That is the paranoid part of paranoid schizophrenia. In paranoia you think that a lot of attention is being focused on you when it isn't. Logically there would be no reason for all that effort and attention by a powerful group of people to spend the time and resources on you.
I'm not trying to dig the rabbit hole deeper, but if psychotropic weapons are real, being unimportant would probably make someone an ideal testing candidate. And sometimes sadism and a desire to control others is enough. Unimportant people get screwed over by self-imposing authority figures all the time.
Or if there is some kind of incorporeal or invisible alien presence on earth, or even a shadow government of humans, they probably have a much more complete picture of our causal interactions with each other than we do. Someone could raise a flag in their system, or they may have predicted a potential unfavorable event that's less likely to occur if they intervene and someone is taken out of the picture.
That assumes a lot about the nature of our reality and is likely implausible, but I also find that a relatively significant minority of the population suffering from the same or similar distinct flavors of hallucinations is pretty suspicious in and of itself. One percent doesn't sound like a lot until you realize that's one in a hundred people. That may speak to the times and common fears, as well as contagious thought, though, which at the very least points to a very unhealthy "society" that drives some people mad and others madder.
Personally I think the truth is somewhere in between. We already know that psychological warfare techniques utilizing uncommon technology have been overtly tested on unsuspecting individuals, and I think it's very likely that social engineering is being practiced en masse as well as selectively through the internet and media. For the rest the fear that it might happen may be enough. The common perception that certain perceptions are meant to be dismissed outright helps a lot in keeping such operations out of the public eye. It sounds schizophrenic of me to say but the whole concept of schizophrenia could be a cover in many cases, a label slapped on an ordinary mind torn to shreds through atypical thought, trauma and drug therapies. Although I know that there are genetic predispositions to it, the onset of schizophrenia is almost always linked to an event, often traumatic, after going through a protracted prodromal phase, instead of being truly spontaneous.
But hell, all it really takes is using post-hypnotic or ordinary suggestion to make someone think they're being targeted by weapons when really driving someone crazy is a much less sophisticated process that requires nothing more than a common language. Or maybe we're all being targeted by energy weapons and it's only by some fluke that some people become aware of it. Or maybe we're not being targeted by energy weapons and it's the brains metaphorical explanation for the fields created by modern technology.
There are a lot of possible explanations and reality is fucking terrifying. Sleep deprivation is one of the more likely ones in this case.