PERSONALITY TO SUBSTANCE MISUSE IN YOUNG PEOPLE: HOW DOES WHO YOU ARE AFFECT WHAT AND WHY YOU USE?
My dissertation sought to better understand the ways in which personality confers vulnerability for substance misuse. Four traits have been reliably implicated: anxiety sensitivity, hopelessness, sensation seeking, and impulsivity. I focused on the developmental periods of adolescence and emerging adulthood, as they are characterized by increased risk for substance use and abuse. I also focused on alcohol and prescription drug misuse. To date, alcohol is the substance that has been studied most extensively. Prescription drug misuse, however, is an emerging issue – that is now considered epidemic. Thus, I validated my model with alcohol before applying it to prescription drugs. Study 1 expanded the extant literature by testing chained mediation from anxiety sensitivity and hopelessness to alcohol misuse (through specific emotional disorder symptoms and coping drinking motives) in N = 1,883 university students. Anxiety sensitivity and hopelessness predicted hazardous alcohol use and drinking harms via symptoms of anxiety/depression and drinking to cope with anxiety/depression. Studies 2 and 3 were novel in that they successively applied this model to prescription drug misuse. Specifically, Study 2 tested theoretical pathways from personality to distinct prescription drug classes and patterns of use in N = 1,755 university students. AS predicted the use and medically-sanctioned use of sedatives/tranquilizers and was marginally associated with sedative/tranquilizer misuse. Hopelessness predicted the use and medically-sanctioned use of opioids. Sensation seeking predicted the use and misuse of stimulants. Impulsivity predicted the following: sedative/tranquilizer use and misuse; opioid misuse; and stimulant use, medically-sanctioned use, and misuse. Finally, Study 3 tested whether specific sets of mental health symptoms mediated these observed personality to prescription drug misuse paths in high school students followed over one year (from Grade 9; n = 3,024 to Grade 10; n = 2,869). Anxiety sensitivity predicted sedative/tranquilizer misuse via anxiety symptoms and hopelessness predicted opioid misuse via depressive symptoms. Sensation seeking was marginally associated with stimulant misuse. Impulsivity predicted stimulant misuse via attention-deficit hyperactivity disorder symptoms. Impulsivity also predicted sedative/tranquilizer, opioid, and stimulant misuse via conduct disorder symptoms. Impulsivity, however, was not directly associated with the misuse of any of these prescription drugs. Taken together, my studies suggest that personality exerts its influence on alcohol and prescription drug misuse through mental health symptoms and substance use motives. These paths vary by trait, and map onto established etiological models of addiction. My dissertation supports the ongoing use (re: alcohol) and the development (re: prescription drugs) of personality-matched prevention and intervention efforts.