Lithium Responders and Non-Responders Have Different Neuron Characteristics

May 22, 2017 · Posted in Current Treatments · Comment 
after hyperpolarization

After hyperpolarization (via Wikimedia Commons)

A 2017 study in the journal Molecular Psychiatry suggests that by observing the neurons of a person with bipolar disorder, you can predict whether they will respond to lithium treatment. The drug is effective in approximately 30% of those to whom it is prescribed.

Researchers led by Shani Stern and Renata Santos used stem cell research to analyze neurons from people with bipolar disorder and healthy controls.

People with bipolar disorder shared some neuron features, namely a large, fast after-hyperpolarization (a phase in which the cell’s membrane changes), which is followed by a resting period before the neuron can fire again. The large, fast hyperpolarization in people with bipolar disorder speeds up this cycle, leading to fast and sustained neuron firing. This replicated previous findings by the same researchers, which found that people with bipolar disorder are more sensitive to stimuli. In people with bipolar disorder, the threshold for a neuron to fire drops with each subsequent after-hyperpolarization.

Chronic lithium treatment reduced this hyperexcitability in some patients—and these were the patients who had a good response to lithium treatment.

Among the study participants with bipolar disorder, there were differences in the neuron profiles of those who responded well to lithium versus those who did not.

Stern and colleagues programmed a computer to recognize the electrophysiological features of neurons from lithium responders and non-responders. The computer could then analyze the neurons of a patient whose response to lithium was unknown and predict with a greater than 92% success rate whether that patient had responded well to lithium treatment.