Alcohol and the young brain: girls at especial risk?

Further light has been thrown on the adverse effects of heavy episodic drinking on the brain in teenagers and young people by new American research. Two research reports suggest that binge drinking among adolescents and young adults may be causing serious damage to a brain that is still developing at this age, with one suggesting that teenage females may be particularly vulnerable. Another finds that the number of alcoholic blackouts experienced in youth are a good predictor of sustaining future injury while under the influence of alcohol.

Possible Brain Damage in Young Adult Binge- Drinkers

The new evidence was presented by researcher Tim McQueeny, a doctoral student in the University of Cincinnati Department of Psychology in the USA, at the 34th annual meeting of the Research Society on Alcoholism in Atlanta, Georgia.

High-resolution brain scans on a sample of 29 weekend binge drinkers, aged 18 to 25, found that binge-drinking – consuming four or more drinks in one incident for females and five or more drinks for males – was linked to cortical-thinning of the pre-frontal cortex, the section of the brain related to executive functioning such as paying attention, planning and making decisions, processing emotions and controlling impulses leading to irrational behavior.

McQueeny examined the brain’s grey matter, the parts of the cells that do the thinking, receiving and transmitting of messages. “We have seen evidence that binge drinking is associated with reduced integrity in the white matter, the brain’s highways that communicate neuron messaging, but alcohol may affect the grey matter differently than the white matter,” he says.

The pilot study examined whether the researchers could see a relationship between grey matter thickness and binge drinking among college-aged young adults. They found that the greater number of drinks per binge is associated with cortical thinning. McQueeny is now interested in pursuing future research to examine whether binge drinking is affecting the brain’s grey matter and white matter differently, or if they’re both equally affected.

“Alcohol might be neurotoxic to the neuron cells, or, since the brain is developing in one’s 20s, it could be interacting with developmental factors and possibly altering the ways in which the brain is still growing,” he says.

The findings affect a significant population. A publication from the National Institute on Drug Abuse reports that 42 percent of young American adults between 18 and 25 have engaged in binge drinking.

McQueeny adds that the depressant effects of alcohol emerge later in life, so, for young adults, the effect of alcohol can be very stimulating and activate tolerance over time.

“In the past, in terms of what’s known about the physical toll of alcohol, the focus on neurobiology has been in pathological populations and adult populations who were disproportionately male, so there was a significant gap in research in terms of when people started risky drinking. We’re looking at developmental aspects at an age when binge drinking rates are highest, and we’re also looking at gender effects,” says McQueeny. “There might actually be indications of early microstructural damage without the onset of pathological symptoms such as abuse, or dependence on alcohol.”

McQueeny’s advisor, UC Psychology Professor Krista Lisdahl Medina, served as senior author on the paper. She adds, “Our preliminary evidence has found a correlation between increased abstinence of binge drinking and recovery of grey matter volume in the cerebellum. Additional research examining brain recovery with abstinence is needed.”

In terms of educating young adults about responsible drinking, Medina says there appear to be better efforts about communicating the dangers of drinking and driving. “However, people can still be doing damage to their brain as a result of the prevalence and acceptance of binge drinking. There is also evidence that drinking below the binge level may be less harmful,” she says.

Young women may be particularly vulnerable to the negative effects of binge drinking on the teenage brain

A team of researchers at the Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine in the US, studies the effects of heavy episodic drinking on “spatial working memory” (SWM), the ability to perceive the space around oneself and then to remember and work with this information. Previous studies have shown spatial working memory is impaired in both adults and adolescents who drink alcohol heavily. Deficits on tasks of spatial working memory could relate to difficulties with driving, figural reasoning (like geometry class), sports (remembering and enacting complex plays), using a map, or remembering how to get to places. Professor Tapert and her colleagues recruited 95 participants from San Diego-area public schools as part of ongoing longitudinal studies: 40 binge drinking (27 males, 13 females) and 55 control (31 males, 24 females) adolescents 16 to 19 years of age. All of the adolescents completed neuropsychological testing, substance use interviews, and a SWM task during functional magnetic resonance imaging (fMRI).

“Our study found that female teenage heavy drinkers had less brain activation in several brain regions than female non-drinking teens when doing the same spatial task,” said Tapert. “These differences in brain activity were linked to worse performance on other measures of attention and working memory ability. Male binge drinkers showed some but less abnormality as compared to male non-drinkers. This suggests that female teens may be particularly vulnerable to the negative effects of heavy alcohol use.”

“These findings remind us that adolescent boys and girls are biologically different and represent distinctive groups that require separate and parallel study,” noted Edith V Sullivan, a professor in the Department of Psychiatry and Behavioral Sciences at Stanford University School of Medicine. “Adding alcohol to the mix of the developing brain and its multifaceted functions likely complicates the normal developmental trajectory, which is already sexually dimorphic.”

Tapert agreed there is a need to examine gender differences associated with alcohol use, particularly during adolescence, as alcohol seems to have a differential effect on the brain. “Females’ brains develop one to two years earlier than males, so alcohol use during a different developmental stage – despite the same age – could account for the gender differences,” she said. “Hormonal levels and alcohol-induced fluctuations in hormones could also account for the gender differences. Finally, the same amount of alcohol could more negatively affect females since females tend to have slower rates of metabolism, higher body fat ratios, and lower body weight. This is similar to what generally has been found in adult alcoholics: while both men and women are adversely affected, women are often more vulnerable than men to deleterious effects on the brain.”

These findings reflect “relatively normal healthy teens” who engage in social drinking, added Tapert, such as having four to five drinks at a party on the weekend but not using for weeks afterwards. “The teens we examined have relatively limited experience with alcohol, are drinking at levels that are widespread for kids their age – almost a quarter of all seniors admit to binge drinking in the preceding two weeks – have no diagnosable alcohol or drug disorder, do not use other drugs, and do not have any mental health disorders,” said Tapert. “And yet binge-drinking is a dangerous activity for all youth,” observed Sullivan. “Long after a young person – middle school to college – enjoys acute recovery from a hang-over, this study shows that risk to cognitive and brain functions endures. The effects on the developing brain are only now being identified.

“Why tamper with normal developmental trajectories that will likely set the stage for cognitive and motor abilities for the rest of one’s life?’”

Results will be published in the October 2011 issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.

Drink fuelled memory blackouts among students predict future injury risk

The higher the number of drink fuelled memory blackouts a student experiences, the greater is his or her risk of sustaining a future injury while under the influence, reveals research published online in ‘Injury Prevention’.

Memory blackouts refer to the inability to recall events; they do not refer to loss of consciousness as a result of drinking too much. Research indicates that alcohol alters nerve cell communication in the hippocampal region of the brain, which affects memory formation. Hazardous drinking - and its consequences - “are pervasive on college campuses,” say the authors, who report that around one in three students say they have experienced a memory blackout in the past year, and around one in 20 say they have had a period of drink fuelled amnesia within the past seven days. Women are just as likely to have blackouts as men, even though they drink less. In 2001, around 600,000 college students were injured as a result of excess drinking in the USA, and in 2005 almost 2,000 died as a result of booze fuelled unintentional injuries. The authors therefore wanted to find out if the number of times a student had a memory blackout as a result of drinking too much could usefully predict who might sustain a potentially serious injury while under the influence in the future. They analysed data from almost 800 undergraduates and more than 150 postgraduate students at five universities in North America between 2004 and 2009, who were monitored for two years. The students were taking part in the College Health Intervention Project Study (CHIPS), which compared the value of screening and brief doctor-led interventions versus nothing for problem drinking, assessed according to quantity and frequency. During the previous 28 days, male problem drinkers had put away an average of just under 82 drinks (as opposed to units); their female peers had downed just under 59. Men had more heavy drinking days, defined as five plus drinks, than women. More than half of all the students had had one or more memory blackouts in the 12 months leading up to the start of the study; 7% reported six or more during this time. Those aged between 18 and 20, “sensation seekers,” and those clocking up the most heavy drinking days reported the highest number of blackouts. The subsequent analysis showed that the overall prevalence of injury associated with alcohol was just over 25%, with women just as likely as men to be injured. And the more blackouts they had, the greater was their risk of unintentional injury. One to two memory blackouts increased the odds by 57%. With six or more memory blackouts, a student was almost three times as likely to sustain an injury. “Our results suggest that memory blackout screening at student health services could be a useful tool in college alcohol related injury prevention,” conclude the authors. This would be more specific than simply asking a student how much s/he drinks, and would help pick up those whose drinking is disrupting their cognitive abilities, they add. “It may be easier for a student to dismiss general health warnings on excessive alcohol drinking harms than to refute that his extreme alcohol drinking is causing impairment in brain function,” they say.

[Alcohol induced memory blackouts as an indicator of injury risk among college drinkers Online First 2011; doi 10.1136/ip.2011.031724]