Characteristics of non-clinical hallucinations: A mixed-methods analysis of auditory, visual, tactile and olfactory hallucinations in a primary voice-hearing cohort

• Published in: Psychiatry research 2020-07, Vol.289, p.112987-112987, Article 112987
• Main Authors: Toh, Wei Lin, Thomas, Neil, Robertson, Michelle, Rossell, Susan Lee
• Format: Article
• Language: English
• Subjects: Adult; Cohort Studies; Female; Hallucinations - diagnosis; Hallucinations - epidemiology; Hallucinations - psychology; healthy voice-hearers; Hearing - physiology; hearing voices; Humans; Male; multimodal hallucinations; multisensory hallucinations; No need-for-care; phenomenology; Psychotic Disorders - diagnosis; Psychotic Disorders - epidemiology; Psychotic Disorders - psychology; Smell - physiology; Touch - physiology; Victoria - epidemiology; Visual Perception - physiology; Voice - physiology; Young Adult
• ISSN: 0165-1781; 1872-7123
• DOI: 10.1016/j.psychres.2020.112987

•Our study examined non-clinical auditory, visual, tactile and olfactory hallucinations.•We employed mixed-method analyses, incorporating qualitative perspectives.•Non-auditory hallucinations were not uncommon in our non-clinical group.•In contrast, delusions and disordered thinking were relatively rare.•Such new knowledge should be interpreted in the context of a psychosis continuum. Phenomenological studies involving hallucinations in non-clinical populations have been relatively neglected, especially within the non-auditory realm. Relevant knowledge would help further a more nuanced understanding of the psychosis continuum. Participants (N=33) were non-clinical voice-hearers, who have experienced auditory verbal hallucinations, but with no known mental health diagnosis and not taking any prescribed psychiatric medications. A comprehensive hallucinations phenomenology interview was conducted to assess physical, cognitive and emotional characteristics of hallucinatory experiences across sensory domains. Mixed methods analysis was employed. Characteristics of reported AVHs were mostly in agreement with existing knowledge, though some deviations did exist (e.g. controllability). In addition, 50%, 24% and 29% of our voice-hearing sample experienced hallucinations in the visual, tactile and olfactory domains at least once a week. In contrast, delusions and disordered thinking were rare. Qualitative thematic analysis yielded added phenomenological insights into contextual triggers as well as the content and perceived purpose(s) of multisensory hallucinations. Our findings highlight lesser-reported data that hallucinations in non-auditory domains are relatively frequent in non-clinical voice-hearers. However, other psychotic-like symptoms (i.e. delusions and thought disorder) seem less common. These insights should be considered in the context of the psychosis continuum argument.