Understanding atypical depression

Atypical depression (A-MDE) is a distinct subtype of major depressive disorder (MDD) that differs from classical depression in both its clinical presentation and biological markers. In this article, leading adult psychiatrist Dr Andrés Herane-Vives explains the signs and science behind atypical depression.

What are the signs of atypical depression?

Unlike typical depression, which is often characterized by persistent low mood and loss of interest, atypical depression features mood reactivity, meaning a person’s mood can improve in response to positive events. It is also associated with symptoms such as increased appetite and weight gain, excessive sleep (hypersomnia), leaden paralysis (a heavy, sluggish feeling in the limbs), and heightened sensitivity to rejection. These symptoms make A-MDE more chronic, difficult to diagnose, and strongly associated with anxiety disorders, particularly social anxiety and panic disorder.

Who can develop atypical depression?

Epidemiological studies estimate that atypical depression affects 15–40% of individuals with major depressive disorder and is more common in women, with a female-to-male ratio of approximately 2:1. It tends to present at a younger age than non-atypical depression and often persists for longer periods, making it a highly disabling condition. Several risk factors contribute to its development, including genetic predisposition, childhood trauma, chronic stress, metabolic disturbances (such as insulin resistance and obesity), and dysregulated cortisol secretion.

What are the biological and chemical indicators of atypical depression?

Dr. Andrés Herane-Vives and his team conducted a study investigating cortisol levels in individuals with A-MDE, non-atypical depression (NA-MDE), and healthy controls, measuring both short-term (salivary) and long-term (hair) cortisol levels. Their findings revealed that individuals with A-MDE had lower short-term cortisol levels in saliva compared to healthy controls, suggesting a blunted hypothalamic-pituitary-adrenal (HPA) axis response. However, long-term cortisol levels measured in hair did not significantly differ between groups, indicating that while overall cortisol exposure may remain stable, the daily regulation of cortisol is impaired in A-MDE. Additionally, the study found that A-MDE patients reported more daily stressors (“hassles”) than those with NA-MDE or healthy controls, and that mid-nocturnal insomnia was associated with lower cortisol levels, reinforcing the link between sleep disturbances and stress hormone dysregulation.

How can atypical depression be treated?

These findings provide important clinical implications. The altered cortisol pattern in A-MDE suggests that its pathophysiology is distinct from non-atypical depression, supporting the idea that A-MDE should be treated as a separate clinical entity. Furthermore, the strong association between A-MDE, metabolic disturbances, and sleep dysfunction highlights the need for a multidisciplinary treatment approach, incorporating psychotherapy, lifestyle interventions, and potential pharmacological treatments targeting both mood and metabolic regulation. Finally, the study underscores the importance of using both short-term (salivary) and long-term (hair) cortisol measurements to improve diagnostic accuracy and develop more personalized treatment strategies for individuals suffering from atypical depression.

To learn more about atypical depression, you can consult with Dr Herane-Vives via his Top Doctors profile