Some people experience the initial effects of alcohol as stimulating and euphoric, while others experience mostly unpleasant sedative effects. How individuals’ immediate responses to alcohol influence their future drinking behavior has been an active area of scientific research. One theory holds that people who have a low level of positive response to alcohol and who also are less sensitive to internal cues and warning signs to stop drinking, are more likely to drink to excess and develop alcohol problems. However, this low-level response theory has been contradicted by studies which suggest that people who drink heavily experience greater alcohol-induced positive effects. To help resolve these issues, scientists investigated the acute effects of alcohol among nearly 200 young adults who were divided into groups of heavy and light drinkers based on their drinking histories. In three separate testing sessions, the subjects received one of three drinks: a placebo, a low dose of alcohol, or a high dose of alcohol. A flavoured drink mix made all of the concoctions taste the same, so none of the subjects knew what they were drinking. For the next three hours, the subjects took breath alcohol tests and answered questions that allowed the researchers to measure a variety of positive and negative effects. The scientists found that alcohol produced greater stimulant and rewarding responses and lower sedative responses among the heavy drinkers than the light drinkers. Over a 2-year follow-up period, greater positive effects and lower sedative effects after alcohol consumption predicted increased binge drinking frequency. In turn, greater frequency of binge drinking during follow-up was associated with greater likelihood of meeting diagnostic criteria for alcohol abuse and dependence. The new data could help clinicians identify and prevent unhealthy drinking habits.
Recent research suggests that receptors for the neurotransmitter GABA(A) that lie outside of the synapse and which contain a molecular fragment known as a delta-subunit are sensitive to alcohol, raising the possibility that these receptors might help produce alcohol’s reinforcing effects after consuming one or a few drinks. In the current study, researchers tested the hypothesis that these extrasynaptic GABA(A) receptors in an area of the brain’s reward circuitry called the nucleus accumbens (NAc) are necessary for oral alcohol consumption. They used genetic-engineering technology to reduce expression of the GABA(A) receptor delta-subunit in adult rats in different parts of the NAc, a structure that consists of a core and a shell, which is subdivided into ventral, medial, and dorsal parts. They found that by inhibiting the delta-subunit in the medial shell region of the NAc, but not in the ventral or lateral shell or in the core, reduced the rats’ alcohol intake. In contrast, delta-subunit inhibition in the medial shell did not affect intake of a 2% sucrose solution, suggesting that the effects of GABA(A) receptor delta-subunit reduction are specific to alcohol. The findings provide strong evidence that extrasynaptic delta-subunit-containing GABA(A) receptors in the medial shell of the NAc are critical for the reinforcing effects of oral ethanol.
Alcohol consumption and its harms are common among young people, including those who are below the legal drinking age of 21. Some people argue that the current age-21 drinking limit in the United States is “not working,” and propose that the drinking age be lowered to 18. Researchers recently conducted economic analyses to estimate the effects of the minimum legal drinking age (MLDA) on deaths, injuries, crime, and alcohol consumption, and to identify the costs and benefits of lowering the drinking age to 18. They report that a large body of evidence shows that setting the MLDA at 21 clearly reduces alcohol consumption and its major harms. They estimate that lowering the MLDA to 18 would result in an additional 8 deaths per 100,000 person years for the 18–20 age group. Using a common estimate of the value of a statistical life of $8.72 million, this suggests that for every 100,000 young adults allowed to drink legally for a year the cost in terms of increased mortality is about $70 million. The researchers also estimate that lowering the drinking age would impose additional costs on others for crime, health care, and deaths of non-drinking drivers and passengers of at least $12 million annually for every 100,000 newly legal drinkers. These estimates suggest that each extra drink consumed as a result of lowering the MLDA would generate harms valued at more than $15 to the drinker plus at least an additional $2.63 in harms imposed on others, all in addition to the purchase price of the drink. The researchers conclude that “…the evidence strongly suggests that setting the minimum legal drinking age at 21 is better from a cost and benefit perspective than setting it at 18 and that any proposal to reduce the drinking age should face a very high burden of proof.”
Underage alcohol use is a pervasive and persistent problem in the United States and many other countries, with serious health and safety consequences, often resulting from binge drinking. Given the significant amount of alcohol advertising to which young people are exposed in virtually all types of media, scientists have sought to learn whether and how such advertising influences underage drinking. In a new study, NIAAA-supported researchers asked 2699 youth aged 16-20 about their alcohol use and alcohol brand preference as part of a long-term telephone survey of U.S. adolescents and media use. Their report shows that a majority of underage drinkers in the study identified a preference for a specific brand of alcoholic beverage, that the most-preferred brands included both distilled spirits and beer, and that brand preferences correlated with levels of brand-specific advertising expenditures. This correlation suggests that alcoholic beverage marketing efforts may be reaching and influencing underage audiences. The researchers also found that young drinkers who identified a preferred brand were also more likely to engage in binge drinking, a finding that highlights the need for further research to identify any causal connections between alcohol advertising, brand preferences, and binge drinking among underage youths.