Major Depressive Disorder- A mood disorder characterized by persistent sadness and other symptoms of a major depressive episode. But without accompanying episodes of mania or hypomania or mixed episodes of depressive and manic or hypomanic symptoms. An occurrence of just one isolated depressive episode in a lifetime is now known to be relatively rare.
If two or more major depressive episodes occurred and were separated by at least 2 months during which the individual was not depressed, the major depressive disorder is noted as being recurrent. Recurrence is important in predicting the future course of the disorder, as well as in choosing appropriate treatments. Single-episode occurrences of major depressive disorder later experience a second episode. In the first year following an episode, the risk of recurrence is 20%, but rises as high as 40% in the second year.
Persistent depressive disorder (dysthymia) shares many of the symptoms of major depressive disorder but differs in its course. There may be fewer symptoms but depression remains relatively unchanged over long periods, sometimes 20 or 30 years or more.
Individuals who suffer from both major depressive episodes and persistent depression with fewer symptoms are said to have double depression. Typically, a few depressive symptoms develop first, perhaps at an early age, and then one or more major depressive episodes occur later only to revert to the underlying pattern of depression once the major depressive episode has run its course. Identifying this particular pattern is important because it is associated with even more severe psychopathology and a problematic future course.
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Diagnostic Criteria for Major Depressive Disorder.
A. At least one major depressive episode.
B. The occurrence of the major depressive episode is not better explained by schizoaffective disorder, schizophrenia, schizophreniform disorder, delusional disorder, or other specified and unspecified schizophrenia spectrum and other psychotic fidisorders.
C. There has never been a manic episode or hypomanic episode.
Note: This exclusion does not apply if all of the manic-like or hypomanic-like episodes are substance induced or are attributable to the direct physiological effects of another medical condition.
- Specify the clinical status and/or features of the current or most recent major depressive episode:
- Single episode or recurrent episode
- Mild, moderate, severe
- With anxious distress
- With mixed features
- With melancholic features
- With atypical features
- With mood-congruent psychotic features
- With mood-incongruent psychotic features
- With catatonia
- With peripartum onset
- With seasonal pattern (recurrent episode only)
- In partial remission, in full remission.
Additional Defining Criteria for Depressive Disorders.
In addition to rating severity of the episode as mild, moderate, or severe, clinicians use eight basic specifiers to describe depressive disorders. These are
1. Psychotic features (mood congruent or mood-incongruent)-
- Some individuals in the midst of a major depressive (or manic) episode may experience psychotic symptoms, specifically hallucinations (seeing or hearing things that aren’t there) and delusions (strongly held but inaccurate beliefs).
- Some may hear voices telling them how evil and sinful they are (auditory hallucinations). Such hallucinations and delusions are called mood congruent, because they seem directly related to the depression.
- Individuals might have other types of hallucinations or delusions such as delusions of grandeur (believing, for example, they are supernatural or supremely gifted) that do not seem consistent with the depressed mood. This is a mood-incongruent hallucination or delusion.
2. Anxious distress (mild to severe)-
- The presence and severity of accompanying anxiety, whether in the form of comorbid anxiety disorders (anxiety symptoms meeting the full criteria for an anxiety disorder) or anxiety symptoms that do not meet all the criteria for disorders.
- For all depressive and bipolar disorders, the presence of anxiety indicates a more severe condition, makes suicidal thoughts and completed suicide more likely, and predicts a poorer outcome from treatment.
3. Mixed features-
- Predominantly depressive episodes that have several (at least three) symptoms of mania as described above would meet this specifier, which applies to major depressive episodes both within major depressive disorder and persistent depressive disorder.
4. Melancholic features-
- This specifier applies only if the full criteria for a major depressive episode have been met, whether in the context of a persistent depressive disorder or not.
- Melancholic specifiers include some of the more severe somatic (physical) symptoms, such as early-morning awakenings, weight loss, loss of libido (sex drive), excessive or inappropriate guilt, and anhedonia (diminished interest or pleasure in activities).
- The concept of “melancholic” does seem to signify a severe type of depressive episode.
5. Atypical features-
- This specifier applies to both depressive episodes, whether in the context of persistent depressive disorder or not.
- While most people with depression sleep less and lose their appetite, individuals with this specifier consistently oversleep and overeat during their depression and therefore gain weight, leading to a higher incidence of diabetes.
- Depression with atypical features, compared with more typical depression, is associated with a greater percentage of women and an earlier age of onset.
6. Catatonic features-
- This specifier can be applied to major depressive episodes whether they occur in the context of a persistent depressive order or not, and even to manic episodes, although it is rare—and rarer still in mania.
- This serious condition involves an absence of movement (a stuporous state) or catalepsy, in which the muscles are waxy and semirigid, so a patient’s arms or legs remain in any position in which they are placed.
7. Peripartum onset-
- Peri means “surrounding”, in this case the period of time just before and just after the birth.
- This specifier can apply to both major depressive and manic episodes. Between 13% and 19% of all women giving birth (one in eight) meet criteria for a diagnosis of depression, referred to as peripartum depression.
- . A close examination of women with peripartum depression revealed no essential differences between the characteristics of this mood disorder and others.
8. Seasonal pattern-
- This temporal specifier applies to recurrent major depressive disorder (and also to bipolar disorders).
- It accompanies episodes that occur during certain seasons (for example, winter depression).
- The most usual pattern is a depressive episode that begins in the late fall and ends with the beginning of spring.
- This condition is called seasonal affective disorder (SAD).
Some of these specifiers apply only to major depressive disorder. Others apply to both major depressive disorder and persistent depressive disorder.
Reference,
David H. Barlow, V. Mark Durand. Abnormal Psychology, An Integrative Approach. (7th ed).