When yesterday's consumption strikes back: deviation from usual consumption inversely predicts amounts consumed the...

Young adults' weekend alcohol consumption is characterised by heavy episodic drinking (HED) with low alcohol use in between. This study investigates whether consuming a lower or higher number of drinks than usual on a given evening predicts consumption the following evening.

In French-speaking Switzerland, 115 young adults (57% female, mean age = 23.2) answered questionnaires on their cellphones six times every Thursday, Friday and Saturday evening over five consecutive weeks. Multilevel models with group-mean centering were used to analyse 462 evening pairs.

Although the sample average number of drinks consumed tended to increase from Thursday [Mmen (SD) = 3.6 (5.0); Mwomen (SD) = 2.9(4.2)] to Saturday [Mmen (SD) = 7.4( 7.1); Mwomen (SD) = 5.2(5.6)], substantial day-to-day variations were observed within individuals. Variations from the usual consumption (i.e. higher or lower number of drinks than usual) on the first day had a significant inverse impact on amounts consumed the following day (unstandardised regression coefficient (B) = -0.27, P < 0.01). This effect was more marked for evening pairs including HED (B = -0.44, P < 0.001). Men and heavy drinkers were less subject to day-to-day variations than women and usually moderate drinkers.

The inverse relationship might result from adverse consequences experienced after HED or an intentional reduction in alcohol consumption in anticipation of a heavy drinking session the next day. Event-specific prevention is needed for women and usually light or moderate drinkers as their more distinct consumption peaks put them at greater risk, particularly of accidents and injuries.