Depersonalisation Disorder

 Depersonalisation Disorder (DPD) is a condition characterized by distressing feelings of being 'spaced out', detached from one's self, body, and the world, as well as atypical 'flat' time perception. Individuals describe feeling as if they are observing themselves from a distance. In addition there are often alterations in perception, including disruptions in the perception of time.

DP is the third most common psychological symptom in the general population (after anxiety and low mood).

Research findings on DP and atypical time perception,

• Distorted perception of time: Research indicate a tendency to overestimate the duration of time intervals, perceiving time as slower than it actually is which can contribute to the overall sense of detachment and disconnection (Simeon et al., 2008; Sierra & David, 2011)
• Neural correlates of time perception in depersonalization: fMRI studies shown differences in brain activity and connectivity patterns in regions associated with time processing, such as the prefrontal cortex and parietal cortex. (Lemche et al., 2007; Simeon et al., 2013)
• Role of attentional processes: Studies show difficulties in allocating attention appropriately, leading to a reduced ability to accurately perceive and process temporal information. (Ainley et al., 2017; Segal & Lynn, 2019)
• Emotional factors: Studies have found that emotional states, such as anxiety and stress, can modulate time perception, leading to temporal distortions. Individuals with DP often experience heightened levels of anxiety and emotional distress, which may contribute to their altered perception of time. (Simeon et al., 2008; Sierra & David, 2011)

Caveat: This is a complex phenomena and further research is needed to fully understand their underlying mechanisms.

References
Simeon, D., Guralnik, O., Schmeidler, J., Sirof, B., Knutelska, M., & Hollander, E. (2008). The role of childhood interpersonal trauma in depersonalization disorder. The American Journal of Psychiatry, 165(7), 897-903.
Sierra, M., & David, A. S. (2011). Depersonalization: A selective impairment of self-awareness. Consciousness and Cognition, 20(1), 99-108.
Lemche, E., Anilkumar, A. P., Giampietro, V. P., Brammer, M. J., Surguladze, S. A., Lawrence, N., ... & Phillips, M. L. (2007). Cerebral and autonomic responses to emotional facial expressions in depersonalization disorder. The British Journal of Psychiatry, 191(6), 531-539.
Simeon, D., Gross, S., Guralnik, O., Stein, D. J., Schmeidler, J., & Hollander, E. (2013). Temporal lobe structure abnormalities in depersonalization disorder. Journal of Psychiatric Research, 47(7), 893-897.
Ainley, V., Maister, L., Brokfeld, J., Farmer, H., & Tsakiris, M. (2017). More of myself: Manipulating interoceptive awareness by heightened attention to bodily and narrative aspects of the self. Consciousness and Cognition, 49, 289-301.
Segal, E. R., & Lynn, S. J. (2019). Time perception in dissociative disorders: A meta-analysis. Consciousness and Cognition, 71, 64-76.