Cognitive Mechanisms of Hallucinations in Psychotic Disorders

Hallucinations in psychotic disorders arise from disruptions in the way the brain generates, monitors and interprets internal experiences. A dominant explanation posits that auditory verbal hallucinations emerge when inner speech is misattributed to an external source, reflecting a self-monitoring failure. Predictive processing frameworks further propose that abnormal expectations or priors overweigh incoming sensory data, leading to perceptions ungrounded in external reality. Aberrant salience, in which irrelevant stimuli are granted undue importance, interacts with impaired source monitoring to distort perceptual and cognitive attributions. Neuroimaging and electrophysiological studies implicate a network of regions—including the superior temporal gyrus, medial prefrontal cortex, anterior cingulate cortex and hippocampus—in these processes. Resting-state dynamics within the default mode network and its interactions with sensory and attention systems appear crucial in modulating vulnerability. These insights have global significance, guiding cognitive remediation strategies, neuromodulatory interventions and personalised therapeutic approaches to reduce the frequency and distress of hallucinatory experiences.

Research from Nature Portfolio

Recent studies have investigated the neurocognitive underpinnings of inner speech monitoring in individuals prone to verbal hallucinations. Experimenters used functional magnetic resonance imaging during word-recognition tasks to compare brain activation in false recognitions of common versus uncommon words. Those with higher proneness to hallucinations showed increased false alarms for familiar words alongside reduced engagement of language, recollective and decisional regions. This pattern indicates a deficit in the evaluation and monitoring of inner speech representations, offering a mechanistic account of why internal verbal thoughts may be misperceived as external voices.

Cognitive Mechanisms of Hallucinations in Psychotic Disorders publication trend

The graph below shows the total number of articles in cognitive mechanisms of hallucinations in psychotic disorders across all publications each year (not limited to Nature Index journals).

Technical terms

Inner speech: Internal verbal thought processes that can be misattributed as external voices.

Source monitoring: The capacity to distinguish self-generated from externally derived perceptions.

Aberrant salience: The misallocation of importance to irrelevant stimuli, contributing to false perceptions.

Default mode network (DMN): A brain network active during rest, involved in self-referential processing.

Electroencephalography (EEG): Non-invasive recording of electrical brain activity to assess neural dynamics.

References

1. Neurocognitive bases of self-monitoring of inner speech in hallucination prone individuals. Scientific Reports (2023).
2. The moderating effect of cognitive impairment on the relationship between inner speech and auditory verbal hallucinations among chronic patients with schizophrenia. BMC Psychiatry (2023).
3. EEG resting state alpha dynamics predict an individual’s vulnerability to auditory hallucinations. Cognitive Neurodynamics (2024).
4. Neural Correlates of Aberrant Salience and Source Monitoring in Schizophrenia and At-Risk Mental States—A Systematic Review of fMRI Studies. Journal of Clinical Medicine (2021).
5. Accounting for the phenomenology and varieties of auditory verbal hallucination within a predictive processing framework. Consciousness and Cognition (2014).