Antonio A. Morgan-Lopez

Demonstration and evaluation of a method for assessing mediated moderation.

Mediated moderation occurs when the interaction between two variables affects a mediator, which then affects a dependent variable. In this article, we describe the mediated moderation model and evaluate it with a statistical simulation using an adaptation of product-of-coefficients methods to assess mediation. We also demonstrate the use of this method with a substantive example from the adolescent tobacco literature. In the simulation, relative bias (RB) in point estimates and standard errors did not exceed problematic levels of ±10%, although systematic variability in RB was accounted for by parameter size, sample size, and nonzero direct effects. Power to detect mediated moderation effects appears to be severely compromised under one particular combination of conditions: when the component variables that make up the interaction terms are correlated and partial mediated moderation exists. Implications for the estimation of mediated moderation effects in experimental and nonexperimental research are discussed.

College drinking behaviors: mediational links between parenting styles, impulse control, and alcohol-related outcomes

Mediational links between parenting styles (authoritative, authoritarian, permissive), impulsiveness (general control), drinking control (specific control), and alcohol use and abuse were tested. A pattern-mixture approach (for modeling non-ignorable missing data) with multiple-group structural equation models with 421 (206 female, 215 male) college students was used. Gender was examined as a potential moderator of parenting styles on control processes related to drinking. Specifically, the parent-child gender match was found to have implications for increased levels of impulsiveness (a significant mediator of parenting effects on drinking control). These findings suggest that a parent with a permissive parenting style who is the same gender as the respondent can directly influence control processes and indirectly influence alcohol use and abuse.

Mediation designs for tobacco prevention research.

This paper describes research designs and statistical analyses to investigate how tobacco prevention programs achieve their effects on tobacco use. A theoretical approach to program development and evaluation useful for any prevention program guides the analysis. The theoretical approach focuses on action theory for how the program affects mediating variables and on conceptual theory for how mediating variables are related to tobacco use. Information on the mediating mechanisms by which tobacco prevention programs achieve effects is useful for the development of efficient programs and provides a test of the theoretical basis of prevention efforts. Examples of these potential mediating mechanisms are described including mediated effects through attitudes, social norms, beliefs about positive consequences, and accessibility to tobacco. Prior research provides evidence that changes in social norms are a critical mediating mechanism for successful tobacco prevention. Analysis of mediating variables in single group designs with multiple mediators are described as well as multiple group randomized designs which are the most likely to accurately uncover important mediating mechanisms. More complicated dismantling and constructive designs are described and illustrated based on current findings from tobacco research. Mediation analysis for categorical outcomes and more complicated statistical methods are outlined.

Youth BMI Trajectories: Evidence From the NLSY97

We examined heterogeneity in BMI trajectory classes among youth and variables that may be associated with trajectory class membership. We used data from seven rounds (1997–2003) of the 1997 National Longitudinal Survey of Youth (NLSY97), a nationally representative, longitudinal survey of people born between 1980 and 1984 who were living in the United States in 1997. The analyses were based on an accelerated longitudinal design. General growth mixture modeling implemented in Mplus (version 4.1) was used to identify subtypes of youth BMI growth trajectories over time. Four distinct youth BMI trajectories were identified. Class 1 includes youth at high risk for becoming obese by young adulthood (at age 12 and 23, ∼67 and 90%, respectively, are classified as obese, and almost 72% will have had a BMI ≥ 40 at some time during this developmental period). Class 2 includes youth at moderate‐to‐high risk (at age 12 and 23, ∼55 and 68%, respectively, are classified as obese). Class 3 includes youth at low‐to‐moderate risk (i.e., at age 12 and 23, ∼8 and 27%, respectively, are classified as obese). Class 4 includes youth at low risk (few of these youth are obese at any age during this developmental period). These results highlight the importance of considering heterogeneity in BMI growth among youth and early interventions among those most at risk of the adverse health consequences of excess weight.

Cognitive behavioral treatment for childhood anxiety disorders: long-term effects on anxiety and secondary disorders in young adulthood

BACKGROUND The present studys aim was to examine the long-term effects (8 to 13 years post-treatment; M = 9.83 years; SD = 1.71) of the most widely used treatment approaches of exposure-based cognitive behavioral treatment for phobic and anxiety disorders in children and adolescents (i.e., group treatment and two variants of individual treatment). An additional aim was to compare the relative long-term efficacy of the treatment approaches. METHOD At long-term follow-up, participants (N = 67) were between 16 and 26 years of age (M = 19.43 years, SD = 3.02). Primary outcome was the targeted anxiety disorder and targeted symptoms. Secondary outcomes were other disorders and symptoms not directly targeted in the treatments including (1) other anxiety disorders and symptoms, (2) depressive disorders and symptoms, and (3) substance use disorders and symptoms. RESULTS Long-term remission for anxiety disorders and symptoms targeted in the treatments was evident 8 to 13 years post-treatment. Long-term remission also was found for the secondary outcomes. There were more similarities than differences in the long-term gains when comparing the treatment approaches. CONCLUSIONS Consistent with past research, the studys findings provide further evidence that the short-term benefits of exposure-based CBT for childhood phobic and anxiety disorders using both group and individual treatment may extend into the critical transition years of young adulthood.

College drinking behaviors: Mediational links between parenting styles, parental bonds, depression, and alcohol problems

Mediational links between parenting styles (authoritative, authoritarian, permissive), parental bond (positive, negative), depression, alcohol use and abuse were tested. A 2-group, multiple-indicator, multiple-cause structural equation model with 441 (216 female, 225 male) college students was examined. In general, a poor parental bond with ones father was highly predictive of depression, a well-known predictor of alcohol abuse and related problems for both genders. In contrast, a positive parental bond with ones father significantly mediated the positive effects of authoritative fathering on depression, which then decreased alcohol use problems for both genders. For women, a negative parental bond with ones father significantly mediated the effect of having an authoritarian father on depression, which increased alcohol use problems. These findings suggest that parental influences on pathways to alcohol abuse through depression (primarily through fathers for both genders) are distinct from pathways stemming from poor impulse control (with influences primarily from the same-sex parents for both genders).

Racial Discrimination and Racial Socialization as Predictors of African American Adolescents’ Racial Identity Development using Latent Transition Analysis

The present study examined perceptions of racial discrimination and racial socialization on racial identity development among 566 African American adolescents over 3 years. Latent class analyses were used to estimate identity statuses (Diffuse, Foreclosed, Moratorium, and Achieved). The probabilities of transitioning from one stage to another were examined with latent transition analyses to determine the likelihood of youth progressing, regressing, or remaining constant. Racial socialization and perceptions of racial discrimination were examined as covariates to assess the association with changes in racial identity status. The results indicated that perceptions of racial discrimination were not linked to any changes in racial identity. Youth who reported higher levels of racial socialization were less likely to be in Diffuse or Foreclosed compared with the Achieved group.

A mediated moderation model of cigarette use among Mexican American youth

The current study tested a model examining both the direct and mediated effects of Ethnic Cultural Norms (ECN) on cigarette use in a sample of Mexican American youth (ages 11-14; N=921). Contextual risk factors (peer smoking and family smoking) were included as potential moderators of this mediational relationship. A product of coefficient (alpha beta) method to test the significance of the mediated effect [Evaluation Review 17 (1993) 144.] was adapted to assess the mediation of interaction effects. Results suggested that Tobacco Avoidance Self-Efficacy mediated the protective influence of ECN on cigarette use. However, as peer smoking increased, the influence of ECN on cigarette use diminished, though it remained a significant, protective influence on cigarette use. Results are discussed in terms of the potential synergy between ECN and social influence training in tobacco preventive intervention development among youth of Latin descent.

Analytic Methods for Modeling Longitudinal Data from Rolling Therapy Groups with Membership Turnover.

Interventions for a variety of emotional and behavioral problems are commonly delivered in the context of treatment groups, with many using rolling admission to sustain membership (i.e., admission, dropout, and discharge from group are perpetual and ongoing). The authors present an overview of the analytic challenges inherent in rolling group data and outline commonly used (but flawed) analytic and design approaches to addressing (or sidestepping) these issues. Moreover, the authors propose use of latent class pattern mixture models (LCPMMs) as a statistically and conceptually defensible approach for modeling treatment data from rolling groups. The LCPMM approach is illustrated with rolling group data from a group-based alcoholism pilot treatment trial (N = 128). Different inferences were made with regard to treatment efficacy under LCPMM vs. the commonly used standard group-clustered latent growth model (LGM); coupled with other preliminary findings in this area, inferences from LGMs may be overly liberal when applied to data from rolling groups. Continued work on data analytic difficulties in groups with membership turnover is critical for furthering the ecological validity of research on behavioral treatments.

Analytic complexities associated with group therapy in substance abuse treatment research: problems, recommendations, and future directions.

In community-based alcoholism and drug abuse treatment programs, the vast majority of interventions are delivered in a group therapy context. In turn, treatment providers and funding agencies have called for more research on interventions delivered in groups in an effort to make the emerging empirical literature on the treatment of substance abuse more ecologically valid. Unfortunately, the complexity of data structures derived from therapy groups (because of member interdependence and changing membership over time) and the present lack of statistically valid and generally accepted approaches to analyzing these data have had a significant stifling effect on group therapy research. This article (a) describes the analytic challenges inherent in data generated from therapy groups, (b) outlines common (but flawed) analytic and design approaches investigators often use to address these issues (e.g., ignoring group-level nesting, treating data from therapy groups with changing membership as fully hierarchical), and (c) provides recommendations for handling data from therapy groups using presently available methods. In addition, promising data-analytic frameworks that may eventually serve as foundations for the development of more appropriate analytic methods for data from group therapy research (i.e., nonhierarchical data modeling, pattern-mixture approaches) are also briefly described. Although there are other substantial obstacles that impede rigorous research on therapy groups (e.g., evaluation and measurement of group process, limited control over treatment delivery ingredients), addressing data-analytic problems is critical for improving the accuracy of statistical inferences made from research on ecologically valid group-based substance abuse interventions.