Thought Insertion

Schizophrenia

Many patients report hearing voices and experiencing alien thoughts.

Stephens and Graham (2000), p120.

@Thought insertion may be, after verbal hallucinations, the most extensively discussed "positive" symptom of schizophrenia. It sits on Schneider's (1959) influential list of "first rank" symptoms of schizophrenia. One careful survey of the relative frequency of psychotic symptoms found that it occurs in 52 percent of patients diagnosed with schizophrenia (Sartorius et al. 1977).@

Frith (1992, p. 66) quotes one patient's account:

@Thoughts are put into my mind like ''Kill God." It is just like my mind working, but it isn't. They come from this chap, Chris. They are his thoughts.@

Mellor (1970, p. 17) quotes a particularly vivid patient report: @I look out the window and I think that the garden looks nice and the grass looks cool, but the thoughts of Eamonn Andrews come into my mind. There are no other thoughts there, only his. . . . He treats my mind like a screen and flashes thoughts onto it like you flash a picture.@

Proposal

  • Thinking is often experienced as inner speech.
  • Thought insertion is a case of auditory verbal hallucination - misattribution of inner speech.

Relevant work

McGuire et al. (1995) Abnormal monitoring of inner speech: a physiological basis for auditory hallucinations. The Lancet. Volume 346, Issue 8975, Pages 596-600.

@Auditory verbal hallucinations ("voices") are thought to arise from a disorder of inner speech (thinking in words). We examined the neural correlates of tasks which involve inner speech in subjects with schizophrenia who hear voices (hallucinators), subjects with schizophrenia who do not (nonhallucinators), and normal controls. There were no differences between hallucinators and controls in regional cerebral blood flow during thinking in sentences. However, when imagining sentences being spoken in another person's voice—which entails both the generation and monitoring of inner speech—hallucinators had a normal left frontal response, but reduced activation in the left middle temporal gyrus and the rostral supplementary motor area, regions which were activated by both normal subjects and nonhallucinators (p<0·001). These findings suggest that a predisposition to verbal hallucinations is associated with a failure to activate areas concerned with the monitoring of inner speech.@ Mind