BLACKOUT IN A CAN: Michigan and Oklahoma have banned the sale of energy drinks that contain alcohol, and other states and cities are considering the same. Caffeine can reduce the sedative effects of alcohol, allowing a person to drink for longer periods of time, Temple's Gould says. Image: COURTESY OF FREDDY, VIA FLICKR
Party beverages that go by "blackout in a can" and other monikers may soon be banned from store shelves in some U.S. states, thanks to a number of incidents that have left drinkers unconscious and with dangerously high blood alcohol levels.
The Michigan Liquor Control Commission (MLCC) last week effectively prohibited the sale of all alcoholic energy drinks after considering several studies regarding such beverages as well as concerns voiced by substance abuse prevention and parental groups, the general public, and an ongoing U.S. Food and Drug Administration (FDA) investigation. The Commission called the packaging of these products "misleading," and an attempt to appeal to younger customers "encouraging excessive consumption while mixing alcohol with various other chemical and herbal stimulants." The ban takes effect in early December.
The MLCC pointed out that a typical alcoholic energy drink is 24 ounces (0.7 liters) and has a 12 percent alcohol content—compared with a 12-ounce (0.35-liter) can of beer, which normally has 4 to 5 percent—plus the caffeine equivalent of five cups of coffee. Some of the beverage lines singled out for their 12 percent alcohol content were Associated Brewing's Axis, United Brands's Max and Phusion Projects's Four Loko offerings. The commission concluded that a person need only consume one can of such a beverage to become intoxicated—and that because these drinks typically cost $2 to $5 per can they are "easily accessible and affordable."
Such beverages were in the news last month when nine Central Washington University students were hospitalized following a party. The blood alcohol levels of the students—who were all under the age of 21 at the time of the incident—ranged from 0.123 to 0.35. (A blood alcohol concentration of 0.3 can be lethal.) That school and others have since banned such drinks from campus pending further investigation.
Not far from Michigan, Chicago's City Council proposed its own ban on energy drinks that contain alcohol. Michigan and Oklahoma are the only states so far to ban such beverages, but New York is considering the same, and the Pennsylvania Liquor Control Board last week asked its licensed sellers to voluntarily stop selling and promoting alcoholic energy drinks such as Four Loko.
Whereas the combination of alcohol and caffeine is nothing new—rum and Coke, anyone?—this new breed of beverage is not meant to be sipped or served on the rocks. Scientific American asked Thomas Gould, an associate professor of psychology at Temple University in Philadelphia, to explain what happens to the body when large amounts of alcohol and caffeine are consumed simultaneously, why such drinks appeal to some drinkers, and the potential consequences of overindulgence.
[An edited transcript of the interview follows.]
What effect does the simultaneous consumption of alcohol and caffeine have on the body?
Alcohol is a sedative. It works in part by potentiating the GABAergic neurotransmitter system. GABA [gamma-aminobutyric acid] is an inhibitory neurotransmitter. When the neurons in the brain release GABA, it acts to slow down or inhibit other neural processes. This can reduce anxiety, increase relaxation while sedating a person. With higher levels of alcohol, problems can arise as important neural and other bodily systems become overinhibited and shut down.
Compared to alcohol, caffeine is on the other end of the spectrum of psychoactive drugs in that it is a stimulant. Caffeine is an antagonist for the neurotransmitter adenosine. Adenosine is an inhibitory neurotransmitter; so similar to GABA, adenosine can dampen or inhibit other neural processors. With caffeine, we have a double negative in that it inhibits an inhibitory neurotransmitter and thus increase levels of arousal and alertness—but higher doses can produce nervousness, anxiety and tachycardia.
One thing both drugs do is increase dopamine levels. Dopamine is a neurotransmitter associated with reward. One thing all drugs of abuse have in common is the ability to activate the dopamine system. The ability of alcohol and caffeine to stimulate the dopamine system may be one factor contributing to their use.
Because the drugs in a sense have opposite effects, one might expect that simultaneous consumption may reduce the effects that are seen when each drug is administered alone, but it really is not as simple as that. Some effects may be reduced while others are increased, and this may vary as the doses of the drugs vary.
Why might someone—an underage drinker in particular—want to drink a beverage that combines alcohol and caffeine?
Caffeine can reduce the sedative effects of alcohol; this may allow someone to drink for longer periods of time. In addition, evidence suggests that caffeine and alcohol together may be more rewarding than alone. This could be due to both drugs producing increases in dopamine levels, which as discussed is involved in reward.