Disorders of thinking

The form of thought may be disjointed, making communication difficult. Although quite characteristic of schizophrenia, it is a symptom which is difficult to elicit reliably. Disorders of possession of thought are also characteristic, and can usually be elicited more reliably. These include as first rank symptoms:

• thought withdrawal - the experience of having thoughts taken out of one's mind
• thought insertion - the experience of the insertion of alien thoughts
• thought broadcast - thoughts are transmitted to others
• delusional perception - the attribution of an abnormal significance, usually personal in nature, to a normal perception, without an understandable justification

Delusions are common, but not specific to schizophrenia. The less understandable the relationship between a delusion and pre-existing thoughts or mood, the more characteristic it is of schizophrenia.

In chronic cases there may be poverty of thought: thinking becomes difficult and slow. This may manifest itself in poverty of speech.