Conjoint developmental trajectories of young adult alcohol and tobacco use

Abstract

Developmental and etiological advances have set the stage for considering trajectories of problem behavior across the life course, but little work thus far addresses co-occurring problem behavior trajectories. Although recent work characterizes drinking and smoking trajectories, none has explored the course of concurrent drinking and smoking. Using panel data from the Monitoring the Future Project (N=32,087), the authors applied growth mixture modeling to 4 waves of heavy drinking and smoking in a young-adult sample. The authors extracted a single latent group membership factor from heavy drinking and smoking. Associations between trajectory classes and risk factors were relatively unique to the substance being predicted. The association of smoking with alcohol expectancies and delinquency appeared to exist by virtue of smoking's comorbidity with drinking.

Figure 1

Heavy drinking (top panel) and smoking (bottom panel) at Times 1–4 as a function of birth cohort. Item responses for heavy or binge drinking were 1 (never drink), 2 (once), 3 (twice), 4 (3–5 times), 5 (6–9 times), and 6 (10 or more times). Item responses for quantity of smoking were 1 (not at all), 2 (less than 1 cigarette per day), 3 (1–5 cigarettes per day), 4 (about 1/2 pack per day), 5 (about one pack per day), 6 (about 1½ packs per day), and 7 (2 packs or more per day)

Figure 2

Mixture model for frequency of heavy drinking (left) and smoking quantity (right) at Times 1–4 weighted by estimated class probabilities. Akaike’s (1987) Information Criterion = 577,348.87; Bayesian Information Criterion (Schwartz, 1978) = 578035.59; Entropy = .92.