Newswise — Friday and Saturday nights seem to be the universal nights for partying. They are the peak times for heavy drinking by young adults, often beyond what is considered heavy episodic drinking (HED) – five or more drinks per occasion for men, four or more for women. Although heavy drinking is assumed to be intentional, in fact very little is known about the extent to which heavy drinking is pre-planned and the factors that might contribute to a person’s drinking more than he or she intended. This study investigated drinking intentions at the beginning of an evening and individual and situational factors linked to subsequent drinking.

Researchers gathered data via a smartphone application from 176 young people (90 males, 86 females), ages 16 to 25, recruited from two major nightlife hubs in Lausanne and Zurich, Switzerland during September 2014. Study participants answered questions about their drinking intentions, consumption, and drinking environments before, during, and after multiple Friday and Saturday nights (n = 757). Statistical analyses determined individual-level and night-level factors associated with previous drinking intentions and subsequent deviations from those intentions.

Participants drank more than intended on almost half of all nights, and they exceeded the thresholds for HED twice as often as planned. For both genders, this was associated in particular with drinking that began early in the evening (before 8 p.m.), when drinking locations changed, and when there were large groups of friends drinking. Heavier consumption than was intended was also influenced by, for men, drinking away from home, and for women, going to nightclubs. Study authors recommended both protective behavioral strategies – such as deciding in advance not to exceed a set number of drinks, and keeping track of the number of drinks consumed – and structural measures – such as restricting late-night opening hours and access to drinking establishments for people who are already intoxicated – as measures to reduce excessive drinking.

Journal Link: Alcoholism: Clinical and Experimental Research