While we are nowhere near a Transhumanist Morphological Freedom Utopia, people are capable of altering their brains through chemistry. They take stimulants to be more focused and energetic; they take antidepressants to ward off one of the most unpleasant experiences it is possible to have; they take euphoria-inducing drugs to make themselves happier. So far, so good.
What strikes me as interesting is how often people take drugs to become psychotic. LSD, mushrooms, peyote: all induce a state remarkably similar to psychosis.
Probably some of this is that it’s relatively easy to make human brains psychotic and relatively difficult to make humans (say) experience romantic love for a specific individual. The fact that no one takes love potions doesn’t provide any evidence about whether they would be desirable, it just says they don’t exist. So we can’t conclude from this that psychosis is one of the top changes people would want to make in their brains.
On the other hand, a drug that induces depression exists. No one fucking takes it because it’s awful.
Of course, the fact that hallucinogen users can control when they’re psychotic matters: schizophrenics don’t get to be nonschizophrenic during the work week. Psychosis does not seem to solely strike people who want to be psychotic, whereas most hallucinogen use is by consenting individuals. And actually psychotic people have far more than the optimal level of psychosis. LSD lasts for about ten hours; r/drugs seems to have a consensus that once a month is fairly heavy use, and once a week is very heavy. Psychotic episodes are, at minimum, a few days long, and often last indefinitely.
(This lines up pretty well with my own experiences. I experience dissociation, and it is the worst, but I can see where it would be really interesting if it happened consensually, for a few hours, once every few months.)
But it still strikes me as interesting that, by revealed preference, there is an optimal level of psychosis for many people, and it isn’t zero.