Measuring fluctuations across the Continuum of Auditory Hallucinations. Development and validation of a state inventory.

In order to identify causes and triggers of hallucinations that can inform therapy, reliable, valid, and change-sensitive instruments to assess hallucinatory experiences in the subclinical and clinical range are needed. We developed and validated a novel scale, the Continuum of Auditory Hallucinations - State Assessment (CAHSA), to be used for repeated assessment of the subclinical factors vivid imagination, intrusive thoughts, and perceptual sensitivity as well as auditory hallucinations. After selecting items for the four factors in a first test sample (n=84), we tested factorial validity using CFA and criterion validity with self-reported psychosis-like experiences (n=534). Finally, within-subject variation of CAHSA scores over 14 days and time-lagged associations between its factors were explored (n=85). A 9-item CAHSA was selected that showed good factorial validity, criterion validity, and substantial, valid within-subject variation. Time-lagged regression showed that vivid imagination, perceptual sensitivity, and intrusive thought precede auditory hallucinations. In sum, the CAHSA validly measures fluctuation along the continuum of auditory hallucinations, is sensitive to change, and well suited for experimental studies, repeated measurement, and longitudinal research.