Atypical Depression (AD) is a subtype of Dysthymia and Major Depression characterized by mood reactivity — being able to experience improved mood in response to positive events. In contrast, sufferers of "melancholic" depression generally cannot experience positive moods, even when good things happen. Additionally, atypical depression is characterized by reversed vegetative symptoms, namely over-eating and over-sleeping. Melancholic Depression, or depression with melancholic features is a subtype of depression characterized by the inability to find pleasure in positive things combined with physical agitation, insomnia, or decreased appetite. ... Reversed vegetative symptoms refer to only oversleeping (hypersomnia) and overeating (hyperphagia), as compared to insomnia and loss of appetite (vegetative symptoms). ...

Despite its name, "atypical" depression is actually the most common subtype of depression[1][2] — up to 40% of the depressed population may be classified as having atypical depression.

Diagnostic criteria (DSM-IV-TR)

The DSM-IV-TR, a widely used manual for diagnosing sleeping disorders, defines Atypical Depression as a subtype of depression or dysthymia, characterized by Atypical Features: The Diagnostic and Statistical Manual of Mental Disorders, published by the American Psychiatric Association, is the handbook used most often in diagnosing mental disorders in the United States and other countries. ... Dysthymia (or dysthymic disorder) is a form of the mood disorder of depression characterized by a lack of enjoyment/pleasure in life that continues for at least two years. ...

A. Mood reactivity (i.e., mood brightens in response to actual or potential positive events:

B. At least two of the following:

1. Significant weight gain or increase in appetite
2. Hypersomnia (sleeping too much, as opposed to the insomnia present in melancholic depression)
3. Leaden paralysis (i.e., heavy, leaden feelings in arms or legs)
4. long-standing pattern of interpersonal rejection sensitivity (not limited to episodes of mood disturbance) that results in significant social or occupational impairment

C. Criteria are not met for Melancholic Depression or Catatonic Depression during the same episode.

By the ICD-10 classification, it will fall in the category of F32 or F39. Melancholic Depression, or depression with melancholic features is a subtype of depression characterized by the inability to find pleasure in positive things combined with physical agitation, insomnia, or decreased appetite. ... The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ...

Research

In general, atypical depression tends to cause greater functional impairment than other forms of depression. Atypical depression is a chronic syndrome that tends to begin earlier in life than other forms of depression — usually beginning in teenage years. Similarly, patients with atypical depression are more likely to suffer from other psychiatric syndromes such as panic disorder, social phobia, avoidant personality disorder, or body dysmorphic disorder. Atypical depression is more common in females — nearly 70% of the atypical population are women^{[citation needed]}. Panic Disorder is a psychiatric condition characterized by reccurring panic attacks in combination with significant behavioral change or at least a month of ongoing worry about the implications or concern about having other attacks. ... Social anxiety, sometimes known as social phobia or social anxiety disorder (SAD), is a common form of anxiety disorder that causes sufferers to experience intense anxiety in some or all of the social interactions and public events of everyday life. ... Avoidant personality disorder (APD or AvPD) [1] or Anxious personality disorder (APD) [2], is a personality disorder characterized by a pervasive pattern of social inhibition, feelings of inadequacy, extreme sensitivity to negative evaluation and avoidance of social interaction. ... Body dysmorphic disorder (BDD) is a mental disorder that involves a disturbed body image. ...

Medication response differs between chronic atypical depression and acute melancholic depression. While some studies^{[citation needed]} suggest that an older class of drugs, MAOIs, may be more effective at treating atypical depression, the modern SSRIs are usually quite effective, while the tricyclic antidepressants are not. In addition, SSRI response can often be enhanced with "booster" medications. And, medication treatment works best when combined with appropriate psychotherapy.[3] It is important to remember that such co-morbid syndromes as panic disorder may not be fully treated without additional medication. Monoamine oxidase inhibitors (MAOIs) are a class of antidepressant drugs prescribed for the treatment of depression. ... SSRI is an acronym that stands for several things: It is a class of antidepressants called selective serotonin reuptake inhibitor SSRI also is used as the stock symbol for Silver Standard Resources Inc. ... Chemical structure of the tricyclic antidepressant amitriptyline. ... SSRI is an acronym that stands for several things: It is a class of antidepressants called selective serotonin reuptake inhibitor SSRI also is used as the stock symbol for Silver Standard Resources Inc. ... Panic Disorder is a psychiatric condition characterized by reccurring panic attacks in combination with significant behavioral change or at least a month of ongoing worry about the implications or concern about having other attacks. ...

It has been noted that patients with atypical depression often suffer from intense cravings for carbohydrates. A mineral supplement, chromium picolinate, was found to assuage these cravings in one study, though the conclusion reached has not been replicated. Lactose is a disaccharide found in milk. ... Chromium picolinate is a bright red solid that is the chromium (III) salt of picolinic acid. ...

Some hypothesize that atypical depression may be related to thyroid dysregulation. Some studies have found subtle thyroid abnormalities in people with atypical depression. Another study suggests that patients may benefit from triiodothyronine, a medication used to treat hypothyroidism^{[citation needed]}. The thyroid hormones, thyroxine (T4) and triiodothyronine (T3), are tyrosine-based hormones produced by the thyroid gland. ... This article or section does not cite its references or sources. ...

References

1. Atypical Depression Actually Very Typical
2. Atypical Depression
3. Atypical Depression: Patient Information
4. Atypical Depression and Triiodothyronine
5. Atypical Depression and Hypothalamic-Pituitary-Adrenal function
6. Chromium treatment for cravings in atypical depression
7. A double-blind, placebo-controlled, exploratory trial of chromium picolinate in atypical depression: effect on carbohydrate craving.

Also see Clinical depression. Clinical depression (also called major depressive disorder, or unipolar depression when compared to bipolar disorder) is a state of intense sadness, melancholia or despair that has advanced to the point of being disruptive to an individuals social functioning and/or activities of daily living. ...