Usually, schizophrenic hallucinations take the form of auditory hallucinations, but there are other types of hallucinations common to schizophrenia as well. The exact description of what an auditory hallucination feels like to a schizophrenic person differs, but many people describe it as hearing voices and believing them to be real. Delusions are also a common symptom of schizophrenia, but these are not considered hallucinations because they are beliefs, not perceptions. Schizophrenic hallucinations may also arise from complete and total misinterpretations of existing stimuli, to the degree that the existing stimuli bear very little relation to what the schizophrenic person sees or hears.
One of the most common types of schizophrenic hallucinations involves hearing voices or other sounds that are not actually present in the world. Most people with schizophrenia describe this type of auditory hallucination as voices, typically with specific messages and often personalities. The mentally ill person may believe that the voices belong to, for example, a supernatural being. This is very different from a person who understands that the voices are coming from an internal place rather than from the outside world. There are many cases in which a person might hear voices that are not present without experiencing any other symptoms of mental illness, so hearing voices is not in itself an indicator of mental illness.
Auditory hallucinations in the form of voices are often frightening because of the malevolence of the voices or the number of separate characters being heard. Voices may command a person to do evil acts, but they may also criticize the listener or command him or her to commit suicide. Very rarely do auditory hallucinations take a purely benevolent form, but some characters within the hallucinations may be purely positive or negative personae.
Other auditory disturbances are also sometimes part of schizophrenic hallucinations. A person might be convinced that he or she hears insects in the walls or that there is music playing. In all these cases, the noises are completely without related stimuli in the world. It is not always easy to differentiate between schizophrenic hallucinations and what are better termed illusions, because the sound that is causing the disturbance may be so slight that it is very difficult to hear.
Visual hallucinations are less common in schizophrenia, but they do still occur. Often, these hallucinations occur in combination with auditory hallucinations. The other senses can also sometimes perceive things that are not present in the world. Which components make up hallucinations depend on the person involved. Hallucinations do not always point directly to schizophrenia, but they are almost always problematic in terms of health, so if someone is experiencing hallucinations it is a good idea to seek medical care immediately.