Project Summary
Prevention of adolescent substance use (SU) and interventions to reduce harmful use has long been a goal of
NIDA in order to improve the health of individuals and lighten the societal burden of substance misuse.
Research from longitudinal observational studies is critical for establishing sufficient evidence that the target of
intervention could be a causal factor prior to developing and for fine-tuning interventions. This R21 responds to
a call (RFA-DA-22-038) to leverage data from the Adolescent Brain and Cognitive Development (ABCD) study
to develop new and advanced statistical methods, in this case, to improve causal inference and inform
intervention target selection. We will develop and test a new model: a Discordant Sibling Random-Intercept
Cross-Lagged Panel Model (DS RI-CLPM) using data on several (child- and parent-driven) facets of parental
monitoring, a likely causal environmental factor for which there is strong extant evidence of an inverse
association with adolescent SU (aim 1). We will also (aim 2) explore the comparability of estimates from the
DS RI-CLPM model to standard RI-CLPM and DS models and other models to understand how the DS RI-
CLPM compares to current models, and (aim 3) conduct a series of simulation studies to explore power and
the minimum sample sizes needed to establish meaningful effects under various circumstances (i.e., effect
sizes, degree of sibling discordance). The initial products of this R21 will include: 1) openly available code to fit
the DS RI-CLPM model in tutorial form, 2) publications explaining the interpretation and utility of the model,
and 3) publications of simulation studies explicating power, sample size, and other (i.e., model specification)
considerations of the model. The expected end-users are twofold: This model can be used by any researcher
interested in testing a stricter model of causality for their focal associations using large-scale, longitudinal data
that includes twins and/or siblings, many of which are publicly available (e.g., ABCD, Add Health, harmonized
data from the NIH Environment in Child Health Outcomes initiative, Twins Early Development Sample).
Second, we have formed an advisory board of intervention experts to help guide our analyses, sensitivity
analyses, presentation, and dissemination of findings to aid in translation of these findings to ongoing work in
the intervention and prevention of adolescent SU. Through discussions with our advisory board, we expect that
scientists who develop and test interventions will find results from this model of use. By subjecting multiple
aspects of key malleable constructs to this model, we will provide intervention scientists with more detailed
information about the likelihood of causal links and key targets for future interventions. A longer-term product of
this R21 will be an R01 grant submission exploring the generalizability of this model (and the standard RI-
CLPM and standard DS design) to intervention samples (extant data provided by members of our advisory
board). Combined with results from this R21, the planned R01 is expected to yield critical information about
how and when nationally representative longitudinal data are more and less informative for interventions.