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What Causes Mental Illness?

Sep 29, 2021

Unfortunately, It’s not known exactly what causes mental illnesses; scientists are continuing research to better understand them, along with many other functions (and dysfunctions) of the human brain. 

“Diagnosing mental illness isn’t like diagnosing other chronic diseases. Heart disease is identified with the help of blood tests and electrocardiograms. Diabetes is diagnosed by measuring blood glucose levels. But classifying mental illness is a more subjective endeavor. No blood test exists for depression; no X-ray can identify a child at risk of developing bipolar disorder. At least, not yet.”

Kirsten Weir, The roots of mental illness, American Psychological Association

Mental illness affects the brain—a complex organ. Unlike other illnesses, such as COVID, where doctors can test for a specific outcome, there is not yet a biological way of testing for a mental illness. 

We do know, however, that there are a number of risk factors that make a person more likely to develop a mental illness—and when combined, can make an illness more likely and more serious.

Here are some of the most common risk factors:


Mental illnesses can run in families. That means that someone whose family member has a specific mental illness is often at a higher risk to develop that illness as well.

Genes can be turned on and off according to environmental inputs. For example, a stressful environment or event could trigger a mental illness in a person who was already more likely to develop it due to genetics. 

Brain Chemistry

Changes in the natural chemicals in the brain can cause disorders. Scientists believe many mental illnesses are caused by problems in the communications between neurons in the brain. 


Living in a stressful environment can be a risk factor for mental illness. Exposure to toxins, a stressful home life, living in poverty, poor nutrition, and other environmental factors can play a role. It’s difficult to thrive when your needs aren’t met.

Stressful Events

Living through traumatic events like abuse or the loss of a loved one can put you at a higher risk for mental illness. This may be due to the effects of stress on the brain.

Drug or Alcohol Abuse

Substance abuse is linked to triggering and making it difficult to recover from mental health conditions.

Though you may not know the cause of your illness, know that there is always hope for recovery. Mental illness is treatable. People can and do get better. If you are struggling, reach out to your primary care provider or a mental health professional today.

Guild Can Help

Guild is a team of professionals offering an array of mental health services. We individualize our approach to each client’s unique needs. Looking for mental health services? Contact our Community Access line at (651) 925-8490.



What Causes Mental Illness?, Mental Health America.

The Roots of Mental Illness, American Psychological Association.

Information About Mental Illness and the Brain, National Institutes of Health.

Causes of Mental Illness, WebMD.