Latent Class Analysis of college women's Thursday drinking.

College students drink in consistent patterns over the course of the academic semester and year (Beets et al., 2009; Del Boca et al., 2004). However, it is unclear if there are naturally occurring groups of female Thursday drinkers who display their own unique patterns of drinking across the semester. In a fall semester 10-week mixed online- and paper-based study of college female drinking, classes of Thursday drinkers were identified using Repeated Measures Latent Class Analysis. The 424 participants were recruited via flyers and advertisements in the student newspaper. It was determined that three latent classes provided optimal fit to the data: 1. Unlikely to report Thursday drinking; 2. Normal probability of Thursday drinkers; and 3. High probability of Thursday drinkers. The proportion of students within the latent classes differed across academic year in school. Seniors were least likely to be in the Unlikely group, and juniors and seniors were not in the Normal group. An additional analysis indicated that women in a sorority were four times more likely to be in the Normal or High groups compared to the Unlikely group. A final set of analyses indicated that women who enrolled in Friday morning classes were more likely to be in the Unlikely or Normal groups compared to the High group. Results indicated that the Unlikely group consumed significantly less alcohol at baseline, had lower levels of negative alcohol-related consequences prior to and during the study, and drank less on the weekends (Friday and Saturday). Female students who report drinking on Thursdays tend to be older, to be part of sororities, to have later classes or no classes on Friday, and to experience more negative alcohol-related consequences. Female students whose "weekends" start early are high-risk drinkers and might be targeted for future prevention and intervention efforts.