Let the science speak for itself, even if it's rapping in closets or chilling attic corners. From the Australian Journal of Parapsychology (Vol. 13, Issue 1, June, 2013) “Psychological phenomena in dead people: Post-traumatic stress disorder in murdered people and its consequences to public health”:
... There is strong evidence that a dead person: (i) continues living, thinking, behaving after death as if he/she still has his/her body because consciousness continues in an embodied state as 'postmortem embodied experiences'; (ii) may not realize for a considerable time that he/she is already dead since consciousness continues to be embodied after death (i.e., 'postmortem perturbation' - the duration of this perturbation can vary from person to person, in principle according to the type of death, and the level of conformation), and (iii) does not like to talk, remember, and/or explain things related to his/her own death because there is evidence that many events related to death are repressed in his/her unconscious ('postmortem cognitive repression'). In addition, there is evidence that dying can be very traumatic to consciousness, especially to the murdered, and PTSD may even develop...
Mindhacks, who we must thank for tipping us to this burgeoning area of exploration, suspects “the concept of post-mortem PTSD was largely invented by Big Parlour as a way of selling seances, when what spirits really need is someone to help them understand their experiences.”