RESUMEN
This study identifies patterns of simultaneous polysubstance use (SPU) in partygoers, their associated characteristics, and their differences in terms of acute effects experienced. We used a web-based survey with 1345 partygoers who reported using at least one substance during the past year, collecting information on drug use and drug-related acute effects experienced at the last party attended. Latent class analysis identified three SPU profiles according to the use of nine substances: low polysubstance use (67.7%), moderate polysubstance use/hallucinogens (11.6%), and extensive polysubstance use/stimulants (20.7%). These profiles differed in their sociodemographic characteristics and were associated with different odds of experiencing adverse drug-related effects. Compared with participants with a profile of low polysubstance use or moderate polysubstance use/hallucinogens, those in the extensive polysubstance use/stimulants group were at higher odds of experiencing memory impairment, tachycardia, and bad mood after drug use. The only differences between the low polysubstance use and moderate polysubstance use/hallucinogens groups were in terms of hangover and headache experiences, which were less likely in the latter group (who consume less alcohol). Knowledge regarding the acute adverse drug-related effects experienced by partygoers who use multiple drugs can help to develop interventions for reducing drug-related risks in this population.