In a new finding that appears to solidify the biological, genetic roots of bipolar disorder, researchers at the University of Michigan Health System have reported that patients with the disorder have about one third more monoamine-releasing cells in their brains than patients who do not have the illness.
In a study of 16 patients with the more severe type 1 disorder—but who had had no acute episodes of illness for more than 6 months—researchers used positron emission tomography scans to track a radioactive tracer that binds only to a protein that is contained in cells that release monoamines—dopamine, serotonin, and norepinephrine. They found that monoamine cell binding sites in the patients were 31% greater in the thalamus and 28% greater in the ventral brain stem than in healthy controls. In addition, the researchers conducted functional tests with the same patients that showed that higher levels of monoamine cells were associated with lower scores on tests of executive function and verbal learning.
Voelker R. Bipolar Brain Chemistry. JAMA. 2000;284(16):2048. doi:10.1001/jama.284.16.2048-JQU00008-3-1