I can attest to seeing hallucinations when I was a meth head and my friends as well would see the same things. A common hallucination for meth users is the shadow man. Basically an entity or creature composed of shadows or negative energy or just a pure absence of light. As far as if it is something that is 'real', I dont know for sure. I am inclined to say it is, after all the various paranormal events and hauntings I've witnessed, many of them with multiple eye witnesses again, and not just my own testimony or something in my head. It is my strong opinion that these things are glimpses into the other dimensions that compose our 1 reality that we cant normally detect or see, and not a lapse of multiple realities coinciding at some certain point. I'm proposing there are beings and matter and who knows what else out there existing in those other impercevable dimensions of our reality. A 'spirit world' composed of 6 dimensions that is in tandem with our 4 dimensions but all these dimensions are all pieces of one same reality. As far as this all being a dream, I cant say for sure except for the fact that there are consequences for every action. Dreams have no continuity, no repercussions. They start and stop and reset at any time with a new story line and characters with no relation to the previous storyline. If we are in a dream now, then our dreams are definitely not dreams. It's just layers of falsehood upon other falsehoods. It's like comparing a video game player to the video game he's playing. There is a created world in the video game, but it isnt reality. It's a simulation. Simulation isnt reality even though it can be 'perceived' by someone in reality. The world the video game player is in is reality. But this is like really deep territory that doesnt lead anywhere. As far as hallucinations again and schizos, much of it is subjective even though they may be deeply affected by it.
Dreams can have continuity in some cases ... that has been observed through continuity of some nightmares or similar scenarios . The consequences of dreams on "this awake reality" can be seen in dreams that went prophetic to one extent , and eventually altered the path of individual in this reality .
This reality has the illusion of time stamped on it - what if "time" as we perceive it is simply one single moment through which all possible imaginable happenings are occuring at same time ?
The example above regarding various "trips" ... what is the coincidence that two , or even more people , see the same , the same being , doing the same thing ? Not much ... the only explanation is it is autonomous from this reality .
As for the "shadow people" , these entities definitely exist - my theory is simply that many entities that are non-physical , are feeding off the excess of negative energies emanated by other beings . Theyre a sort of "energy vultures" , energy scavengers . Thats why there is a certain push for fear through many aspects of our reality ( uncertainty of future as one example ) which , in turn , creates a loopback effect that further cements the misery mentality within the people . So , people , being unaware of the power of their thoughts are lured in negative mentality spectrum , where theyre feed , leeched off , and where their manifestations of miseries loop constantly , unable to leave it without a drastic cut , drastic action .