October 16, 2012
Effects Of Binge Drinking May Include Brain Impairment In Just Months
Alan McStravick for redOrbit.com - Your Universe Online
Bill Cosby was on to something when he addressed this country´s propensity for binge drinking. Speaking in his ℠Bill Cosby, Himself´ special from 1983, he said, “It's always strange. I've had a lot of people work for me, and I've found out it's a funny thing that you give them Saturday and Sunday off, and they work so hard to get to those two days and those are the two days that they totally destroy themselves. I mean, you know you think to yourself, you say, ℠My goodness, I've really pounded these people and worked to them to death.´ And Friday comes and they say, ℠Yeah!´ And then they come in Monday and say, ℠Boy, am I glad to be back here. I'm no good on my own. I was given two whole days and I just went crazy.´”
We do have a culture of binge drinking. Binge drinking is defined as men who drink 5 or more alcoholic drinks and women who drink 4 or more in a short period of time. It´s important to understand that someone who binge drinks is not necessarily someone who would be classified as alcohol-dependent. In fact, the Centers for Disease Control (CDC) recently issued some surprising statistics on binge drinking demographics.
Binge drinking increases the likelihood that one might hurt themselves or others, increasing accidents, violent behavior and the likelihood of suicide. Binge drinking is estimated to claim some 80,000 lives in the United States each year. In 2006, the last year with statistics available, it was estimated that the cost of binge drinking to our economy was $223.5 billion. This is reflected across all states, regardless of population size, as people are binge drinking in higher quantities and more often.
With binge drinking factored in, drinking too much costs, on average, $746 per person, or $1.90 a drink. These costs include health care expenses, crime and lost productivity. The CDC has identified 54 individual injuries and diseases that are closely associated with excessive drinking. These include car crashes, violence and sexually-transmitted diseases. And the likelihood that one might get sick and/or die from binge drinking is significantly increased as well.
We now have evidence of a new threat to human health in a report commissioned by The Scripps Research Institute (TSRI). In it, scientists examining the effects of binge-drinking in rodents postulated that a person who throws back a few drinks every couple of days may swiftly reduce their ability to control their alcohol intake.
Researchers were able to link the rats´ impairment to a small group of neurons that inhibit what are known as “executive control” functions in the prefrontal cortex of the brain. Between binges, these neurons were unusually active. They found the rats that had the most neural activity were least able to control the amount of alcohol imbibed the next time they had access to alcohol.
The researchers believe if they can link this same neuro-response to humans, it could help to develop better treatments, preventive approaches and diagnostic tests for problem drinking and other addiction-like behaviors.
"We suspect that this very early adaptation of the brain to intermittent alcohol use helps drive the transition from ordinary social drinking to binge drinking and dependence," said Olivier George, senior staff scientist at TSRI and lead author of the study.
"This research is giving us a window into the early development of the addiction process," said another senior author, George F. Koob, chairman of the Committee on the Neurobiology of Addictive Disorders and co-director of the Pearson Center for Alcoholism and Addiction Research at TSRI.
Their new study appears online in the Early Edition of the Proceedings of the National Academy of Sciences.
While the effect on the prefrontal cortex has long been known, in relation to alcohol dependence, little has been understood regarding the sequencing that occurs that allows changes in neural events to come about.
It was these early events that the scientists wanted to focus their research upon. Dr. George set up a study of rats that had access to alcohol only 3 days per week. Previous research had already demonstrated that drinking on such an intermittent schedule tended to cause subjects to progress from moderate drinking to binge drinking. Interestingly, those with intermittent access to alcohol eventually drank even more than those rats that were given unlimited access to alcohol.
"It's like a lot of things in life that the brain perceives as good — if it loses access to it, you feel bad, you get into a negative emotional state, say a little bit frustrated, and so you take more the next time you have access," said Dr. George.
"We normally see such changes in the brains of humans or other animals that are highly dependent on alcohol, but here we found these changes in the rats after only a few months of intermittent alcohol use," said explained George.
Of particular interest was the fact that these impairments did not occur in the rats with access to alcohol on a 24/7 basis. “They just drink a bit like the French way, the equivalent of a couple of glasses of wine every day, and they´re fine,” said George. “They don´t escalate.”
The binge-drinking rats were found to experience a reduction in cognitive impairment if they were kept off alcohol for about two weeks. However, the impairment quickly returned if they simply started drinking again.
“One can see the vicious cycle here,” said George. “They drink to restore normal prefrontal function, but ultimately that leads to even greater impairment.”
"This process would be of particular concern in adolescents and young adults, in whom the prefrontal cortex isn't even fully developed,” said Koob.
The team also found that the immediate cause of the impairment in the binge-drinking rats was located in a small population of medial prefrontal cortex neurons known as GABA interneurons. The GABA act as a type of dimmer switch for the nearby excitatory neurons within the medial prefrontal cortex. It was in the binge-drinking rats that the GABA neurons were unusually active during periods of impairment. The more active the GABA neurons are, the less the prefrontal cortex is able to do its primary job of exerting control over other, relatively impulse-driven brain regions.
The study also noted that the GABA interneurons in binge-drinking rats were activated by adjacent prefrontal neurons that secrete the stress neurotransmitter corticotrophin releasing factor (CRF). A link between CRF and alcoholism has already been established by previous research. In alcohol-dependent rats — and probably in human alcoholics as well — abstinence from alcohol triggers a flood of CRF in the central nucleus of the amygdala. This rush of CRF creates a feeling of anxiety that typically can only be alleviated by drinking again.
“Now we see that this early dysregulation of the prefrontal cortex by binge drinking may also be driven by CRF,” said Koob.
This finding has led the Koob lab and other addiction researchers to investigate possible CRF-blocking drugs as potential treatments for established alcohol dependence. With the new findings of this study, Dr. Koob also believes these CRF-inhibiting drugs could find use in preventing alcohol dependence, as well.
“When someone develops a molecule that binds to CRF with high enough specificity, so that we can measure CRF activity in the living human brain with a PET scan, we might then have a good way to detect if someone is alcohol-dependent or on the path to dependency,” he explained.
The CDC has suggested possible social strategies that could be used to offset the occurrence and effects of binge drinking. Their recommendations take aim at the federal government, working with states, health care professionals, local governments, communities and even individuals.
The CDC recommends a robust commitment to outreach efforts, support of drinking laws and individual responsibility for moderate drinking.
Funding for the TSRI research was supported by grants from the National Institutes of Health and the Pearson Center for Alcoholism and Addiction Research at TSRI.
The Scripps Research Institute is one of the world´s largest independent, not-for-profit organizations with a focus on research in the biomedical sciences. Over the past decades, TSRI has developed a lengthy track record of major contributions to science and health, including laying the foundation for new treatments of cancer, rheumatoid arthritis, hemophilia and other diseases. The TSRI has campuses in La Jolla, California and Jupiter, Florida.