Modico, MaggieBased on theoretical work on the role of autonomic dysregulation in the development of psychopathology, previous work has shown relations between respiratory sinus arrhythmia (RSA) and anxiety (Chalmers et al., 2016; Blom et al., 2010; Monk et al., 2001). RSA serves as an indicator of adaptability, where high levels of RSA reflect flexible and low levels of RSA demonstrate less flexible responding (Pitting et al., 2013). We hypothesized that participants with an anxiety disorder will have lower RSA at baseline and during social situations than those without anxiety. Participants (N=92) were 15-year-olds selected as part of a larger longitudinal study examining the role of infant temperament on adolescent mental health. 33 participants were diagnosed with an anxiety disorder and 59 participants had no diagnosis. RSA was measured using electrocardiogram (EKG) during baseline, an unstructured social interaction task (Get to Know You, GTKY) and a stressful speech task. We derived RSA from the EKG. Independent t-tests were used. Those with an anxiety disorder (M= 6.44) compared to those with no clinical diagnosis (M= 7.08) demonstrated significantly lower baseline RSA, t =2.97, p=.004. Compared to those with no diagnosis, participants with an anxiety disorder showed lower RSA during GTKY and Speech, t =2.83, p=.006 and t = 2.62, p=.01, respectively. Our results showed that individuals diagnosed with anxiety have lower RSA across both baseline and social tasks than those without anxiety. The role of RSA in anxiety should be examined as it may serve as a biomarker used for treatment and intervention.en-USHuman DevelopmentEDUCModicoanxietyautonomic regulationrespiratory sinus arrhythmia(RSA)Presentation