Interesting explanation of what's going on in the brain

While the causes of bipolar disorder are still unknown, symptoms are thought to be caused by an imbalance of some key chemicals in the brain.

The brain is madeup of billions of nerve cells that move a constant stream of information from one cell to another. To keep the information flowing, the cells release chemicals known as “neurotransmitters” that are needed for brain function.
Many scientists believe that when the levels of these neurotransmitters are too high or too low, it may result in symptoms of bipolar disorder, such as extreme happiness, irritability, sadness, or a lack of energy.
Manic episodes is when the levels of the neurotransmitters are too high.
Depressive episodes have levels of neurotransmitters that are too low.

(from www.bipolaroptions.com)