Search

Background: Previous research has shown that various memory errors reflecting failure in the self-monitoring of speech were associated with auditory/verbal hallucinations in schizophrenia patients and with proneness to hallucinations in non-clinical individuals. Method: We administered to 57 schizophrenia patients and 60 healthy participants a verbal memory task involving free recall and recognition of lists of words with different structures (high-frequency, low-frequency, and semantically organisable words). Extra-list intrusions in free recall were tallied, and the response bias reflecting tendency to make false recognitions of non-presented words was computed for each list. Results: In the male patient subsample, extra-list intrusions were positively associated with verbal hallucinations and inversely associated with negative symptoms. In the healthy participants the extra-list intrusions were positively associated with proneness to hallucinations. A liberal response bias in the recognition of the high-frequency words was associated with verbal hallucinations in male patients and with proneness to hallucinations in healthy men. Meanwhile, a conservative response bias for these high-frequency words was associated with negative symptoms in male patients and with social anhedonia in healthy men. Conclusion: Misattribution of inner speech to an external source, reflected by false recollection of familiar material, seems to underlie both clinical and non-clinical hallucinations. Further, both clinical and non-clinical negative symptoms may exert on verbal memory errors an effect opposite to that of hallucinations. [ABSTRACT FROM AUTHOR]

Introduction. The sense of agency over thoughts is the experience of oneself qua agent of mental action. Those suffering certain psychotic symptoms are thought to have a deficient sense of agency. Here I seek to explain this sense of agency in terms of metacognition. Method. I start with the proposal that the sense of agency is elicited by metacognitive monitoring representations that are used in the intentional inhibition of thoughts. I apply this model to verbal hallucinations and the like and examine the plausibility of this model explaining deficits associated with these symptoms. Results. By tying the sense of agency to metacognitive inhibition I propose that the loss of a sense of agency in certain psychotic symptoms is accompanied by a particular deficit in the patient's ability to control their own thinking. This is consistent with the experiences of those at high risk of developing hallucinations, who report more intrusive thoughts than controls. The model I present is able to explain why those at risk of developing verbal hallucinations and those suffering from verbal hallucinations have deficits in the intentional inhibition of thought. I defend this account from a possible objection by distinguishing the form of the intentional inhibition deficit displayed by those suffering verbal hallucination from that displayed by those suffering from orbital-frontal cortex lesions and posttraumatic stress disorder. Conclusion. A plausible hypothesis is that the sense of agency over thoughts is elicited by the metacognitive monitoring representation used to intentionally inhibit thoughts. The deficit in the sense of agency over thoughts associated with certain psychotic symptoms could be explained by a failure to properly metacognitively monitor certain thought processes. [ABSTRACT FROM AUTHOR]

Introduction. Verbal hallucinations could result from attributing one's own inner speech to another. Inner speech is usually experienced in inner space, whereas hallucinations are often experienced in outer space. To clarify this paradox, we investigated schizophrenia patients' ability to distinguish between speech experienced in inner space, and speech experienced in outer space. Methods. 32 schizophrenia patients and 26 matched healthy controls underwent a two-stage experiment. First, they read sentences aloud or silently. Afterwards, they were required to distinguish between the sentences read aloud (experienced in outer space), the sentences read silently (experienced in inner space), and new sentences not previously read (no space coding). The sentences were in the first, second, or third person in equal proportions. Linear mixed models were used to investigate the effects of group, sentence location, pronoun, and hallucinations status. Results. Schizophrenia patients were similar to controls in recognition capacity of sentences without space coding. They exhibited both inner-outer and outer-inner space confusion (they confused silently read sentences for sentences read aloud, and vice versa). Patients who experienced hallucinations inside their head were more likely to have outer-inner space bias. Conclusions. For speech generated by one's own brain, schizophrenia patients have bidirectional failure of inner-outer space distinction (inner-outer and outer-inner space biases); this might explain why hallucinations (abnormal inner speech) could be experienced in outer space. Furthermore, the direction of inner-outer space indistinction could determine the spatial location of the experienced hallucinations (inside or outside the head). [ABSTRACT FROM AUTHOR]