%0 Journal Article
%T An Epidemiological Model for Examining Marijuana Use over the Life Course
%A Susan M. Paddock
%A Beau Kilmer
%A Jonathan P. Caulkins
%A Marika J. Booth
%A Rosalie L. Pacula
%J Epidemiology Research International
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/520894
%X Trajectories of drug use are usually studied empirically by following over time persons sampled from either the general population (most often youth and young adults) or from heavy or problematic users (e.g., arrestees or those in treatment). The former, population-based samples, describe early career development, but miss the years of use that generate the greatest social costs. The latter, selected populations, help to summarize the most problematic use, but cannot easily explain how people become problem users nor are they representative of the population as a whole. This paper shows how microsimulation can synthesize both sorts of data within a single analytical framework, while retaining heterogeneous influences that can impact drug use decisions over the life course. The RAND Marijuana Microsimulation Model is constructed for marijuana use, validated, and then used to demonstrate how such models can be used to evaluate alternative policy options aimed at reducing use over the life course. 1. Introduction Marijuana is the most widely used illicit substance in the United States, with use rates being the highest among youth and young adults. Average thirty-day use rates among high school seniors in the United States have been about 20% since 1994 and in 2009, and 5.4% of high school seniors reported daily use of marijuana during the past month [1]. Use rates among young adults are also high, with 59% of all individuals between the ages of 19 and 28 reporting having ever used marijuana, 17% of individuals reporting use in the past thirty days, and 5.4% reporting use of marijuana on a daily basis in the past 30 days [2]. Although a large number of studies have examined risk and vulnerability factors associated with the general use and onset of marijuana, only recently have scientists started examining factors associated with marijuana use careers, the duration and severity of marijuana use, and quit behavior. Current work suggests that age of onset, frequency of use at an early age, drug-using peers, and stressful life events are important factors influencing both duration and the probability of quitting [3¨C6]. Other work suggests that while these various factors are important, there are alternative trajectories of use that people seem to follow because of heterogeneous experiences [7¨C10]. The vast majority of these trajectory studies have focused only on the periods of late adolescence and young adulthood during which marijuana use peaks [11¨C13]. None of these analyses have examined the longer-term implications of marijuana use careers, such as the
%U http://www.hindawi.com/journals/eri/2012/520894/