Acceptability and Perceived Usefulness of a Digital Gambling Harm Minimization Tool: Cross-Sectional Study.

Sighing has long been clinically observed in anxiety and historically regarded as a symptom of pathological states such as neuroses and chronic anxiety [,]. Subsequent research in anxiety disorders (ADs) has reinforced this link, demonstrating that patients with ADs generally exhibit elevated sighing compared to healthy controls (HCs) across various experimental conditions, ranging from resting states and breath-holding challenges to laboratory-induced panic and recovery [-]. This pattern of persistent sighing, coupled with alterations in breathing rate and variability, may reflect an underlying state of “respiratory rigidity” [,-], with frequent sighing representing a compensatory attempt to restore regulatory flexibility. This compensatory view is formalized in the contemporary “psychophysiological reset” model, which posits that sighing functions as a critical homeostatic safety valve to alleviate tension and restore breathing variability [-]. Consistent with this model, recent studies demonstrate that sighing increases specifically during relief from stress or following sustained cognitive load [,]. These findings raise the possibility that sighing dynamics could provide a noninvasive window into regulatory capacity. Yet, translating these laboratory-based observations into an ecologically valid digital biomarker has been difficult. Although ambulatory studies have quantified sigh frequency, findings remain mixed, with some reporting no significant group differences in aggregate measures between patients with ADs and HCs [,]. One explanation is that aggregating sighs across time and contexts compresses an event-like, state-dependent phenomenon into a static count, thereby attenuating the signal of interest. To be clinically useful in real-world monitoring, sighing needs to be examined as a dynamic, state-dependent process. Its clinical value lies not in how much one sighs on average, but in when and why sighing occurs in relation to fluctuating states of anxiety []. This shift in focus highlights an unresolved question: whether altered sighing in anxiety reflects a stable, trait-like deficit in respiratory flexibility (“rigidity”) or a preserved, state-sensitive regulatory response to momentary distress. Validating this state-trait dissociation is therefore essential and requires evidence on whether sighing covaries with within-person fluctuations in anxiety and whether the strength of this anxiety-sigh coupling differs between diagnostic groups. Addressing this question requires high-resolution, multimodal data that synchronize subjective experience with objective physiology in daily life.