Bipolar disorder, also known as manic-depressive illness, is a brain disorder characterized by extreme mood changes. The exact cause of bipolar disorder in children is currently unknown, but scientists believe that it may be influenced by a variety of genetic, biochemical and environmental factors.

Biochemical

According to TeensHealth from Nemours, scientists believe that children suffering from bipolar disorder may have abnormal levels of neurotransmitters in their brains. The American Academy of Child and Adolescent Psychiatry also notes that manic-depressive children appear to use their brains differently than healthy children do.

Genetics

According to the American Academy of Child and Adolescent Psychiatry, genetics clearly play a role in causing bipolar disorder, as children who have a parent or sibling with bipolar disorder are four to six times more likely to also develop the disorder.

But Not Just Genetics

The American Academy of Child and Adolescent Psychiatry also points out, however, that genetics cannot be the sole cause of bipolar disorder, as studies on identical twins found that the twin of a person with manic-depressive illness only has a 70 percent chance of also developing the disorder. Other factors are clearly involved.

Environmental Factors

According to Merck, manic-depressive illness can sometimes be brought on by a traumatic event, such as a death in the family. As the American Academy of Child and Adolescent Psychiatry explains, however, an experience of trauma is not present in all cases.

Anxiety Disorders

While not a specific cause, the National Institute of Mental Health also notes that children who suffer from an anxiety disorder are more likely to develop bipolar disorder.

Source:

National Institute of Mental Health: Bipolar Disorder in Children and Teens

TeensHealth from Nemours: Bipolar Disorder

American Academy of Child and Adolescent Psychiatry: FAQs on Bipolar Disorder