Serotonin acts as a neurotransmitter, a type of chemical that helps relay signals from one area of the brain to another. Although serotonin is manufactured in the brain, where it performs its primary functions, some 90% of our serotonin supply is found in the digestive tract and in blood platelets.
Acupuncture: An ancient Chinese method of healing. It aims to prevent and cure specific diseases and conditions by sticking very fine, solid needles into specific points on the body.
Anorexia nervosa: An eating disorder in which people have an irrational fear of weight gain and therefore severely restrict their food intake in order to achieve or maintain an abnormally low body weight. The diagnosis of anorexia requires that a person weigh at least 15% less than his or her normal body weight.
Antidepressants: Drugs used to treat depression. Antidepressants are not addictive. They do not make you "high," have a tranquilizing effect or produce cravings for more.
Anxiety disorder: An illness that produces an intense, often unrealistic and excessive state of apprehension and fear. This may or may not occur during, or in anticipation of, a specific situation and may be accompanied by a rise in blood pressure, increased heart rate, rapid breathing, nausea and other signs of agitation or discomfort.
Attention deficit hyperactivity disorder (ADHD): A common developmental and behavioral disorder characterized by poor concentration, distractibility, hyperactivity, and impulsiveness that are inappropriate for the child's age. Children and adults with ADHD are easily distracted by sights and sounds in their environment, cannot concentrate for long periods of time, are restless and impulsive, or have a tendency to daydream and be slow to complete tasks.
Bipolar disorder (manic-depressive illness): A mental illness that causes people to have severe high and low moods. People with this illness recurrently have episodes in which they feel uncharacteristically euphoric or irritable accompanied by high energy and at other times periods of depression in which they feel sad and hopeless. In between these episodes, a person's mood may be normal.