What is Comorbidity?

Article Details
  • Written By: Mary McMahon
  • Edited By: O. Wallace
  • Last Modified Date: 29 September 2019
  • Copyright Protected:
    Conjecture Corporation
  • Print this Article
Free Widgets for your Site/Blog
In 1961, the Kennedy family was given a puppy named Pushinka; her mother was one of the first Soviet space dogs.  more...

October 17 ,  1777 :  The British surrendered to US military forces in the Battle of Saratoga.  more...

Comorbidity is a term which is used to refer both to conditions beyond a primary medical condition of interest, and the consequences of interactions between multiple medical conditions. It is not uncommon for people to have multiple medical problems or diagnoses, and understanding how comorbidity works can be an important part of treatment. When something is said to be “comorbid,” it means that it is occurring in addition to something else.

Patients with cormorbidities can experience a variety of health problems. In addition to experiencing symptoms associated with each condition they have, they can also experience problems as a result of the interactions of the diseases. For example, someone with diabetes and cardiovascular disease could experience circulatory problems caused by the interactions of the two conditions, in addition to the actions of each condition independently.

Treating a patient with one or more comorbidities is challenging. Medications and treatments which are effective for one condition might exacerbate another, for example, or the approach to treatment might need to be adjusted to account for the patient's life expectancy. Using a system known as the Charlson comorbidity index, doctors can assign scores to the conditions the patient has and add them up to get an idea of the patient's expected lifespan. This information might be used when making decisions about treatment; for example, if a patient is likely to die of liver failure within six months, the costs of treating stomach cancer might not be worth it.


In psychiatry, cormorbidity is a common topic of discussion. Many people with mental illness have multiple diagnoses, reflecting the fact that their symptoms are varied and cannot be explained by a single diagnosis. Mental illness can also be a common problem in people with developmental disorders. Individuals with psychiatric comorbidities need treatments which address all of their diagnoses as a collective, rather than just looking at one. Treating depression alone, for example, will not be effective in a patient who also has an anxiety disorder.

Patients should discuss the implications of comorbidity with their doctors. They may need to take special care to address their conditions, or to observe precautions which other patients do not. Comorbidities should also be weighed when discussing treatment options, and patients should make sure that doctors are familiar with their complete medical history before discussing diagnosis and treatment, to ensure that errors are not made as a result of lacking access to important information about a comorbidity.


You might also Like


Discuss this Article

Post 4

Nerves of the brain and autonomic nervous system firing inappropriately can explain bipolar disorder comorbid with cardiovascular disease, diabetes, and/or thyroid disorders. A low blood calcium level can lower the trigger threshold of nerves such that they fire without appropriate stimulus.

Post 3

@fify-- Are you sure? I assumed that diseases which are comorbid don't have to be linked to each other because my younger brother also has bipolar comorbidity with attention deficit disorder. I asked his doctor if they are related, specifically if the attention deficit is caused by bipolar disorder and he said no.

Maybe it changes from individual to individual or maybe we don't know enough about all diseases to know if they are related or not. I guess we should say that comorbid diseases might or might not be related to one another until science proves us otherwise.

Post 2

@burcidi-- I think comorbidity is a little different than a medication for something resulting in another disease. Your mom might have comorbidity if her diabetes resulted from high blood pressure.

The way I think about comorbidity is that two or more diseases tend to appear together and might possibly be linked or resulting from one another. Like my sister who has depression and chronic migraines. There are studies which say that most depression patients also have migraines and vice versa. So depression and migraines are comorbid problems.

The same is said for bipolar disorder which has comorbidity with other psychotic disorders most of the time.

Post 1

What the article said is so true. Comorbidity makes treatment much more confusing and difficult. I've seen this in my family.

My mom for example has both high blood pressure and type two diabetes. She has to take separate medications for both daily. Sometimes when she's experiencing a lot of side effects, she gets confused as to which medication is causing it. And her circulation has definitely gotten worse since she also developed diabetes. She only had high blood pressure prior to that.

I've experienced comorbidity as well. I took an anti-anxiety medication for several years which was really hard on my stomach. It gave me acid-reflux and upset stomach. When I told my doctor about

this, he prescribed a proton pump inhibitor to treat the acid-reflux. But this medication also had a side effect, it caused iron deficiency when used in the long term. So then, I also had to take an iron supplement in addition to everything.

It was so chaotic, one thing led to the next which led to the next problem. I wish illnesses only came one at a time and medications had no side-effects so that we wouldn't have to deal with comorbidity.

Post your comments

Post Anonymously


forgot password?