Cocaine use trajectories of club drug-using young adults recruited using time-space sampling.

Cocaine is the most widely used club drug. Yet, little is known about how patterns of cocaine use vary over time among young adults of diverse gender and sexual identities. This study used latent class growth analysis to identify trajectories of cocaine use over a year and explored individual and substance use factors associated with these trajectories. A sample of 400 young adults (mean age=23.9 years) with recent club drug use were recruited from New York City bars and nightclubs using time-space sampling. Participants completed quantitative measures at baseline, 4-, 8- and 12-months follow-up. A 4-class model fit the data best. Patterns were: Consistent use (48%), Inconsistent use (14%), Decreasing Likelihood of use (28%), and Consistent non-use (11%). Those most likely to be in the Consistent use class had the highest frequency of baseline club drug dependence (χ2 (3, 397)=15.1, p<.01), cocaine dependence (χ2 (3, 397) = 18.9, p<.01), recent alcohol use (χ2 (3, 397)=12.48, p<.01), and drug sensation-seeking (χ2 (3, 397)=9.03, p<.01). Those most likely to be in the Consistent Non-use class had the highest frequency of baseline marijuana use (χ2 (3, 397)=2.71, p<.05). Contrary to hypotheses, there were no differences in most-likely trajectory class by gender/sexual-orientation, age, ethnicity, education, employment status, or income. Findings highlight the diversity of cocaine use patterns over time among young adults, and the personal and substance use characteristics that are associated with each.