Using a single-subject design to assess the development of anxiety in humans

Laboratory studies of conditioned anxiety using a between-subjects group design typically involve only one session of conditioning trials. Because research suggests that anxiety disorders develop and change with repeated exposure to aversive events, these studies may fail to mimic the developmental course of anxiety in the natural environment. We highlight the limitations of single-session studies for examining the development of conditioned anxiety within individual participants and discuss how many of these limitations can be avoided using single-subject designs. Furthermore, we suggest that the most comprehensive account of anxiety can be attained by using a single-subject design in conjunction with more commonly used group designs.