This review from the International Consortium on Hallucinations Research intends to question the pertinence of the excitatory-to-inhibitory (E/I) imbalance hypothesis as a model for hallucinations. A large number of studies suggest that subtle impairments of the E/I balance are involved in neurological and psychiatric conditions, such as schizophrenia. Emerging evidence also points to a role of the E/I balance in maintaining stable perceptual representations, suggesting it may be a plausible model for hallucinations. In support, hallucinations have been linked to inhibitory deficits as shown with impairment of gamma-aminobutyric acid transmission, N-methyl-d-aspartate receptor plasticity, reductions in gamma-frequency oscillations, hyperactivity in sensory cortices, and cognitive inhibition deficits. However, the mechanisms by which E/I dysfunctions at the cellular level might relate to clinical symptoms and cognitive deficits remain unclear. Given recent data advances in the field of clinical neuroscience, it is now possible to conduct a synthesis of available data specifically related to hallucinations. These findings are integrated with the latest computational frameworks of hallucinations, and recommendations for future research are provided.

It is not only unclear why hallucinations in schizophrenia occur with different prevalence by modality, but also to what extent they do. Reliable prevalence estimates of hallucinations by modality in schizophrenia are currently lacking, particularly for non-auditory hallucinations. Studies have also tended to report lifetime, not point prevalence by modality. This study assessed the prevalence and co-occurrence of hallucinations, for both lifetime and point prevalence, across the auditory, visual, olfactory, and tactile modalities, in people diagnosed with chronic schizophrenia-spectrum disorders in Ireland (N=693) and Australia (N=218). Lifetime prevalence was 64-80% auditory, 23-31% visual, 9-19% tactile, and 6-10% olfactory. Past month prevalence was 23-27% auditory, 5-8% visual, 4-7% tactile, and 2% olfactory. The majority of participants had only hallucinated in one modality, with this nearly always being the auditory. Approximately one-third had hallucinated in two modalities, most commonly the auditory and visual. Most currently hallucinating patients also hallucinated in a single modality, again, nearly always the auditory. Whereas 30-37% of patients with lifetime auditory hallucinations had experienced visual hallucinations, 83-97% of patients with experience of visual hallucinations had experienced auditory hallucinations. These findings help delineate the modality distribution of hallucinations in schizophrenia, and provide an explanatory target for theoretical models.

Despite the recent proliferation of scientific, clinical, and narrative accounts of auditory verbal hallucinations (AVHs), the phenomenology of voice hearing remains opaque and undertheorized. In this article, we outline an interdisciplinary approach to understanding hallucinatory experiences which seeks to demonstrate the value of the humanities and social sciences to advancing knowledge in clinical research and practice. We argue that an interdisciplinary approach to the phenomenology of AVH utilizes rigorous and context-appropriate methodologies to analyze a wider range of first-person accounts of AVH at 3 contextual levels: (1) cultural, social, and historical; (2) experiential; and (3) biographical. We go on to show that there are significant potential benefits for voice hearers, clinicians, and researchers. These include (1) informing the development and refinement of subtypes of hallucinations within and across diagnostic categories; (2) “front-loading” research in cognitive neuroscience; and (3) suggesting new possibilities for therapeutic intervention. In conclusion, we argue that an interdisciplinary approach to the phenomenology of AVH can nourish the ethical core of scientific enquiry by challenging its interpretive paradigms, and offer voice hearers richer, potentially more empowering ways to make sense of their experiences.

Background: A quick method of assessing readiness to change was needed for a major study of implementing screening and alcohol brief intervention in England. For this purpose, a ReadinessRuler that had been validated among a sample of male college students in the USA was adapted and applied to a sample of excessive drinkers in a general medical practice located in a deprived area of Gateshead, England.Methods: 72 participants identified as excessive drinkers by health professionals completed a singleitem Readiness Ruler, the 12-item Readiness to Change Questionnaire (RCQ) and the AUDIT questionnaire.Results: In terms of concurrent validity, the relationships between the Readiness Ruler, on the one hand, and either stage of change allocation or a dimensional score derived from the RCQ, on the other hand, were highly significant but weaker than expected. When patients who endorsed the "maintenance" point on the Readiness Ruler were excluded from the analysis, the above relationships were considerably strengthened for reasons that are discussed. On this basis and with another small change, a final Readiness Ruler was developed.Conclusion: If the validity of the Readiness Ruler is confirmed in subsequent research, a quick and simple way of measuring readiness to change will be available for research or clinical work with alcohol brief interventions.

Proneness to unusual perceptual states – such as auditory or visual hallucinations – has been proposed to exist on a continuum in the general population, but whether there is a cognitive basis for such a continuum remains unclear. Intentional cognitive inhibition (the ability to wilfully control thoughts and memories) is one mechanism that has been linked to auditory hallucination susceptibility, but most evidence to date has been drawn from clinical samples only. Moreover, such a link has yet to be demonstrated over and above relations to other cognitive skills (source monitoring) and cognitive states (intrusive thoughts) that often correlate with both inhibition and hallucinations. The present study deployed two tests of intentional inhibition ability – the Inhibition of Currently Irrelevant Memories (ICIM) task and Directed Forgetting (DF) task – and one test of source monitoring (a source memory task) to examine how cognitive task performance relates to self-reported i) auditory hallucination-proneness and ii) susceptibility to intrusive thoughts in a non-clinical student sample ( N = 76). Hierarchical regression analyses were used to assess the independent and combined contributions of task performance to proneness scores. ICIM performance but not DF or source memory scores were significantly related to both hallucination-proneness and intrusive thoughts. Further analysis suggested that intrusive thoughts may mediate the link between intentional inhibition skills and auditory hallucination-proneness, suggesting a potential pathway from inhibition to perception via intrusions in cognition. The implications for studying cognitive mechanisms of hallucination and their role in “continuum” views of psychosis-like experiences are discussed.