Targeting Cognitive and Physiological Mechanisms of Social Anxiety in Youth: A Randomized Controlled Trial of Slow Breathing and Detached Mindfulness
Ruya Akdag, Milica Nikolić, Evin Aktar, Mariska Esther Kret
May 13, 2026 preprint DOI: 10.17605/osf.io/nyzs7 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Randomized controlled trial Pilot study Preregistered |
|---|---|
| Population | Highly socially anxious adolescents |
| Interventions | Slow breathing Detached mindfulness |
| Duration | 4-week intervention |
| Topics | Anxiety Meditation |
| Key findings | The trial tests whether slow breathing and detached mindfulness produce sustained benefits over 4 weeks in highly socially anxious youth, with HRV and negative metacognitive beliefs as primary mechanistic outcomes and observable nervous behaviors and blushing as secondary outcomes. The authors propose that the two interventions target distinct physiological and cognitive pathways whose interaction can be examined side by side. |
Abstract
Social anxiety is highly prevalent among adolescents, with up to 50% of adolescents reporting subclinical levels of social anxiety symptoms (Walder et al., 2025), and if left untreated, social anxiety often persists into adulthood and increases the risk for comorbid disorders (Beintner et al., 2023). Despite this burden, adolescents rarely seek formal help, highlighting the urgent need for accessible, low-threshold interventions that young people can use independently. Two promising candidates are slow breathing and detached mindfulness. Slow breathing is thought to reduce anxiety by increasing heart rate variability (HRV), an index of autonomic regulation, and RCTs in youth have shown significant anxiety and stress benefits from slow breathing interventions (Bentley et al., 2023). Detached mindfulness is a technique from Metacognitive Therapy (MCT) in which individuals learn to notice and disengage from anxious thoughts rather than engaging with or suppressing them. Its proposed mechanism of change is the reduction of negative metacognitive beliefs (NMCB), that is, beliefs about the uncontrollability and dangerousness of one's own thoughts, which are considered central to the maintenance of anxiety. Systematic reviews report a medium to large effect size for the association between metacognitions and anxiety in youth (Lønfeldt et al., 2017), and emerging evidence supports MCT's effectiveness in adolescent populations (Perkins et al., 2023). Importantly, these two interventions target theoretically distinct mechanisms, one physiological and one cognitive, making them particularly well-suited for examining how these pathways interact in the context of social anxiety. According to the neurovisceral integration model (Thayer & Lane, 2000), cognitive and physiological systems are closely interconnected, such that changes in one domain may cascade into the other. Consistent with this, our pilot study (Akdag et al., 2025) found that slow breathing primarily influenced HRV, while detached mindfulness influenced both NMCB and HRV, suggesting that cognitive and physiological pathways in social anxiety may be more intertwined than previously assumed. By testing both interventions side by side within the same paradigm, the current study offers a unique opportunity to examine not only whether these interventions work, but how their respective mechanisms unfold and interact over time. Despite the promise of both approaches, research directly examining HRV and NMCB as mechanisms of change in the context of social anxiety in youth remains scarce, and few studies have provided long-term follow-up data, leaving the sustainability of intervention effects largely unknown (Walder et al., 2025). Building on a series of preliminary studies, including a pilot study (Akdag et al., 2025) and a laboratory study examining the immediate effects of both interventions using a public speaking paradigm (Akdag et al., in preparation), the current pre-registered study examines whether these acute effects translate into sustained benefits over a longer period. We present a 4-week randomized controlled trial with three arms, slow breathing, detached mindfulness, and an active control condition, in highly socially anxious youth. Both interventions are brief and self-administered, designed to be easy to practice independently. In addition to the primary mechanistic outcomes (HRV and NMCB), secondary outcomes including observable nervous behaviors and blushing are examined to capture the broader symptomatic picture of social anxiety. The broader aim is to contribute to scalable and accessible mental health tools for adolescents, while advancing understanding of the cognitive and physiological mechanisms underlying subclinical social anxiety.
Comparable studies
Other randomized controlled trials on anxiety, most cited first.