Standardized assessment of hallucinations

Abstract

Hallucinations are subjective, phenomenologically heterogeneous experiences that likely result from heterogeneous neural circuitries. A proper assessment of hallucinations is a crucial fi rst step in the research for the mechanisms and treatment of these experiences. Current assessment procedures use continuous scale, binary scale, combined binary and continuous scale measures to evaluate the phenomenology, severity as well as specific aspects of hallucinations such as the acceptance of and beliefs about “voices.” The relevance of the phenomenology of hallucinations to their neural mechanisms indicates that there may be advantages to conducting a comprehensive phenomenological evaluation even when interest is focused on one speci fi c aspect of hallucinations. In this chapter, I review current instruments for assessing hallucinations and identify a number of areas for future improvement. These improvements include the development of agreed upon terminology for the description of the phenomenology of hallucinations, an appropriate and agreed upon use of binary or continuous scale measurements for given hallucination characteristics, and improvement in the validation of instruments whereby one instrument is examined against a second with different content but with presumed similar psychometric properties. Finally, further research for the evaluation of the reliability of the report of hallucinations is needed as, currently, only the computerized binary Scale of Auditory Speech Hallucinations provides such assessment.