Supplementary Material for: Visual and auditory verbal hallucinations in schizophrenia and their relation to self-disorders

Introduction
The current definition of hallucinations as perception-like experiences has been criticized for neglecting their experiential character and context. This study examined the phenomenology of auditory verbal hallucinations (AVH) and visual hallucinations (VH) in schizophrenia and their relation to other psychopathology, particularly basic self-disorders.
Methods
Twenty patients with schizophrenia-spectrum psychosis and hallucinations participated in phenomenologically oriented, semi-structured interviews exploring the experiential characteristics and context of AVH and VH as well as a comprehensive psychopathological examination, including the Examination of Anomalous Self-experience (EASE).
Results
The far majority of participants considered their hallucinations distinct from perceptual experience and described alterations of the ordinary experiential structure of sensory experience. Generally, both AVH and persistent VH were experientially intertwined with self-disorders and other subjective pathological phenomena. Moreover, AVH were characterized by alterations of spatiality and experienced as private, i.e., not being accessible to others. Compared to a control group, the participants with hallucinations had significantly higher levels of self-disorders, earlier onset of psychopathology, and lower IQ.
Conclusion
The findings align with prior research proposing that most AVH in schizophrenia reflect an underlying alteration of the structure of subjectivity (i.e., disorder of basic self). We report novel findings suggesting that a similar link between self-disorders and VH should be further investigated. Our study highlights the importance of assessing hallucinations within the broader context of the patient’s psychopathology for adequate differential diagnostic evaluation and understanding of lived experience.