The Multisensory Hallucinations Schedule to assess hallucinations across multiple sensory modalities in psychosis: A...

Hallucination studies in psychiatry have typically focused on the auditory domain, despite mounting evidence that non-auditory hallucinations are prevalent, and elicit distress and functional interference. Proponents have called for more in-depth phenomenological enquiries into hallucinations across multiple sensory modalities, but there are no comprehensive, validated assessment tools to date. This study aimed to document the design and pilot validation of such a transdiagnostic instrument - the Multisensory Hallucinations Schedule.

Leveraging off a precursor measure, the Multisensory Hallucinations Schedule comprised eight modules: Auditory, Visual, Olfactory, Somatic-tactile, Gustatory, Other modalities, Multimodal and Delusions, across lifetime and current time frames. Pilot validation analyses sought to confirm its factor structure via principal components analyses, verify acceptability, convergent and divergent validities, and compute reliability (equivalence and stability) statistics as well as internal consistencies.

Based on 76 participants diagnosed with a primary psychotic illness, the Multisensory Hallucinations Schedule demonstrated acceptable factor structure, with two- to four-factor solutions generated across its subscales, explaining 39.2-76.9% of variance. It displayed excellent acceptability (98.7% completion) as well as robust convergent (r < 0.807) and divergent (r > 0.005) validities. Moderate to high equivalence (intraclass correlation coefficient = 0.574-0.993) and stability (intraclass correlation coefficient = 0.535-0.991), and good internal consistency (Cronbach's α = 0.462-0.851) were shown.

The Multisensory Hallucinations Schedule represents an initial foray into inclusively documenting multisensory hallucinations in psychosis. Future validation endeavours should look towards replication using more robust participant numbers as well as expanding to other psychiatric and neurological cohorts experiencing prominent hallucinations.