Editorial: new directions in hallucination research

Abstract

Hallucinations are deeply intriguing phenomena but conducting research on them can be challenging. Ineffable experiences can test the limits of traditional research methods and can rely on individuals sharing deeply personal and sometimes deeply distressing experiences. In addition, research is now moving beyond the established psychiatric paradigm of “voices and visions as symptoms” to examine how alterations to experience across the range of human experience can inform models of perception, meaning and memory. This special issue of Cognitive Neuropsychiatry is focused on new directions in hallucination research – and who better to expand the horizons of hallucinations research than early career researchers with the vision and foresight to tackle this area anew. The articles in this special issue comprise nine papers from the early career network of the International Consortium on Hallucination Research. Each of these papers has been led by a working group of early career researchers – often attracting more established and senior researchers as the work gathered momentum. The papers are an exciting collection of new visions for hallucinations research. The special issue begins with research on groups who have intense hallucinatory experiences but have rarely been the focus of systematic research. Palmer-Cooper and colleagues (Palmer-Cooper et al., 2021) examine the role of metacognition in two groups of people. Firstly, in people with ASMR (Autonomous Sensory Meridian Response) – a perceptual condition in which low-level audio-visual stimuli triggers intense somatic sensations in the head and neck regions that can spread throughout the body; and second in Tulpamancers individuals who, through self-training, develop the experience of seemingly autonomous identities existing in their consciousness. The study found a complex relationship between these experiences and measures of meta-cognition that did not simply mirror what is typically found in studies on patients with psychosis, suggesting that these experiences are unlikely to be simply “mild” experiences on the clinical spectrum. The paper by Montagnese and colleagues (Montagnese et al., 2021) examines types of hallucinations that are well-known clinically but are drastically under-researched – namely, hallucinations associated with neurodegenerative disorders and eye disease. One long-standing puzzle has been why hallucinations in these conditions relate so variably to insight, with some hallucinations associated with eye disease being visually spectacular but often clearly recognised as hallucinations. Montagnese and colleagues examined correlates of insight and found that it was predicted by better cognition and lower levels of distress, potentially suggesting a commonality with hallucinations in other domains, although the exact relationships varied across clinical conditions. Four studies focused on hallucinated voices, although took markedly different approaches. Using a simulation study, Bortolon and colleagues (Bortolon et al., 2021) found that both neutral and negative simulated voices triggered similar levels of subjective shame in volunteers, suggesting that the emotional impact of voices may be partly down to their intrusive