What is Atypical Depression?

Depression is a unique experience for each individual, but sometimes it does not fit the standard mold. When it presents with distinctly different symptom patterns, depression may be labeled as atypical.

So what is atypical depression? Read further to learn what it is, its biological and functional features, and treatment options.

What Is Atypical Depression? Definition and Debate

Atypical depression was named a specifier for major depressive disorder in the American Psychiatric Association’s (APA’s) Diagnostics and Statistical Manual from 1994 (the DSM-IV). By that point, however, the definition of atypical depression had already been evolving for decades. While a single viewpoint has not yet been universally accepted, several aspects have been frequently tied to atypical depression. Estimates state that 15%-30% of people with depression present with purely atypical symptoms. And so, in spite of its name, atypical depression is actually not that uncommon.

Atypical Depression Symptoms

The main symptoms of atypical depression distinguish it from typical major depression, though the presentation may vary among individuals. They include:

• Mood Reactivity: An individual’s depressed mood can lift during positive situations, a departure from how mood presents in typical depression.
• Interpersonal Rejection Sensitivity: Individuals sensitive to social rejection may perceive, expect, or overinterpret social signals, leading to social or occupational impairment.
• Physical Symptoms: To qualify for the atypical diagnosis, an individual must have at least two physical symptoms, including hypersomnia, lethargy (also called leaden paralysis), increased appetite, or weight gain.

Mood reactivity and interpersonal rejection sensitivity are two key features often linked to atypical depression. However, other symptoms also present consistently, and a clear understanding of what causes atypical depression is not clearly understood. In light of this, there is some disagreement about what symptoms should be considered essential for diagnosis.

Early definitions of atypical depression highlighted mood reactivity and lethargy as defining symptoms. Later studies, though, implicated anxiety as a more distinctive feature than mood symptoms, with sensitivity to interpersonal rejection as a significant feature. Another proposal suggests that mood reactivity may not be a helpful criterion for atypical depression. Despite the debate, there is agreement that atypical depression is clinically valid.

Comorbidities

Anxiety disorders are often comorbid with atypical depression, particularly social anxiety disorder. Considering the disagreement surrounding the defining symptoms of atypical depression, this comorbidity is not surprising.

Atypical depression also appears to be associated with the following personal factors:

• Being female.
• Smoking.
• Social isolation.
• A sedentary lifestyle.
• Adverse life events.
• Chronic health conditions.
• Comorbid psychiatric conditions.

Biological and Functional Aspects of Atypical Depressive Disorder

As researchers further attempt to distinguish atypical depression, biological and functional differences have been revealed.

• Cognitive abilities, such as memory, executive function, and attention, seem to be more impaired in typical melancholic depression than atypical depression. The poorer functioning associated with a persistent low mood may be a key distinguishing factor.
• Brain scan analysis also shows differences in blood flow for various brain regions, with distinguished patterns for both typical and atypical depression. These abnormalities suggest higher levels of activity and processing in these regions, which may also be associated with symptoms.
• Low levels of the hormone leptin have been linked with obesity and atypical depression symptoms. The leptin hormone’s key function is to regulate the body’s energy reserves and appetite. It may also have the potential to regulate stress-induced depression and antidepressant response by influencing neurotransmitter activity.

Atypical Depression Treatment

Treatment guidelines for atypical depression are notably lacking. In the past, atypical depression was defined as MAOI-resistant, as it did not seem to respond well to monoamine oxidase inhibitors (MAOIs) antidepressants that were more widely used at the time.

As MAOIs are considered a rather effective antidepressant family, they are still sometimes prescribed to treat atypical depression. However, due to their significant adverse effects, they are usually given as a last resort.

In light of concerns over side effects, some patients and practitioners prefer treating atypical depression without drugs. One such alternative is cognitive behavioral therapy (CBT), a more pragmatic form of psychotherapy than its predecessors, whose efficacy can sometimes rival that of MAOIs.

Looking Ahead: Guidelines for Atypical Depression

Features of atypical depression are more common than its name suggests, but the question remains: what is atypical depression? With continued discernment of its biological and psychological underpinnings, a cohesive set of treatment guidelines for atypical depression may emerge over time. Until then, treatment outcomes may vary for each individual affected by atypical depression.