Abnormalities in the content or structure or though, as reflected in a person’s writing, speech, or behaviour. Schizophrenia causes various types of though disorder, including the loss of logical connections between associations, the invention of new words (neologisms), thought blocking (instant interruption in the train of thought), the feeling that thoughts are being inserted into or withdrawn from the mind, and hallucinations, often in an auditory form.
Incoherent thoughts occur in all types of confusion, including dementia and delirium. Quickly jumping from one idea to another occurs in mania and hypomania. In depression, thinking becomes slow, and there is a lack of association and a tendency to dwell in great detail on irrelevant subjects. In obsessive-compulsive disorder, recurrent ideas seem to come into a person’s mind involuntarily. Delusions, which arise in schizophrenia and other psychotic illnesses, can be an expression of distorted thinking.