In a dark time: development, validation, and correlates of the Durham hypnagogic and hypnopompic hallucinations questionnaire

One factor limiting research involving hypnagogic and hypnopompic (H&H) hallucinations is the lack of a brief, valid and reliable self-report measure of such experiences. The present paper reports on the development of the Durham Hypnagogic and Hypnopompic Hallucinations Questionnaire (DHQ), which consists of three unidimensional subscales assessing the presence of auditory, visual, and felt-presence experiences in the H&H state. In a sample of 18-29 year olds (N = 365) this scale was found to have satisfactory psychometric properties. A subsample (n = 293) completed self-report measures of intrusive thoughts, thought suppression and transliminality. Intrusive thoughts and the conscious desire to undertake thought suppression both correlated with levels of auditory, but not visual or felt-presence H&H hallucinations. Transliminality correlated with all DHQ subscales, but significantly more strongly with felt-presence than visual H&H experiences. Implications of these findings are considered, and recommendations for future research made.