I’ve watched a few episodes of Ghost Hunters, but they didn’t mention alternative universes, etc..
That show definitely can leave one feeling afraid - there are some very creepy ghost stories on there. But, I find that show to be more about entertainment than “education.”
There have been quite a few scientific studies done that have suggested and in some cases concluded, that most of what our brains interpret as ghostly activity is really stemming from an alternate state of consciousness - like lucid dreaming, hallucinations from sleep deprivation, drug side effects, and so on. My mind isn’t closed to the possibility that ghosts may exist, but I’d say there are probably mundane explanations for the majority of claims.
Having said that, I’m not volunteering anytime soon to spend a night alone in an alleged haunted house/prison/hospital. lol