Thought blocking, a phenomenon that occurs in people with psychiatric illnesses (usually schizophrenia), occurs when a person's speech is suddenly interrupted by silences that may last a few seconds to a minute or longer[1]. Blocking is often brought on by questioning or discussing something of particularly large personal significance. When the person begins speaking again, after the block, they will often speak about a subject unrelated to what was being discussed when blocking occurred. People with thinking disorders usually have a very un organized thought process. They may say words that are completely unrelated to the previous topic they were just talking about. It is described as being experienced as an unanticipated, quick and total emptying of the mind (Gelder, Mayou and Geddes 2005). People with schizophrenia commonly experience thought blocking and may comprehend the experience in peculiar ways (Gelder, Mayou and Geddes 2005). For example a person with schizophrenia might remark that another person has removed their thoughts from their brain (Gelder, Mayou and Geddes 2005).
When doctors diagnose thought blocking, it is important that they consider other causes of pauses in speech and expression, such as petit mal seizures, aphasia, hesitation brought on by anxiety, or slow thought processes. When looking for schizophrenia they may look for thought blocking. It is a common issue with schizophrenia patients.[2]