Presumably the person with latent schizophrenia would see it emerge at later date even if they didn't take psychedelics. If the drug is only making symptoms emerge earlier, the cost of the trip is only however many years of sanity you had left (say, 5) rather than a lifetime of sanity (~65 years).
My understanding is that 'latent schizophrenia' is a term referring to the predisposition towards developing schizophrenia if certain environmental, social or other stressors trigger it.
It may never truly manifest itself as schizophrenia because of the lack of non-genetic factors involved in the illness.
The nature of schizophrenia isn't that genetics will absolutely determine whether or not someone will develop the disease. One can be diagnosed with prodromal schizophrenia and, with proper intervention, will never be diagnosed as schizophrenic or experience those symptoms again.
To say that the drugs will make symptoms emerge earlier instead of later in life isn't entirely accurate. Those symptoms may _never_ emerge at all, given the right circumstances.
It seems that the 'right circumstances' for those with a predisposition towards developing schizophrenia include never ingesting certain types of drugs.
