What Bipolar Disorder Is
Bipolar disorder, another name for manic depression, is a psychiatric illness that affects the brain and behavior. According to the Mayo Clinic, the cause of bipolar disorder is a bit of a mystery. It is thought, however, to be triggered by a combination of a few things. These include genetics, the environment--including stressors or the way one is raised--and changes in the brain. Bipolar disorder causes cycles of extreme ups and downs in mood, ranging from depression to mania.
Brain Chemicals and Bipolar Disorder
One of the possible causes of bipolar disorder is altered levels of neurotransmitters, chemicals that cause reactions in the brain. According to PsychCentral, neurotransmitters like serotonin and norepinephrine may be the culprits of bipolar disorder, as these chemicals are associated with different moods. Imbalances of certain neurotransmitters in the brain can cause the extreme mood changes associated with bipolar disorder, including severe depression and mania. However, a neurotransmitter imbalance is likely not the only cause of bipolar disorder. The Mayo Clinic reports that environmental factors or hormonal changes may trigger this imbalance.
Brain Changes in Bipolar Disorder
Another potential cause of bipolar disorder is an altered brain structure. It may sound strange, but the Mayo Clinic reports that images taken of the brains of people with bipolar disorder are often structurally different than the brains of healthy individuals. The National Institute of Mental Health reports that these structural changes are similar to those seen in people with other related mental health disorders, such as schizophrenia and multidimensional impairment. These changes in the brain's structure may begin to develop as early as childhood. In fact, the Mayo Clinic also reports that similar genetic factors are associated with both schizophrenia and bipolar disorder. Brain structure alone may not be the cause of bipolar disorder, but it can predispose a person to the mental illness.
Brain Changes During Mania and Depression
The ups and downs of bipolar disorder also affect the brain differently. A brain imaging study reported in the American Journal of Psychiatry reported that during periods of depression, the prefrontal cortex in the brain was shown to function abnormally in brain scan images. This was a dramatic change from the images of the brains of people in the manic phase of bipolar disorder, which showed an abnormally high metabolism throughout the whole brain.
Bipolar Disorder Brain Changes Over Time
Over time, bipolar disorder may permanently affect the brain. While this has not been studied to a great extent, the Society of Biological Psychiatry noted gradual differences in different brain structures in people with bipolar disorder. How these changes compare with the general population are not completely certain but are under investigation.
