Substance misuse is responsible for approximately 11.8 million deaths each year, with alcohol misuse alone accounting for 5.3% of all deaths worldwide. One challenge in studying substance misuse is its co-morbidity with other mental health issues. Researchers have identified emotion-driven impulsivity, motives to drink or use, and mindfulness (or lack thereof) as reliable risk factors for substance misuse, yet the interactive nature among these constructs is relatively unknown. Materialism, which is not usually associated with substance misuse, shares many of the same risk factors, with negative affect, experiential avoidance, and impulsivity playing predictive and mediating roles in both outcomes. Path analytic modelling, combined with online research methods, can harness large datasets to identify the complex associations between these variables. Using a combination of mediation analysis and structural equation modelling, this thesis sought to simultaneously assess these variables to identify potential predictive and mediating effects of alcohol misuse across positive and negative emotion-based models. This thesis also applied comparative analyses to investigate potential mechanisms of change following 8-weeks of mindfulness-based treatment for individuals in early recovery from substance use disorder.