An introduction to comorbidity – when you suffer with one or more illnesses or disorders at the same time.
We talk a lot about mental health, and often we talk about it as if it exists separately to physical health, or, as if one mental illness exists separately to another mental illness. But what happens when you suffer from more than one illness at the same time?
Comorbidity is when two or more disorders or illnesses manifest in the same person. They can present at the same time, or, one after the other. The term comorbidity also suggests a relationship between the illnesses, meaning that one could worsen or affect the other.
Comorbidity can be categorised into two different types – random and non-random. Random is when two or more illnesses occur by chance. For example someone may suffer from seasonal allergies in addition to having arthritis. In this instance, the comorbidity is purely coincidental – but does not necessarily mean the person does not suffer. Non-random comorbidity is where one illness or disorder may cause the other or vice versa. For example, if someone were to suffer with depression in addition to alcohol addiction. The question may be, did someone become addicted because they were depressed and used it to cope, or did they suffer from alcoholism and then as a result suffers from depression?
Comorbidity involving mental illnesses can be pretty common, with one study in the US (National Institute of Drug Abuse) suggesting that
“About half of people who experience a mental illness with also experience a substance use disorder at some point in their lives and vice versa”.
So why do disorders co-occur so often? Illnesses can sometimes share common risk factors, for example mental illness and substance abuse. They may share risk factors such as genetic – genes which increase susceptibility to either illness, or environmental, – experiencing significant stress or trauma which may give rise to the growth of mental illnesses or a substance abuse disorder. Additionally, mental illnesses may be risk factors for a substance abuse disorder. For example, some people who suffer with mental illness may use drugs or alcohol to self-medicate in the hopes that it may help cure their mental illness. Substance abuse may contribute to mental illness by changing the brain in ways that makes a person more susceptible and developing an addiction that somehow makes the individual feel their original symptoms are alleviated, but in actuality they are not. Therefore, it can worsen an already established mental illness, but also make one more likely to develop a mental illness.
If you think you may suffer from more than one illness, mental or physical, then please ensure you speak to your doctor and discuss with them all the symptoms you may have. It is important to understand that just as we humans are complex, so are illnesses, for each individuals – there is not one jar of mental and physical health issue but a mixture of, and many.