Complex sentence: Although religious delusions are a commonplace phenomenon in schizophrenic patients, religious delusions are not unique to schizophrenics alone; rather, it is entirely possible for an otherwise healthy individual to experience such a delusion separate from any mental disorder.
Split into simpler sentences: Although religious delusions are a commonplace phenomenon in those with schizophrenia, they are not unique to schizophrenia. It is possible for an otherwise healthy individual to experience such a delusion separate from any mental disorder.