Temporal displacement, also known as being "unstuck in time", is an illness suffered by those whose consciousness undergoes time travel. It has been shown to be often fatal, although curable.
Temporal displacement has three known causes, though the relationship between these causes is unknown. The first known cause, intense or prolonged radiation or electromagnetism exposure, was mentioned by Daniel Faraday when trying to save Desmond Hume from the effects of temporal displacement. Daniel had determined this as a possibility several years earlier, when his rat Eloise died due to radiation-induced temporal displacement, which led to a cerebral hemorrhage. ("The Constant")
The second known cause of temporal displacement is approach or proximity to the Island, whereby crew members of the freighter Kahana became afflicted. George Minkowski and Brandon were struck with temporal displacement while rowing toward the Island in the Zodiac raft. Brandon died soon after being afflicted, while Minkowski died several days afterward. Desmond Hume was struck with temporal displacement while flying in a helicopter away from the Island, though he was later saved from its fatal effects. ("The Constant") Regina, afflicted with temporal displacement, committed suicide to escape the torturous effects. Captain Gault described the illness as "a heightened case of cabin fever". ("Ji Yeon")
The third and most often seen cause of temporal displacement is time travel. After Benjamin Linus turned the frozen wheel, the remaining survivors on the Island became unstuck in time, traveling corporeally to different time periods of the Island. Though there was no immediate reaction to this travel, Charlotte Lewis soon began experiencing headaches and double vision. Soon afterward, she began passing out and her nose began to bleed profusely. ("Jughead") The other survivors eventually began to exhibit these symptoms, though at a much slower rate. Eventually, Charlotte was incapacitated, and died soon afterward. ("This Place Is Death") The survivors were saved due to the cessation of the time travel, caused by John Locke once again turning the frozen wheel. ("This Place Is Death")
Symptoms and outcomes
Aside from the aforementioned headaches, double vision, and nosebleeds, victims of temporal displacement often exhibit memory loss, confusion, or the inability to distinguish between past, present and future. This proves fatal if the victim is unable to find a constant permitting them to differentiate between times.
If untreated, temporal displacement almost always leads to death by cerebral hemorrhage, as was the case with Eloise the rat, George Minkowski, Brandon, and Charlotte Lewis. However, in some cases, the untreated displacement may simply lead to permanent invalidity, as was the case with Theresa Spencer, an associate of Faraday's who may have been exposed to radiation from some of his experimental apparatus. ("Jughead")
|Picture||Name||Episodes afflicted||History with temporal displacement|
|Brandon||"The Constant"||After journeying with George Minkowski toward the island, he was struck with temporal displacement. He died soon afterward.|
|Charlotte Lewis||"Because You Left", "The Lie", "Jughead", "The Little Prince", "This Place Is Death"||After the island began shifting in time, Charlotte began exhibiting the symptoms of temporal displacement, though at a much faster rate than anyone else, due to her having spent six years on the Island as a child. She soon died as a result.|
|Daniel Faraday||"Confirmed Dead", "Eggtown", "The Constant", "The Little Prince", "This Place Is Death", "The Variable"||As a scientist studying time travel, Daniel conducted several experiments on himself after these experiments he began to suffer from recurring short term memory loss. However, upon arrival to the island, his memory loss problems seemed to be cured. Also, after the Island began shifting in time, Daniel was afflicted with temporal displacement. However, his symptoms were never serious, and he was cured when the Island was reaffixed in time.|
|Desmond Hume||"The Constant"||Became "unstuck in time" while en route to the Kahana. With the help of Daniel Faraday, found his constant and survived.|
|Eloise||"The Constant"||A lab rat named after Daniel Faraday's mother, she was used in experiments until one of them was finally successful. However, the result of Eloise becoming unstuck in time was a brain hemorrhage, causing her death.|
|George Minkowski||"The Constant"||After journeying with Brandon toward the Island, he was struck with temporal displacement. Although it took him longer to succumb than Brandon, he eventually died in Desmond's arms.|
|James "Sawyer" Ford||"The Little Prince", "This Place Is Death"||After the Island began shifting in time, Sawyer was afflicted with temporal displacement. However, his symptoms were never serious, and he was cured when the Island was reaffixed in time.|
|John Locke||"The Little Prince""This Place Is Death"||After the Island began shifting in time, Locke was afflicted with mild temporal displacement. He only suffered from head aches and was cured upon leaving the island.|
|Juliet Burke||"The Little Prince", "This Place Is Death"||After the Island began shifting in time, Juliet was afflicted with temporal displacement. Due to her having spent three years on the Island, the onset of symptoms was more rapid than Miles, Daniel, Locke, Jin, or Sawyer, but she was cured when the Island was reaffixed in time.|
|Miles Straume||"The Little Prince", "This Place Is Death"||After the Island began shifting in time, Miles was afflicted with temporal displacement. Due to his time spent on the Island for four months as a child, his symptoms were slightly more serious than those of Locke, Daniel, Sawyer, and Jin, but he was cured when the Island was reaffixed in time.|
|Jin Kwon||"The Little Prince", "This Place Is Death"||After the Island began shifting in time, Jin was afflicted with mild temporal displacement. He only suffered from head aches and was cured when the Island was reaffixed in time.|
|Theresa Spencer||"Jughead"||Temporally displaced due to Faraday's research, Theresa was rendered permanently invalid.|
- Daniel Faraday colloquially referred to temporal displacement as being "unstuck in time". ("The Constant") This is a reference to the science fiction novel Slaughterhouse-Five, in which the protagonist, Billy Pilgrim, experiences being "unstuck in time" and lives various moments throughout his life out of chronological sequence.
- The term "temporal displacement" is commonly used in science fiction, e.g., in Star Trek  and Back to the Future. 
- The illness was first given an official name in "Ji Yeon-Enhanced". It was also mentioned in "The Lie-Enhanced", "Jughead-Enhanced", and "This Place is Death-Enhanced".