I don't believe in ghosts. I'd be curious to do a broader study, but it seems to me that our idea of a ghost is actually rather modern. There were a few stories of ghosts in antiquity -- the epic of Gilgamesh seems to be the oldest -- but these seem more directly related to spiritism than anything else. The idea of "haunting" seems to come from the Greeks.
Now, I'll say again that I could be very wrong about that. I've not studied it very much at all. I'm sure you can find stories from various cultures which would then need to be classified. In any case, it is clear that the only direct OT reference to a ghost is related to spiritism and clearly very out of the ordinary; outside of that, the entire practice of communing with the dead is forbidden. I don't think we can infer from that that communing with the dead was actually possible. By NT times, people had pretty clearly come to believe in ghosts (the disciples thought Jesus was a ghost both when He walked on the water and after his resurrection). But that, again, could have more to do with the infusion of Greek mythology into people's thinking than anything else.
Besides that, the OT, in and of itself, seems to have a general leaning toward soul-sleep. Obviously, a lot of people disagree with that, but I find absolutely no evidence of substance dualism there. I think it can be infered (rightly or wrongly) from the NT and then read back into the OT, but from a strictly historical perspective, I doubt ancient Hebrews would have thought much of our modern ideas on ghosts.
So any "real" ghost experiences, I would probably take as demonic. The rest--along with the vast majority of NDEs, I'd take to be psychological phenomena.