Acute right opercular stroke-associated polyopic heautoscopy and hallucinations caused by disconnection to the inferior parietal lobule through the superior longitudinal fasciculus III: A single case study

Illusory neuropsychiatric symptoms such as hallucinations or the feeling of a presence (FOP) can occur in diffuse brain lesion or dysfunction, in psychiatric diseases as well as in healthy individuals. Their occurrence due to focal brain lesions is rare, most probably due to underreporting, which limits progress in understanding their underlying mechanisms and anatomical determinants. In this single case study, an 86-year-old patient experienced, in the context of an acute right central opercular ischemic stroke, visual hallucinatory symptoms (including palinopsia), differently lateralized auditory hallucinations and FOP. This unusual clinical constellation could be precisely documented and illustrated while still present, allowing a realistic and immersive visual experience validated by the patient. The acute stroke appeared to be their most plausible cause (after exclusion of other etiologies). Furthermore, accurate analysis of tractographic data suggested that disruption in the posterior bundle of the superior longitudinal fasciculus connecting the stroke lesion to the inferior parietal lobule was the anatomical substrate explaining the FOP and, indirectly, also hallucinations through whiter matter involvement, in coherence with existing literature. We could finally elaborate on symptoms taxonomy and phenomenology (e.g., polyopic heautoscopy, hallucinatory FOP, etc), and on patient's remarkable distancing from them (with some therapeutic implications supported by plausibly engaged mechanisms). This case not only authentically enriched the description of such rare combination of heterogenous illusory symptoms through this novel visualization-based reporting approach, but disclosed an unrevealed anatomo-clinical link relating all of them to the acute stroke lesion through an association fiber, thereby contributing to the understanding of these intriguing symptoms and their determinants.

A clinico-anatomical dissection of the magnocellular and parvocellular pathways in a patient with the Riddoch syndrome

KEY MESSAGE

The Riddoch syndrome is thought to be caused by damage to the primary visual cortex (V1), usually following a vascular event. This study shows that damage to the anatomical input to V1, i.e., the optic radiations, can result in selective visual deficits that mimic the Riddoch syndrome. The results also highlight the differential susceptibility of the magnocellular and parvocellular visual systems to injury. Overall, this study offers new insights that will improve our understanding of the impact of brain injury and neurosurgery on the visual pathways. The Riddoch syndrome, characterised by the ability to perceive, consciously, moving visual stimuli but not static ones, has been associated with lesions of primary visual cortex (V1). We present here the case of patient YL who, after a tumour resection surgery that spared his V1, nevertheless showed symptoms of the Riddoch syndrome. Based on our testing, we postulated that the magnocellular (M) and parvocellular (P) inputs to his V1 may be differentially affected. In a first experiment, YL was presented with static and moving checkerboards in his blind field while undergoing multimodal magnetic resonance imaging (MRI), including structural, functional, and diffusion, acquired at 3 T. In a second experiment, we assessed YL's neural responses to M and P visual stimuli using psychophysics and high-resolution fMRI acquired at 7 T. YL's optic radiations were partially damaged but not severed. We found extensive activity in his visual cortex for moving, but not static, visual stimuli, while our psychophysical tests revealed that only low-spatial frequency moving checkerboards were perceived. High-resolution fMRI revealed strong responses in YL's V1 to M stimuli and very weak ones to P stimuli, indicating a functional P lesion affecting V1. In addition, YL frequently reported seeing moving stimuli and discriminating their direction of motion in the absence of visual stimulation, suggesting that he was experiencing visual hallucinations. Overall, this study highlights the possibility of a selective loss of P inputs to V1 resulting in the Riddoch syndrome and in hallucinations of visual motion.

A systematic review and meta-analysis of synthetic cathinone use and psychosis

RATIONALE

Synthetic cathinones (SC), commonly referred to as "bath salts", are stimulants resembling the natural alkaloid cathinone found in the khat plant. These substances have the potential to induce serious health risks such as hallucinations, delusions, paranoia and agitation which can lead to substance-induced psychotic disorders. Despite growing concerns, there is a limited understanding of the association between SC consumption and the devolvement of such psychopathologies.

METHODS

We conducted a systematic review to investigate the frequency of substance-induced psychotic disorder (SIPD) and associated conditions in humans following synthetic cathinone consumption. We qualitatively and quantitatively analyzed SC exposure cases.

RESULTS

A total of 32 studies were included, with a diverse range of demographics, synthetic cathinone types, and consumption patterns. The proportion of individuals developing psychotic symptoms was reported at 0.380 (Random-effects model, 95% CI 0.289 - 0.475). Additionally, the significant heterogeneity in diagnostic approaches limited our ability to provide a precise estimate of prevalence.

CONCLUSIONS

Synthetic cathinone consumption is associated with the risk of developing psychotic symptoms as indicated by the prevalence of hallucinations and/or delusions. Due to the lack of information on classifying factors, particularly duration of symptoms, we are unable to conclude synthetic cathinone-induced psychosis. Further research is warranted to elucidate the underlying mechanism linking synthetic cathinone consumption and psychosis. This review underscores the urgency of addressing the growing health risks posed by synthetic cathinone use. Additionally, it highlights the necessity of proper quantification of psychotic symptoms through scales and reporting of classification criteria to accurately diagnose SIPD.

A Unique Delusion with Depression in Early Stage of Neurocognitive Disorder Due to Vascular Disease: Considerations for Clinicians

As global aging becomes more prominent, neurocognitive disorders (NCD) incidence has increased. Patients with NCD usually have an impairment in one or more cognitive domains, such as attention, planning, inhibition, learning, memory, language, visual perception, and spatial or social skills. Studies indicate that 50-80% of these adults will develop neuropsychiatric symptoms (NPS), such as apathy, depression, anxiety, disinhibition, delusions, hallucinations, and aberrant motor behavior. The progression of NCD and subsequent NPS requires tremendous care from trained medical professionals and family members. The behavioral symptoms are often more distressing than cognitive changes, causing caregiver distress/depression, more emergency room visits and hospitalizations, and even earlier institutionalization. This signifies the need for early identification of individuals at higher risk of NPS, understanding the trajectory of their NCD, and exploring treatment modalities. In this case report and review, we present an 82-year-old male admitted to our facility for new-onset symptoms of depression, anxiety, and persecutory delusions. He has no significant past psychiatric history, and his medical history is significant for extensive ischemic vascular disease requiring multiple surgeries and two episodes of cerebrovascular accident (CVA). On further evaluation, the patient was diagnosed with major NCD, vascular subtype. We discuss differential diagnoses and development of NPS from NCD in order to explain the significance of more thorough evaluation by clinicians for early detection and understanding of NCD prognosis.

Case of tizanidine withdrawal showing hallucination, decorticate posture and tremor, with hypersympathetic vital signs

Tizanidine, an α2-adrenergic receptor agonist commonly prescribed as a muscle relaxant, has been associated with limited cases of acute intoxication or withdrawal. Here, we present a case of tizanidine withdrawal in a woman in her 40s who presented with an unusual combination of systemic and neurological symptoms. These included hallucinations, decorticate posture, limb and eyelid tremors, along with hypertension, tachycardia and tachypnoea. The diagnosis of tizanidine withdrawal was established by a comprehensive assessment of the patient's medical history and the systematic exclusion of other potential diseases. Our approach to managing the withdrawal symptoms was to initiate symptomatic treatment with a combination of a beta-blocker and a calcium channel blocker. Remarkably, this intervention successfully resolved both vital signs and neurological manifestations by the following day. In conclusion, tizanidine withdrawal is associated with a distinct and diagnostically significant neurological syndrome characterised by hallucinations, decorticate posture, tremors and hypersympathetic vital signs.

The mechanisms underlying conditioning of phantom percepts differ between those with hallucinations and synesthesia

There are many different kinds of 'phantom' percepts but it is unknown whether they are united by common mechanisms. For example, synaesthesia (e.g., numbers evoking colour) and hallucinations appear conceptually and phenomenologically similar: both result in a percept that does not have an environmental correlate. Here, people with synaesthesia (n = 66) performed a conditioned hallucinations paradigm known to be sensitive to hallucination susceptibility, and we asked whether synaesthetes would show the same behavioural profile as hallucinators in this task. Repeated pairing of checkerboards with tones, and gratings with colours encourages the participant to draw on prior knowledge when asked to report on the presence of the difficult-to-detect target stimulus. Synaesthetes show increased modelled expectancies for the stimulus association across the board, resulting in a higher number of detections at all stimulus intensities. This is in contrast to the pattern observed in hallucinators, who weigh their prior beliefs more strongly than controls, giving rise to more conditioned hallucinations. Results indicate that fundamentally different perceptual processes may be at the core of these seemingly similar experiences.

The model student: GPT-4 performance on graduate biomedical science exams

The GPT-4 large language model (LLM) and ChatGPT chatbot have emerged as accessible and capable tools for generating English-language text in a variety of formats. GPT-4 has previously performed well when applied to questions from multiple standardized examinations. However, further evaluation of trustworthiness and accuracy of GPT-4 responses across various knowledge domains is essential before its use as a reference resource. Here, we assess GPT-4 performance on nine graduate-level examinations in the biomedical sciences (seven blinded), finding that GPT-4 scores exceed the student average in seven of nine cases and exceed all student scores for four exams. GPT-4 performed very well on fill-in-the-blank, short-answer, and essay questions, and correctly answered several questions on figures sourced from published manuscripts. Conversely, GPT-4 performed poorly on questions with figures containing simulated data and those requiring a hand-drawn answer. Two GPT-4 answer-sets were flagged as plagiarism based on answer similarity and some model responses included detailed hallucinations. In addition to assessing GPT-4 performance, we discuss patterns and limitations in GPT-4 capabilities with the goal of informing design of future academic examinations in the chatbot era.

Abdominal Compartment Syndrome with Super-K (Ketamine) for Super-R(efractory) Status Epilepticus: A Case Report

Refractory status epilepticus is commonly defined as status epilepticus that fails to respond to two or more appropriately dosed intravenous anti-seizure medications including at least one non-benzodiazepine drug. Super-refractory status epilepticus (SRSE) is when status epilepticus continues for ≥24 h despite anesthetic treatment or recurs on an attempted wean of the anesthetic drugs. There is little evidence to guide the management of SRSE. Of late, unconventional therapies have been described in the literature regarding the management of SRSE, with ketamine leading the pack. Studies have noted ketamine's therapeutic efficacy up to 91% in SRSE cessation. Common side effects of ketamine include nausea, vomiting, headache, and hallucinations; but to our knowledge, ketamine has not been implicated in the pathogenesis of abdominal compartment syndrome. We describe a 74-year-old male who developed severe abdominal compartment syndrome in the setting of ketamine infusion for new-onset SRSE to increase awareness about this potential complication.

Older people living in the community with delusion

AIM

This study explores the intricate relationship between social interactions and the development of persecutory delusions among older women living alone in Japan. Focusing on the unique perspective of individuals experiencing delusions outside clinical settings, the aim was to understand the impact of interpersonal interactions on delusion formation.

METHODS

Cases of older women living alone with persecutory delusions were selected from records of municipal psychogeriatric services and medical consultations within a community space. This study employed a descriptive approach to propose a hypothesis regarding the possible connection between social interactions and the development of persecutory delusions within this demographic.

RESULTS

Two relevant cases were identified, from which a three-step hypothesis emerged regarding the potential link between social interactions and the development of persecutory delusions in this demographic. Insights from these cases suggest that anxiety can trigger hallucinations, which, when unaddressed, evolve into delusional interpretations. Addressing these unmet needs could mitigate the progression of persecutory delusions.

CONCLUSIONS

The findings of this study underline the critical relationship between social interactions and persecutory delusions among older women living alone. The unmet need for empathy influences the progression from anxiety-driven hallucinations to fully formed delusions. Early intervention can prevent the escalation of delusions and involuntary psychiatric hospitalization. This study underscores the importance of recognizing the link between social isolation and delusion emergence. It advocates for compassionate environments to meet the psychological needs of older individuals grappling with delusions. Geriatr Gerontol Int 2024; 24: 118-122.

Insomnia moderates the association between psychotic-like experiences and suicidal ideation in a non-clinical population: a network analysis

Psychotic-like experiences (PLEs) have been associated with poor sleep quality and increased suicide risk. However, the association between PLEs, insomnia and suicide risk has not been thoroughly investigated in prior studies. In this study, we aimed to explore as to whether insomnia moderates the association between PLEs and suicidal ideation. The study was performed in 4203 young adults (aged 18-35 years, 63.8% females). Data were collected using self-reports. Moderation analysis demonstrated that PLEs are associated with higher levels of the current suicidal ideation only in participants with greater severity of insomnia (B = 0.003, p < 0.001). This analysis included age, gender, education, occupation and depressive symptoms as covariates. Moreover, the network analysis demonstrated that nodes representing PLEs are connected to the node of current suicidal ideation only in participants with greater severity of insomnia. The nodes of PLEs connected to the current suicidal ideation node captured PLEs representing deja vu experiences, auditory hallucination-like experiences and paranoia (edge weights between 0.011 and 0.083). Furthermore, nodes representing PLEs were the three most central nodes in the network analysis of individuals with higher levels of insomnia (strength centrality between 0.96 and 1.10). In turn, the three most central nodes were represented by depressive symptoms in the network analysis of individuals with lower levels of insomnia (strength centrality between 0.67 and 0.79). Findings from this study indicate that insomnia might be an important risk factor of suicide in people with PLEs, especially those reporting deja vu experiences, auditory hallucination-like experiences and paranoia.

Risk for Complicated Grief After the COVID-19 Death of a Marital Partner in Late Life

OBJECTIVE

To identify 1) complicated grief symptom clusters among acutely-bereaved older adults who have lost a spouse to COVID-19 and 2) if spousal death due to COVID-19 increased risk of developing probable PGD METHODS: Eighty adults participating in a randomized controlled trial for depression prevention (mean age [± SD] = 70.4 [6.6]) completed the Inventory of Complicated Grief, every 3 months over a maximum of 15 months. Twenty-four percent (n = 19) of participants lost a spouse to COVID-19; 76% (n = 61) lost a spouse to other causes of death. Adjusted linear regression examined the associations between COVID-19 bereavement and six symptom clusters: yearning and preoccupation, anger and bitterness, shock and disbelief, estrangement from others, hallucinations, and behavior change.

RESULTS

Compared to the non-COVID-19 group, the COVID-19 bereaved group reported greater shock and disbelief, hallucinations of the deceased, and estrangement from others. COVID-19 death was also associated with higher risk for probable prolonged grief disorder (PGD) at 12 months (odds ratio = 4.38, p = 0.027).

CONCLUSIONS

Older adults who have lost a spouse to COVID-19 present with specific symptoms of distress and may eventually require clinical care for PGD.

Enhanced Beta2-band Oscillations Denote Auditory Hallucination in Schizophrenia Patients and a Monkey Model of Psychosis

An electroencephalographic (EEG) signature of auditory hallucinations (AHs) is important for facilitating the diagnosis and treatment of AHs in schizophrenia. We recorded EEG from 25 schizophrenia patients with recurrent AHs. During the period of AHs, EEG recordings exhibited significantly elevated beta2-band power in the temporal region, as compared to those recorded in the absence of AHs or during stimulation with verbal sounds. We further generated methamphetamine-treated rhesus monkeys exhibiting psychosis-like behaviors, including repetitive sudden searching actions in the absence of external intrusion, suggesting the occurrence of AHs. Epidural EEG beta2-band power in the temporal region of these monkeys was enhanced immediately after methamphetamine treatment and positively correlated with the frequency of sudden searching actions. Thus, the enhancement of temporal beta2-band oscillations represents a signature for AHs in both patients and a monkey model of psychosis, and this monkey model can be used for developing closed-loop neuromodulation approaches for the treatment of refractory AHs in schizophrenia.

Can ChatGPT assist authors with abstract writing in medical journals? Evaluating the quality of scientific abstracts generated by ChatGPT and original abstracts

INTRODUCTION

ChatGPT, a sophisticated large language model (LLM), has garnered widespread attention for its ability to mimic human-like communication. As recent studies indicate a potential supportive role of ChatGPT in academic writing, we assessed the LLM's capacity to generate accurate and comprehensive scientific abstracts from published Randomised Controlled Trial (RCT) data, focusing on the adherence to the Consolidated Standards of Reporting Trials for Abstracts (CONSORT-A) statement, in comparison to the original authors' abstracts.

METHODOLOGY

RCTs, identified in a PubMed/MEDLINE search post-September 2021 across various medical disciplines, were subjected to abstract generation via ChatGPT versions 3.5 and 4, following the guidelines of the respective journals. The overall quality score (OQS) of each abstract was determined by the total number of adequately reported components from the 18-item CONSORT-A checklist. Additional outcome measures included percent adherence to each CONOSORT-A item, readability, hallucination rate, and regression analysis of reporting quality determinants.

RESULTS

Original abstracts achieved a mean OQS of 11.89 (95% CI: 11.23-12.54), outperforming GPT 3.5 (7.89; 95% CI: 7.32-8.46) and GPT 4 (5.18; 95% CI: 4.64-5.71). Compared to GPT 3.5 and 4 outputs, original abstracts were more adherent with 10 and 14 CONSORT-A items, respectively. In blind assessments, GPT 3.5-generated abstracts were deemed most readable in 62.22% of cases which was significantly greater than the original (31.11%; P = 0.003) and GPT 4-generated (6.67%; P<0.001) abstracts. Moreover, ChatGPT 3.5 exhibited a hallucination rate of 0.03 items per abstract compared to 1.13 by GPT 4. No determinants for improved reporting quality were identified for GPT-generated abstracts.

CONCLUSIONS

While ChatGPT could generate more readable abstracts, their overall quality was inferior to the original abstracts. Yet, its proficiency to concisely relay key information with minimal error holds promise for medical research and warrants further investigations to fully ascertain the LLM's applicability in this domain.

Kamin blocking is disrupted by low-dose ketamine in mice: Further implications for aberrant stimulus processing in schizophrenia

Previous studies have shown that low doses of ketamine, an N-methyl-D-aspartate receptor antagonist, produce aberrantly strong internal representations of associatively activated but absent stimuli in humans and nonhuman animals, suggesting the validity of ketamine treatment as a preclinical model of the positive symptoms of schizophrenia, including hallucinations and delusions. However, whether acute ketamine treatment also impairs the ability to ignore present but informationally redundant stimuli, which is another hallmark of schizophrenia, remains unclear. Accordingly, the present study investigated whether injections of low-dose ketamine attenuate Kamin blocking in an appetitive conditioning preparation in mice. Mice in the blocking group were initially trained with A+ conditioning (i.e., conditioned stimulus A paired with a sucrose solution), followed by compound AX+ training, before the conditioned responses to the cue X were tested in extinction. The animals in the control group received B+ training before the AX+ training. Half of the mice in each group received an injection of 16 mg/kg ketamine before each compound conditioning session and the extinction test, whereas the other half received saline. The results showed a reliable blocking effect in the saline-treated mice, whereas the blocking effect was absent in the ketamine-treated mice. Specifically, the absence of blocking was due to the ketamine-treated mice learning about the blocked cues. This finding further validates the use of low-dose ketamine as a preclinical model of schizophrenia. It also suggests a possible link between hallucination-like aberrant processing of absent events and a reduced ability to suppress attentional processing of task-irrelevant stimuli. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Psychotic Disorder after Left Posterior Cerebral Artery Stroke-An Atypical Event

INTRODUCTION

Stroke survivors usually present physical and neuropsychiatric complications. Post-stroke psychosis (PSPsy) is a particularly neglected sequel despite its disruptive nature.

OBJECTIVES

To present a case of early emerging neuropsychiatric symptoms following a left posterior cerebral artery (PCA) stroke. To review and discuss PSPsy clinical manifestations, pathophysiology, and clinical outcomes.

CLINICAL CASE

A previously autonomous 68-year-old woman with vascular risk factors and depressive disorder presented to the emergency department with a 5-day history of disorientation, motor aphasia, and right hypoesthesia. Computer tomography revealed a left PCA stroke. She was started on acetylsalicylic acid and rosuvastatin and discharged the next day. Afterward, the patient developed a depressive mood, emotional lability, periods of confusion, delusions of persecution, guilt and unworthiness, auditory hallucinations, and suicide ideation. She was admitted to a psychiatric hospital and started on risperidone with a good response, being discharged after 15 days with the resolution of psychiatric symptoms.

CONCLUSIONS

PSPsy is more common after right hemisphere lesions and usually develops after some months. Nevertheless, our patient presented PSPsy following an ischemic event of the left PCA, with neuropsychiatric symptomatology dominating the clinic since the beginning. The involvement of the retrosplenial cortex or its connections was likely important for this atypical presentation. Due to the lack of guidelines on approaching PSPsy, most patients are treated with the same strategies used for non-stroke patients. A better comprehension of the anatomical basis underlining the symptomatology in these patients could deepen the understanding of psychosis and psychotic disorders.

A rare case report of Huntington's disease with severe psychiatric symptoms as initial manifestations

INTRODUCTION

Huntington's disease (HD) stands as an inherited and progressive neurodegenerative ailment distinguished by chorea-esque movement patterns, which manifest as archetypal symptoms. The presence of pronounced psychiatric onset symptoms in patients can considerably amplify the intricacies of accurate diagnosis.

CASE PRESENTATION

A 43-year-old gentleman was admitted with a five-year chronicle of delusions, hallucinations, and irritability. He had previously received a diagnosis of schizophrenia and had been subjected to a regimen of antipsychotic medications for a span exceeding four years. However, subsequent to the application of cerebral MRI and genetic testing, his condition was conclusively redetermined as HD.

CONCLUSION

The salient attribute of this case resides in the deferred diagnosis of HD attributable to the presence of acute psychiatric initial symptoms, a scenario bearing noteworthy ramifications for disease oversight and prognostication. This instance warrants attentive scrutiny and discourse within the professional community.

Maternal 15q11.2-q13.1 duplication syndrome-associated psychosis and mania: a new case and review of the literature

Maternal 15q11.2-q13.1 duplication syndrome is associated with a variety of developmental and neuropsychiatric abnormalities. Although schizophrenia-like presentations have been reported, details pertaining to the nature of the corresponding psychotic symptoms and their response to treatment have only been described in a few cases, and no reviews summarizing the literature currently exist. As such, we describe a new case of 15q11.2-q13.1 duplication syndrome-associated schizoaffective disorder and also performed a systematic review of the literature. Our patient's presentation is somewhat unique as she experienced visual hallucinations in the absence of auditory hallucinations. This is also the first report to describe full symptomatic remission in response to relatively low-dose atypical antipsychotic therapy.

Neural response properties predict perceived contents and locations elicited by intracranial electrical stimulation of human auditory cortex

Intracranial electrical stimulation (iES) of auditory cortex can elicit sound experiences with a variety of perceived contents (hallucination or illusion) and locations (contralateral or bilateral side), independent of actual acoustic inputs. However, the neural mechanisms underlying this elicitation heterogeneity remain undiscovered. Here, we collected subjective reports following iES at 3062 intracranial sites in 28 patients (both sexes) and identified 113 auditory cortical sites with iES-elicited sound experiences. We then decomposed the sound-induced intracranial electroencephalogram (iEEG) signals recorded from all 113 sites into time-frequency features. We found that the iES-elicited perceived contents can be predicted by the early high-γ features extracted from sound-induced iEEG. In contrast, the perceived locations elicited by stimulating hallucination sites and illusion sites are determined by the late high-γ and long-lasting α features, respectively. Our study unveils the crucial neural signatures of iES-elicited sound experiences in human and presents a new strategy to hearing restoration for individuals suffering from deafness.

A Novel Evaluation Model for Assessing ChatGPT on Otolaryngology-Head and Neck Surgery Certification Examinations: Performance Study

BACKGROUND

ChatGPT is among the most popular large language models (LLMs), exhibiting proficiency in various standardized tests, including multiple-choice medical board examinations. However, its performance on otolaryngology-head and neck surgery (OHNS) certification examinations and open-ended medical board certification examinations has not been reported.

OBJECTIVE

We aimed to evaluate the performance of ChatGPT on OHNS board examinations and propose a novel method to assess an AI model's performance on open-ended medical board examination questions.

METHODS

Twenty-one open-ended questions were adopted from the Royal College of Physicians and Surgeons of Canada's sample examination to query ChatGPT on April 11, 2023, with and without prompts. A new model, named Concordance, Validity, Safety, Competency (CVSC), was developed to evaluate its performance.

RESULTS

In an open-ended question assessment, ChatGPT achieved a passing mark (an average of 75% across 3 trials) in the attempts and demonstrated higher accuracy with prompts. The model demonstrated high concordance (92.06%) and satisfactory validity. While demonstrating considerable consistency in regenerating answers, it often provided only partially correct responses. Notably, concerning features such as hallucinations and self-conflicting answers were observed.

CONCLUSIONS

ChatGPT achieved a passing score in the sample examination and demonstrated the potential to pass the OHNS certification examination of the Royal College of Physicians and Surgeons of Canada. Some concerns remain due to its hallucinations, which could pose risks to patient safety. Further adjustments are necessary to yield safer and more accurate answers for clinical implementation.

Hallucination-Proneness is Associated With a Decrease in Robust Averaging of Perceptual Evidence

BACKGROUND AND HYPOTHESIS

Hallucinations are characterized by disturbances in perceptual decision-making about environmental stimuli. When integrating across multiple stimuli to form a perceptual decision, typical observers engage in "robust averaging" by down-weighting extreme perceptual evidence, akin to a statistician excluding outlying data. Furthermore, observers adapt to contexts with more unreliable evidence by increasing this down-weighting strategy. Here, we test the hypothesis that hallucination-prone individuals (n = 38 high vs n = 91 low) would show a decrease in this robust averaging and diminished sensitivity to changes in evidence variance.

STUDY DESIGN

We used a multielement perceptual averaging task to elicit dichotomous judgments about the "average color" (red/blue) of an array of stimuli in trials with varied strength (mean) and reliability (variance) of decision-relevant perceptual evidence. We fitted computational models to task behavior, with a focus on a log-posterior-ratio (LPR) model which integrates evidence as a function of the log odds of each perceptual option and produces a robust averaging effect.

STUDY RESULTS

Hallucination-prone individuals demonstrated less robust averaging, seeming to weigh inlying and outlying extreme or untrustworthy evidence more equally. Furthermore, the model that integrated evidence as a function of the LPR of the two perceptual options and produced robust averaging showed poorer fit for the group prone to hallucinations. Finally, the weighting strategy in hallucination-prone individuals remained insensitive to evidence variance.

CONCLUSIONS

Our findings provide empirical support for theoretical proposals regarding evidence integration aberrations in psychosis and alterations in the perceptual systems that track statistical regularities in environmental stimuli.

ChatGPT on guidelines: Providing contextual knowledge to GPT allows it to provide advice on appropriate colonoscopy intervals

BACKGROUND AND AIM

Colonoscopy is commonly used in screening and surveillance for colorectal cancer. Multiple different guidelines provide recommendations on the interval between colonoscopies. This can be challenging for non-specialist healthcare providers to navigate. Large language models like ChatGPT are a potential tool for parsing patient histories and providing advice. However, the standard GPT model is not designed for medical use and can hallucinate. One way to overcome these challenges is to provide contextual information with medical guidelines to help the model respond accurately to queries. Our study compares the standard GPT4 against a contextualized model provided with relevant screening guidelines. We evaluated whether the models could provide correct advice for screening and surveillance intervals for colonoscopy.

METHODS

Relevant guidelines pertaining to colorectal cancer screening and surveillance were formulated into a knowledge base for GPT. We tested 62 example case scenarios (three times each) on standard GPT4 and on a contextualized model with the knowledge base.

RESULTS

The contextualized GPT4 model outperformed the standard GPT4 in all domains. No high-risk features were missed, and only two cases had hallucination of additional high-risk features. A correct interval to colonoscopy was provided in the majority of cases. Guidelines were appropriately cited in almost all cases.

CONCLUSIONS

A contextualized GPT4 model could identify high-risk features and quote appropriate guidelines without significant hallucination. It gave a correct interval to the next colonoscopy in the majority of cases. This provides proof of concept that ChatGPT with appropriate refinement can serve as an accurate physician assistant.

Overview of late-onset psychoses

BACKGROUND

Several etiologies can underlie the development of late-onset psychosis, defined by first psychotic episode after age 40 years. Late-onset psychosis is distressing to patients and caregivers, often difficult to diagnose and treat effectively, and associated with increased morbidity and mortality.

METHODS

The literature was reviewed with searches in Pubmed, MEDLINE, and the Cochrane library. Search terms included "psychosis," "delusions," hallucinations," "late onset," "secondary psychoses," "schizophrenia," bipolar disorder," "psychotic depression," "delirium," "dementia," "Alzheimer's," "Lewy body," "Parkinson's, "vascular dementia," and "frontotemporal dementia." This overview covers the epidemiology, clinical features, neurobiology, and therapeutics of late-onset psychoses.

RESULTS

Late-onset schizophrenia, delusional disorder, and psychotic depression have unique clinical characteristics. The presentation of late-onset psychosis requires investigation for underlying etiologies of "secondary" psychosis, which include neurodegenerative, metabolic, infectious, inflammatory, nutritional, endocrine, and medication toxicity. In delirium, psychosis is common but controlled evidence is lacking to support psychotropic medication use. Delusions and hallucinations are common in Alzheimer's disease, and hallucinations are common in Parkinson's disease and Lewy body dementia. Psychosis in dementia is associated with increased agitation and a poor prognosis. Although commonly used, no medications are currently approved for treating psychosis in dementia patients in the USA and nonpharmacological interventions need consideration.

CONCLUSION

The plethora of possible causes of late-onset psychosis requires accurate diagnosis, estimation of prognosis, and cautious clinical management because older adults have greater susceptibility to the adverse effects of psychotropic medications, particularly antipsychotics. Research is warranted on developing and testing efficacious and safe treatments for late-onset psychotic disorders.

Administration of oxathridine, a first-in-class histamine-3 receptor partial agonist in healthy male volunteers: Central nervous system depression and pseudo-hallucinations

AIMS

To characterise the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of single ascending doses of oxathridine, a first-in-class histamine-3 receptor partialagonist, in healthy male volunteers.

METHODS

A randomised, double-blind, placebo-controlled study including the NeuroCart, consisting of a battery of drug sensitive neurophysiological tests, was performed. Oxathridine was administered orally as an aqueous solution. After dosing, safety and NeuroCart tests (adaptive tracking [AT], body sway [BS], saccadic peak velocity [SPV], smooth pursuit [SP] eye movements, VAS according to Bond and Lader, VAS according to Bowdle [VAS B&L, Bowdle], pharmaco-electroencephalogram [pEEG], Sustained Attention to Response Task [SART]) were performed at set times.

RESULTS

Forty volunteers completed the study. Given doses were: 0.5, 2.5, 5, 0.25 and 1.5 mg. At 5 mg, unacceptable and unanticipated adverse events (AEs) of (orthostatic) hypotension and pseudo-hallucinations were reported. Statistically significant effects ([CI]; p-value) of 2.5 mg and 5 mg oxathridine were observed on AT ([-8.28, -1.60]; p = 0.0048), ([-8.10, -1.51]; p = 0.00530), BS ([0.6, 80.2]; p = 0.0455), ([5.9, 93.1]; p = 0.0205) and SPV ([-59.0, -15.9]; p = 0.0011), ([-43.9, -1.09]; p = 0.0399), respectively. Oxathridine 5 mg significantly increased all three VAS Bowdle subscale scores; VAS external ([0.183, 0.476]; p = <.0001), VAS internal ([0.127, 0.370]; p = 0.0001) and VAS feeling high ([0.263, 0.887]; p = 0.0006).

CONCLUSION

NeuroCart tests indicated central nervous system (CNS) depressant effects. Oxathridine also unexpectedly caused pseudohallucinations. Although this led to the decision to stop further development of oxathridine, these observations suggest that the H3R system could be an interesting new target for the development of novel antipsychotics.

Long-term follow-up of subthalamic nucleus deep brain stimulation in patients with Parkinson's disease: An analysis of survival and disability milestones

BACKGROUND

Data on the long-term survival and incidence of disability milestones after subthalamic nucleus deep brain stimulation (STN-DBS) in Parkinson's disease (PD) is limited.

OBJECTIVES

To estimate mortality and assess the frequency/time-to-development of disability milestones (falls, freezing, hallucinations, dementia, and institutionalization) among PD patients post STN-DBS.

METHODS

A longitudinal retrospective study of patients undergoing STN-DBS. For mortality, Cox proportional hazards regression analysis was performed. For disease milestones, competing risk analyses were performed and cumulative incidence functions reported. The strength of association between baselines features and event occurrence was calculated based on adjusted hazard ratios.

RESULTS

The overall mortality for the 109 patients was 16 % (62.1 ± 21.3 months after surgery). Falls (73 %) and freezing (47 %) were both the earliest (40.4 ± 25.4 and 39.6 ± 28.4 months, respectively) and most frequent milestones. Dementia (34 %) and hallucinations (32 %) soon followed (56.2 ± 21.2 and mean 60.0 ± 20.7 months after surgery, respectively). Higher ADL scores in the OFF state and higher age at surgery were associated with falls, freezing, dementia and institutionalization.

CONCLUSIONS

Long-term mortality rate is low after STN-DBS. Disease milestones occur later during the disease course, with motor milestones appearing first and at a higher frequency than cognitive ones.

Pain is common in early onset Parkinson's disease and pain severity is associated with age and worsening of motor and non-motor symptoms

The consequences of pain in early onset Parkinson's disease (EOPD) remain under appreciated even though pain may exert an increasingly negative impact on patient quality of life as motor and non-motor symptoms worsen. In this prospective study, we investigate the prevalence and severity of pain in 135 Vietnamese patients with EOPD from three medical centers using the King's PD Pain Scale (KPPS), the Mini Mental Status Exam (MMSE), the Unified Parkinson's Disease Rating Scale (UPDRS) and the Non-Motor Symptoms Scale (NMSS). Pain was reported by 79.3%. The most common subtype of pain was musculoskeletal (70.1%), followed by nocturnal (43.9%), radicular (43.0%), chronic (42.1%), fluctuation-related (34.6%) and orofacial pain (16.8%). Most patients (74.8%) experienced more than one pain subtype. Fluctuation-related pain and orofacial pain were significantly more prevalent among patients with higher Hoehn & Yahr (H&Y) stages (3-5) versus lower H&Y stages (1-2). Pain subtype and severity were not significantly related to gender or age of PD onset. Patients with H&Y stages 3-5 had statistically significantly higher KPPS scores for fluctuation-related pain (p = 0.018) and radicular pain (p = 0.026). Independent associations were found between pain severity and age (p = 0.028), depression severity (p = 0.018), perceptual problems/hallucinations (p = 0.033) and sexual function (p = 0.024). Patients with depression and higher H&Y stages (3-5) had statistically significantly higher mean KPPS scores versus patients without depression and at lower H&Y stages (1-2). Pain may be more common and severe in EOPD patients than previously appreciated. Older age, depression, perceptual problems/hallucinations and sexual dysfunction were independently associated with higher pain severity.

An exploration of the relationship between voices, dissociation, and post-traumatic stress disorder symptoms

OBJECTIVES

Extensive research has shown voice hearing to be associated with symptoms of Post-Traumatic Stress Disorder (PTSD) and dissociation. However, most studies have adopted a quantitative design, using cross-sectional data sampling methods, precluding temporal relationships between variables from being defined.

DESIGN

Using a qualitative design, this study sought to identify potential symptom relationships by addressing the research question: what is the nature of the temporal relationship between voices, dissociation and PTSD symptoms?

METHODS

Seven voice hearers (aged 27 to 68 years) participated in a semi-structured interview exploring voice hearing, PTSD symptoms, and dissociation. The interviews were analysed using Interpretative Phenomenological Analysis.

RESULTS

One superordinate theme was identified in the data. Voices were observed to occur in dynamic interrelationship with PTSD symptoms and dissociation, and were frequently experienced before and after PTSD symptoms and dissociative episodes.

CONCLUSIONS

Implications for theoretical understandings of voice hearing and future research are discussed.

Refractory Depression With Persistent Sore Throat and Hypochondriacal Delusion of SARS-CoV-2 Infection: A Case Study

ABSTRACT

Herein, we present a case of a female patient with a persistent sore throat, which preceded a hypochondriacal delusion of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Both the sore throat and hypochondriacal delusion persisted together, despite the repeatedly negative results of reverse transcription polymerase chain reaction (RT-PCR) for SARS-CoV-2 and a moderate improvement in her depression. Four possibilities for the patient's sore throat were discussed: pain symptoms of somatic symptom disorder, pain symptoms of depression, delusion of pain in her throat, and somatic hallucination as a sore throat. Consequently, somatic hallucinations were considered the most likely. In any case, the present findings suggest that sore throat can precede hypochondriacal delusion of SARS-CoV-2 infection in some noninfected patients. When patients continue to complain of a sore throat despite the negative results of SARS-CoV-2 by the RT-PCR test, we should consider that it might be a somatic hallucination and soon hypochondriacal delusions may occur, leading to the manifestation of other symptoms of psychiatric disorders, such as depression, which may be refractory and/or suicidal.

Effective connectivity abnormalities in Lewy body disease with visual hallucinations

OBJECTIVE

To assess the changes in effective connectivity of important regions of the visual network (VIS) and dorsal attention network (DAN) underlying visual hallucinations (VHs) in Dementia with Lewy Bodies (DLB), Parkinson's Disease (PD) and Parkinson's Disease Dementia (PDD), as measured by a transcranial magnetic stimulation-electroencephalographic technique (TMS-EEG).

METHODS

We stimulated the right visual cortex (V1/V2), the right intraparietal sulcus and the right frontal eye fields, two key regions of the DAN, and measured TMS-evoked cortical activation within the VIS and the DAN. We compared 11 patients with VHs and 15 patients without VHs.

RESULTS

Patients with VHs showed lower TMS-evoked cortical activation within the DAN following intraparietal sulcus and frontal eye fields stimulation than patients without VHs. No difference was found between patients with and without cognitive impairment. Also, when considering only patients with cognitive impairment, VHs were associated with lower TMS-evoked cortical activation following intraparietal sulcus stimulation.

CONCLUSIONS

DLB, PD, and PDD patients with VHs had less effective connectivity of the right intraparietal sulcus within the DAN than patients without VHs.

SIGNIFICANCE

We provided the first evidence that VHs are associated with specific intraparietal sulcus dysfunction within the DAN in patients with PDD, PD, and DLB.

Perceiving those who are gone: Cultural research on post-bereavement perception or hallucination of the deceased

Experiencing the continued presence of the deceased is common among the bereaved, whether as a sensory perception or as a felt presence. This phenomenon has been researched from psychological and psychiatric perspectives during the last five decades. Such experiences have been also documented in the ethnographic literature but, despite the extensive cross-cultural research in the area, anthropological data has generally not been considered in the psychological literature about this phenomenon. This paper provides an overview aimed at bridging these two areas of knowledge, and approaches the post-bereavement perception or hallucination of the deceased in cultural context. Ongoing debates are addressed from the vantage point of ethnographic and clinical case study research focusing on the cultural repertoires (in constant flux as cultures change) from which these experiences are labelled as desirable and normal, on the one hand, or as dangerous and pathological, on the other.

Efficacy of transcranial alternating current stimulation for schizophrenia treatment: A systematic review

BACKGROUND

Transcranial alternating current stimulation (tACS) is an innovative noninvasive technique in brain stimulation that involves applying a low-intensity electrical current to the scalp. And increasing evidence has revealed its potential in schizophrenia treatment.

OBJECTIVE

This systematic review aimed to evaluate the efficacy of tACS as a novel neurostimulation technique for improving cognitive impairment and alleviating psychotic symptoms in schizophrenia. Additionally, this review attempted to explore the impact of stimulation parameters on the effectiveness of tACS treatment.

METHODS

A systematic literature search was conducted across five databases, including Web of Science, Embase, PubMed, CENTRAL, and PsycINFO, to identify studies investigating the use of tACS in schizophrenia. Only studies that involved the experimental use of tACS in patients with schizophrenia were included in this review.

RESULTS

Nineteen studies were included in this review. The most frequently used current intensities were 2 mA and 1 mA, and the most commonly used frequencies were alpha (10 Hz), theta (4.5 Hz and 6 Hz), and gamma (40 Hz). Some studies showed that tACS may have a potential therapeutic effect by improving cognitive functions in various cognitive domains and/or ameliorating negative symptoms, hallucinations, and delusions in patients with schizophrenia, while others showed no significant change. These studies also implicated that tACS treatment is safe and well tolerated.

CONCLUSIONS

Overall, this systematic review suggests that tACS has promise as a novel, effective, and adjunctive treatment approach for treating schizophrenia. Future research is needed to determine the optimal parameters of tACS for treating this complex disorder.

[Belladonna (Atropine), in The Labours of Hercules]

The Labours of Hercules, written by Agatha Christie, contains twelve short stories, with 'atropine' playing a crucial role in the seventh story, The Cretan Bull (1939). Atropine easily crosses the blood-brain barrier (BBB), leading to central nervous system (CNS) side effects such as delirium, hallucinations, disorientation, memory problems, coma or stupor, and convulsive seizures when overdosed. In this episode, a concentrated form of atropine obtained from prescribed eye drops was misused to induce a hereditary incurable neurodegenerative disorder, similar to Huntington's Chorea, in the client's fiancée. However, Mr. Poirot discerned this by careful examination of his symptoms and resolved the case.

Differences in olfactory dysfunction and its relationship with cognitive function in schizophrenia patients with and without auditory verbal hallucinations

Olfactory discrimination dysfunction has been observed in patients with schizophrenia (SCZ), but its relationship with cognitive function has not been clarified. The purpose of this study was to examine the differences in olfactory identification function in SCZ patients with and without auditory verbal hallucinations (AVHs) and its relationship with cognitive function. Olfactory identification function was measured in 80 SCZ patients with AVHs, 57 SCZ patients without AVHs, and 87 healthy controls (HC). Clinical symptom scores and neuropsychological measures were also administered to all corresponding subjects. Compared to HC, SCZ patients showed significant deficits in olfactory identification and cognitive function, but there were no differences in olfactory identification dysfunction and cognitive dysfunction between the two subgroups. In the non-AVHs subgroup only, poorer Olfactory Stick Identification Test for Japanese (OSIT-J) scores were significantly and positively correlated with total and delayed recall (Bonferroni correction, p < 0.002). Stepwise regression analysis revealed that factors affecting olfactory identification impairment differed in the two SCZ patient subgroups. In conclusion, this study highlights the commonality of olfactory identification dysfunction in SCZ patients and the importance of olfactory assessment of different subtypes of SCZ patients.

The interplay between suicidal experiences, psychotic experiences and interpersonal relationships: a qualitative study

BACKGROUND

Suicidal thoughts, acts, plans and deaths are considerably more prevalent in people with non-affective psychosis, including schizophrenia, compared to the general population. Social isolation and interpersonal difficulties have been implicated in pathways which underpin suicidal experiences in people with severe mental health problems. However, the interactions between psychotic experiences, such as hallucinations and paranoia, suicidal experiences, and the presence, and indeed, absence of interpersonal relationships is poorly understood and insufficiently explored. The current study sought to contribute to this understanding.

METHODS

An inductive thematic analysis was conducted on transcripts of 22, individual, semi-structured interviews with adult participants who had both non-affective psychosis and recent suicidal experiences. A purposive sampling strategy was used. Trustworthiness of the analysis was assured with researcher triangulation.

RESULTS

Participants relayed both positive and negative experiences of interpersonal relationships. A novel conceptual model is presented reflecting a highly complex interplay between a range of different suicidal experiences, psychosis, and aspects of interpersonal relationships. Three themes fed into this interplay, depicting dynamics between perceptions of i. not mattering and mattering, ii. becoming disconnected from other people, and iii. constraints versus freedom associated with sharing suicidal and psychotic experiences with others.

CONCLUSION

This study revealed a detailed insight into ways in which interpersonal relationships are perceived to interact with psychotic and suicidal experiences in ways that can be both beneficial and challenging. This is important from scientific and clinical perspectives for understanding the complex pathways involved in suicidal experiences.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT03114917), 14th April 2017. ISRCTN (reference ISRCTN17776666 .); 5th June 2017). Registration was recorded prior to participant recruitment commencing.

Bridging phenomenology and neural mechanisms of inner speech: ALE meta-analysis on egocentricity and spontaneity in a dual-mechanistic framework

The neural mechanisms of inner speech remain unclear despite its importance in a variety of cognitive processes and its implication in aberrant perceptions such as auditory verbal hallucinations. Previous research has proposed a corollary discharge model in which inner speech is a truncated form of overt speech, relying on speech production-related regions (e.g. left inferior frontal gyrus). This model does not fully capture the diverse phenomenology of inner speech and recent research suggesting alternative perception-related mechanisms of generation. Therefore, we present and test a framework in which inner speech can be generated by two separate mechanisms, depending on its phenomenological qualities: a corollary discharge mechanism relying on speech production regions and a perceptual simulation mechanism within speech perceptual regions. The results of the activation likelihood estimation meta-analysis examining inner speech studies support the idea that varieties of inner speech recruit different neural mechanisms.

Pareidolias are a function of visuoperceptual impairment

Pareidolias, or the misperception of ambiguous stimuli as meaningful objects, are complex visual illusions thought to be phenomenologically similar to Visual Hallucination (VH). VH are a major predictor of dementia in Parkinson's Disease (PD) and are included as a core clinical feature in Dementia with Lewy Bodies (DLB). A newly developed Noise Pareidolia Test (NPT) was proposed as a possible surrogate marker for VH in DLB patients as increased pareidolic responses correlated with informant-corroborated accounts of VH. This association could, however, be mediated by visuoperceptual impairment. To understand the drivers of performance on the NPT, we contrasted performances in patient groups that varied both in terms of visuoperceptual ability and rates of VH. N = 43 patients were studied of whom n = 13 had DLB or PD with Dementia (PDD); n = 13 had PD; n = 12 had typical, memory-onset Alzheimer's Disease (tAD); and n = 5 had Posterior Cortical Atrophy (PCA) due to Alzheimer's disease. All patient groups reported pareidolias. Within the Lewy body disorders (PD, DLB, PDD), there was no significant difference in pareidolic response rates between hallucinating and non-hallucinating patients. Visuoperceptual deficits and pareidolic responses were most frequent in the PCA group-none of whom reported VH. Regression analyses in the entire patient cohort indicated that pareidolias were strongly predicted by visuoperceptual impairment but not by the presence of VH. These findings suggest that pareidolias reflect the underlying visuoperceptual impairment of Lewy body disorders, rather than being a direct marker for VH.

Characteristics of amnestic patients with hypometabolism patterns suggestive of Lewy body pathology

A clinical diagnosis of Alzheimer's disease dementia (ADD) encompasses considerable pathological and clinical heterogeneity. While Alzheimer's disease patients typically show a characteristic temporo-parietal pattern of glucose hypometabolism on 18F-fluorodeoxyglucose (FDG)-PET imaging, previous studies have identified a subset of patients showing a distinct posterior-occipital hypometabolism pattern associated with Lewy body pathology. Here, we aimed to improve the understanding of the clinical relevance of these posterior-occipital FDG-PET patterns in patients with Alzheimer's disease-like amnestic presentations. Our study included 1214 patients with clinical diagnoses of ADD (n = 305) or amnestic mild cognitive impairment (aMCI, n = 909) from the Alzheimer's Disease Neuroimaging Initiative, who had FDG-PET scans available. Individual FDG-PET scans were classified as being suggestive of Alzheimer's (AD-like) or Lewy body (LB-like) pathology by using a logistic regression classifier trained on a separate set of patients with autopsy-confirmed Alzheimer's disease or Lewy body pathology. AD- and LB-like subgroups were compared on amyloid-β and tau-PET, domain-specific cognitive profiles (memory versus executive function performance), as well as the presence of hallucinations and their evolution over follow-up (≈6 years for aMCI, ≈3 years for ADD). Around 12% of the aMCI and ADD patients were classified as LB-like. For both aMCI and ADD patients, the LB-like group showed significantly lower regional tau-PET burden than the AD-like subgroup, but amyloid-β load was only significantly lower in the aMCI LB-like subgroup. LB- and AD-like subgroups did not significantly differ in global cognition (aMCI: d = 0.15, P = 0.16; ADD: d = 0.02, P = 0.90), but LB-like patients exhibited a more dysexecutive cognitive profile relative to the memory deficit (aMCI: d = 0.35, P = 0.01; ADD: d = 0.85 P < 0.001), and had a significantly higher risk of developing hallucinations over follow-up [aMCI: hazard ratio = 1.8, 95% confidence interval = (1.29, 3.04), P = 0.02; ADD: hazard ratio = 2.2, 95% confidence interval = (1.53, 4.06) P = 0.01]. In summary, a sizeable group of clinically diagnosed ADD and aMCI patients exhibit posterior-occipital FDG-PET patterns typically associated with Lewy body pathology, and these also show less abnormal Alzheimer's disease biomarkers as well as specific clinical features typically associated with dementia with Lewy bodies.

Advances in the Diagnosis and Management of Psychotic Symptoms in Neurodegenerative Diseases: A Narrative Review

Background: Approximately 15% of older adults may experience psychotic phenomena. Primary psychiatric disorders that manifest with psychosis (delusions, hallucinations, and disorganized thought or behavior) account for less than half. Up to 60% of late-life psychotic symptoms are due to systemic medical or neurological conditions, particularly neurodegenerative diseases. A thorough medical workup including laboratory tests, additional procedures if indicated, and neuroimaging studies is recommended. This narrative review summarizes current evidence regarding the epidemiology and phenomenology of psychotic symptoms encountered as part of the neurodegenerative disease continuum (including prodromal and manifest stages). Results: Prodromes are constellations of symptoms that precede the onset of overt neurodegenerative syndromes. Prodromal psychotic features, particularly delusions, have been associated with an increased likelihood of receiving a neurodegenerative disease diagnosis within several years. Prompt prodrome recognition is crucial for early intervention. The management of psychosis associated with neurodegenerative diseases includes behavioral and somatic strategies, although evidence is scarce and mostly limited to case reports, case series, or expert consensus guidelines, with few randomized controlled trials. Conclusion: The complexity of psychotic manifestations warrants management by interprofessional teams that provide coordinated, integrated care.

Neural patterns of conscious visual awareness in the Riddoch syndrome

The Riddoch syndrome is one in which patients blinded by lesions to their primary visual cortex can consciously perceive visual motion in their blind field, an ability that correlates with activity in motion area V5. Our assessment of the characteristics of this syndrome in patient ST, using multimodal MRI, showed that: 1. ST's V5 is intact, receives direct subcortical input, and decodable neural patterns emerge in it only during the conscious perception of visual motion; 2. moving stimuli activate medial visual areas but, unless associated with decodable V5 activity, they remain unperceived; 3. ST's high confidence ratings when discriminating motion at chance levels, is associated with inferior frontal gyrus activity. Finally, we report that ST's Riddoch Syndrome results in hallucinatory motion with hippocampal activity as a correlate. Our results shed new light on perceptual experiences associated with this syndrome and on the neural determinants of conscious visual experience.

Associations between sleep variables and ostensibly paranormal experiences and paranormal beliefs: A scoping review

Night-time is a period of great significance for many people who report paranormal experiences. However, there is limited understanding of the associations between sleep variables and seemingly paranormal experiences and/or beliefs. The aim of this review is to improve our understanding of these associations while unifying a currently fragmented literature-base into a structured, practical review. In this pre-registered scoping review, we searched for relevant studies in MEDLINE (PubMed), PsycINFO (EBSCO), Web of Science and EMBASE using terms related to sleep and ostensibly paranormal experiences and beliefs. Forty-four studies met all inclusion criteria. All were cross-sectional and most investigated sleep paralysis and/or lucid dreaming in relation to ostensibly paranormal experiences and paranormal beliefs. Overall, there were positive associations between many sleep variables (including sleep paralysis, lucid dreams, nightmares, and hypnagogic hallucinations) and ostensibly paranormal experiences and paranormal beliefs (including those of ghosts, spirits, and near-death experiences). The findings of this review have potential clinical implications such as reducing misdiagnosis and treatment development and provide foundations for further research. Our findings also highlight the importance of understanding why so many people report 'things that go bump in the night'.

The association between visual hallucinations and secondary psychosis: a systematic review and meta-analysis

INTRODUCTION

Visual hallucinations are often considered to be suggestive of a secondary cause of psychosis, however, this association has never been assessed meta-analytically. We aimed to compare the presence of visual hallucinations in patients with psychosis due to a primary or secondary cause.

METHOD

We conducted a meta-analysis of case-control studies directly comparing primary and secondary psychosis. A random-effects model, following the DerSimonian and Laird method, was used to pool studies and generate overall odds ratios (OR), 95% confidence intervals (CI) and prediction intervals (PI).

RESULTS

Fourteen studies (904 primary and 804 secondary psychosis patients) were included. Visual hallucinations were significantly associated with secondary psychosis (OR = 3.0, 95% CI = 1.7-5.1, p < 0.001) with moderate between-study heterogeneity (I2 = 70%). Subgroup analysis by type of secondary psychosis (organic, drug-induced, mixed) was non-significant. Analysis of the content of visual hallucinations (51 primary and 142 secondary psychosis patients) found hallucinations of inanimate objects were significantly more likely to be associated with secondary psychosis (OR = 0.1, 95% CI = 0.01-0.8, p = 0.03).

CONCLUSIONS

Visual hallucinations were strongly associated with a secondary cause of psychosis. The presence of visual hallucinations in a patient presenting with psychosis may serve as a potential "red flag" for a secondary cause and warrant further investigation.

Hallucination of closed repeat proteins containing central pockets

In pseudocyclic proteins, such as TIM barrels, β barrels, and some helical transmembrane channels, a single subunit is repeated in a cyclic pattern, giving rise to a central cavity that can serve as a pocket for ligand binding or enzymatic activity. Inspired by these proteins, we devised a deep-learning-based approach to broadly exploring the space of closed repeat proteins starting from only a specification of the repeat number and length. Biophysical data for 38 structurally diverse pseudocyclic designs produced in Escherichia coli are consistent with the design models, and the three crystal structures we were able to obtain are very close to the designed structures. Docking studies suggest the diversity of folds and central pockets provide effective starting points for designing small-molecule binders and enzymes.

Time will tell: Associations between unbalanced time perspectives and symptom severity in individuals with schizophrenia spectrum disorders

Patients with schizophrenia spectrum disorder (SSD) experience disrupted temporality on the immediate timescale. However, insufficient information is available for longer time frames, and the interaction of temporal perspectives with the clinical manifestations of SSD is unknown. We explored the association between unbalanced time perspectives and symptom severity. Thirty-seven Italian mental health services participating in the DiAPAson project recruited 620 patients with DSM-5 SSD (68 % males, mean age = 41.3 ± 9.5 years). Time perspective biases were measured using the Deviation from the Balanced Time Perspective-revisited (DBTP-r) indicator, based on Zimbardo Time Perspective Inventory (ZTPI) scores. Psychiatric symptoms were assessed using the Brief Psychiatric Rating Scale (BPRS) and Brief Negative Symptoms Scale (BNSS). Preliminary analyses examined the associations between ZTPI/DBTP-r and BPRS/BNSS total scores. In secondary analyses, we first tested the associations between the ZTPI/DBTP-r and BPRS/BNSS subscales and then compared ZTPI differences between patients with and without hallucinations, delusions, and conceptual disorganisation. Statistical significance was set at Holm-Bonferroni corrected p < 0.05. Low-to-moderate positive correlations were found between the DBTP-r and BPRS/BNSS total scores (r = 0.29/0.22). The strongest associations were between DBTP-r/ZTPI_Past-Negative and anxiety/depression (r = 0.34/0.36), followed by DBTP-r/ZTPI_Present-Fatalistic with thought disturbances (r = 0.22/0.20). DBTP-r was associated with BNSS anhedonia and avolition (r = 0.21/0.24). DBTP-r was higher in patients with hallucinations (ES = 0.391) and conceptual disorganisation (ES = 0.397) than in those without these symptoms. Unbalanced time perspective was positively associated with the severity of primary and secondary SSD features. These findings provide a rationale for empirical tests focused on balancing time perspectives in patients with SSD.

B - 24 Neuropsychological Profile of a Child with ASD, ADHD, and Psychotic Features

OBJECTIVE

Autism Spectrum Disorder (ASD), Attention Deficit-Hyperactivity Disorder (ADHD), and psychotic traits, although highly comorbid, have rarely been studied in children. Existing research indicates that impulsivity, comprehension difficulties, and inflexibility are overlapping symptoms within the ASD and ADHD populations. Adult research shows high comorbidity estimates between ASD and psychosis. Here we describe the neuropsychological profile of a 14-year-old boy with diagnoses of ASD and ADHD with psychotic features. We highlight the value of comprehensive and flexible neuropsychological assessment while integrating detailed testing, behavioral observations, and collateral report.

METHODS

Medical history of this child included late-term and breech birth with his first Apgar score at expected level and his second score falling below expected level. Delayed acquisition of developmental milestones, learning difficulties, speech difficulties, anxiety, and hyperactivity, were reported. Auditory hallucinations triggered by stress were observed during evaluation. Comprehensive neuropsychological evaluation requires nonstandard exploration of cognitive domains and time-limited testing sessions to acquire robust estimates of functioning.

RESULTS

Overall cognitive abilities were in the borderline range with highly variable academic performances (extremely low to average). All performances were grossly below age level and were significantly impacted by auditory hallucinations but were consistent with the diagnoses of ASD and ADHD.

CONCLUSION

This case of a boy with ASD, ADHD, and auditory hallucinations demonstrates the diagnostic overlap among these conditions and the necessity for flexible neuropsychological testing, detailed behavioral observations and caregiver report in the assessment of overlapping clinical features. Multiple sources of data are required to identify patterns in symptomatology to inform differential diagnosis and comorbidities.