PROJECT SUMMARY/ABSTRACT Cannabis use (CU) to manage mental health symptoms is increasing in both clinical and recreational contexts, particularly among young adults. This emerging trend reflects evolving attitudes surrounding cannabis and underlines a need to evaluate the physical, psychological, and sociocultural factors involved. The present study examines how cognitive processes related to decision-making (i.e., reward motivation and inhibitory control) relate to CU during emerging adulthood (age 18-25) – a crucial developmental period – following a potentially traumatic event. We hypothesize that disruptions to these decisional processes post-trauma drive alterations to CU that result in a mutually reinforcing behavioral pattern whereby pleasurable sensations from CU in the short-term result in lowered hedonic tone overall and long-term adverse cannabis-related outcomes (i.e., cannabis use disorder, greater frequency/quantity of use, cannabis-related problems). The present study leverages methodological advantages of the parent study (R01DA054116; e.g., psychophysiological measurement, ecological momentary assessment, wearable biosensors, longitudinal follow-ups) and implements additional objective measures of cognitive processes related to discrete choice behavior. Specifically, the present project will recruit 70 participants from the parent project, add two baseline self-report measures of hedonic tone and impulsivity, and add two behavioral tasks assessing reward motivation and inhibitory control at two study timepoints – 2-weeks post-trauma and 6-months post-trauma. The present study will use sequential sampling modeling (SSM), which unites trial-level data from behavioral tasks with physiological data to derive inferences into latent decision-making processes that cannot be inferred by group averages. We will develop computational models of these behavioral tasks using SSM and integrate parameters derived from them into intensive longitudinal analyses to evaluate cognitive mechanisms underlying the relationship between psychobiological trauma reactivity and CU. Specifically, we will assess relationships between traumatic stress reactivity, reward motivation, and inhibitory control (Aim 1); detect how decisional processes and CU are affected by fluctuations in psychophysiology and hedonic tone (Aim 2); and evaluate psychophysiological and behavioral markers of the developmental trajectories of problematic CU following trauma (Aim 3). Through this National Research Service Award, the PI will further develop and refine his program of research to integrate naturalistic behavioral and physiological observations with advanced quantitative modeling which will lead to both crucial scientific insights in the short-term and set the stage for future studies. This project will be conducted within an individualized training program to facilitate the acquisition of key skills and knowledge progress toward career goals. This includes advanced didacti...