(PS1-B37) Exploring Momentary Predictors of Polysubstance Use

Polysubstance use (e.g., the simultaneous use of two or more substances) is related to several serious consequences including risk for using more substances, developing substance use disorder, and overdose. Research has yet to identify key situational factors that predict polysubstance use and using ambulatory assessment is an ideal methodology to address this question. To this end, we explored momentary social and locational factors related to polysubstance use.
 

Participants (N = 59) with illicit substance use in the past two weeks completed 14 days of ambulatory assessment on their mobile devices. Assessments were sent four times a day and assessed stressors, positive events, where the individual was located, who the individual was with, and whether the individual had used any substances since the last assessment. Poisson regression was used to examine predictors of polysubstance use. There were no a priori hypotheses; these analyses were exploratory.
 

Results showed both who an individual was with and where they were located significantly predicted the number of substances an individual used. The options for who an individual was with included being alone, with a co-worker, family, friends, romantic partner, stranger, or other. Location options included a bar, car, friend’s, home, outside, romantic partner’s, school, work, or other. Being with a friend predicted the greatest number of substances used while being with a co-worker or stranger predicted the least number of substances used. However, there was no significant difference between being with a friend or being with a romantic partner (p = 0.13) or other (p = 0.14). For location, being at a friend’s house predicted the greatest number of substances used, and being at work predicted the least number of substances used. However, there was no significant difference between being at a friend’s or at a romantic partner’s (p = 0.10) or a bar (p = 0.29).
 

Overall, these findings suggest that being with individuals one feels comfortable with and being in a familiar environment can contribute to polysubstance use. These findings are in contrast with the literature on alcohol use, context, and social familiarity. This literature has found drinking with unfamiliar groups and in unfamiliar contexts is a predictor of heavy drinking while drinking with familiar individuals has been shown to be a protective factor against hazardous drinking. However, the literature on familiar context and individuals has focused on the use of one substance, not polysubstance use. Future research should be done to replicate these findings and begin to explore mechanisms.