Longitudinal Dynamics of Substance Use and Psychiatric Symptoms in Count Data with Zero Inflation

Multilevel modeling in single-case studies with zero-inflated and overdispersed count data

Count outcomes are frequently encountered in single-case experimental designs (SCEDs). Generalized linear mixed models (GLMMs) have shown promise in handling overdispersed count data. However, the presence of excessive zeros in the baseline phase of SCEDs introduces a more complex issue known as zero-inflation, often overlooked by researchers. This study aimed to deal with zero-inflated and overdispersed count data within a multiple-baseline design (MBD) in single-case studies. It examined the performance of various GLMMs (Poisson, negative binomial [NB], zero-inflated Poisson [ZIP], and zero-inflated negative binomial [ZINB] models) in estimating treatment effects and generating inferential statistics. Additionally, a real example was used to demonstrate the analysis of zero-inflated and overdispersed count data. The simulation results indicated that the ZINB model provided accurate estimates for treatment effects, while the other three models yielded biased estimates. The inferential statistics obtained from the ZINB model were reliable when the baseline rate was low. However, when the data were overdispersed but not zero-inflated, both the ZINB and ZIP models exhibited poor performance in accurately estimating treatment effects. These findings contribute to our understanding of using GLMMs to handle zero-inflated and overdispersed count data in SCEDs. The implications, limitations, and future research directions are also discussed.

The role of effortful control in the development of ADHD, ODD, and CD symptoms

Many adolescents have difficulty regulating their impulses and become prone to externalizing problems (e.g., attention-deficit/hyperactivity disorder [ADHD], oppositional defiant disorder [ODD], and conduct disorder [CD]) and other adverse consequences. Using multimethod data from a longitudinal study of Mexican-origin youth (N = 674), assessed annually from age 10 to 16, we examined the relations between effortful control and ADHD, ODD, and CD symptoms over time. Bivariate latent growth curve models showed negative correlations between the trajectories of effortful control and ADHD, ODD, and CD, indicating that steeper decreases in effortful control were related to steeper increases in ADHD, ODD, and CD symptoms. Using a novel statistical technique, the factor of curves model (FOCUS), we found that ADHD, ODD, and CD share a common "externalizing" trajectory during adolescence. Although effortful control was strongly associated with this common trajectory, it had few unique associations with the individual disorder trajectories, above and beyond their shared trajectory. When we extended the FOCUS model to include the effortful control trajectory as an indicator, we found that ADHD and ODD had strong loadings, whereas effortful control and CD had comparatively weak loadings on the shared developmental trajectory. Follow-up analyses showed that a two-factor solution, with externalizing symptom trajectories on one factor and the effortful control facet trajectories on a separate factor, was a better fit to the data than a one-factor solution. Finally, parent ASPD symptoms were related to increases in CD, but had no significant influence on effortful control, ADHD, or ODD. We discuss the implications for personality and externalizing problem development. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Changes in implicit alcohol attitudes across adolescence, and associations with emerging alcohol use: Testing the reciprocal determinism hypothesis

Implicit alcohol-related cognitions develop during adolescence and are thought to play an important role in the etiology of adolescent alcohol use. Rooted in reciprocal determinism, a developmental theory of alcohol-related cognitions, the current study sought to enhance our understanding of the development of automatic alcohol associations and their relationship with alcohol use. To provide a theoretically aligned test of reciprocal determinism, we used latent change score models to examine whether growth in automatic alcohol associations and alcohol use was related to each other (between-person effects) and whether each construct led to changes in the other over time (within-person effects). Adolescents (N = 378) completed 4 annual assessments, spanning early to middle adolescence. Automatic alcohol associations were assessed with a Single Category Implicit Association Test, and we used a quadruple processing tree model to extract a more "process pure" index of these associations. Alcohol use increased from early to middle adolescence, as negative automatic alcohol associations weakened over that same time period. Although there was no support for between-person associations, on the within-person level, weak negative automatic alcohol associations at Waves 2 and 3 were associated with increases in drinking at subsequent waves. Alcohol use did not significantly predict changes in automatic alcohol associations. Findings suggest the utility of distinguishing within- and between-person associations to understand the development of automatic alcohol associations and that automatic alcohol associations are prospectively associated with alcohol use and a potential target for intervention, one that becomes an increasingly salient influence on drinking as adolescence progresses. (PsycINFO Database Record (c) 2018 APA, all rights reserved).