Lithium is a salt which treats both mania and depression in a lucky thirty percent of people with bipolar disorder. But prior to the discovery of a new method to predict who will respond to lithium, people were playing roulette.
Now scientists at the Salk Institute can predict, with 92 percent accuracy, who will be a lithium responder. All they need is five cells and a test. They discovered that the neurons of people with bipolar disorder are more excitable when exposed to stimuli and fire more rapid electrical impulses than individuals without the disorder. This means that people with bipolar are more easily stimulated.
In an old study, the scientists found that soaking skin cells from bipolar patients in a lithium solution calmed the hyperexcitability–but only for some of them. The next study proved even more fruitful. The researchers soaked lymphocytes (immune cells) rom known lithium responders in lithium solutions, and found the same results–the hyperexcitabilty was calmed. But even though both responders and non-responders had the same excitability, the electrophysiological properties were different.
The Salk team looked for electrical firing patterns in neuronal lines, measuring the threshold for evoking a reaction, and other qualities. Overall, the patterns in responders were completely different than in non-responders.
The scientists were able to replicate the results again and again, which means that this test is proven to work. Now a blood draw is all that’s needed to test whether a patient with bipolar disorder will respond to lithium.