Maternal predictors of comorbid trajectories of cigarette smoking and marijuana use from early adolescence to adulthood

Abstract

This is the first study to examine maternal predictors of comorbid trajectories of cigarette smoking and marijuana use from adolescence to adulthood. Participants (N = 806) are part of an on-going longitudinal psychosocial study of mothers and their children. Mothers were administered structured interviews when participants were adolescents, and participants were interviewed at six time waves, from adolescence to adulthood. Mothers and participants independently reported on their relationships when participants were $\overline{\text{X}}$ age 14.1 years. At each time wave, participants answered questions about their cigarette and marijuana use from the previous wave to the present. Latent growth mixture modeling determined the participants' membership in trajectory groups of comorbid smoking and marijuana use, from $\overline{\text{X}}$ ages 14.1 to 36.6 years. Multivariate logistic regression was used to assess the association of maternal factors (when participants were adolescents) with participants' comorbid trajectory group membership. Findings showed that most maternal risk (e.g., mother–child conflict, maternal smoking) and protective (e.g., maternal affection) factors predicted participants' membership in trajectory groups of greater and lesser comorbid substance use, respectively. Clinical implications include the importance of addressing the mother–child relationship in prevention and treatment programs for comorbid cigarette smoking and marijuana use.

Introduction

There have been a number of important studies (typically, from adolescence into young adulthood) on trajectories of tobacco use (e.g., Chassin et al., 2000, Orlando et al., 2004), and somewhat fewer investigations on marijuana use trajectories (e.g., Windle & Wiesner, 2004). Little research, however, has examined the comorbid trajectories of both cigarette smoking and marijuana use. Jackson, Sher, and Schulenberg (2008) discerned seven comorbid trajectory groups of tobacco and marijuana use (including abstainers) from late adolescence to young adulthood, and identified psychosocial factors, such as delinquency, which were related to trajectory group membership. Brook, Lee, Finch, and Brown (2010) found that greater emotional and behavioral problems, as well as deviant peer affiliations, were each associated with the heaviest comorbid cigarette and marijuana use group, among African Americans and Puerto Ricans.

To our knowledge, this is the first study of the maternal predictors of comorbid smoking and marijuana use trajectories across several developmental periods (i.e., adolescence to adulthood). Our theoretical framework is based on Family Interactional Theory (FIT; Brook, Brook, Gordon, Whiteman, & Cohen, 1990), which posits that the parent–child relationship is the nexus of several interrelated domains (e.g., family, peer group) that may affect child outcomes, such as substance use. According to FIT, these domains are linked with the child's behavior via social modeling, parent–child attachment, and the child's identification with parental values and behaviors as a result of this attachment. The child's social modeling and introjection of parental pro-social affect and behavior, in turn, will facilitate the child's own emotional control, and the development of conventional personal attributes, as well as foster the child's affiliation with non-substance-using peers. Here, we extend the FIT paradigm to an adult cohort.

The research literature has established the important etiological role of family factors, and especially, the parent–child relationship, in both cigarette smoking and marijuana use during adolescence and young adulthood (e.g., Gutman et al., 2011, Marti et al., 2010). For example, Butters (2002) demonstrated that poor parent–child relationships predicted marijuana use and marijuana use problems among adolescents.

Cigarette smoking and marijuana use often co-occur. Degenhardt, Hall, and Lynskey (2001), for instance, found that regular tobacco use was associated with marijuana use, abuse, and dependence among adults. Much less is known, however, about the long-term patterns of comorbid smoking and marijuana use or, moreover, their predictors. Based on previous research on trajectories of substance use (e.g., Ellickson, Martino, & Collins, 2004), we hypothesized the following 5–6 comorbid cigarette smoking and marijuana use trajectory groups: a) chronic heavy, b) moderate, c) late-onset, d) mixed groups (in which one substance was used more heavily than the other over time), e) non- or experimental users, and possibly, f) a group that matured out of both cigarette and marijuana use. We further hypothesized that the quality of several aspects of the mother–child relationship when participants were adolescents, as well as maternal smoking, would serve as risk (e.g., maternal–child conflict) or protective (e.g., maternal affection) factors for trajectory group membership.

Our specific hypotheses were: 1) heavy cigarette smokers/heavy marijuana users would score lower on the measures of mother–child attachment (e.g., less maternal affection), and higher on maternal smoking, than the other comorbid trajectory groups; 2) heavy cigarette smokers who engaged in occasional or moderate marijuana use would report a weaker attachment relationship with their mothers, and have mothers with higher smoking scores, than the non- or experimental cigarette smokers/marijuana users; 3) occasional cigarette smokers who were moderate or heavy marijuana users would have a weaker mother–child attachment relationship (e.g., greater conflict), and more maternal smoking, than non- or experimental smokers/marijuana users; and 4) late-starting cigarette and marijuana users would have less mutual attachment with their mothers, and more maternal smoking, than the non- or experimental users.