Grim Neurology of Teenage Drinking
Times, July 4, 2006
Teenagers have been
drinking alcohol for centuries. In
pre-Revolutionary America, young apprentices
were handed buckets of ale. In the 1890's, at
the age of 15, the writer Jack London regularly
drank grown sailors under the table.
For almost as long,
concerned adults have tried to limit teenage
alcohol consumption. In the 1830's, temperance
societies administered lifelong abstinence
pledges to schoolchildren. Today, public health
experts regularly warn that teenage drinkers run
greatly increased risks of involvement in car
accidents, fights and messy scenes in Cancún.
what was once a social and moral debate may soon
become a neurobiological one.
The costs of early heavy
drinking, experts say, appear to extend far
beyond the time that drinking takes away from
doing homework, dating, acquiring social skills,
and the related tasks of growing up.
Mounting research suggests
that alcohol causes more damage to the
developing brains of teenagers than was
previously thought, injuring them significantly
more than it does adult brains. The findings,
though preliminary, have demolished the
assumption that people can drink heavily for
years before causing themselves significant
neurological injury. And the research even
suggests that early heavy drinking may undermine
the precise neurological capacities needed to
protect oneself from alcoholism.
The new findings may help
explain why people who begin drinking at an
early age face enormous risks of becoming
alcoholics. According to the results of a
national survey of 43,093 adults, published
yesterday in Archives of
Pediatrics & Adolescent Medicine, 47 percent
of those who begin drinking alcohol before the
age of 14 become alcohol dependent at some time
in their lives, compared with 9 percent of those
who wait at least until age 21. The correlation
holds even when genetic risks for alcoholism are
taken into account.
The most alarming evidence
of physical damage comes from federally financed
laboratory experiments on the brains of
adolescent rats subjected to binge doses of
alcohol. These studies found significant
cellular damage to the forebrain and the
And although it is unclear
how directly these findings can be applied to
humans, there is some evidence to suggest that
young alcoholics may suffer analogous deficits.
Studies conducted over the
last eight years by federally financed
researchers in San Diego, for example, found
that alcoholic teenagers performed poorly on
tests of verbal and nonverbal memory, attention
focusing and exercising spatial skills like
those required to read a map or assemble a
"There is no doubt about
it now: there are long-term cognitive
consequences to excessive drinking of alcohol in
adolescence," said Aaron White, an assistant
research professor in the psychiatry department
Duke University and the co-author of a
recent study of extreme drinking on college
"We definitely didn't know
5 or 10 years ago that alcohol affected the teen
brain differently," said Dr. White, who has also
been involved in research at Duke on alcohol in
adolescent rats. "Now there's a sense of
urgency. It's the same place we were in when
everyone realized what a bad thing it was for
pregnant women to drink alcohol."
One of two brain areas
known to be affected is the hippocampus, a
structure crucial for learning and memory. In
1995, Dr. White and other researchers placed
delicate sensors inside living brain slices from
the hippocampi of adolescent rats and discovered
that alcohol drastically suppressed the activity
of specific chemical receptors in the region.
Normally, these receptors
are activated by the neurotransmitter glutamate
and allow calcium to enter neurons, setting off
a cascade of changes that strengthen synapses,
by helping to create repeated connections
between cells, aiding in the efficient formation
of new memories.
But at the equivalent of
one or two alcoholic drinks, the receptors'
activity slowed, and at higher doses, they shut
down almost entirely. The researchers, led by
Scott Swartzwelder, a neuropsychologist at Duke
and at the Veterans Affairs Medical Center in
Durham, N.C., found that the suppressive effect
was significantly stronger in adolescent rat
brain cells than in the brain cells of adult
As might be predicted, the
cellular shutdown affected the ability of the
younger rats to learn and remember. In other
experiments, the team found that adolescent rats
under the influence of alcohol had far more
trouble than did tipsy adult rats when required
repeatedly to locate a platform submerged in a
tub of cloudy water and swim to it.
Swartzwelder said it was likely that in human
teenagers, analogous neural mechanisms might
explain alcohol "blackouts" — a lack of memory
for events that occur during a night of heavy
drinking without a loss of consciousness.
Blackouts were once thought to be a symptom of
advanced adult alcoholism, but researchers have
In a 2002
e-mail survey of 772 Duke undergraduates, Dr.
White and Dr. Swartzwelder found that 51 percent
of those who drank at all had had at least one
blackout in their drinking lifetimes; they
reported an average of three blackouts apiece.
These averages barely
suggest the frequency of blackouts among young
adults at the extreme end of the drinking scale.
Toren Volkmann, 26, is a graduate of the
University of San Diego who, at 14, started
drinking heavily almost every weekend and at 24
checked himself into a residential alcohol
"It was common for me to
basically black out at least once or twice every
weekend in late high school and definitely
through college, and it wasn't a big deal to
me," said Mr. Volkmann, a co-author, with his
mother, Chris, of "From Binge to Blackout: A
Mother and Son Struggle With Teen Drinking," to
be published in August. "I wouldn't even worry
about what happened, because I wouldn't know."
Blackouts are usually
mercifully brief, and once they are over, the
capacity to form new memories returns. But
younger rats subjected to binge drinking also
displayed subtler long-term problems in learning
and memory, the researchers found, even after
they were allowed to grow up and "dry out."
In experiments conducted
by the Duke team, the reformed rat drinkers
learned mazes normally when they were sober. But
after the equivalent of only a couple of drinks,
their performance declined significantly more
than did that of rats that had never tippled
before they became adults. The study was
published in 2000 in the journal Alcoholism:
Clinical and Experimental Research. Other
research has found that while drunken adolescent
rats become more sensitive to memory impairment,
their hippocampal cells become less responsive
than adults' to the neurotransmitter gamma-amino
butyric acid, or GABA, which helps induce
calmness and sleepiness.
This cellular mechanism
may help explain Jack London's observation, in
"John Barleycorn: Alcoholic Memoirs," that when
he was a teenager he could keep drinking long
after his adult companions fell asleep.
"Clearly, something is
changed in the brain by early alcohol exposure,"
Dr. Swartzwelder said in an interview. "It's a
double-edged sword and both of the edges are
"Teenagers can drink far
more than adults before they get sleepy enough
to stop, but along the way they're impairing
their cognitive functions much more powerfully."
Alcohol also appears to
damage more severely the frontal areas of the
adolescent brain, crucial for controlling
impulses and thinking through consequences of
intended actions — capacities many addicts and
alcoholics of all ages lack.
In 2000, Fulton Crews, a
neuropharmacologist at the
University of North Carolina, subjected
adolescent and adult rats to the equivalent of a
four-day alcoholic binge and then autopsied
them, sectioning their forebrains and staining
them with a silver solution to identify dead
All the rats showed some
cell die-off in the forebrain, but the damage
was at least twice as severe in the forebrains
of the adolescent rats, and it occurred in some
areas that were entirely spared in the adults.
Although human brains are
far more developed and elaborate in their
frontal regions, some functions are analogous
across species, Dr. Crews said, including
planning and impulse control. During human
adolescence, these portions of the brain are
heavily remolded and rewired, as teenagers learn
— often excruciatingly slowly — how to exercise
adult decision-making skills, like the ability
to focus, to discriminate, to predict and to
ponder questions of right and wrong.
disruption in parts of the brain essential for
self-control, motivation and goal setting," Dr.
Crews said, and can compound pre-existing
genetic and psychological vulnerabilities.
"Early drinking is affecting a sensitive brain
in a way that promotes the progression to
"Let's say you've been
arrested for driving while drunk and spent seven
days in jail," Dr. Crews said. "You'd think, 'No
way am I going to speed and drive drunk again,'
because you have the ability to weigh the
consequences and the importance of a behavior.
This is exactly what addicts don't do."
In another experiment,
published this year in the journal Neuroscience,
Dr. Crews found that even a single high dose of
alcohol temporarily prevented the creation of
new nerve cells from progenitor
stem cells in the forebrain that appear to
be involved in brain development.
The damage, far more
serious in adolescent rats than in adult rats,
began at a level equivalent to two drinks in
humans and increased steadily as the dosage was
increased to the equivalent of 10 beers, when it
stopped the production of almost all new nerve
Dr. Crews added, however,
that adult alcoholics who stop drinking are
known to recover cognitive function over time.
The same may hold true for
hard-drinking teenagers. In 1998, Sandra Brown
and Susan Tapert, clinical psychologists at the
University of California, San Diego, and at
the Veterans Affairs Medical Center there, found
that 15-to-16-year-olds who said they had been
drunk at least 100 times performed significantly
more poorly than their matched nondrinking peers
on tests of verbal and nonverbal memory.
The teenagers, who were
sober during the testing, had been drunk an
average of 750 times in the course of their
"Heavy alcohol involvement
during adolescence is associated with cognitive
deficits that worsen as drinking continues into
late adolescence and young adulthood," Dr.
Two M.R.I. scan studies,
one conducted by Dr. Tapert, have found that
hard-drinking teenagers had significantly
smaller hippocampi than their sober
counterparts. But it is also possible, the
researchers said, that the heavy drinkers had
smaller hippocampi even before they started to
Teenagers who drink
heavily may also use their brains differently to
make up for subtle neurological damage, Dr.
Tapert said. A study using functional M.R.I.
scans, published in 2004, found that
alcohol-abusing teenagers who were given a
spatial test showed more activation in the
parietal regions of the brain, toward the back
of the skull, than did nondrinking teenagers.
When female drinkers in
the group were tested in their early 20's, their
performance declined significantly in comparison
with nondrinkers, and their brains showed less
activation than normal in the frontal and
Dr. Tapert hypothesized
that when the drinkers were younger, their
brains had been able to recruit wider areas of
the brain for the task.
"This is a fairly
sensitive measure of early stages of subtle
neuronal disruption, and it is likely to be
rectifiable if the person stops drinking," Dr.
The good news is that the
brain is remarkably plastic, she added, and
future studies may show that the teenage brain,
while more vulnerable to the effects of alcohol,
is also more resilient.
She pointed to test
results from the original group of teenagers,
recruited from substance abuse treatment centers
and brought into the lab when they were 15 by
Dr. Brown. When Dr. Tapert retested the
teenagers eight years later, those who had
relapsed and who continued to get drunk
frequently performed the worst on tests
requiring focused attention, while those who
reported the most hangovers performed the worst
on spatial tasks.
On the other hand, the
relative handful of teenagers and young adults
in the group who stayed sober — 28 percent of
the total — performed almost as well, at both
the four-year and the eight-year mark, as other
San Diego teenagers who had rarely, if ever, had
Mr. Volkmann, the
University of San Diego graduate, was not part
of Dr. Tapert's study. While in college, Mr.
Volkmann said, he thought he drank for the fun
of it. His moment of truth came in the
Peace Corps in Paraguay, when he began
waking up with sweats and tremors. He discovered
he could not control his drinking even when he
The son of an
anesthesiologist and a former teacher in
Olympia, Wash., Mr. Volkmann spent a month in a
residential treatment program and six months in
a halfway house. He has since returned to San
He said in an interview
that he had no way of knowing exactly how
drinking affected his overall brain function.
But on one point, he is clear.
"My memory is definitely
better now," he said. "Every day now, I can
count on the fact that when I think back to the
night before, I know what happened."