Hangover is the widely used term for a collection of short-term side effects that can appear after a person consumes excessive amounts of alcohol. Previous research has shown that drinkers who frequently experience these side effects are more likely to eventually receive a diagnosis for alcohol use disorder (alcohol abuse\/alcoholism) than drinkers who typically don\u2019t experience them. In a study scheduled for publication in 2014 in the journal Addiction, researchers from the U.S. and Australia used data from a large-scale project to help determine if genetic inheritance influences the odds of developing a hangover after a bout of drinking. Hangovers Alcohol is a body and brain toxin. This means that the substance has a poisonous effect on your organ function, particularly when consumed above light or moderate levels. The poisonous impact of drinking is especially obvious during active alcohol intoxication. In fact, many of the effects commonly associated with a drunk or intoxicated state (e.g., loss of balance, thought impairment and slurred speech) actually highlight the presence of harmful changes in your normal organ function. In extreme cases, alcohol poisoning can produce life-threatening alteration of your basic ability to do such things as breathe or maintain body temperature. As a rule, hangovers first appear after your body has processed and eliminated large amounts of alcohol from your system. Although no one knows precisely why they occur, key contributing factors include the dehydrating effects of significant alcohol intake and the buildup of a toxic alcohol breakdown product called acetaldehyde. Symptoms of a hangover commonly include headaches, a nauseous feeling, fatigue, diarrhea, listlessness, a lack of interest in food and adverse reactions to movement, sound and light. Most people experience these symptoms only after binging on enough alcohol to approach or reach a legally drunken state. In a study published in 2014 in the journal Alcoholism: Clinical & Experimental Research, a team of American researchers investigated whether the experience of a hangover can delay the amount of time it takes a habitual alcohol consumer to start his or her next session of drinking. These researchers concluded that hangovers do delay drinking participation in habitual consumers, but not by any substantial or statistically meaningful amount. Alcohol and Genetics Researchers and public health officials are well aware that genetic inheritance plays an important role in any given person\u2019s susceptibility to the effects of alcohol and long-term chances of developing diagnosable alcohol problems. For example, while most people only experience nausea and other unpleasant sensations after drinking in large amounts, some individuals with Asian ancestry carry genes that help trigger unpleasant effects after they consume even small amounts of alcohol. Since these individuals don\u2019t typically view drinking as a pleasurable activity, they may have substantially diminished odds of ever developing alcohol use disorder. Conversely, some people carry genes that delay the onset of disagreeable drinking side effects; these individuals may have increased chances of developing the disorder. Are Hangover Risks Hereditary? In the study scheduled for publication in Addiction, researchers from the University of Missouri, the Midwest Alcoholism Research Center and two Australian institutions used data gathered from 4,496 participants in a project called the Australian Twin Registry to calculate the role that genetic inheritance plays in the risks for experiencing hangovers. Twins are especially helpful in such projects because they share the same genetic profile and the same baseline susceptibility to genetically influenced conditions. All of the study participants originally submitted information on their drinking practices and hangover exposure in interviews conducted between 2004 and 2007. The researchers looked at three factors: relative susceptibility to developing a hangover, relative resistance to developing a hangover and the number of hangovers experienced within a year. After reviewing the data, the researchers concluded that when it comes to hangover frequency, genetic inheritance accounts for roughly 45 percent of the risk in men and 40 percent of the risk in women. Approximately 24 percent of men\u2019s relative susceptibility to developing a hangover has a genetic basis; about 16 percent of women\u2019s hangover susceptibility is genetic. In addition, roughly 43 percent of both men\u2019s and women\u2019s ability to avoid developing a hangover comes from genetic inheritance. Numerous non-genetic factors also influence overall hangover risks; however, the researchers could not find any consistent non-genetic influences for either men or women.