Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.650
Filtrar
1.
Cureus ; 16(4): e57510, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38707040

RESUMO

Very late-onset schizophrenia-like psychosis (VLOSLP) is still a paradox; certain characteristics such as episodic progression of psychosis including delusions and hallucinations involving various modalities, as well as the absence of negative symptoms, are strongly predictive of VLOSLP. We describe an interesting case of a 61-year-old male who presented with a second episode of psychosis along with mild to moderate cognitive impairment like having difficulty in buttoning for over eight months at our tertiary care hospital. Previously, during the first episode, he was treated by a private practitioner; adequate doses for an adequate duration of two atypical antipsychotics were given; and up to 25% global improvement was reported by the caregiver. During the current episode, he experienced delusions, in which he had a conviction that a "WIFI" was capable of "thought-making" functions. During the past four months, his delusions exacerbated and were accompanied by hallucinations of other modalities, like visual and kinesthetic hallucinations, which profoundly impacted his daily life. He used to hear voices. While listening to the voices, he also experienced voices coming out of his mouth. All these were experienced by him in clear consciousness daily for a few hours. All plausible medical causes of late-onset psychosis, such as neuroinflammatory/immunological disorders, were ruled out. Neuroimaging revealed T2-weighted image (T2WI)/fluid-attenuated inversion recovery (FLAIR) hyperintensity in bilateral subcortical and periventricular deep white matter, suggestive of small vessel ischemic changes in the brain. The diagnosis of VLOSLP is completely rationalized by evidence-based medicine. Hence, the role of cerebrovascular risk factors, as well as age-related neurobiological processes, in the pathogenesis of VLOSLP is discussed. Future research ought to emphasize identifying a particular biomarker that would be highly predictive for accurately diagnosing VLOSLP and giving it an identity to separate it from various overlapping clinical conditions such as dementia with Lewy bodies (DLB) and other types of dementia with psychosis so that the patient can be given specific treatment.

2.
Heliyon ; 10(9): e30194, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38707410

RESUMO

Background: Auditory Verbal Hallucinations (AVH) constitute a prominent feature of schizophrenia. Although low-frequency repetitive transcranial magnetic stimulation (rTMS) has demonstrated therapeutic benefits in ameliorating AVH, the underlying mechanisms of its efficacy necessitate further elucidation. Objective: This study investigated the cortical gradient characteristics and their associations with clinical responses in schizophrenia patients with AVH, mediated through 1 Hz rTMS targeting the left temporoparietal junction. Method: Functional gradient metrics were employed to examine the hierarchy patterns of cortical organization, capturing whole-brain functional connectivity profiles in patients and controls. Results: The 1 Hz rTMS treatment effectively ameliorated the positive symptoms in patients, specifically targeting AVH. Initial evaluations revealed expanded global gradient distribution patterns and specific principal gradient variations in certain brain regions in patients at baseline compared to a control cohort. Following treatment, these divergent global and local patterns showed signs of normalizing. Furthermore, there was observed a closer alignment in between-network dispersion among various networks after treatment, including the somatomotor, attention, and limbic networks, indicating a potential harmonization of brain functionality. Conclusion: Low-frequency rTMS induces alternations in principal functional gradient patterns, may serve as imaging markers to elucidate the mechanisms underpinning the therapeutic efficacy of rTMS on AVH in schizophrenia.

3.
Clin Psychol Psychother ; 31(3): e2993, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38723656

RESUMO

INTRODUCTION: Visual hallucinations (VH) are more common than previously thought and are linked to higher levels of distress and disability in people with a psychotic illness. Despite this, scant attention has been given to VHs in the clinical literature, and the few therapy case series of cognitive behavioural therapy (CBT) published to date have not demonstrated reliable change. In other areas of clinical research, problematic mental imagery has been found to be more strongly related to negative affect in psychological disorders than negative linguistic thinking, and imagery focused techniques have commonly been found to improve the outcomes in CBT trials. Given VHs have many similarities with visual mental imagery and many of the distressing beliefs associated with VHs targeted in CBT are maintained by accompanying mental imagery (i.e., imaging a hallucinated figure attacking them), it seems plausible that an imagery-focused approach to treating VHs may be most effective. METHODS: The current study is a multiple baseline case series (N = 11) of a 10-session imagery-focused therapy for VH in a transdiagnostic sample. RESULTS: The study had good attendance and feedback, no adverse events and only one [seemly unrelated] drop-out, suggesting good feasibility, safety and acceptability. The majority of clients reported reduction on both full-scale measures (administered at 3 baselines, midtherapy, posttherapy and 3-month follow-up) and weekly measures of VH severity and distress, ranging from medium to large effect sizes. CONCLUSIONS: The case series suggests that an imagery-focused approach to treating VHs may be beneficial, with a recommendation for more rigorous clinical trials to follow.


Assuntos
Alucinações , Imagens, Psicoterapia , Humanos , Alucinações/terapia , Alucinações/psicologia , Feminino , Masculino , Adulto , Imagens, Psicoterapia/métodos , Pessoa de Meia-Idade , Resultado do Tratamento , Transtornos Psicóticos/terapia , Transtornos Psicóticos/psicologia , Transtornos Psicóticos/complicações
4.
Ir J Med Sci ; 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38724758

RESUMO

Musical hallucinations (MH) are the subjective experience of hearing music when none is played. They are a rare, understudied area of psychiatry. MH are more common in women and older age and have several underlying aetiologies and predisposing factors such as hearing impairment, mental illness and certain medications. There are no consensus guidelines on treatment; thus, current treatment has two broad approaches: (1) the removal of potential inciting factors (e.g. optimising hearing aids, medications) or (2) pharmacotherapy (antipsychotics, antidepressants, mood stabilisers and cognitive enhancers). This paper presents a case series of patients presenting with MH to a psychiatry of old age service in Dublin City and reviews the current literature of MH. Older age, female gender and hearing impairment are known risk factors for MH. Our findings concurred with the literature-two of three patients were female, and two of three patients suffered from hearing impairment. As this was a psychiatry of old age service, all patients were elderly. One case had a swift resolution of symptoms with a combination of an antipsychotic and antidepressant. The other two cases had limited responses to treatment despite optimising their hearing aids and trials of a number of medications at therapeutic levels. Further research into MH is needed to establish a treatment that is evidence based and symptom focused.

5.
Schizophr Bull ; 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38715384

RESUMO

BACKGROUND: Diagnostic criteria for mental disorders are subject to change. This is particularly true for schizophrenia, whose diagnostic criteria in the current DSM-5 bear little resemblance to what Kraepelin once named "dementia praecox" and Bleuler termed "the schizophrenias." The present study reports results from a survey of experts on two core topics of schizophrenia: (a) whether subsequent editions of the DSM should once again give the Schneiderian first-rank symptoms (FRS; eg, thought broadcasting) the prominent role they had in the DSM-IV and (b) whether the currently quite narrow definition of hallucinations in the DSM-5 requiring them to be vivid and clear and have the full force and impact of normal perceptions should be broadened to incorporate perceptual-like phenomena that the individual can differentiate from proper perceptions but still perceives as real and externally generated. HYPOTHESIS: The aim of the survey was to learn about experts' opinions with no clear hypotheses. STUDY DESIGN: International experts on schizophrenia were recruited via various sources and invited to participate in a short online survey. The final sample comprised 136 experts with a subgroup of 53 experts with verified identity and at least 6 years of clinical and/or research experience. STUDY RESULTS: Slightly more experts voted in favor (49.3%) of returning FRS to the prominent role they had in earlier versions of the DSM than against (34.6%). Approximately four out of five experts agreed that the definition of hallucinations in the DSM should be expanded. According to the results, alongside internal symptoms that are phenomenologically indistinguishable from true perceptions, sensory intrusions that the holder is convinced were inserted from another source (ie, not self-generated) should be included in the definition. CONCLUSIONS: While a large majority of experts recommend a change in the definition of hallucinations, the experts' opinions on FRS are more mixed. We hope that this article will stimulate future studies targeting the diagnostic relevance of these symptoms and encourage discussion about the definition of core psychotic symptoms and the diagnostic criteria for the upcoming edition of the DSM.

6.
J Psychiatr Res ; 175: 81-88, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38718443

RESUMO

BACKGROUND: Mismatch negativity (MMN) amplitude is attenuated in schizophrenia patients (SZ). However, variability in illness course among SZ samples and types of deviant stimuli used in MMN paradigms have contributed to inconsistent findings across studies. Though MMN is suggested to be impaired in schizotypy, the potential link between the two is yet to be systematically examined in unaffected first-degree relatives of schizophrenia patients (FDR). METHODS: The SZ sample had twenty-two drug-naïve or drug-free patients (dSZ) and thirty chronic/medicated patients (cSZ). dSZ and cSZ patients were compared with thirty-six unaffected FDR and thirty-two healthy controls (HC) using a two-tone passive auditory oddball MMN paradigm in an event-related potential experiment with two conditions (presented as separate blocks)-duration-deviant (duration-MMN) and frequency-deviant (frequency-MMN). Schizotypy scores and MMN indices were examined for correlation in FDR. RESULTS: Duration-MMN amplitude was significantly attenuated in both dSZ and cSZ compared to other groups. dSZ and cSZ did not differ on MMN indices. Psychopathology scores and features of illness (illness duration, medication dosage, etc.) did not correlate with MMN indices. In FDR, Schizotypal trait measures did not correlate with MMN indices. CONCLUSIONS: Duration-MMN emerged as a more robust indicator of prediction error signalling deficit in SZ. Frequency-MMN amplitude did not significantly differ among the groups, and MMN indices did not correlate with state and trait measures of schizophrenia-related psychopathology. These findings reiterates that auditory sensory processing captured by MMN is likely reflective of dynamic cognitive functions at the point of testing, and is unlikely to be an expression of enduring symptomatology.

7.
Rev Neurol (Paris) ; 2024 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-38806361

RESUMO

Discussing Marian apparitions in the light of current knowledge in neuroscience is a challenge: the testimonies are often old and indirect, and the "visionaries" could not be questioned or even examined according to current neurological or psychiatric standards. In doing so, we are not unaware of the heterogeneity of seers and the facts they reported: there is not necessarily a single hypothesis. It is the appearances of Île Bouchard that will be discussed here. Our interpretation calls on two non-exclusive "mechanisms": on the one hand, mental imagery, which we know can be unconscious and is modulated or generated by frontal "top-down" mechanisms; on the other hand, the sociological consideration of events, using the concept of enchantment.

8.
Cogn Neuropsychiatry ; : 1-8, 2024 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-38798061

RESUMO

Introduction: We report an epileptic patient who experienced hallucinatory visual experiences of autobiographical memories from her past. These visual experiences were confined to the lower left quadrant of her visual field.Methods: We carried out a single-case study that used brain-imaging, EEG and behavioural methods to study this patient.Results: We found that this patient had an incomplete left inferior homonymous quadrantanopia due to a lesion of right occipital cortex, and also that she showed neurological abnormalities in right temporal cortex, a region that is part of the brain's autobiographical-memory circuit.Conclusion: We attribute the occurrence of this patient's autobiographical-memory hallucinations to the combination of degraded visual input to right temporal cortex plus hyperexcitability of that region.

9.
Schizophr Res ; 269: 123-129, 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38772324

RESUMO

BACKGROUND: Persistent auditory verbal hallucinations (pAVHs) are a fundamental manifestation of schizophrenia (SCZ), yet the exact connection between pAVHs and brain structure remains contentious. This study aims to explore the potential correlation between pAVHs and alterations in grey matter volume (GMV) within specific brain regions among individuals diagnosed with SCZ. METHODS: 76 SCZ patients with pAVHs (pAVH group), 57 SCZ patients without AVHs (non-AVH group), and 83 healthy controls (HC group) were investigated using 3 T magnetic resonance imaging. The P3 hallucination item of the Positive and Negative Syndrome Scale was used to assess the severity of pAVHs. Voxel-based morphometry was used to analyze the GMV profile between the three groups. RESULTS: Compared to the non-AVH and HC groups, the pAVH group exhibited extensive reduction in GMV within the frontotemporal cortex. Conversely, no significant difference in GMV was observed between the non-AVH and HC groups. The severity of pAVHs showed a negative correlation with GMV in several regions, including the right fusiform, right inferior temporal, right medial orbitofrontal, right superior frontal, and right temporal pole (p = 0.0036, Bonferroni correction). Stepwise linear regression analysis revealed that GMV in the right temporal pole (ß = -0.29, p = 0.001) and right fusiform (ß = -0.21, p = 0.01) were significantly associated with the severity of pAVHs. CONCLUSIONS: Widespread reduction in GMV is observed within the frontotemporal cortex, particularly involving the right temporal pole and right fusiform, which potentially contribute to the pathogenesis of pAVHs in individuals with chronic SCZ.

10.
J Am Psychiatr Nurses Assoc ; : 10783903241252162, 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38767121

RESUMO

BACKGROUND: Stigmatization of individuals diagnosed with psychosis, especially those who experience auditory hallucinations, is a well-documented issue with negative outcomes on provision of care. Existing research has predominantly concentrated on experiential training for students, leaving a significant gap in knowledge regarding the training's impact on practicing psychiatric nurses and technicians. AIMS: This study aims to address this gap by investigating the efficacy of a concise, 1-hour educational activity designed to improve empathy, confidence, competence, and knowledge in psychiatric professionals. METHODS: Participants engaged in a 1-hour training session that included simulated activities while listening to distressing voices and completed pretraining and posttraining assessments. RESULTS: Results demonstrated a notable increase in empathy toward individuals who hear voices, suggesting that the training had a positive effect. Furthermore, significant differences were observed in the participants' perceptions of the level of difficulty as well as increased levels of confidence and perceived competence in their ability to provide care. CONCLUSIONS: The results underscore the practicality and effectiveness of brief hearing voices simulations as a means to enhance the skills of existing health care providers. This approach allows professionals to better express empathy and gain a deeper understanding of the experiences of voice hearers.

11.
J Alzheimers Dis Rep ; 8(1): 609-614, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38746644

RESUMO

Identifying the coexistence of Lewy body (LB) pathology with Alzheimer's disease (AD) in clinical practice is important in the era of anti-amyloid-ß antibody therapy. However, few studies have predicted the presence of comorbid LB pathology with AD using indicative biomarkers of dementia with Lewy bodies or by collecting detailed clinical symptoms. We report the clinical progression of a 67-year-old patient diagnosed with AD who developed rapid eye movement sleep disorder-like symptoms and transient visual hallucinations 10 years after AD onset and was considered to have comorbid LB pathology based on imaging indicative biomarkers of dementia with Lewy bodies.

12.
Schizophr Res ; 269: 86-92, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38754313

RESUMO

Hallucinations are a core feature of psychosis, and their severity during the acute phase of illness is associated with a range of poor outcomes. Various clinical and sociodemographic factors may predict hallucinations and other positive psychotic symptoms in first episode psychosis (FEP). Despite this, the precise factors associated with hallucinations at first presentation to an early intervention service have not been extensively researched. Through detailed interviews and chart reviews, we investigated sociodemographic and clinical predictors in 636 minimally-medicated patients who entered PEPP-Montréal, an early intervention service for FEP, between 2003 and 2018. Hallucinations were measured using the Scale for the Assessment of Positive Symptoms (SAPS), while negative symptoms were assessed using the Scale for the Assessment of Negative symptoms (SANS). Depressive symptoms were evaluated through the Calgary Depression Scale for Schizophrenia (CDSS), and anxiety symptoms via the Hamilton Rating Scale for Anxiety (HAS). A majority (n = 381, 59.9 %) of the sample presented with clinically significant hallucinations (SAPS global hallucinations score ≥ 3) at program entry. These patients had an earlier age at onset, fewer years of education, and a higher severity of delusions, depression and negative symptoms than those without clinical-level hallucinations. These results suggest that individuals with clinically significant hallucinations at admission tend to be younger and have a greater overall symptom burden. This makes it especially important to monitor hallucinations alongside delusions, depression and negative symptoms in order to identify who might benefit from targeted interventions. The implications of these findings for early intervention and person-centered care are discussed.

13.
Psychiatry Res Neuroimaging ; 341: 111824, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38754348

RESUMO

Auditory verbal hallucinations (AVHs) involve perceptions, often voices, in the absence of external stimuli, and rank among the most common symptoms of schizophrenia. Metrical stress evaluation requires determination of the stronger syllable in words, and therefore requires auditory imagery, of interest for investigation of hallucinations in schizophrenia. The current functional magnetic resonance imaging study provides an updated whole-brain network analysis of a previously published study on metrical stress, which showed reduced directed connections between Broca's and Wernicke's regions of interest (ROIs) for hallucinations. Three functional brain networks were extracted, with the language network (LN) showing an earlier and shallower blood-oxygen-level dependent (BOLD) response for hallucinating patients, in the auditory imagery condition only (the reduced activation for hallucinations observed in the original ROI-based results were not specific to the imagery condition). This suggests that hypoactivation of the LN during internal auditory imagery may contribute to the propensity to hallucinate. This accords with cognitive accounts holding that an impaired balance between internal and external linguistic processes (underactivity in networks involved in internal auditory imagery and overactivity in networks involved in speech perception) contributes to our understanding of the biological underpinnings of hallucinations.

14.
Schizophr Res ; 269: 64-70, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38733801

RESUMO

BACKGROUND AND HYPOTHESIS: Hearing voices is a common and often distressing experience for people with psychosis, and many individuals experience medication-resistant auditory verbal hallucinations (AVH). Psychosocial interventions are often employed to address distress over hearing voices. However, although links have been made between adverse social experiences and psychosis broadly, no work has yet delineated the relationship between day-to-day social stress and hallucination severity. We aimed to define that relationship in both clinical and non-clinical voice-hearers. STUDY DESIGN: A sample of 278 participants with a history of hearing voices was selected from the Yale Control Over Perceptual Experiences (COPE) Project. They were administered self-report measures of recent stress and recent auditory experiences within a cross-sectional design. Regression models were used to evaluate whether self-reported aspects of recent stress-and social stress in particular-were related to recent frequency of and distress over hearing voices. Related demographics and clinical characteristics were included as covariates. STUDY RESULTS: A significant relationship was observed between recent social stress and both recent frequency of and distress over hearing voices. While other aspects of recent stress were also related to recent distress over voices, social stressors uniquely predicted distress over voice-hearing, beyond the influence of other stressors. Depressive symptom severity was also related to distress over voices. CONCLUSIONS: Results suggest that daily social stress may be an important consideration and a potential treatment target for individuals experiencing clinical distress over auditory hallucinations.

15.
Cureus ; 16(4): e57932, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38738099

RESUMO

Focal seizures with subjective auditory phenomena, known as auditory seizures, are uncommon and can include simple to complex auditory hallucinations. We present a case of a 59-year-old man who presented with motor and non-motor seizures. He had a four-month history of hearing things resembling continuous metallic sounds, pennies dropping into a bank, persistent music after radio cessation, and the sound of a passing train. Brain MRI showed multiple serpiginous flow voids in the right temporal lobes, consistent with an arteriovenous malformation that was confirmed eventually with a diagnostic brain angiogram. The etiology of the seizures was related to a structural lesion in the setting of a right temporal arteriovenous malformation (AVM). Treatment with 2000mg of levetiracetam twice daily and 300mg of oxcarbazepine twice daily improved symptoms, and subsequent stereotactic radiosurgery ablation successfully treated the AVM. Post-treatment MRI showed reduced visibility of parasitized vessels, with controlled generalized seizures but partial control of auditory seizures.

16.
Clin Psychol Psychother ; 31(3): e2991, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38706173

RESUMO

The experience of hearing voices is common to an estimated 7% of the general population, with the presence of negative content being the best predictor of whether individuals will require clinical support. Whilst largely neglected in the literature to date, there are calls to consider the significance of voice content for reducing voice-related distress. However, no quantitative and comprehensive measure of voice content with suitability for research and clinical use exists. This pilot study aimed to demonstrate preliminary psychometric properties of a newly developed measure, the Perth Voice Content Questionnaire (PVCQ), designed to measure the intensity and themes of positively and negatively valenced voice content, primarily of the dominant voice. The PVCQ and measures of voice severity and related beliefs were completed by 47 voice-hearing participants. The measure was found to be internally consistent, loaded onto two distinct factors of positive and negative content, and these factors were associated with voice-related distress and negative beliefs about voices and positive beliefs about voices, respectively, indicating good validity. The PVCQ offers the first self-report measure of voice content, with preliminary psychometric properties indicating its suitability for clinical and research use.


Assuntos
Alucinações , Psicometria , Humanos , Feminino , Masculino , Adulto , Inquéritos e Questionários/normas , Projetos Piloto , Reprodutibilidade dos Testes , Pessoa de Meia-Idade , Alucinações/psicologia , Alucinações/diagnóstico , Adulto Jovem , Idoso
17.
Cogn Neuropsychiatry ; : 1-13, 2024 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-38787633

RESUMO

INTRODUCTION: We investigated the degree of cognitive insight in patients with Alzheimer's Disease (AD) regarding their hallucinations, aiming to elucidate the subjective experiences and perceptions associated with this phenomenon. METHODS: Using a cross-sectional design, we invited both AD patients (n = 31) and their informants to evaluate the occurrence of hallucinations. Degree of cognitive insight was based upon the discrepancy between the patients' and informants' evaluations. RESULTS: Analysis demonstrated that AD patients rated the occurrence of hallucinations lower than their informants, indicating that patients tended to underestimate the frequency of their hallucinations. The discrepancy between the ratings of patients and informants was negatively correlated with cognitive functioning, suggesting that a greater discrepancy (indicating poorer insight) was associated with lower cognitive functioning in patients. DISCUSSION: Our findings highlight the deficits in insight into hallucinations among AD patients, specifically indicating that AD patients have limited awareness of their own hallucinations. Furthermore, our findings support the idea that deficits in insight into hallucinations are associated with the progression of AD.

18.
Drug Alcohol Depend ; 260: 111319, 2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38788533

RESUMO

BACKGROUND: Psychotic-like experiences (PLEs) are common in the general population and have been linked to alcohol misuse and abuse. However, much of this research has been undertaken in Western countries. To address this deficit, the current study examined the association between PLEs and problem drinking in the Japanese general population. METHODS: Data were used from 3717 adults (age 18-89) collected in an online survey in 2023. Information was obtained on PLEs with the PRIME Screen-Revised (PS-R), while problem drinking was assessed with the CAGE questionnaire (where a score of ≥ 2 was used to categorize cases). Logistic regression was used to examine the associations. RESULTS: Problem drinking was prevalent in the study sample (12.5%). In an analysis that was adjusted for sociodemographic factors, self-rated health, smoking status and depressive symptoms, PLEs were associated with significantly higher odds for problem drinking in the total sample (OR: 1.70, 95%CI: 1.13-2.55). In a sex-stratified analysis PLEs were not linked to problem drinking in men (OR: 1.16, 95%CI 0.68-2.00), whereas women with PLEs had over 2.8 times higher odds for problem drinking (OR: 2.83, 95%CI: 1.54-5.21). CONCLUSION: PLEs are associated with problem drinking in the Japanese general population and this association is especially pronounced in women. As problem drinking has been linked to a number of detrimental outcomes, future research should examine the potential effects of problem drinking in individuals with PLEs.

19.
Ann Indian Acad Neurol ; 27(2): 178-182, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38751916

RESUMO

Objective: Homer1, a postsynaptic protein coded by the HOMER1 gene, presumably has a role in homeostatic plasticity that dampens neuronal responsiveness when the input activity is too high. HOMER1 polymorphism has been studied in major psychiatric disorders such as schizophrenia. The objective of this study is to investigate if polymorphisms of the HOMER1 gene are associated with psychosis in Parkinson's disease (PD-P). Methods: One hundred patients with Parkinson's disease (PD) and 100 healthy controls were enrolled consecutively in a PD-P biomarker study at the National Institute of Mental Health and Neurosciences, Bangalore, India. Of the 100 PD patients, 50 had psychosis (PD-P) and 50 did not have psychosis (PD-NP). Two single-nucleotide polymorphisms of HOMER1 (rs4704559 and rs4704560) were analyzed from the DNA isolated from peripheral blood. The allele and genotype frequencies in the PD-P and PD-NP groups were compared. Results: Analysis of HOMER1 rs4704560 revealed a significant difference in both genotype and allele levels between PD-P and PD-NP groups. There was an overrepresentation of T-allele (42% vs. 16%; P < 0.001) and TT genotype (24% vs. 6%; P < 0.001) in the PD-P group compared to PD-NP group. There was no significant difference between PD-P and PD-NP groups when various genotypes and allele frequencies related to HOMER1 rs4704559 were compared. Conclusion: PD-P is probably associated with overrepresentation of T-allele of HOMER1 rs4704560, and larger studies are warranted to confirm our results.

20.
ArXiv ; 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38699166

RESUMO

The mechanisms of psychotic symptoms like hallucinations and delusions are often investigated in fully-formed illness, well after symptoms emerge. These investigations have yielded key insights, but are not well-positioned to reveal the dynamic forces underlying symptom formation itself. Understanding symptom development over time would allow us to identify steps in the pathophysiological process leading to psychosis, shifting the focus of psychiatric intervention from symptom alleviation to prevention. We propose a model for understanding the emergence of psychotic symptoms within the context of an adaptive, developing neural system. We will make the case for a pathophysiological process that begins with cortical hyperexcitability and bottom-up noise transmission, which engenders inappropriate belief formation via aberrant prediction error signaling. We will argue that this bottom-up noise drives learning about the (im)precision of new incoming sensory information because of diminished signal-to-noise ratio, causing an adaptive relative over-reliance on prior beliefs. This over-reliance on priors predisposes to hallucinations and covaries with hallucination severity. An over-reliance on priors may also lead to increased conviction in the beliefs generated by bottom-up noise and drive movement toward conversion to psychosis. We will identify predictions of our model at each stage, examine evidence to support or refute those predictions, and propose experiments that could falsify or help select between alternative elements of the overall model. Nesting computational abnormalities within longitudinal development allows us to account for hidden dynamics among the mechanisms driving symptom formation and to view established symptomatology as a point of equilibrium among competing biological forces.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...