What Causes Mood Disorders ?

Mood disorders, such as bipolar disorder and depression, are among the most common mental health illnesses in the country. They’re characterized by drastic and often unpredictable changes in mood. This can include depression (prolonged periods of sadness or empty mood) or mania (periods of abnormally elevated moods or irritability). Some people may experience both types of episodes, while others may only experience one.

It’s estimated that around 21.4 percent of adults in the United States will experience a mood disorder at some point in their lifetime. There is no single known cause of mood disorders – but rather an interaction of different factors. These include genetic vulnerability, brain structure and chemistry, environmental events, and psychological factors.


Mood disorders tend to run in families, which points to an inherited trait. Studies with identical twins have shown that if one identical twin has a mood disorder, the other twin has a 70 percent likelihood of developing the condition as well.

However, just because you have a close relative with a mood disorder does not guarantee you’ll develop the disorder as well. Not everyone who has a family history of mood disorders will go on to develop the mental illness themselves. Similarly, not everyone diagnosed with a mood disorder has a family history of mental illness.

This shows that although genetic predisposition may play a significant role in the development of mood disorders, other factors are also involved.

Abnormalities in Brain Structure and Functioning

The brain is the command center for the entire body and affects everything from mood to emotional processing. It is made up of billions of cells that communicate with one another through electrical and chemical signals.

When these signals are disrupted, it can lead to changes in mood, thinking, and behavior. Brain imaging studies in people with depression have shown subtle abnormalities in brain structure and chemistry, which researchers believe could also play a role in the development of mood disorders.

Environmental Factors

It is not just the genes you inherit from your parents that can play a role in your risk for developing a mood disorder – it is also the environment you were brought up in. Research has shown that children who experience abuse, neglect, or trauma are more likely to develop mood disorders later in life. Stressful life events such as the death of a loved one, divorce, losing a job, and financial problems may also trigger the onset of mood disorders like depression or bipolar disorder.

Psychological Factors

Certain personality traits have been linked to an increased risk of developing mood disorders. For example, individuals with low self-esteem or who are overly self-critical may be more likely to develop depression. People diagnosed with other mental health disorders such as anxiety or substance use disorder are also at a higher risk for mood disorders.

The Takeaway

Mood disorders are complex illnesses that are caused by a combination of different factors, including genetics, brain structure and chemistry, environmental events, and psychological factors. Although you cannot entirely prevent mood disorders, knowing the risk factors can help you be more aware of your mental health and seek treatment early if necessary