All brain function--normal and pathological, intellectual and emotional--is bioelectric as well as biochemical. In fact, the brain communicates to itself and organizes its activity through its constant creation of brain waves of differing frequencies. The degree of our mental or emotional arousal largely depends on the frequency of our predominating brain waves. We know that large-amplitude, slow brain waves--known as delta waves--are associated with sleep. Theta waves are associated with a dreamy, sometimes hypnogogic, state. Alpha waves are usually associated with a relaxed meditative state of "open focus." Narrowly focused states of attention, needed to perform tasks, are characterized by beta-frequency brain waves.
Although the brain's electrical activity plays a major role in how an individual functions, until recently, surprisingly little attention has been paid to the electrical aspect of the brain. Instead, we've tended to view the brain solely as a biochemical organ, devoting billions of dollars to the development and promotion of psychotropic drugs.
At the same time, researchers and therapists have been teaching people to change their brains' bioelectric activity--and hence their functioning--without chemical intervention. Today, this method, called neurofeedback, is being used by therapists around the world to address an increasing number of disorders, from ADD and AD/HD to bipolar illness, autism, and learning disability.