Breakthrough As you’ll see in the next chapter, in the mid-1900s scientists discovered by accident that the moods of people with bipolar disorders often are stabilized by lithium, one of Earth’s 98 basic chemical elements. Researchers have since worked backward, determining how lithium affects the cells of the brain and body and, in turn, identifying the possible biological causes of bipolar disorders. A computer graphic representation of the electronic structure of lithium is shown in this photo.