Are shyness and sociability still a dangerous combination for substance use? Evidence from a US and Canadian sample

A number of studies have suggested that shyness and sociability may be orthogonal dimensions of personality, each of which is associated with distinct behavioral and psychophysiological correlates, and that a combination of shyness and sociability may be a risk factor for illicit drug use. We examined whether self-reported shyness, sociability, and sensation seeking measures predicted substance use and substance use related behaviors in separate samples of undergraduates in the US and Canada. We found that a combination of shyness and sociability predicted substance use related behaviors in the US sample above and beyond either shyness or sociability alone, replicating and extending previous research. However, this pattern was not found for the Canadian sample. Interestingly, individuals in the Canadian sample who were low in shyness and low in sociability were likely to report high substance use. We also noted that individuals who scored high on measures of sensation seeking were likely to score high on substance use and substance use related behaviors across both samples, replicating previous work. Findings suggest that, while shyness alone may be a protective factor for substance use, a combination of shyness and sociability may be a possible risk factor for substance use and abuse in some cultural contexts.