The Comorbidity of Two Disorders

Different minds.
Comorbidity means having more than one diagnosis. Getty / DrAfter123
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In simple terms, comorbidity refers to the presence of more than one disorder in the same person. For example, if a person is diagnosed with both social anxiety disorder (SAD) and major depressive disorder (MDD), they are said to have comorbid (meaning co-existing) anxiety and depressive disorders.

Other conditions that are seen to overlap include physical ailments such as diabetes, cardiovascular illness, cancer, infectious diseases, and dementia. Mental disorders that tend to show comorbidity also include eating disorders, anxiety disorders, and substance abuse.

The History of Comorbidity

The term comorbidity was coined in the 1970s by A.R. Feinstein, a renowned American doctor, and epidemiologist. Feinstein demonstrated comorbidity through the example of how people who suffered from rheumatic fever also usually suffered from multiple other diseases.

Since that time, comorbidity has come to be associated with the presence of multiple mental or physical illnesses in the same person.

Comorbidity Prevalence

It's not uncommon for people to suffer from two disorders or illnesses at once. Comorbidity in mental illness can include a situation where a person receives a medical diagnosis that is followed by the diagnosis of a mental disorder (or vice versa), or it can involve the diagnosis of a mental disorder that is followed by the diagnosis of another mental disorder.

A 2009 large cross-sectional national epidemiological study of comorbidity of mental disorders in primary care in Spain published in the Journal of Affective Disorders showed that among a sample of 7936 adult patients, about half had more than one psychiatric disorder.

Furthermore, in the U.S. National Comorbidity Survey, 51% of patients with a diagnosis of major depression also had at least one anxiety disorder and only 26% of them had no other mental disorder.

However, in the Early Developmental Stages of Psychopathology Study, 48.6% of patients with a diagnosis of major depression also had at least one anxiety disorder and 34.8% of them had no other mental disorder.

Treatment Challenges

Overlap of medical conditions with psychiatric conditions is a significant challenge for healthcare professionals and creates additional costs for the healthcare system.

For example, a person diagnosed with both diabetes and depression would be treated for both conditions, but consideration for overlap between medications and symptoms would need to be coordinated by the various health care professionals offering treatment.

If you live with multiple conditions or disorders, it is important that your doctor is aware of all medications and over-the-counter drugs you are taking, to ensure the risk of medication interactions is reduced.

Prevention of Comorbidity

Healthcare professionals also play a role in the prevention of comorbidity. For example, if a social anxiety disorder is left untreated for a long period of time, a person may also develop depression and/or substance abuse in response to the anxiety symptoms.

At a broader level, coordination between primary doctors and mental health professionals is key to preventing comorbid conditions. If you've been diagnosed with a physical and/or mental health condition, keep good records of the care that you receive from various professionals, so that each can be aware of the various treatments you are receiving.

A Word From Verywell

If you feel that you have symptoms of more than one mental disorder or those of a physical health condition in addition to a mental disorder, it is important to consult with your primary care physician or mental health professional to determine the best course of action. The unique combination of symptoms that you experience will determine whether medication and/or therapy is best for your situation.

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