Medical Health Encyclopedia

Even if genetic factors can be identified, however, they are unlikely to explain all cases of alcoholism. It is important to understand that, whether they inherit the disorder or not, people with alcoholism are still legally responsible for their actions. Inheriting genetic traits does not doom a child to an alcoholic future. Environment, personality, and emotional factors also play a strong role.

Brain Chemical Imbalances After Long-Term Alcohol Use

Alcohol has widespread effects on the brain and can affect neurons (nerve cells), brain chemistry, and blood flow within the frontal lobes of the brain. Researchers are particularly interested in systems of neurotransmitters (chemical messengers) in the brain that are affected by alcohol. Some research is focusing on the way these neurotransmitters are employed in the brain after long-term alcohol use in order to adapt to the cravings and pain of withdrawal. Such chemical changes may lead to dependency or to relapse after quitting in two ways:

• They increase the need to reduce agitation; and
• They increase the desire to restore pleasurable feelings.

Reducing Agitation. When a person who is dependent on alcohol stops drinking, the following chemical responses create an overexcited nervous system and agitation:

• A drop in gamma-aminobutyric acid (GABA), a brain chemical that inhibits impulsivity
• An increase in glutamate, a brain chemical that excites nerve cells
• An increase in norepinephrine and corticotropin releasing factor, hormones linked to stress

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High norepinephrine levels, in fact, may be the primary factor in withdrawal symptoms such as an increase in blood pressure and heart rate. This hyperactivity in the brain produces an intense need to calm down and to use more alcohol. One study suggested that the need to relieve agitation may be the more important factor in causing a relapse than restoring mood.