From Thoughts to Voices: Understanding the Development of Auditory Hallucinations in Schizophrenia

Hallucinations and Delusions as Low-Quality Attributions: Influencing Factors and Proposal for Their Analysis

Hallucinations and delusions, in keeping with the distress accompanying them, are major features in the diagnosis of psychosis in international classifications. In spite of their human and clinical importance, the concepts are unclear. The distinction between hallucinations and delusions in terms of perception-thought is not precise enough, causing problems in analyzing the patient's words. Nor are the differentiations or variations within each precise enough. Continuing the long clinical tradition discussing the distinction between hallucinations and delusions while assuming their similarities, this study poses a concept integrating the two phenomena as attributions people make about themselves and their settings. Then the elements of any attribution can be used as guides for structuring significant literature on both, and reduce analytical ambiguity. Such attributions make more sense within the structure of two-way relationships with factors in a person's own framework and setting. This structure is described with its variables and relationships as a guide to assessment, follow-up, and intervention. Two checklists are provided for orientation.

Hallucinations Under Psychedelics and in the Schizophrenia Spectrum: An Interdisciplinary and Multiscale Comparison

The recent renaissance of psychedelic science has reignited interest in the similarity of drug-induced experiences to those more commonly observed in psychiatric contexts such as the schizophrenia-spectrum. This report from a multidisciplinary working group of the International Consortium on Hallucinations Research (ICHR) addresses this issue, putting special emphasis on hallucinatory experiences. We review evidence collected at different scales of understanding, from pharmacology to brain-imaging, phenomenology and anthropology, highlighting similarities and differences between hallucinations under psychedelics and in the schizophrenia-spectrum disorders. Finally, we attempt to integrate these findings using computational approaches and conclude with recommendations for future research.

Hallucinations both in and out of context: An active inference account

Hallucinations, including auditory verbal hallucinations (AVH), occur in both the healthy population and in psychotic conditions such as schizophrenia (often developing after a prodromal period). In addition, hallucinations can be in-context (they can be consistent with the environment, such as when one hallucinates the end of a sentence that has been repeated many times), or out-of-context (such as the bizarre hallucinations associated with schizophrenia). In previous work, we introduced a model of hallucinations as false (positive) inferences based on a (Markov decision process) formulation of active inference. In this work, we extend this model to include content–to disclose the computational mechanisms behind in- and out-of-context hallucinations. In active inference, sensory information is used to disambiguate alternative hypotheses about the causes of sensations. Sensory information is balanced against prior beliefs, and when this balance is tipped in the favor of prior beliefs, hallucinations can occur. We show that in-context hallucinations arise when (simulated) subjects cannot use sensory information to correct prior beliefs about hearing a voice, but beliefs about content (i.e. the sequential order of a sentence) remain accurate. When hallucinating subjects also have inaccurate beliefs about state transitions, out-of-context hallucinations occur; i.e. their hallucinated speech content is disordered. Note that out-of-context hallucinations in this setting does not refer to inference about context, but rather to false perceptual inference that emerges when the confidence in–or precision of–sensory evidence is reduced. Furthermore, subjects with inaccurate beliefs about state transitions but an intact ability to use sensory information do not hallucinate and are reminiscent of prodromal patients. This work demonstrates the different computational mechanisms that may underlie the spectrum of hallucinatory experience–from the healthy population to psychotic states.

Hallucinations Beyond Voices: A Conceptual Review of the Phenomenology of Altered Perception in Psychosis

Recent psychiatric research and treatment initiatives have tended to move away from traditional diagnostic categories and have focused instead on transdiagnostic phenomena, such as hallucinations. However, this emphasis on isolated experiences may artificially limit the definition of such phenomena and ignore the rich, complex, and dynamic changes occurring simultaneously in other domains of experience. This article reviews the literature on a range of experiential features associated with psychosis, with a focus on their relevance for hallucinations. Phenomenological research on changes in cognition, perception, selfhood and reality, temporality, interpersonal experience, and embodiment are discussed, along with their implications for traditional conceptualizations of hallucinations. We then discuss several phenomenological and neurocognitive theories, as well as the potential impact of trauma on these phenomena. Hallucinations are suggested to be an equifinal outcome of multiple genetic, neurocognitive, subjective, and social processes; by grouping them together under a single, operationalizable definition, meaningful differences in etiology and phenomenology may be ignored. It is suggested that future research efforts strive to incorporate a broader range of experiential alterations, potentially expanding on traditional definitions of hallucinations. Relevance for clinical practice, including emphasizing phenomenologically responsive techniques and developing targeted new therapies, is discussed.

From Computation to the First-Person: Auditory-Verbal Hallucinations and Delusions of Thought Interference in Schizophrenia-Spectrum Psychoses

Schizophrenia-spectrum psychoses are highly complex and heterogeneous disorders that necessitate multiple lines of scientific inquiry and levels of explanation. In recent years, both computational and phenomenological approaches to the understanding of mental illness have received much interest, and significant progress has been made in both fields. However, there has been relatively little progress bridging investigations in these seemingly disparate fields. In this conceptual review and collaborative project from the 4th Meeting of the International Consortium on Hallucination Research, we aim to facilitate the beginning of such dialogue between fields and put forward the argument that computational psychiatry and phenomenology can in fact inform each other, rather than being viewed as isolated or even incompatible approaches. We begin with an overview of phenomenological observations on the interrelationships between auditory-verbal hallucinations (AVH) and delusional thoughts in general, before moving on to review several theoretical frameworks and empirical findings in the computational modeling of AVH. We then relate the computational models to the phenomenological accounts, with a special focus on AVH and delusions that involve the senses of agency and ownership of thought (delusions of thought interference). Finally, we offer some tentative directions for future research, emphasizing the importance of a mutual understanding between separate lines of inquiry.

The Italian version of the 16-item prodromal questionnaire (iPQ-16): Field-test and psychometric features

OBJECTIVE

Among current early screeners for psychosis-risk states, the Prodromal Questionnaire-16 items (PQ-16) is often used. We aimed to assess validity and reliability of the Italian version of the PQ-16 in a young adult help-seeking population.

METHODS

We included 154 individuals aged 18-35years seeking help at the Reggio Emilia outpatient mental health services in a large semirural catchment area (550.000 inhabitants). Participants completed the Italian version of the PQ-16 (iPQ-16) and were subsequently evaluated with the Comprehensive Assessment of At-Risk Mental States (CAARMS). We examined diagnostic accuracy (i.e. specificity, sensitivity, negative and positive likelihood ratios, and negative and positive predictive values) and content, convergent, and concurrent validity between PQ-16 and CAARMS using Cronbach's alpha, Spearman's rho, and Cohen's kappa, respectively. We also tested the validity of the adopted PQ-16 cut-offs through Receiver Operating Characteristic (ROC) curves plotted against CAARMS diagnoses and the 1-year predictive validity of the PQ-16.

RESULTS

The iPQ-16 showed high internal consistency and acceptable diagnostic accuracy and concurrent validity. ROC analyses pointed to a cut-off score of ≥5 as best cut-off. After 12months of follow-up, 8.7% of participants with a PQ-16 symptom total score of ≥5 who were below the CAARMS psychosis threshold at the baseline, developed a psychotic disorder.

CONCLUSIONS

Psychometric properties of the iPQ-16 were satisfactory.