State-Dependent Distortions of Short-Range Internal Timing: A Narrative Review Across Stress, Anxiety, Depression, Parkinson's Disease, and Epilepsy.

Short-range internal timing supports coordinated movement, attention, and physiological regulation, yet distortions of time experience are frequently reported across clinical and high-arousal states. Patients with anxiety or acute stress often describe an apparent acceleration of time, whereas depressive states are more commonly associated with a slowing of subjective time. Neurological conditions, including Parkinson's disease and epilepsy, further demonstrate alterations in temporal processing that cannot be reduced to a single mechanism. This narrative review synthesizes evidence from experimental timing paradigms, subjective passage-of-time judgments, and chronobiological approaches to examine how internal timing varies across biological states. In this study, we highlight the distinction between experiential time distortion and performance-based interval timing and discuss how task characteristics, arousal level, and neural context contribute to heterogeneous findings. Historical and methodological foundations are reviewed, including early chronobiological work linking subjective time estimation to biological rhythms. The reviewed evidence suggests that many timing distortions observed in stress-related, affective, and neurological conditions reflect state-dependent reconfiguration rather than irreversible dysfunction. Framing timing variability as a potential marker of internal state may help reconcile inconsistent results across paradigms and inform future clinical and translational research on temporal processing.