Alcohol and the Developing Brain


            Alcohol can cause alterations in the structure and function of the developing brain, which continues to mature
            into a person’s mid 20s, and it may have consequences reaching far beyond adolescence.

            In adolescence, brain development is characterized by dramatic changes to the brain’s structure, neuron
            connectivity (i.e., “wiring”) and physiology. These changes in the brain affect everything from emerging
            sexuality to emotionality and judgment.

            Not all parts of the adolescent brain mature at the same time, which may put an adolescent at a disadvantage in
            certain situations. For example, the limbic areas of the brain mature earlier than the frontal lobes. The limbic
            areas regulate emotions and are associated with an adolescent’s lowered sensitivity to risk. The frontal lobes
            are responsible for self-regulation, judgment, reasoning, problem-solving and impulse control. Differences in
            maturation among parts of the brain can result in impulsive decisions or actions and a disregard
            for consequences.



            How Alcohol Affects the Brain

Alcohol affects an adolescent’s brain
development in many ways. The effects
of underage drinking on specific brain
activities are explained below.

Alcohol is a central nervous system
depressant. Alcohol can appear to be a
stimulant because, initially, it depresses
the part of the brain that controls
inhibitions.

CEREBRAL CORTEX - Alcohol slows
down the cerebral cortex as it works
with information from a person’s senses.

CENTRAL NERVOUS SYSTEM - When
a person thinks of something he wants
his body to do, the central nervous
system - the brain and the spinal
cord - sends a signal to that part of the
                                                                                                                             body. Alcohol slows down the central
                                                                                                                             nervous system, making the person
                                                                                                                             think, speak and move slower.

            FRONTAL LOBES - The brain’s frontal lobes are important for planning, forming ideas, making decisions and
            using self-control.

            When alcohol affects the frontal lobes of the brain, a person may find it hard to control her emotions and urges.
            She may act without thinking or even become violent.

            Drinking alcohol over a long period of time can damage the frontal lobes forever.

            HIPPOCAMPUS - The hippocampus is the part of the brain where memories are made.

                  • When alcohol reaches the hippocampus, a person may have trouble remembering something he just
                    learned, such as a name or a phone number. This can happen after just one or two drinks.

                  • Drinking a lot of alcohol quickly can cause a blackout - not being able to remember entire events, such as
                    what he did last night.

                  • If alcohol damages the hippocampus, a person may find it hard to learn and to hold on to knowledge.

            CEREBELLUM - The cerebellum is important for coordination, thinking and being aware. A person may have
            trouble with these skills when alcohol enters the cerebellum. After drinking alcohol, her hands may be so shaky
            that she can’t touch or grab things normally. She may lose her balance and fall.

            HYPOTHALAMUS - The hypothalamus is a small part of the brain that does an amazing number of the body’s
            housekeeping chores. Alcohol upsets the work of the hypothalamus. After a person drinks alcohol, blood
            pressure, hunger, thirst and the urge to urinate increase while body temperature and heart rate decrease.

            MEDULLA - The medulla controls the body’s automatic actions, such as a person’s heartbeat. It also keeps the
            body at the right temperature. Alcohol actually chills the body. Drinking a lot of alcohol outdoors in cold weather
            can cause a person’s body temperature to fall below normal. This dangerous condition is called hypothermia.

            * We refer to a child as "him" in some places and "her" in others. We do this for easier reading. All information
            applies to both boys and girls unless otherwise specified.

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            Sources

            • U.S. Department of Health and Human Services, Office of the Surgeon General. (2007).
              The Surgeon General’s Call to Action To Prevent and Reduce Underage Drinking (PDF 1.41MB).
            • U.S. Department of Health and Human Services, Office of the Surgeon General. (2007).
              The Surgeon General’s Call to Action To Prevent and Reduce Underage Drinking: A Guide for Families
              (PDF 900KB).
            • U.S. Department of Health and Human Services, Substance Abuse and Mental Health Services Administration.
              Reach Out Now Teach-In Lesson Plan.



            More information available at www.toosmarttostart.samhsa.gov