I read about people craving what is familiar, even if the familiar is a bad situation, rather than the novelty of a changed state.
The problem with applying this principle here is that psychosis is itself a novel, change-oriented state.
Yes, I myself have a tendency to want to be psychotic, but given that I'm not psychotic most of the time, not being psychotic is the familiar state. But it feels like stagnation. It's boring. I like the feeling of having my unconscious kinda take over and send me on a magical adventure. Really. Yes some bits are hellish, and I don't want those to repeat, but a desire to experience a life of magic - as I suppose is the case here - is not simply about longing for familiarity.
From what I understand, pot activates your mind down to the 8th function, then takes a step beyond that into the zone associated with self-actualisation. So the desire to become psychotic is about wanting to self-actualise and then self-transcend. Doing it the natural way (I mean through psychosis and other similar states) is probably preferable to doing it artificially with substances, but the forces of life which keep people out of touch with their unconscious (in this case we have anti-psychotics as a substantial component of that) can be such that bypassing that through simple means can be or seem like a great idea.
I would say that anyone who enjoys the "mind-opening" drugs like pot and hallucinogens can understand why someone would want to become psychotic. Then there are the people who are strongly opposed to both, because they find the unconscious to be a threatening idea. These people are likely entrenched in their ego, and feel entitled to force their views onto others.
To me, psychosis is about functioning on a higher level. Yes there's the kind of functioning that leads to someone being able to hold a 9-5 job, but then you realise that there's much more to life than that. High functioning now becomes about the ability to process life through a set of eyes which most people can't, or don't (want to) access. 8 circuits of consciousness - activating circuits 5-8 becomes increasingly rare and there's "plots" going on to keep people from doing it, but that's part of what it means to be a human and to take life to the next level. Spiritual systems throughout time have sought such states, but the materialism of the time, and the low-mindedness of those who won't access it become forces to contend with.
So, this longing... it's a longing for the novel, really. A longing for intensity. A longing for experiential learning when book learning isn't doing the trick. A longing for contact - with the mind, with the minds of others, with the minds of non-physical beings, and non-entitic forces.
Of course, I could be said to be romanticising psychosis. Am I? Humans have romanticised it throughout history, only it's only now that we've conjured up the term "psychosis" - a way of condemning that which one does not understand.
And of course, it can be unpleasant. In tribal societies, when a person presented with psychotic symptoms, they were sent to the Shaman, because he'd been through all that and could guide the person through the experiences and on to becoming the next Shaman. But today we don't have that. So people fumble around in the dark, attempting to navigate the wild without a map. And that really can be dangerous. But danger shouldn't stop you, if what you can gain is well worth the risk. It's just that... it's necessary to take certain precautions, to integrate the lessons of the unconscious into your life so that it's not just about being in contact or out of contact, but in bridging the gap between the two so that higher life becomes the driving force even when living a lower life...
[a disclaimer that there may be conceptual problems associated with the idea of having the unconscious take control; a large part is likely about not being overtaken by it but maintaining control yourself; Jung likely wrote on this idea]