Schizophrenia is an affliction of degree, not of kind.
Every human is born with multiple personalities, typically in the form of personas. This is the norm. We have to be different people to the various folks we encounter in life; otherwise, we can’t get much done.
So if someone is always exactly the same person at all times, it makes things difficult for everyone else. It constitutes an inconsiderate demand that everyone accommodate this one persona at whatever cost. We are designed by God to adapt to varying degrees by wearing different roles. In a truly biblical society, adults would be at least a dozen different people at any given time, depending on the context. The only question is just how flexible we can be without losing our grip on who God meant for us to be. It is a balancing act each of us must engage in our own way.
Of course, this presumes a heart-led atmosphere. That is, when the focus of your conscious awareness is in your heart instead of your head, you are in a position to see and manage the multiple personas that reality demands of us. You can keep it all in safe mode. Without that superposition of awareness above the intellect, you easily lose track, since no one persona is truly competent to manage the others.
Thus, it’s easy for folks lacking a heart-led awareness to become schizoid. Most of our society is poorly managed in that sense, and some folks suffer enough damage to separate the personas more completely. There is no competent manager for the interaction between them. The various personas are far less seamless, as we are designed to be, and the shifts are abrupt as each follows their own line of thinking and consciousness simultaneously, but without the normal traffic control. When there’s a collision, things get broken.
Once we get used to the idea, we are less shocked when fairly ordinary people exhibit hidden personas that manifest in odd ways. If most of the world around you is secretly schizoid, and you are aware of it, there’s less struggle inside of yourself when dealing with the manifestations. You have to view it from your own heart-led perspective and take appropriate action.
We could go on all day about the various ways people ought to handle their multiple personas, and clinical literature is abundant, if highly varied in quality. None of it assumes the heart-led way, so take it all with a grain of salt. Still, we can learn some things from reading it, if so inclined. My point here is to establish a biblical heart-led awareness of reality, particularly regarding how people think and act.