Ghosts can be found within religion and Christianity.
Christianity, especially fundamental christianity, does not believe in the existence of ghosts, due to the teaching of an eternal hell . Fundamentalists believe that people cannot become ghosts, as upon
death, one will either find their self in either a state of bliss called, heaven, or in an eternal place of suffering taught as, hell. Therefore, there is no place left for a ghost to exist, as teachers of the religion do not recognize any biblical passages stating to the contrary. Amazingly, Judaism teaches the existence of ghosts and ghost possession , in stark contrast to the religion that has its' roots in some of the same
Catholicism, the forerunner to most other christian sects and denominations does allow for the existence of ghosts, as it teaches a place that exists between heaven and hell called purgatory. Purgatory is believed to be a place for souls who die in a state of grace to go through temporary punishment as a cleansing process, eventually preparing them for heaven. This idea of a cleansing process is paralleled somewhat by the teachings of Judaism; and an offshoot of Catholicism,
Mormonism, teaches the eventual redemption of all of mankind.
The Catholic idea of purgatory has been described often as a place of intense, painful fire, though it better metaphorically symbolizes the inner cleansing of a person, as going through a refiner's fire. Roman Catholics believe the fate of a person in purgatory can be affected by the actions of those on earth. Perhaps, purgatory's cleansing process is similar to how ghosts suffer, remaining earthbound, interacting with the living, and in a state of trauma until they can move on unto peace and continue their life journey.