific disorder label to use is not yet known. Like Depressive Disorder NOS, this label is most typically used as a temporary or stop-gap diagnosis, which gets re-written into a more specific diagnosis as soon as the necessary information has been collected.
Mood Disorder NOS is a rather vague diagnosis, even for an NOS diagnosis. It is an order of magnitude more vague than either Depressive Disorder NOS or Bipolar Disorder NOS, both of which at least suggest that the mood problem observed is either unipolar in nature or bipolar (cyclical). It is possible that a diagnosis of Mood Disorder NOS might be re-written as Bipolar Disorder NOS, which in turn might be re-written as a more specific form of Bipolar Disorder as additional information about course, symptoms and severity become known.
Adjustment Disorder With Depressed Mood or Anxiety
An adjustment disorder is a severe emotional reaction to a stressor or multiple stressors (e.g., stressful life events other than someone's death) that can impact someone's feelings, thoughts and behavior. Someone with an Adjustment Disorder can experience significant impairment with regard to normal functioning, but this impairment typically does not last indefinitely.
The DSM criteria require that a person must develop symptoms within three months of the onset of the event(s) or stressor(s) to be diagnosed with an Adjustment Disorder. Events that trigger an Adjustment Disorder are often the same as those that can trigger a Major Depressive Episode, such as the termination of a romantic relationship or professional difficulties. Stressors are not always negative; life events such as getting married, retiring, or moving can also precipitate an Adjustment Disorder. In addition, the diagnostic criteria specify that a person's response is in excess of what would be normally expected. Finally, by definition, once the stressor has ended, a person's symptoms do not last more than an additional six months.
There are a variety of ways that people experience Adjustment Disorders. If a person with Adjustment Disorder is experiencing mostly depressive symptoms in response to the stressor, a diagnosis of Adjustment Disorder With Depressed Mood is appropriate. Similarly, a person with predominant anxiety symptoms such as nervousness or excessive worry will be given a diagnosis of Adjustment Disorder With Anxiety.
Since anxiety and depression can co-occur, monitoring for signs of a Major Depressive Episode is still important if someone has a diagnosis of an Adjustment Disorder. For example, an individual may have trouble dealing with going away to college, become very homesick and receive a diagnosis of Adjustment Disorder With Depressed Mood. If the depressive symptoms persist beyond six months or become more severe, the diagnosis may be re-written as Major Depression or Dysthymic Disorder as the symptoms and course warrant. Thus, Adjustment Disorder diagnoses, like NOS diagnoses, can be made on a provisional basis and replaced with more specific diagnoses when sufficient information to support those more specific labels becomes clear.