"Seeing Rain": Integrating phenomenological and Bayesian predictive coding approaches to visual hallucinations and self-disturbances (Ichstörungen) in schizophrenia

Explanatory power by vagueness. Challenges to the strong prior hypothesis on hallucinations exemplified by the Charles-Bonnet-Syndrome

Predictive processing models are often ascribed a certain generality in conceptually unifying the relationships between perception, action, and cognition or the potential to posit a 'grand unified theory' of the mind. The limitations of this unification can be seen when these models are applied to specific cognitive phenomena or phenomenal consciousness. Our article discusses these shortcomings for predictive processing models of hallucinations by the example of the Charles-Bonnet-Syndrome. This case study shows that the current predictive processing account omits essential characteristics of stimulus-independent perception in general, which has critical phenomenological implications. We argue that the most popular predictive processing model of hallucinatory conditions - the strong prior hypothesis - fails to fully account for the characteristics of nonveridical perceptual experiences associated with Charles-Bonnet-Syndrome. To fill this explanatory gap, we propose that the strong prior hypothesis needs to include reality monitoring to apply to more than just veridical percepts.

Sensed Presence, Attenuated Psychosis, and Transliminality: At the Threshold of Consciousness

INTRODUCTION

The experience of "sensed presence" or "felt presence" in the absence of "other" has been described as a complex multimodal experience to which meaning is given. Sensed presence (SenP) is a transdiagnostic experience that exists along a continuum that can appear during isolation, spirit quests, exposure to extreme elements, bereavement, anxiety, and psychosis. Given the prevalence and vast heterogeneity of SenP, in addition to a surprising lack of targeted research into this phenomenon, this research examined the interrelationship of SenP, attenuated psychosis symptoms (APS), and transliminality. Transliminality is composed of absorption, fantasy proneness, paranormal belief, mystical experiences, increased creativity, and hyperaesthesia.

METHODS

A completely anonymous online survey of unusual experiences and mental health was distributed via social media (i.e., Twitter, Facebook, Reddit, and mass emailing lists) to recruit participants. Demographic data were analyzed using χ2 tests and one-way ANOVAs. A two-step cluster analysis was conducted to identify distinct sub-categories of transliminality followed by ANOVAs with bootstrapping at 1,000 iterations to compare SenP, increased APS, and transliminality. Pearson's bivariate correlations were conducted to determine the association between SenP, APS, and transliminality.

RESULTS

Together with descriptive findings, we show distinct characteristics between clusters. T1 cluster consisted of individuals with few SenP experiences, low APS, and low transliminality. T2 consisted of individuals with a moderate prevalence of SenP, low APS, moderate transliminality, and increased overall feeling of closeness to G-d. There was no significant difference in APS between T1 and T2 or in the level of distress associated with APS. T3 individuals showed a significantly higher prevalence of SenP in all domains (frequency, distress, vividness, and total score), higher APS, and higher transliminality, compared to T1 and T2. The T3 cluster met criteria for high risk to develop psychosis.

CONCLUSION

Thus, our findings demonstrate a strong association and entanglement of these experiences which suggests that the interrelatedness of transliminality/absorption and APS may serve as a potentially provocative underlying structure in the phenomenology of SenP.

Thinking about hallucinations: why philosophy matters

Introduction: Hallucinations research is increasingly incorporating philosophy or the work of philosophically trained individuals. We present three different ways in which this is successfully implemented to the enhancement of knowledge and understanding of hallucinations and related phenomena.Method: We review contributions from phenomenology, philosophy of cognitive science, and philosophy of science and psychiatry.Results: We demonstrate that these areas of philosophy make significant contributions to hallucinations research. Phenomenology gives us a sophisticated and critical understanding of the lived experience of hallucinations. Philosophy of cognitive science enables big-picture theorising and synthesis of ideas, as well as a critical engagement with new paradigms. Philosophy of science and psychiatry raises valuable and theoretically informed questions about diagnosis and categorisation.Conclusions: These contributions reflect both the methodological variety within philosophy and its relevance to the hallucinations researcher.

Prevalence and assessment of self-disorders in the schizophrenia spectrum: a systematic review and meta-analysis

Self-disorders have been proposed as the "clinical core" of the schizophrenia spectrum. This has been explored in recent studies using self-disorder assessment tools. However, there are few systematic discussions of their quality and utility. Therefore, a literature search was performed on Medline, Embase, PsychINFO, PubMed and the Web of Science. Studies using these assessment tools to explore self-disorders within schizophrenia spectrum disorders (SSDs) were included. A meta-analysis was performed on the outcomes of total self-disorder score and odds ratios of self-disorders, using Comprehensive Meta-Analysis software. Weighted pooled effect sizes in Hedge's g were calculated using a random-effects model. 15 studies were included, giving a sample of 810 participants on the schizophrenia spectrum. Self-disorders showed a greater aggregation within schizophrenia spectrum groups compared to non-schizophrenia spectrum groups, as measured with the Bonn Scale for the Assessment of Basic Symptoms (Hedge's g = 0.774, p < 0.01) and Examination of Anomalous Self-Experiences (Hedge's g = 1.604, p < 0.01). Also, self-disorders had a greater likelihood of occurring within SSDs (odds ratio = 5.435, p < 0.01). These findings help to validate self-disorders as a core clinical feature of the broad schizophrenia spectrum.

The phenomenology of auditory verbal hallucinations in schizophrenia and the challenge from pseudohallucinations

In trying to make sense of the extensive phenomenological variation of first-personal reports on auditory verbal hallucinations, the concept of pseudohallucination is originally introduced to designate any hallucinatory-like phenomena not exhibiting some of the paradigmatic features of "genuine" hallucinations. After its introduction, Karl Jaspers locates the notion of pseudohallucinations into the auditory domain, appealing to a distinction between hallucinatory voices heard within the subjective inner space (pseudohallucination) and voices heard in the outer external space (real hallucinations) with differences in their sensory richness. Jaspers' characterization of the term has been the target of a number of phenomenological, conceptual and empirically-based criticisms. From this latter point of view, it has been claimed that the concept cannot capture distinct phenomena at the neurobiological level. Over the last years, the notion of pseudohallucination seems to be falling into disuse as no major diagnostic system seems to refer to it. In this paper, we propose that even if the concept of pseudohallucination is not helpful to differentiate distinct phenomena at the neurobiological level, the inner/outer distinction highlighted by Jaspers' characterization of the term still remains an open explanatory challenge for dominant theories about the neurocognitive origin of auditory verbal hallucinations. We call this, "the challenge from pseudohallucinations". After exploring this issue in detail, we propose some phenomenological, conceptual, and empirical paths for future research that might help to build up a more contextualized and dynamic view of auditory verbal hallucinatory phenomena.

Computational models of the "active self" and its disturbances in schizophrenia

The notion that self-disorders are at the root of the emergence of schizophrenia rather than a symptom of the disease, is getting more traction in the cognitive sciences. This is in line with philosophical approaches that consider an enactive self, constituted through action and interaction with the environment. We thereby analyze different definitions of the self and evaluate various computational theories lending to these ideas. Bayesian and predictive processing are promising approaches for computational modeling of the "active self". We evaluate their implementation and challenges in computational psychiatry and cognitive developmental robotics. We describe how and why embodied robotic systems provide a valuable tool in psychiatry to assess, validate, and simulate mechanisms of self-disorders. Specifically, mechanisms involving sensorimotor learning, prediction, and self-other distinction, can be assessed with artificial agents. This link can provide essential insights to the formation of the self and new avenues in the treatment of psychiatric disorders.

Innovations in the psychopathology of schizophrenia: a primer for busy clinicians

Significant developments in schizophrenia psychopathology are ready to be incorporated into clinical practice. These advances allow a way forward through the well-described challenges experienced with current diagnostic and psychopathological frameworks. This article discusses approaches that will enable clinicians to access a wider and richer spectrum of patient experience; describes process-based models of schizophrenia in the domains of both the brain and the mind; and considers how different levels of analysis might be linked via the predictive processing framework. Multiple levels of analysis provide different targets for varying modalities of treatment – dopamine blockade at the molecular level, psychological therapy at the level of the mind, and social interventions at the personal level. Psychiatry needs to align itself closer to neuroscientific research. It should move from a symptom-based understanding to a model based on process. That is – after having asked about a patient's symptoms and experience clinicians need to introduce steps involving a consideration of what might be the brain and mind processes underlying the experience.

The Phenomenology and Neurobiology of Visual Distortions and Hallucinations in Schizophrenia: An Update

Schizophrenia is characterized by visual distortions in ~60% of cases, and visual hallucinations (VH) in ~25-50% of cases, depending on the sample. These symptoms have received relatively little attention in the literature, perhaps due to the higher rate of auditory vs. visual hallucinations in psychotic disorders, which is the reverse of what is found in other neuropsychiatric conditions. Given the clinical significance of these perceptual disturbances, our aim is to help address this gap by updating and expanding upon prior reviews. Specifically, we: (1) present findings on the nature and frequency of VH and distortions in schizophrenia; (2) review proposed syndromes of VH in neuro-ophthalmology and neuropsychiatry, and discuss the extent to which these characterize VH in schizophrenia; (3) review potential cortical mechanisms of VH in schizophrenia; (4) review retinal changes that could contribute to VH in schizophrenia; (5) discuss relationships between findings from laboratory measures of visual processing and VH in schizophrenia; and (6) integrate findings across biological and psychological levels to propose an updated model of VH mechanisms, including how their content is determined, and how they may reflect vulnerabilities in the maintenance of a sense of self. In particular, we emphasize the potential role of alterations at multiple points in the visual pathway, including the retina, the roles of multiple neurotransmitters, and the role of a combination of disinhibited default mode network activity and enhanced state-related apical/contextual drive in determining the onset and content of VH. In short, our goal is to cast a fresh light on the under-studied symptoms of VH and visual distortions in schizophrenia for the purposes of informing future work on mechanisms and the development of targeted therapeutic interventions.

The Strasbourg Visual Scale: A Novel Method to Assess Visual Hallucinations

The experience of oneself in the world is based on sensory afferences, enabling us to reach a first-perspective perception of our environment and to differentiate oneself from the world. Visual hallucinations may arise from a difficulty in differentiating one's own mental imagery from externally-induced perceptions. To specify the relationship between hallucinations and the disorders of the self, we need to understand the mechanisms of hallucinations. However, visual hallucinations are often under reported in individuals with psychosis, who sometimes appear to experience difficulties describing them. We developed the "Strasbourg Visual Scale (SVS)," a novel computerized tool that allows us to explore and capture the subjective experience of visual hallucinations by circumventing the difficulties associated with verbal descriptions. This scale reconstructs the hallucinated image of the participants by presenting distinct physical properties of visual information, step-by-step to help them communicate their internal experience. The strategy that underlies the SVS is to present a sequence of images to the participants whose choice at each step provides a feedback toward re-creating the internal image held by them. The SVS displays simple images on a computer screen that provide choices for the participants. Each step focuses on one physical property of an image, and the successive choices made by the participants help them to progressively build an image close to his/her hallucination, similar to the tools commonly used to generate facial composites. The SVS was constructed based on our knowledge of the visual pathways leading to an integrated perception of our environment. We discuss the rationale for the successive steps of the scale, and to which extent it could complement existing scales.

Validation of the Launay-Slade Hallucination Scale among Indian Healthy Adults

Psychotic Like Experiences (PLEs) have been reported in several cultures. The 16 item Launay-Slade Hallucination Scale-Extended (LSHS-E) measures hallucination like experiences (HLEs) in the general population. This study investigated the psychometric properties and the factor structure of LSHS-E Hindi among healthy adults of Delhi. LSHS-E was translated from English to Hindi and then back to English. It was administered as a paper pencil questionnaire to 182 adults from the general population. Reliability of LSHS-E Hindi was measured using Cronbach's alpha and factor structure was established using confirmatory factor analysis (CFA). It was tested against the Community Assessment of Psychic Experiences (CAPE-42) for convergent and divergent validity. Latent Class Analysis (LCA) was performed to identify subgroups with different endorsement of HLEs. Among 182, 18 participants reporting mental and neurological disorders were excluded. LSHS-E Hindi had good reliability (0.85; 95% CI: 0.82 to 0.88). CFA of Hindi LSHS-E revealed the a priori four-factor solution to be best, namely: 'intrusive thoughts', 'vivid daydreams', 'multisensory HLEs', 'auditory and visual HLEs'. LSHS-E Hindi showed stronger correlation with positive domain of CAPE than with negative and depression domains. LCA revealed three classes: low, intermediate and high endorsement of HLEs. Participants with highest endorsement of HLEs were less educated and had highest endorsement on all CAPE dimensions. LSHS-E Hindi has good psychometric properties and can be used to study HLEs in Indians. The four-factor structure model depicts the multidimensionality of HLEs, with 'intrusive thoughts' being the most commonly reported HLE in the sample. LCA supports the continuum hypothesis of HLEs.

Thinking, believing, and hallucinating self in schizophrenia

In this Personal View, we discuss the history and concept of self-disturbance in relation to the pathophysiology and subjective experience of schizophrenia in terms of three approaches: the perceptual anomalies approach of the early Heidelberg School of Psychiatry, the ipseity model, and the predictive coding framework. Despite the importance of these approaches, there has been a notable absence of efforts to compare them and consider how they might be integrated. This Personal View compares the three approaches and offers suggestions as to how they might work together, which represents a novel position. We view self-disturbances as transformations of self that form the inseparable background against which psychotic symptoms emerge. Integrating computational psychiatric approaches with those used by phenomenologists in the first two listed approaches, we argue that delusions and hallucinations are inferences produced under extraordinary conditions and are both statistically and experientially as real for patients as other mental events. Such inferences still approximate Bayes-optimality, given the personal, neurobiological, and environmental circumstances, and might be the only ones available to minimise prediction error. The added contribution we hope to make focuses on how the dialogue between neuroscience and phenomenology might improve clinical practice. We hope this Personal View will act as a timely primer and bridging point for the different approaches of computational psychiatry and phenomenological psychopathology for interested clinicians.