# Multidimensionality of hallucination-like experiences: A factor structure refinement of the Launay-Slade Hallucination Scale

## TL;DR

This study improves the understanding of hallucination-like experiences by refining the structure of a widely used psychological scale.

## Contribution

The study introduces a new factor, 'Personified HLEs,' related to perceiving the presence of another person or voice.

## Key findings

- A four-factor structure of hallucination-like experiences was identified, including 'Multisensory HLEs' and 'Personified HLEs'.
- The new 'Personified HLEs' factor aligns with theories about self-monitoring and external attribution bias in hallucination proneness.
- Refined factors may better represent individual differences in hallucination-like experiences.

## Abstract

Previous research on the multidimensionality of hallucination-like experiences (HLEs) across the psychosis continuum highlights methodological disparities, emphasizing the need for a cautious interpretation of findings and transparent reporting of parameters used in the analysis.

This study aimed to refine the factorial structure of the 16-item Launay-Slade Hallucination Scale (LSHS), enhance methodological clarity, and improve the robustness of LSHS factor solutions. To this end, an Exploratory Factor Analysis (EFA) was performed on a heterogeneous sample (N = 278) with specified parameters (e.g., estimation procedure) that remain true to data characteristics and assumptions underlying EFA.

The results revealed a four-factor structure including “Multisensory HLEs”, “Auditory daydreaming”, “Vivid thoughts and inner speech”, and “Personified HLEs”. Our investigation introduces a new factor specific to the perceived presence of another person or another voice. This aligns with theories on self-monitoring difficulties associated with an external attribution bias as hallucination proneness (HP) increases across the continuum.

The current results provide an opportunity for investigating neurophysiological and neurobehavioral correlates of HP considering highly differentiated individual profiles of HLEs. Future studies should focus on validating the robustness of the four-factor structure derived from this research across diverse samples of the general population (e.g., different age groups and cultural backgrounds). Specified composite scores underlying HLEs could be of additive value when assessing emerging clinical risk on the psychosis continuum.

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•Methodological inconsistencies in acquiring LSHS factor structures are outlined.•A transparent “true-to-data” EFA of LSHS data was performed on a non-clinical sample.•The multidimensionality of HP is highlighted.•The new “Personified HLEs” factor implies the perceived presence of another person.•Refined factors might be more representative of individual differences in HLEs.

Methodological inconsistencies in acquiring LSHS factor structures are outlined.

A transparent “true-to-data” EFA of LSHS data was performed on a non-clinical sample.

The multidimensionality of HP is highlighted.

The new “Personified HLEs” factor implies the perceived presence of another person.

Refined factors might be more representative of individual differences in HLEs.