Threat Responsiveness as a Function of Cannabis and Alcohol Use Disorder Severity

Two of the most commonly abused substances by adolescents in the United States are alcohol and cannabis, both of which are associated with adverse medical and psychiatric outcomes throughout the lifespan. Both are assumed to impact the development of emotional processing although findings on the direction of this impact have been mixed. Preclinical animal work and some functional magnetic resonance imaging (fMRI) work with humans have suggested cannabis use disorder (CUD) and alcohol use disorder (AUD) are associated with increased threat responsiveness. However, other fMRI work has indicated CUD/AUD are associated with diminished threat responsiveness. In this study, we report on a study examining the relationship of severity of CUD/AUD and threat responsiveness in an adolescent population. The study involved 87 (43 male) adolescents with varying levels of CUD/AUD symptomatology (N = 45 above clinical cutoffs for CUD or AUD). They were scanned with fMRI during a looming threat task that involved images of threatening and neutral human faces or animals that appeared to be either looming or receding. Increasing levels of CUD symptomatology were associated with decreased responding to looming stimuli within regions, including rostral frontal and fusiform gyrus as well as the amygdala. There were no relationships with AUD symptomatology. These data indicate that CUD in particular is associated with a decrease in responsiveness to the looming threat cue possibly relating to the putative neurotoxic impact of cannabis abuse.