To establish a trait-dispositional variable as an indicator of liability for the development of substance use disorders (SUDs), the trait must share heritable variance with SUDs and its association should not be primarily attributable to a direct impact of SUDs on characteristics that define the trait. The current work applied a co-twin control (CTC) modeling approach to data from two monozygotic twin samples to investigate the degree to which different measures of trait-impulsiveness represent indicants of vulnerability to SUDs (liability indicators), or outcomes or concomitants of SUDs (exposure indicators). The Five Factor Model (FFM) trait of conscientiousness was assessed via self-report, and a counterpart neurobehavioral trait of disinhibition was assessed both through self-report and using self-report and brain response measures combined. FFM trait data were available for one twin sample (N = 298); data for variants of P3 brain response were available along with a scale measure of disinhibition in the other (N = 258). CTC analyses revealed only an exposure effect of SUD symptomatology on FFM conscientiousness, indicating that this self-report assessed trait does not index liability for SUDs. By contrast, the disinhibition scale measure showed pronounced liability and weaker exposure-based associations with SUDs – and when quantified using scale scores together with P3 brain response, the exposure-based association was eliminated, such that this disinhibition measure related to SUD symptoms exclusively as a function of liability influences. These findings highlight a distinct advantage of quantifying traits in neurobehavioral terms – namely, the capacity to effectively index dispositional liability for psychopathological outcomes.
Bibliographical noteFunding Information:
C. J. Patrick was supported by U.S. Army grant W911NF-14-1-0018 . N. C. Venables and S. J. Burwell were supported by National Institute on Drug Abuse Grant T32-DA037183 . K. J. Joyner was supported by a Ford Foundation Predoctoral Fellowship administered by the National Academies of Sciences, Engineering, and Medicine. Only the authors of the current work are responsible for the content and any views expressed herein do not represent official views of the U.S. Government, Department of Defense, Department of the Army, Department of Veterans Affairs, or U.S. Recruiting Command. Data were provided [in part] by the Human Connectome Project, WU-Minn Consortium (Principal Investigators: David Van Essen and Kamil Ugurbil; 1U54MH091657) funded by the 16 NIH Institutes and Centers that support the NIH Blueprint for Neuroscience Research; and by the McDonnell Center for Systems Neuroscience at Washington University. The authors are deeply grateful for the willingness of the HCP PIs to share data openly.
© 2019 Elsevier B.V.
- Co-twin control
- Substance use disorder