Hallucinations are false perceptions not experienced by others. Smelling the odor of rotting flesh and hearing voices in an empty room when there are no voices or odors are examples of hallucinations. An example of a thought disturbance is when a person reports that thoughts not their own are being inserted into their head by someone else. Inappropriate affect refers to the showing of an emotion that is inconsistent with the person's speech or thoughts. For example, the person may say that he or she is being persecuted by the devil and then laugh.
Examples are the use of a monotonous tone of voice and lack of facial expression.
The third or residual phase follows the active phase and is indicated by a persistence of at least two of the symptoms experienced during the pre-illness phrase. It is not uncommon for patients in the residual stage to experience periods when the prominent psychotic symptoms seen in the active phase reemerge for a brief period of time and then subside. These are not psychiatric terms but are popular descriptions for strange, irrational behavior. Most people suffering from schizophrenia are not violent although an occasional individual will have violent outbursts. There is also concern among some families that they might be the cause of schizophrenia.