Lithium is a naturally occuring chemical element that is found throughout the world. It is a metal much like sodium, and is most commonly found in the form of a salt. It has a number of industrial applications as well as medical ones.
Lithium has been used to treat various illnesses since the late 19th Century, though it is only in recent decades that it has been systemically investigated and prescribed for specified, recognised conditions. It's particularly useful in reducing the risk of relapse in bipolar disorder (manic depression).
When prescribed appropriately and taken correctly, lithium is generally well tolerated. For some with bipolar disorder, lithium greatly reduces the number of episodes experienced but this is not the case for everyone. Understanding and eventually predicting response to lithium is the subject of a coordinated, world-wide research effort.
One of the most important questions to answer is how much lithium actually enters the brain during a course of treatment. This has been difficult to answer, but recent advances in technology have allowed us to develop a brain scan that directly assesses lithium concentration.
As the title suggests, this was just to give you a brief introduction into lithium. If you'd like to learn more about its history and use, we recommend you take a look at the long version.