Neurodevelopmental Disorder Traits in Taijin-Kyofu-sho and Social Anxiety Disorder: A Cross-Sectional Study among University Students.

Taijin-Kyofu-sho is an East Asian culture-bound anxiety disorder with similarities to social anxiety disorder. However, few studies have examined these two disorders from the perspective of neurodevelopmental disorders. This study is aimed at examining the association of Taijin-Kyofu-sho and social anxiety disorder with the attention-deficit/hyperactivity disorder (ADHD) trait and autism spectrum disorder (ASD) trait. The Liebowitz Social Anxiety, Taijin-Kyofu-sho, and Adult Attention-Deficit/Hyperactivity Disorder Self-Report scales and the 16-item Autism-Spectrum Quotient were administered to 818 university students. Participants were divided into four groups: control (neither Taijin-Kyofu-sho nor social anxiety disorder), pure Taijin-Kyofu-sho (Taijin-Kyofu-sho alone), pure social anxiety disorder (social anxiety disorder alone), and mixed Taijin-Kyofu-sho-social anxiety disorder (both Taijin-Kyofu-sho and social anxiety disorder). We used logistic regression analysis to examine whether the ADHD trait and ASD trait were associated with Taijin-Kyofu-sho and social anxiety disorder. ASD trait was significantly associated with pure Taijin-Kyofu-sho (p = 0.006, odds ratio: 3.99). Female sex and ADHD trait were significantly associated with pure social anxiety disorder (sex: p = 0.013, odds ratio: 2.61; ADHD trait: p = 0.012, odds ratio: 2.46). Female sex, ADHD trait, and ASD trait were significantly associated with mixed Taijin-Kyofu-sho-social anxiety disorder (sex: p = 0.043, odds ratio: 2.16; ADHD trait: p = 0.003, odds ratio: 2.75; ASD trait: p < 0.001, odds ratio: 16.93). Neurodevelopmental disorder traits differed between individuals with Taijin-Kyofu-sho and those with social anxiety disorder. Overall, our study reveals that Japanese individuals with the ADHD or ASD traits are at a heightened risk of developing Taijin-Kyofu-sho or social anxiety disorder.