Dr. Goldstein believes that neurotransmitters, chemical substances that act as information messengers in the brain, are abnormally low in this condition. Norepinephrine and dopamine are two such neurotransmitters lacking in CFS patients. When these are decreased, the brain has difficulty assessing relevance of the numerous messages it constantly receives. Because of this, mentally challenging situations such as taking a test or sensory stimulating situations such as a shopping at a mall can be overwhelming.
Another cause of this easily distractible state is elevated levels of substance P. Substance P is a chemical that transmits pain messages. Overproduction of substance P results in increased sensations of pain.
Article by John W. Addington on Jay A. Goldstein's book:
Betrayal by the Brain: The Neurologic Basis of Chronic Fatigue Syndrome, Fibromyalgia Syndrome, and Related Neural Network Disorders
Published by Haworth Press, 1996