Adolescent Alcohol Dependence May Damage Brain Function
University of California at San Diego and VA Researchers Report First Findings
A study in the February 2000 Alcoholism: Clinical and Experimental
Research (Volume 24, Number 2) presents the first concrete evidence that
protracted, heavy alcohol use can impair brain function in adolescents. It is
unclear at present whether the damage is reversible.
Supported by the National Institute on Alcohol Abuse and Alcoholism, a
research team led by Sandra A. Brown, Ph.D., chief of psychology at the VA San
Diego Healthcare System and professor of psychology and psychiatry at the
University of California, San Diego, assessed neuropsychological function in
thirty-three 15- and 16-year-old adolescents with more than 100 lifetime
alcohol use episodes and without dependence on other drugs. The alcohol
dependent teens were recruited from inpatient treatment programs and compared
after a minimum of 3 weeks of abstinence with twenty-four age, gender,
socioeconomic status, and education-matched adolescents with no history of
alcohol or other drug problems. Through structured clinical interviews
corroborated by parent reports, the researchers assessed both groups for
recent and lifetime involvement with alcohol and other drugs, alcohol or other
drug disorders, and alcohol or other drug withdrawal symptoms. Both groups
then participated in psychological tests of learning, memory, visuospatial
functioning, language skills, problem solving, and attention.
"Significant brain development continues through adolescence," said Dr.
Brown. "For example, certain brain nerve cell connections disappear up until
about age 16 as a function of environmental stimulation and redundancy, and
cerebral metabolic rates increase in childhood, then taper toward adult levels
by about age 20. Thus, alcohol may have quite different toxic effects on
adolescent brains than on those of adults."
But, while adolescent neurological and cognitive development may be
disrupted, altered or impeded by exposure to alcohol, young brains have more
resilience and more opportunities for compensatory development, Dr. Brown
added.
Dr. Brown and her colleagues found several differences in memory function
between the alcohol dependent and the control adolescents. Adolescents who had
drunk heavily over time scored lower on verbal and nonverbal retention in the
contexts of intact learning and recognition discriminability. Recent alcohol
withdrawal was associated with poor visuospatial functioning, while lifetime
alcohol withdrawal was associated with poorer retrieval of verbal and
nonverbal information.
The study has several limitations, the authors point out: An example is
that longitudinal studies will be required to determine the direction of the
alcohol and neurocognitive relationship. "While protracted alcohol involvement
may cause neuropsychological impairment, it also is probable that cognitive
deficits are a risk factor for alcohol disorders," said Dr. Brown. In
addition, the use of other drugs may have affected cognitive performance.
"None of our heavy drinking adolescents was dependent on other drugs, although
all reported some exposure, especially to marijuana and stimulants. On the
basis of animal research by others, we would expect that heavy alcohol use
alone can produce behavioral abnormalities in humans."
"This work is an important step toward confirming what many scientists have
suspected for some time," said NIAAA Director Enoch Gordis, M.D. "Certainly,
it raises important questions for researchers and, if borne out by additional
studies, for young people, parents, educators, and policy makers."
"Of course, other consequences associated with underage drinking
interference with learning, social, other competencies, fatal traffic crashes,
unintentional injuries, homicide, suicide, and early, more frequent, and less
safe sexual activity already are well known. Initiatives to keep youth
alcohol free and define research-based interventions for college drinking are
current NIAAA priorities."
"Our youth are an especially vulnerable part of Americas alcohol problem,"
said Dr. Gordis. "It is time that we face underage drinking head on."
Coauthors of the study are Susan F. Tapert, Ph.D., Eric Granholm, Ph.D.,
and Dean C. Delis, Ph.D., Psychology Service, VA San Diego Healthcare System
and Department of Psychiatry, University of California, San Diego. The
Veterans Medical Research Service and the National Institute of Mental Health
contributed additional support for the study.
For an interview with Dr. Brown, contact (telephone) 858/822-1887. For an
interview with Dr. Gordis, contact NIAAA Press (telephone) 301/443-3860. For
additional alcohol research information and publications, visit
http://www.niaaa.nih.gov/.
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