Certain errors in visual perception in people with schizophrenia are consistent with interference or 'noise' in a brain signal known as a corollary discharge, a new study shows. Schizophrenia is a disorder that interferes with the ability to think clearly and to manage emotions. People with schizophrenia often attribute their own thoughts and actions to external sources, as in the case of auditory hallucinations. Other common symptoms include delusions and disorganized thinking and speech.