Time sickness referred to any negative medical condition resulting from temporal displacement, temporal disruption, or time travel.
Types of time sickness included:
- temporal psychosis, which affected people who used temporal transporters too frequently (VOY: "Relativity")
- temporal narcosis, caused by exposure to different time continuums such as those caused by temporal fragments (TNG: "Timescape")
- Af-Kelt, a condition unique to El-Aurians due to their temporal sensitivity (PIC: "Watcher")
- painful, and ultimately fatal physiological symptoms experienced by those rare individuals who travel across both time and dimensions, such as Yor of the alternate reality and Philippa Georgiou of the mirror universe. In Yor's case, it was fatal and became so bad that he petitioned for euthanasia. In Georgiou's case, it was because she was both too far from her own time and because the prime and mirror universes had drifted too far apart. The Guardian of Forever was able to cure Georgiou's illness by sending her back to a time when the two universes were still aligned where she could survive without having to return to her own universe. (citation needed • edit)