In the first study to use 1H NMR spectroscopy to examine post-mortem brain tissue from patients with bipolar disorder, researchers have identified several molecular changes associated with the condition.

In the study, which is reported in February 5th issue of Molecular Psychiatry, senior author Dr. Sabine Bahn and colleagues compared the NMR spectroscopic findings with the brain changes seen in rats treated with mood stabilizers.

Dr. Bahn, from the University of Cambridge in the UK, and colleagues found that glutamate levels were elevated in the post-mortem brain tissue. In the animal study, treatment with valproate seemed to decrease the glutamate/glutamine ratio, while lithium therapy increased GABA levels.

Taken together, the authors note, these findings suggest that the balance of excitatory and inhibitory neurotransmission plays a key role in the pathophysiology of bipolar disorder.

Other findings included elevated brain levels of creatine and myo-inositol, which appeared to decrease with mood stabilizer therapy. Neither valproate nor lithium seemed to influence levels of N-acetyl aspartate, an important marker of neuron viability.

"These findings promise to provide new insight into the pathophysiology of bipolar disorder and may be used to direct research into novel therapeutic strategies," the investigators conclude.