Understanding Auditory Hallucinations: Cognitive and Neurobiological Insights into Abnormal Auditory Perceptions

Auditory verbal hallucinations (AVHs), or perceptions of speech in the absence of external stimuli, are a defining feature of schizophrenia and a transdiagnostic phenomenon with significant clinical and existential implications. In order to understand the processes and subjective aspects of AVHs, this dissertation combines phenomenological, neurocognitive, and neurobiological perspectives. The subjective experiences of AVHs are characterized by delayed disclosure, fragmented self-agency ("loss of mineness"), and a split reality framework where psychotic and shared worlds coexist ("double bookkeeping"). Phenomenologically, AVHs vary widely in linguistic complexity, spatial perception, and emotional valence. According to neurobiology, AVHs result from abnormalities in auditory processing systems, where abnormal top-down expectations override bottom-up sensory information, abnormal activation of fronto-temporal networks (such as the superior temporal gyrus and Broca's region), and altered cortico-cortical communication. The distinction between internally generated speech and external perception is further blurred by dysfunctional reality monitoring, resting-state hyperactivity in the default mode network, and disturbed corollary discharge mechanisms. Atypical language processing is implicated as a phenotypic marker of psychosis in schizophrenia patients with AVHs, as evidenced by diminished left-hemisphere dominance and attenuated right-ear advantage as seen via a critical lens on cerebral lateralization. Notably, non-psychotic voice-hearers continue to exhibit conventional lateralization patterns, highlighting psychosis as the main mediator of neurocognitive disturbances rather than only hallucinations. This work synthesizes these findings and proposes that altered self-experience, cognitive misattribution, and neuronal miscommunication all combine to produce AVHs.