Comorbidities in MDD

CME

Comorbidity Considerations in Major Depressive Disorder and Treatment Augmentation

Physicians: Maximum of 1.00 AMA PRA Category 1 Credit

Released: April 13, 2020

Expiration: April 12, 2021

Christoph U. Correll
Christoph U. Correll, MD

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Pathophysiology of Depression

The pathophysiology of depression is complex. Several risk factors are associated with depression, such as childhood adversity and socioeconomic disadvantage, sedentary lifestyle, smoking, poor diet, and poor self-care. Hence, an individual who is depressed might develop a sedentary lifestyle, poor diet, and poor self-care, might start smoking—which is more common in people who are depressed vs the general population—and might also start engaging in substance abuse and misuse, often as part of a self‑medication approach.1,2

We believe that psychiatric disorders follow a stress diathesis model. As part of the genetic and early behavioral risk factors, stress can lead to an increase in stress hormones, including cortisol, norepinephrine, vasopressin, and aldosterone, and these are related to an increase in cardiovascular risk, obesity, diabetes, and disruption of normal carbohydrate and lipid metabolism.2 Cardiovascular risk and cardiovascular disorders are associated with depression, and both depression and cardiovascular risk factors and morbidity are related to inflammation and neurodegeneration, which can also worsen depression.

This model slide depicts the intricate interrelationship between depression and interrelated risk factors for depression and cardiovascular illness, pointing toward the clinician’s need to (1) know about these different factors, (2) measure and diagnose them, and (3) address them.

MDD Is Common in Chronic Diseases

We know that people who have a chronic physical disorder are also prone to having depression.

The prevalence of major depressive disorder (MDD) in the general population within a certain period of time is 7%.3 By comparison, among individuals with a physical morbidity, depression is far more common.

Examples of common comorbidities associated with a higher prevalence of depression include Alzheimer’s disease, cardiovascular disease, coronary heart disease, cancer, Parkinson’s disease, and stroke.

We also know that patients with physical disorders who have depression as a comorbidity have poorer physical outcomes than patients with these chronic disorders who do not have depression.4 These patients with comorbid conditions tend to require more care, but also experience suboptimal treatment outcomes and increased mortality.