The Diagnosis of Depression
The term depression actually refers to a variety of depressive disorders. The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Revision (DSM-IV-TR) refers to major depressive disorder, dysthymia and depressive disorder not otherwise specified as three classifications of depression, determined by symptoms.
A formal diagnosis of depression is given when certain clinical features are present. These include a seriously compromised mood and at least four additional cognitive, behavioral, or physical symptoms that last all or most of the day, for at least two weeks. These symptoms must be sufficiently severe to cause personal distress or impaired functioning. Moreover, alternative causes for the symptoms such as bereavement, illness, medication or substance misuse must be ruled out. Once these factors have been taken into consideration a diagnosis of depression may be reached.
Other Depression Diagnoses
It is fairly common for people to present with depressive symptoms that do not fit the criteria for major depression or dysthymic disorder. Dysthymic disorder refers to a milder but still chronic form of depression. Where this occurs the person may fit within one of several residual categories known as depressive disorder not otherwise specified.
Depression Not Otherwise Specified
Premenstrual dysphoric disorder (PMDD) is characterized by the presence of five or more symptoms of depression during most menstrual cycles in a year. PMDD is just one example of a depressive disorder not otherwise specified. It is regarded as distinctly different to major depression, partly because of the pattern of depression and partly because of the responsiveness the person has to selective serotonin reuptake inhibitor (SSRI) medication. In PMDD, there is a substantially faster and more effective response to SSRIs, suggesting a distinctive biological base to depression.
Other examples include:
- Minor depressive disorder. At least two weeks of symptoms but with fewer than five required for major depressive disorder.
- Recurrent brief depression. Episodes of depression that last anywhere between two days to two weeks, occurring at least once a month for 12 months.
- Post-psychotic depression (PPD) which sometimes develops during the phase of remission in schizophrenia.
A Useful Category?
Questions have been raised by some professionals over the use of a category known simply as depressive disorder not otherwise specified. At best it provides a way of saying the person is effectively experiencing depression but they do not cross the somewhat arbitrary dividing line between not being depressed and being very depressed. At worst, the category represents a catch-all that is a kind of dumping ground because the person doesn’t neatly fit within some previously determined criteria for depression.
A counter argument points to some very clear examples of different types of depression that fall into this category. The fact that every type of depression does not attract its own unique diagnostic category does not mean it is less significant. Depressive disorder not otherwise specified, represents a way of looking at types of depression differently. To this end it acts as a class of depression that attracts a different approach to research which may indicate differences in terms of causation and possibly treatment.
Hammen, C & Watkins, E. (2008) Depression (2nd edition) Psychology Press.
Wasserman, D. (2006) the Facts: Depression Oxford University Press.