Effects of Bipolar Disorder on the Brain

Bipolar disorder is a psychiatric disorder that is characterized by mood swings between depression and mania. Some people have predominantly manic symptoms, while others have predominantly depressive. Symptoms include severe mania, hypomania, normal mood, mild depression and severe depression in varying cycles and durations. Bipolar I, a severe form with rapid cycling, may include psychotic symptoms such as hallucinations and paranoid behavior.

Executive Function

• Executive function gives the ability to think, plan and act appropriately. Researchers (Altshuler et al.) at the Department of Psychiatry and Biobehavioral Sciences at UCLA studied men with psychiatric disorders, and those with bipolar disease had significant impairment of executive functioning and verbal memory. Impairment ranged from none in a small group to severe in another group.

Additional Cognitive Impairment

• Cognitive impairment interferes with the ability to reason. In "Psychiatry Times," Glahn and Velligan of the Department of Psychiatry of the University of Texas Health Science Center report that 75 percent of patients with bipolar disorder scored lower than healthy subjects in four measures of cognitive ability, including the ability to focus attention, manage execute function, and describe and retain long-term memories. Impairment of memory was similar among those who received treatment (lithium) and those who did not, suggesting that it is the disorder rather than the treatment that is responsible for cognitive impairment.

Gray Matter

• Gray matter is found throughout much of the brain and contains the functioning neurons (nerve cells) that control the flow of information in and out of the brain. Science Daily reports on a study in Madrid, led by Gregorio Maranon, where researchers used MRIs to study to volume of gray matter (nerve cells) in both healthy people and those with psychotic episodes during childhood or adolescence. Results showed that those with bipolar disorder, schizophrenia and some other psychoses had less gray matter in their brains. Age of onset of symptoms correlated with specific areas where loss of gray matter was more pronounced.

N-acetylaspartate

• Science Blog reports on a study at the San Francisco VA Medical Center, where researchers, led by Raymond Deicken, M.D., found that people with bipolar disorder have progressive damage to certain areas of the brain. They monitored an essential chemical (the amino acid N-acetylaspartate, or NAA) in the hippocampus area of the brain and found that a decrease in levels of NAA correlated with duration of illness. A low level of NAA suggests that there has been damage to neurons, impairing brain function. Similar findings are common in Alzheimer's disease and other neurodegenerative diseases, such as multiple sclerosis.

Neurotransmitters

• Neurotransmitters are substances that carry impulses from one neuron to another. A study published by the Imperial College of London in conjunction with the National Institutes of Mental Health reports that changes in the balance of neurotransmitters are specific to bipolar disease. Glutamate (an amino acid) levels increase with bipolar disease. The balance of chemicals was impaired in areas of the brain necessary for higher levels of cognitive function. Researchers found that drugs commonly used to treat bipolar disease (valproate, lithium) tend to reverse this imbalance, reducing symptoms.