My mother highly valued intelligence, and her way of putting down someone she saw as sub-par in the smarts department was saying, "He's no brain surgeon, I'll tell you that." But I, literally, am no brain surgeon, so to discuss this latest research I have to do one of those "let's start at the very beginning" Julie Andrews routines.
So, you've got a brain. So far, so good. And the brain has what is known as a limbic system. The limbic system is a set of structures that make up the inside of the cortex, which, in turn, is the tissue that is just outside [I know this is getting to be like "The House That Jack Built," but hang in there for just a few more moments] the cerebrum, which basically heads up your central nervous system. The limbic system is crucial in the experience of emotion--and memory, too, by the way.
Ok, one of those structures in the limbic system [and this is where I really wanted to get to] is known as the hippocampus. Essentially, it's part of the brain's mood center. And it's negatively impacted by stress, including the stress of bipolar episodes.
For years, brain autopsies on people with bipolar illness showed decreased density in the hippocampus. Additionally, a freshly published study entitled "Hippocampal Interneurons in Bipolar Disorder," published in the 2011 volume of the Archives of General Psychiatry compared brains of those with bipolar disorder to those of healthy control subjects. The abstract results are too wonderfully arcane to deprive you of, so here goes: "the bipolar disorder group showed reduced volume of the nonpyramidal cell layers, reduced somal volume in cornu ammonis sector 2/3, reduced number of somatostatin- and parvalbumin-positive neurons, and reduced messenger RNA levels for somatostatin, parvalbumin, and glutamic acid decarboxylase 1." Got it?
What they're really saying is that the hippocampus functions differently--and less well--in bipolar patients, partially due to reduced volume.
That being the case, it becomes of primary importance, if you're suffering from bipolar disorder, to take care of those hippocampal cells, and prevent whatever volume loss possible.
Despite our rather disheartening knowledge that there is brain atrophy in the bipolar nervous system, there is much cause for hope. A 2007 article showed that taking lithium increased volume in the paralimbic regions of the brain, and it has since been demonstrated that consistent treatment with adequate doses of antidepressants increases hippocampal volume, as well.
And, medication aside, we now get to return to one of my favorite topics, which is, as I've mentioned in other articles, exercise. Just to be clear--I firmly believe that bipolar disorder needs to be treated with a strict medicine regime, rigorously adhered to. I'm not a proponent of going all-natural, or organic, with such a serious illness.
However, in addition to whatever medicine your doctor has prescribed, exercise also holds much promise for not just slowing the shrinkage of the hippocampus cells-but actually reversing the process.
Numerous studies have found that 30 minutes of aerobic exercise three times a week will slow hippocampus volume loss in the elderly, thus working against age-related memory loss. A research study published in the Proceedings of the National Academy of Science entitled "Exercise Training Increases Size of Hippocampus and Improves Memory" found that the exercise impacted hippocampal volume so positively that it was the equivalent or reversing age-related volume loss by 1-2 years.
Schizophrenia is associated with hippocampal shrinkage to an even greater extent than bipolar disorder. Yet in a study of control-sample healthy men and men with schizophrenia entitled "Hippocampal Plasticity in Response to Exercise in Schizophrenia" in the February 2010 issue of the Archives of General Psychiatry, authors Frank-Gerald Pajonk et al found that cycling for 30 minutes 3 times per week increased hippocampal volume--for both groups, even the schizophrenics.