Does substance use during youth cause lasting changes in resting-state neurophysiology and brain functional connectivity? A co-twin control investigation

Abstract

This dissertation comprises two studies aimed at disentangling potential causal effects of recreational substance use (alcohol, cannabis, tobacco) on resting-state electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) brain outcomes in a community sample of young adults. As noted by the introductory text for each study, there is a dearth of causally-informative research designs in published literature regarding whether drug and alcohol use has lasting effects on human EEG and fMRI. These two studies intend to bridge this gap by utilizing a causally-informative co-twin control (CTC) research design which utilizes the fact that twins reared in the same home are matched on many factors (e.g., genes, parental substance use, SES) that contribute to confounding in the hypothetical causal link between substance use and brain outcomes in extant cross-sectional research. As such, within twin-pair differences in use can be exploited to study within twin-pair differences in brain outcome (e.g., EEG, fMRI) to understand possible causal effects.