Other hormones, having a target area primarily in the brain, may affect emotion more directly. These include dopamine, serotonin, and endorphins, and they have powerful effects on emotions ranging from chronic depression to euphoria. Because these hormones can be used up faster than they are produced, sometimes people self medicate in order to feel particular emotions. For example, prolonged physical or emotional stress can lead to the use of substitute substances such as alcohol, caffeine, or drugs of abuse. Whether an individual turns to drugs for emotional stimulation depends upon numerous factors, including genetic background and environmental circumstances.
