Atypical Depression

Atypical Depression (also known as Major Depressive Disorder with atypical features in the DSM-5) is a subtype of depression characterized by mood reactivity (moods that are strongly reactive to environmental circumstances, and feeling extremely sensitive - this is a must have feature), hypersomnia, carbohydrate craving/increased appetite, leaden paralysis (profound fatigue), and chronic rejection sensitivity. Atypical depression results in more disability than melancholic depression, because individuals often have more interpersonal difficulties.

  • Atypical depression has a historical significance. It is called atypical depression to distinguish from the more classical melancholic or “endogenous” depression, when depression was rarely diagnosed in outpatients.
    • Atypical depression lacks the classic melancholic depression features such as insomnia, weight loss, loss of reactivity of mood. The DSM-5 diagnostic specifier “with atypical features” is also used in bipolar disorder.
  • The mood reactivity in atypical depression is the capacity to be cheered up when presented with positive events (e.g. - a visit from children, compliments from others). The individual's mood may become euthymic even for extended periods of time if the external circumstances remain favourable.
  • Increased appetite may be manifested by an obvious increase in food intake or by weight gain. Hypersomnia may include either an extended period of nighttime sleep or daytime napping that totals at least 10 hours of sleep per day (or at least 2 hours more than when not depressed).
  • Leaden paralysis is defined as feeling heavy, leaden, or weighted down, usually in the arms or legs. This sensation is generally present for at least an hour a day but often lasts for many hours at a time.
  • Unlike the other atypical features, pathological sensitivity to perceived interpersonal rejection is a trait that has an early onset and persists throughout most of adult life. Rejection sensitivity occurs both when the person is and is not depressed, though it may be exacerbated during depressive periods.
Comorbidity
  • Atypical depression is also associated with conduct disorder, social phobia, interpersonal dependency, low self-esteem, and parental substance abuse.[1] Atypical depression is also associated with higher rates of early childhood trauma, whereas melancholic depression is not.[2] This again suggests a difference in the etiology and pathophysiology of different depression subtypes.[3]

In addition to meeting the criteria for major depressive disorder, the following specifier criteria are required to make the diagnosis of atypical depression:

With atypical features

This specifier can be applied when these features predominate during the majority of days of the current or most recent major depressive episode or persistent depressive disorder.

  • A. Mood reactivity (i.e. - mood brightens in response to actual or potential positive events)
  • B. 2 or more of the following:
    • (1) Significant weight gain or increase in appetite
    • (2) Hypersomnia
    • (3) Leaden paralysis (i.e. - heavy, leaden feelings in arms or legs)
    • (4) A 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 “with melancholic features” or “with catatonia” during the same episode

Are atypical depression, borderline personality disorder, bipolar II disorder, and cyclothymic disorder overlapping conditions?

The common feature in all these diagnoses are emotional dysregulation and mood reactivity. The research hints that these disorders may all exist on a continuum.[4][5][6] Clinically, it can be challenging to distinguish between these disorders.
  • Atypical depression has a poor response to TCAs and ECT, but excellent response to MAOis, due to suspected elevated MAO activity that occurs in the disorder.[7][8]