Almost no drug blocks brain development better than alcohol.
It just stops it in its tracks.

Aaron White, Assistant Professor, Department of Psychiatry, Duke University Medical Center, Too Much – HMR Video

Alcohol, neurotransmitter systems, and behavior.

Alcohol affects several neurotransmitter systems within the brain.

After ethyl alcohol (ethanol) is ingested, it quickly enters the bloodstream and crosses the blood--brain barrier. Alcohol moves into membranes and changes the environment of the protein molecules embedded therein, although its most dramatic effects may be in interacting with several sites inside neurons in the brain. …

In addition to the immediate effects of alcohol on transmitter action, related adaptations occur neurally with repeated exposure to alcohol…

… a major excitatory neurotransmitter … most affected by alcohol is the N-methyl-D-aspartate (NMDA) receptor, … NMDA receptors have a role in several effects of alcohol: memory loss associated with intoxication, a rebound effect that causes behavioral hyperactivity during withdrawal after prolonged alcohol abuse, and alcoholic brain damage caused by chronic drinking.

Alcohol decidedly reduces the effectiveness of glutamate at NMDA receptors, which impairs learning and memory even at blood alcohol levels of social drinkers (as low as .03%; Fadda & Rossetti, 1998). Alcohol also reduces glutamate release in the hippocampus, which results in the impairment of spatial memory. Serotonin plays a role in the regulation of mood, eating, arousal, sleep, pain, and many other behaviors (Carlson, 1998). Alcohol increases serotonin release in the nervous system. Studies have shown that, after a single drink, there has been increase in concentrations of serotonin in the urine and blood. The resulting effects are on behaviors such as emotion, mood, and thinking.

Conclusion

Ethyl alcohol has been shown to modify neural function and thereby produce intoxication, memory impairment, reinforcement, and dependence. Several neurotransmitter systems are affected by alcohol in a decisive and dramatic way.

From: The Journal of General Psychology | Date: 10/1/2006 | Author:  Chastain, Garvin

BRAIN RESEARCHERS LOOK AT ADOLESCENT RECKLESSNESS

A November 30, 2007 Wall Street Journal article describes preliminary research results on adolescent reckless behavior presented recently at the annual meeting of the Society for Neuroscience. Psychologist Gerry Jager, who studies the effect of drugs on brain development at the Rudolf Magnus Institute of Neuroscience in Utrecht, the Netherlands, stated “The adolescent brain is really a different piece of cake,” more sensitive to chemical highs and lows than child or adult brains, and especially vulnerable to substance abuse and stress—more prone to addiction, more resistant to the treatment of withdrawal, and more susceptible to relapse—than that of adults. Harvard University Medical School neurologist Frances Jensen said the susceptibility to substance abuse may be a consequence of the greater learning capacity of the adolescent brain, stating “Just as a teenager will do a much better job than an adult of picking up a language, they will also, sadly, do a better job of becoming addicted. Addiction is a form of learning.” Furthermore, teenagers also appear to be more sensitive to rewards than are children, which may be why teenagers seek experiences they find rewarding even though they might also be potentially harmful. A recent brain-imaging study of 26 young people conducted at UCLA revealed that a region of the brain called the ventral striatum, which normally responds to a reward or any new, unexpected stimulus, overreacts in teenagers. On the other hand, adolescents perceive risk and uncertainty differently than do adults, according to psychiatrist Amy Krain of New York University’s Institute for Pediatric Neuroscience. Contrary to conventional wisdom, teenagers try to avoid risks more than do adults.

The cerebrum is the part of your brain that controls advanced functions like recognition, vision, reasoning, and emotion. At the lowest levels, alcohol lowers inhibitions, and affects judgment. As alcohol levels increase, vision, movement, and speech are impaired.  This occurs at a blood alcohol level of .01% -.30%.

The cerebellum is the part of your brain that is involved with coordinating movement. Alcohol consumption causes problems with coordination, reflexes, and balance This occurs at a blood alcohol level of .15-.35%.

The medulla is the part of your brain that controls basic survival functions such as breathing and heartbeat.  When you've consumed so much alcohol that the medulla is affected, your brain's ability to control respiration and heart rate is severely diminished.  Your heart rate can drop and breathing cease, causing death, at blood alcohol levels as low as .30%.

The AMA report on the effects of alcohol on the brains of adolescents takes note of a study comparing magnetic resonance imaging of the brains of 14- to 21-year-olds who abused alcohol with those of  nondrinkers. That study found that drinkers had about 10 percent smaller hippocampi—the area of the brain that handles memory and learning. Researchers call such a reduction significant and possibly irreversible.

"Our brains go through important transformations during adolescence," says Sandra Brown, Ph.D., chief of psychology services at the Veterans Affairs Medical Center in San Diego … . "This study shows that alcohol use during the adolescent years is associated with damage to memory and learning capabilities as well as to the decision-making and reasoning areas in the brain."

According to Brown, alcohol takes a greater toll on brain development of those under twenty-one than on any other age group. Findings indicate that adults would have to consume twice as many drinks to suffer the same damage as adolescents and that even occasional heavy drinking injures young brains.

New research on adolescent brain development suggests that early heavy alcohol use may also have negative effects on the actual physical development of brain structure (Reducing Underage Drinking, 64).

Youth with alcohol use disorders also performed worse on memory tests than nondrinkers, further suggesting that the structural difference in hippocampus size was affecting brain functioning (Reducing Underage Drinking, 65).

Alcohol use during adolescence may have a direct effect on brain functioning: negative effects included decreased ability in planning and executive functioning, memory, spatial operations, and attention (Reducing Underage Drinking, 65).

Scientific evidence suggests that even modest alcohol consumption in late childhood and adolescence can result in permanent brain damage. —Testimony of Dr. John Nelson, American Medical Association, 2002

Research shows teen drinkers score worse than their non-drinking peers on vocabulary, visual-spatial, and memory tests, and are more likely to perform poorly in school as a whole.
—“Underage Drinkers at Higher Risk of Brain Damage,” American Medical Association, 2003

Teens who drink alcohol may remember 10 percent less of what they learned compared to non-drinking adolescents.
—Alcoholism: Clinical and Experimental Research, 2000

Among current drinkers aged 12 to 17, 31 percent suffered extreme levels of psychological distress, and 39 percent exhibited serious behavioral problems. —Substance Abuse and Mental Health Services Administration, 1999

Among 12 to 16 year olds, regular alcohol use is associated with attention-deficit disorder. In one study, adolescents who reported higher levels of drinking were more likely to have attention-deficit disorder.
 —Substance Abuse and Mental Health Services Administration, 1999

Teenage drinkers score worse than their non-drinking peers on vocabulary, visual-spatial, and memory tests.

“Underage Drinkers at Higher Risk of Brain Damage,” American Medical Association, 2003

Recent research shows that the human brain continues to develop into the early twenties.

HOW DOES UNDERAGE ALCOHOL USE IMPACT HEALTHY DEVELOPMENT?

Excerpt from the American Medical Association’s

Report on Alcohol's Adverse Effects On the Brains of Children, Adolescents And College Students

Adverse effects of alcohol on the brain: research findings Youth who drink can have a significant reduction in learning and memory, and teen alcohol users are most susceptible to damaging two key brain areas that are undergoing dramatic changes in adolescence:

            • The hippocampus handles many types of memory and learning and suffers from the worst alcohol-related brain damage in teens. Those who had been drinking more and for longer had significantly smaller hippocampi (10 percent).

            • The prefrontal area (behind the forehead) undergoes the most change during adolescence. Researchers found that adolescent drinking could cause severe changes in this area and others, which play an important role in forming adult personality and behavior and is often called the CEO of the brain.

            • Adolescent drinkers scored worse than non-users on vocabulary, general information, memory, memory retrieval and at least three other tests.

            • Verbal and nonverbal information recall was most heavily affected, with a 10 percent performance decrease in alcohol users.

            • Significant neuropsychological deficits exist in early to middle adolescents (ages 15 and 16) with histories of extensive alcohol use.

            • Adolescent drinkers perform worse in school, are more likely to fall behind and have an increased risk of social problems, depression, suicidal thoughts and violence.

            • Alcohol affects the sleep cycle, resulting in impaired learning and memory as well as disrupted release of hormones necessary for growth and maturation.

The Underage Drinking Prevention and Social Marketing Project at the West Virginia Prevention Resource Center is federally funded though the following grants: The Center for Substance Abuse Prevention's Substance Abuse Prevention & Treatment Block Grant administered through the WV Division on Alcoholism & Drug Abuse; The Office of Juvenile Justice and Delinquency Prevention's Enforcing the Underage Drinking Laws (EUDL) Grant administered through the WV Division of Criminal Justice Services; and The Center for Substance Abuse Prevention's Strategic Prevention Framework State Incentive Grant also administered through the WV Division of Criminal Justice Services. This project is also supported in part by funds from the WV Governor's Highway Safety Program. For more information about this project, please contact Stephanie Southall at (304) 766-6301 x25 or Stephanie.Southall@marshall.edu

Alcohol consumption is associated with structural damage to the brain.

➾ Results of autopsy studies show that individuals with a history of chronic alcohol consumption have smaller, lighter, more shrunken brains than nonalcoholic adults of the same age and gender.1
➾ Alcohol differs from illicit drugs in the complexity of its actions on the brain and other organs. While most illicit drugs work on one or several brain neurotransmitters, alcohol influences multiple neurotransmitter systems and brain circuits in ways that may differ from one drinker to the next.2
➾ Moderate consumption of alcohol affects the function of a variety of brain systems associated with emotion, learning, motivation, and coordination.3

Repeated exposure to alcohol can produce long-lasting changes in adolescent behavior and brain function.

➾ The hippocampus is the part of the brain where new memories are transferred from short-term to long-term storage. The hippocampus plays a prominent role in forming memories for events such as what you did last night, and facts like someone’s name or phone number. Alcohol dramatically impairs the functioning of the hippocampus, and researchers now believe that this plays a critical role in the ability of alcohol to produce memory impairments, including blackouts.4
➾ MRIs used to assess the size of the hippocampus in subjects with adolescent-onset alcohol use disorders and in normal control subjects showed that the longer one abused alcohol, the smaller the hippocampus became.5
➾ Research suggests that heavy alcohol exposure produces more damage in the adolescent brain than the adult brain, including the hippocampus and regions associated with it.6
➾ Studies indicate that alcohol-dependent teens have impaired memory, altered perception of spatial relationships, and verbal skill deficiencies.7
➾ Cognitive impairments have been detected in adolescent alcohol abusers weeks after they stop drinking. The causes of these long-lasting changes are unclear, but they might involve brain damage and/or alterations in normal brain development.8

The AMA report on the effects of alcohol on the brains of adolescents takes note of a study comparing magnetic resonance imaging of the brains of 14- to 21-year-olds who abused alcohol with those of nondrinkers. That study found that drinkers had about 10 percent smaller hippocampi—the area of the brain that handles memory and learning. Researchers call such a reduction significant and possibly irreversible. "Our brains go through important transformations during adolescence," says Sandra Brown, Ph.D., chief of psychology services at the Veterans Affairs Medical Center in San Diego and whose brain research is included in the report. "This study shows that alcohol use during the adolescent years is associated with damage to memory and learning capabilities as well as to the decision-making and reasoning areas in the brain."

According to Brown, alcohol takes a greater toll on brain development of those under twenty-one than on any other age group. Findings indicate that adults would have to consume twice as many drinks to suffer the same damage as adolescents and that even occasional heavy drinking injures young brains. The AMA report also shows adolescent drinkers scored worse than non-users on vocabulary, visual spatial and memory tests and were more likely to perform poorly

An American Medical Association (AMA) report on the effects of alcohol on the brain Harmful Consequences of Alcohol Use on the Brains of Children, Adolescents, and College Students

1 National Institute on Alcohol Abuse and Alcoholism (NIAAA). Imaging and Alcoholism: A Window on the Brain. Alcohol Alert No. 47, 2000. http://www.niaaa.nih.gov/publications/aa47.htm (accessed 10/28/02).
2 Gordis, E. Statement made at Substance Abuse in the Twenty-First Century: Positioning the Nation for Progress, a conference of The National Center on Addiction and Substance Abuse at Columbia University and the Ronald Reagan Presidential Foundation, Simi Valley, CA, February 29, 2000.
3 Eckardt MJ, File SE, Gessa GL et al. Effects of moderate alcohol consumption on the central nervous system. Alcohol Clin Exp Res 22(5): 998-1040, 1998.
4 White AM, Matthews DB, Best PJ. Ethanol, memory and hippocampus function: a review of recent findings. Hippocampus 10: 88-93, 2000.
5 De Bellis MD, Clark DB, Beers SR, et al. Hippocampus volume in adolescent-onset alcohol use disorders. Am J Psychiatry 157(5):737-744, 2000.
6 Crews FT, Braun CJ, Hoplight B, et al. Binge ethanol consumption causes differential brain damage in young adolescent rats compared with adult rats.. Alcohol Clin Exp Res 24(11):1712-23, 2000.
7 Brown SA, Tapert SF, Granholm E, et al. Neurocognitive functioning of adolescents: effects of protracted alcohol use. Alcohol Clin Exp Res 24(2):164-171, 2000.
8 Ibid.