'Prepartying' involves the consumption of alcohol before going out to the main event of the evening. It is linked to high levels of consumption of alcohol and negative consequences such as blacking out, throwing up and getting into trouble. Researchers from the University of Washington in Seattle studied prepartying in 444 college students. They found the most common reasons for it were arriving at a social event already 'buzzing,' saving money and making the night more interesting. Men were more likely to drink to boost their chances with the opposite sex than women. Underage and legal age drinkers (the legal age for drinking in the U.S. is 21) drank before going out to the same extent, and as often, as each other, but underage students had higher blood-alcohol levels.
Pedersen, Eric R., LaBrie, Joseph W. and Kilmer, Jason R. - Before you slip into the night, you'll want something to drink: exploring the reasons for prepartying behavior among college student drinkers Issues in Mental Health Nursing 2009, 30(6), 354-363