When words and pictures come alive: Relating the modality of intrusive thoughts to modalities of hypnagogic/hypnopompic hallucinations

Hypnagogic and hypnopompic (H&H) hallucinations are those experienced on the borders of sleep and waking. Intrusive thoughts have been proposed to relate to the occurrence of such experiences. In a sample of students (N = 299), the present study investigated the relation between auditory and felt-presence H&H experiences, and specific modalities of intrusive thought (auditory and visual) whilst controlling for age, gender, depression, anxiety and thought suppression. The psychometric properties of the Durham Hypnagogic and Hypnopompic Hallucinations Questionnaire (DHQ) were also examined. Exploratory (N = 299) and, in a second sample, confirmatory (N = 502) factor analyses showed good internal and test-retest reliability for the auditory and felt-presence subscales of the DHQ, but not for the visual subscale. Regression analyses indicated that the sole predictor of auditory H&H hallucinations was intrusive auditory imagery, and the sole predictor of felt-presence H&H experiences was intrusive visual imagery. Explanations for these findings are considered and implications for future research are discussed.