I replied to your post about residual schizophrenia on the depression board, but you posed a different question here. Though schizophrenia is obviously extraordinarily more severe than what I have, Obsessive-Compulsive Disorder, the pure obsessional kind, the two are similar in two aspects: they involve bizarre thoughts and they tend to have a waxing-waning quality. (It has actually been proposed that pure obessional OCD and schizophrenia both involve a malfunction in the prefrontal cortex, but it's the different location in the prefrontal cortex that brings about the striking differences in the disorders and the severity.) People with a less severe form of schizophrenia, often those who are paranoid schizophrenics, as the disorganized types are often the ones with the worst prognosis for cure, can go for bits of time without showing any hallucinations or delusions whatsoever, or they might only be mildly afflicted with them, but they can still function. A perfect example of this would be the character of John Nash in "A Beautiful Mind," who was able to overcome his schizophrenic symptoms when a low-stress environment was provided. Again, hallucinations/delusions and pure obsessions both seem to worsen with stress, and both can disappear for awhile, but then creep up again surreptiously. This is extremely devastating because the patient may be doing quite successfully and think that they have finally managed their mental illness, only to be stricken with a particularly bad bout a month later. However, in answer to your question, if someone hasn't EVER had hallucinations and/or delusions, it simply cannot be schizophrenia. It's a type of psychosis, characterized by psychotic symptoms: hallucinations and delusions. If you have any more questions, feel free to ask! God bless!