Numerous factors have been implicated as potential causes of bipolar disorder, and researchers continue investigating the specific reasons why this disorder develops. The results of one recent study, which was conducted by researchers from the University of Cambridge, Imperial College in London, and the National Institute of Mental Health (NIMH), furthers our understanding of this debilitating disorder and may have implications for future treatment options. When comparing bipolar brains to healthy brains, the researchers discovered differences in the chemical makeup of the bipolar brain.
The researchers studied postmortem brain tissue samples taken from the dorsolateral prefrontal cortex, an area of the brain that helps regulate executive functions, such as organization, decision-making, and memory. Using Nuclear Magnetic Resonance (NMR) spectroscopy, they analyzed samples both from patients who had had bipolar disorder and patients who had not had the disorder. When comparing the brain tissue, they found that concentrations of certain chemicals within the dorsolateral prefrontal cortex differed between the two groups. Bipolar brains showed higher levels of the neurotransmitter glutamate and lower levels of the neurotransmitter gamma-aminobutyric acid (GABA). These brains also had higher levels of the chemicals myo-inositol, which forms the structural basis for some signaling molecules, and creatine, which helps supply energy to cells.
In an effort to better understand why medications used to treat bipolar disorder are effective, the researchers also studied the effects of lithium and valproic acid on non-bipolar brains. Using rats, they found that the changes caused by these drugs in the non-bipolar rat brains differed from the chemical makeups observed in the bipolar brain. Glutamate levels, which were seen at high levels in the bipolar brain, were decreased in the rats given valproic acid. GABA, which was seen at lower levels in the bipolar brain, was increased in rats receiving lithium. Both myo-inositol and creatine were decreased in the rats taking these medications. These results provide evidence that lithium and valproic acid may work by correcting these chemical imbalances.
According to NIMH, 2.6% of the American population over the age of 18 grapples with the alternating highs and lows of bipolar disorder. Numerous reasons, both environmental and biological, could interact to result in bipolar disorder, and further research on the mechanisms underlying bipolar symptoms will be beneficial. With a clearer understanding of the environmental and biological factors associated with bipolar disorder, we may be able to develop more effective medications that target the specific factors involved.
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