A phenomenological survey of auditory verbal hallucinations in the hypnagogic and hypnopompic states

The phenomenology of auditory verbal hallucinations (AVHs) occurring in hypnagogic and hypnopompic (H&H) states has received little attention. In a sample of healthy participants (N=325), 108 participants reported H&H AVHs and answered subsequent questions on their phenomenology. AVHs in the H&H state were found (1) to be more likely to only feature the occasional clear word than to be clear, (2) to be more likely to be one-off voices than to be recurrent voices, (3) to be more likely to be voices of people known to the individual than unknown persons, (4) to be more likely to talk directly to the person rather than not, and (5) to only rarely give commands, ask questions, or to result in an interactive conversation. Their phenomenology was similar to normative AVHs in wakefulness (as established by previous research) in that the voice-hearer was usually the target of the voice, and the voice was more likely to be of a recognized person. However, H&H AVHs differed from AVHs in wakefulness in that commands and questions were rare, and there was typically no dialogical engagement with the voice. We conclude by proposing that two distinct types of H&H AVHs may exist (which we term "dialogic" and "monologic"), based on an analysis of the phenomenology of the experience, and suggest avenues for future research.