From Nature:
Grey matter in the brains of people with bipolar disorder is destroyed with each manic or depressive episode. This was the finding of an MRI study of 21 patients with bipolar disorder, a mental illness marked by successive episodes of mania followed by deep depression. The patients’ brains were scanned at either end of a four-year period, during which time each patient had at least one episode and some as many as six. In all cases, the amount of grey matter in the temporal lobe and the cerebellum decreased compared to the grey matter in control subjects. These areas of the brain are associated with memory and coordination.
Patients that had suffered more episodes over the four years had the most marked difference in the amount of grey matter that had disappeared.
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