In the dream sense, the complex symbiology of a Ghost, involving memory, guilt, fear or repression, seems highly dependent on the "personage" of the apparition itself. For example, if the ghost is a deceased friend or relative who appears sad or disheartened, we may be expressing guilt concerning our past relationship with this person. Conversely, if the deceased specter seems warm and friendly, our Unconscious may be illustrating support for a recent action enacted by the dreamer whose moral basis may be rooted in a parallel history with the departed individual.
On the other hand, if the apparition is unknown to us, we may be depicting a complex symbol of our own repressed fears. Appropriately, we may need to come face to face with our fears by interpreting the full expression, and any verbal message possibly conveyed, by our ghostly guest. What does this wise apparition need to tell us?
For Freud a ghost was a symbol of mother.
Celtic folklore is full of ghosts, driven by both good and evil intentions. Generally speaking, it is unhealthy to meet a ghost. The most spectacular spectres in the repertory of Breton legend are the kannerezed-noz or nocturnal washer-women, women or girls who wash the shrouds of those fated to die. Almost inevitably they cause the deaths of those who encounter them upon the road. They correspond to the banshees of Irish folklore and the banshidhe of medieval writers, which Christianity consigned to the category of evil spirits. In modern Breton folklore, the skarz-prenn, the stick used to clean the ploughshare, is believed to have the power of driving off ghosts .
Among those unquiet spirits which return to Earth to trouble the living are the souls of young women who have died in childbirth. This belief was current among the Aztecs and recurred in Siberia where the Buryat believed that these ghosts "grasp children by throat on which their fingers leave bluish marks" or else "cause a dangerous form of gastric catarrh to those who eat food which they have touched". As a protection against this type of ghost they used the skin of the eagle-owl which, they believed, hunted it by night. These ghosts are characterized by a smell of garlic. Mongolo-Turkic peoples were just as afraid of the ghosts of the unburied dead.
The image of the ghost embodies, and in a sense symbolizes, the fears of beings who dwell in another world. The ghost returning may perhaps also be an apparition of the ego, of the unknown ego, springing out of the unconscious, inspiring an almost panic fear and being thrust back into darkness.