Perceived Risk of Emerging Recreational Drugs: Impact of Anecdotal and Statistical Evidence

This study investigated the relative impact of personal stories and base rate evidence on the perceived risk of using two emerging recreational drugs: kratom and Spice. A 3 × 2 × 2 mixed-methods design was employed. Four hundred fifty-three young adults were randomly assigned to read internet postings that presented either 1) base rate information depicting the frequency of adverse reactions to Spice and kratom; 2) base rate information plus four personal web-postings describing beneficial reactions to Spice and kratom; or 3) base rate information plus four personal web-postings describing adverse reactions to Spice and kratom. Respondents subsequently evaluated the risk of using both drugs. Anecdotal evidence (personal stories) outweighed the impact of base rate evidence only when the personal stories described adverse drug reactions. Effective risk communication will benefit from differential use of both base rate evidence and personal stories.