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.
Despite
its name, "atypical" depression is actually the most
common subtype of depression — 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 mental disorders,
defines Atypical Depression as a subtype of depression or dysthymia,
characterized by Atypical Features:
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 ("comfort
eating")
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.
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].
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. It is important to remember
that such co-morbid syndromes as panic disorder may not be fully
treated without additional medication.
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.
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.
