I found a statistic that 25% of schizophrenics recover entirely after a single episode, 25% have chronic schizophrenia with no remission, and 50% have schizophrenic episodes mixed with periods of remission. I think schizophrenia is best described as an episodic or chronic disorder, depending on the particular case, but it definitely does not appear to be a progressive illness, other than perhaps from the onset to the peak of an individual episode, or from onset to symptomatic in chronic schizophrenics (but not progressive through the course of life of those afflicted by it).