Comorbidities in Mental Health

Comorbidities are 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 comorbid conditions include physical ailments such as diabetes, cardiovascular disease, cancer, infectious diseases, and dementia. Mental health conditions that tend to show comorbidity include eating disorders, anxiety disorders, and substance abuse.

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 with 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 health conditions in the same person.

Prevalence of Mental Health Comorbidities

It's common for people to be diagnosed with two disorders or conditions simultaneously. 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.

Large-scale studies suggest that comorbid mental health conditions are very common. Having one mental disorder can increase a person's risk of developing other mental health conditions.

Certain conditions may be associated with a higher risk of having a comorbid mental health condition. One study found that 75% of people with a high risk for psychosis also have a comorbid mental disorder. Disorders that commonly co-occurred in this population included depressive disorders, anxiety disorders, trauma-related disorders, and personality disorders.

Effects of Mental Health Comorbidities

Having two or more mental health conditions at the same time is associated with a range of issues. Research suggests that there is a strong relationship between comorbid mental disorders and:

• An increased risk of suicidal thinking
• An increased risk of suicide
• Worse symptom severity
• Lower social support
• Decreased quality of life
  

People who have comorbid mental health conditions tend to be less responsive to treatments and have a poorer prognosis. Research also suggests that having two or more comorbid disorders creates a higher demand for healthcare resources.

Diagnosing Comorbid Mental Health Conditions

Having two or more mental health conditions at the same time can make diagnosis more challenging. Doctors, therapists, and other healthcare professionals must get a clear picture of what a person is experiencing to determine if more than one condition might be causing a person's symptoms.

Some of the challenges that can occur include:

• Symptom overlap: Symptoms of mental health conditions can overlap, which makes it hard to differentiate between them. For example, people with bipolar disorder may also experience symptoms of depression and anxiety.
• Interactions: Symptoms of mental health conditions can interact, which can make diagnosing each condition more difficult. For example, a substance use disorder can worsen symptoms of many mental health conditions.
• Symptom reporting: People with comorbid mental health conditions may not always accurately report what they are experiencing. This can stem from difficulty explaining their symptoms, lack of insight into symptoms, or feelings of shame or embarrassment due to stigma.

Doctors and mental health professionals may use a range of tools and tests to accurately diagnose mental health conditions. These can include physical exams and lab tests to rule out medical conditions, psychological assessments, medical histories, and interviews.

How Mental Health Comorbidities Create Treatment Challenges

Overlap of medical conditions with psychiatric conditions is a significant challenge for healthcare professionals. 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 healthcare professionals offering treatment.

Having a comorbid psychiatric condition can also affect the success of treatments for substance use disorders. In one study, people who had psychiatric conditions were more likely to drop out or not complete their drug or alcohol treatment program.

Can Mental Health Comorbidities Be Prevented?

Healthcare professionals can play a role in preventing 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.

Keep in Mind

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.