Consumption questions were standard questions that investigated the subject’s consumption habits (frequency and quantity) considering the particular drink in question, with a focus on beverage consumption in the past 30 days. These questions were adapted from the Quick Drinking Screen (QDS). The QDS contains four consumption questions that have been shown to be highly reliable and consistent when compared to the 12-month Timeline Followback method.33 (link),34 (link) The QDS was also employed by Woolsey et al.20 If applicable, the consumption questions were asked for consuming AO, consuming AMED, and for mixing alcohol with other non-alcoholic beverages. The consumption questions are listed in Table 1. Regarding the other non-alcoholic mixers, participants had to choose the one mixer they usually preferred. They had the choice between eight mixers that are popular in The Netherlands, including cola, diet cola, orange-flavored carbonated soft drink, blackcurrant-flavored carbonated soft drink, lemon soda, tonic water, orange juice, and apple juice. Participants then completed the consumption questions concerning the preferred mixer they chose. Finally, if applicable, participants were required to report their reasons for: (1) consuming energy drinks alone; (2) mixing alcohol with energy drinks; and (3) mixing alcohol with other non-alcoholic beverages (ie, the non-alcoholic beverage they preferred). Table 2 summarizes the questions surrounding the reasons and motivations involved with energy drink consumption, as well as the reasons for mixing alcohol with energy drinks or other mixers. Participants could report multiple reasons and add additional motives behind their beverage consumption patterns.