I never understood why seeing ghosts is deemed a mental health issue, not real, and why psychology can't be more open minded instead of trying to dismiss it. To be honest, many of us who believe in ghosts don't want it explained away. We cling to it for hope.
The idea that I was wrong seeped into my head last February..I started thinking that ghosts aren't real, that the other side doesn't exist, that there really is nothing after life...and that is why I sat in my car and sawed away at my wrist with cheap crappy fingernail scissors, trying to end it all. But the psychology field puts more importance on 'logic' than on the hope people need to survive. I had a large stack of very heavy boxes (still not opened up and put together), leaning on my mom's chair right after she passed. There is no breeze in here, no pet, I was sitting well away from them, nothing near them to push them, leaning too much not even close to toppling over the other way on their own, and yet, after the news showed something that would have pissed her off, that stack got kicked over. Spirits are real. I've seen too much to believe the field of psychology that just wants to make believing in it a problem because they won't accept the possibility. All the scientists I know have said that science actually made them believe in an afterlife. Think about it, it's something I see some of your responders don't even consider...energy doesn't stop existing with the death of our carrier body. It has to go somewhere. So ghosts are a scientific possibility.
Fact is, no one will know till we each kick the bucket, so no one can say with any positivity that they aren't real, and are just the mind playing tricks. The idea they aren't real is just conjecture.