The Disordered Mind: What Unusual Brains Tell Us About Ourselves

by Eric R. Kandel

Once the first manic episode is initiated—usually at the age of seventeen or eighteen—the brain is changed in ways we do not yet understand, such that even minor events can trigger a later manic episode. After the third or fourth manic episode, a trigger may not be required. As a person with bipolar disorder grows older, the disease advances and the intervals between episodes may become shorter, particularly if he or she discontinues treatment. Bipolar disorder affects about 1 percent of Americans, or more than 3 million people. While depression affects more women than men, bipolar disorder affects men and women equally. The disorder takes several forms, but the most common forms are known as bipolar I and bipolar II. People with bipolar I disorder have manic episodes, and sometimes cross over into psychosis with symptoms such as delusions and hallucinations, whereas people with bipolar II disorder have less severe, hypomanic episodes. Some people experience symptoms of both mania and depression at the same time, a condition known as a mixed state.