“…Further, it has been demonstrated to be efficacious for a variety of different populations, affecting a wide range of targets (e.g., anxiety, depression, stress, psychological flexibility; Gloster et al, 2020 ). Rooted in relational frame theory (RFT; Hayes, 2004 ; McEnteggart, 2018 ), ACT proposes that humans suffer in a unique manner due to arbitrarily applicable relational responding and the rapid development of human language (Hayes et al, 2006 ; McEnteggart, 2018 ). RFT posits that individuals relate stimuli based not only on formal similarity but also arbitrary cues (Hayes et al, 2013 ), and through these derived relations, stimulus function can be transformed.…”