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Smoking Cessation with a Time-Varying Mediation Effect Model (309563)

Keywords: Mediation, time varying effect, smoking craving, friend's substance use

Craving to smoke plays a critical role in continued smoking behavior. We will examine if the effect of a text-based smoking intervention reduces craving and if this effect is mediated by their friend's substance use. Mediation analysis allows examination of the mechanisms where a treatment influences an outcome. Current methods cannot examine how a mediation effect may change non-parametrically over time. This study applies a newly developed time varying mediation effect model in which the mediation effect varies as a continuous function of time. The data were collected from 188 adolescents over 6-months using ecological momentary assessment (EMA). Adolescents were randomly assigned to treatment vs. control groups and received 3 EMA prompts for 4 days each month. The results show that the effect of the text-based intervention on craving via their friend's substance use changes monthly with the strongest effect in the 2nd month and the weakest in the 4th month. The new time-varying mediation model helps to better understand continued smoking behavior by identifying when their friend's substance use is having the strongest impact on the participant's craving.