Deficits in Source Monitoring in Subjects with Auditory Hallucinations May be Due to Differences in Verbal...

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Psychology

Background:

• Auditory hallucinations in schizophrenia are theorized to result from impaired self-monitoring of verbal mental imagery.
• Existing neuropsychological evidence supporting this theory is inconsistent and contradictory.

Purpose of the Study:

• To investigate the relationship between auditory hallucinations and source monitoring in schizophrenia.
• To compare source monitoring performance in hallucinating schizophrenics, non-hallucinating schizophrenics, and healthy controls, controlling for cognitive covariates.

Main Methods:

• A source monitoring task was administered to three groups: male schizophrenic inpatients (hallucinators and nonhallucinators) and matched normal controls.
• Participants were matched for age, education, and medication.
• Verbal IQ and Verbal Memory were assessed and controlled for in the analysis.

Main Results:

• Verbal IQ and Verbal Memory performance were significantly correlated with source monitoring task performance.
• After controlling for Verbal IQ and Verbal Memory, no significant differences were found between the three groups in overall accuracy of self-generated item attribution.
• No significant differences were observed in the rate of self-to-experimenter misattribution errors between groups.

Conclusions:

• The findings suggest that previously inconsistent results in this research area may be due to unacknowledged variations in verbal intelligence and memory.
• The proposed link between auditory hallucinations and a specific failure in source monitoring may require re-evaluation.
• Controlling for cognitive covariates is crucial for accurately understanding the mechanisms underlying auditory hallucinations in schizophrenia.