In recent years, there have been significant advances in our understanding of the positive symptoms of schizophrenia, such as hallucinations and delusions. This progress has been significantly aided by the use of associative learning-based approaches in human subjects and preclinical animal models. Here, we first review experimental research focusing on the abnormal processing of absent stimuli using three different conditioning phenomena: conditioned hallucinations, mediated conditioning, and trace conditioning. We then review studies investigating the ability to reduce focal processing of physically present but informationally redundant stimuli using habituation, latent inhibition, and blocking. The results of these different lines of research are then summarized within the framework of Wagner\'s (1981) standard operating procedures model, an associative learning model with explicit reference to the internal representations of both present and absent stimuli. Within this framework, the central deficit associated with positive symptoms can be described as a failure to suppress the focal processing of both absent stimuli and present but irrelevant stimuli. This can explain the wide range of results obtained in different experimental settings. Finally, we briefly discuss the role of the hippocampus and its interaction with dopaminergic transmission in the emergence of such abnormal stimulus representations and learning. Overall, we hope that the theoretical framework and empirical findings offered by the associative learning approach will continue to facilitate and integrate analyses of schizophrenia conducted at the psychological and behavioral levels on the one hand, and at the neural and molecular levels on the other, by serving as a useful interface between them. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

A growing body of literature indicates that mediated learning techniques have specific utility for tapping into reality testing in animal models of neuropsychiatric illness. In particular, recent work has shown that animal models that recapitulate various endophenotypes of schizophrenia are particularly vulnerable to impairments in reality testing when undergoing mediated learning. Multiple studies have indicated that these effects are dopamine receptor 2-dependent and correlated with aberrant insular cortex (IC) activity. However, until now, the connection between dopamine and the IC had not been investigated. Here, we utilized a novel intersectional approach to label mesencephalic dopamine cells that specifically project to the insular cortex in both wild-type controls and transgenic mice expressing the dominant-negative form of the Disrupted-in-Schizophrenia-1 (DISC-1) gene. Using these techniques, we identified a population of cells that project from the ventral tegmental area (VTA) to the IC. Afterward, we conducted multiple studies to test the necessity of this circuit in behaviors ranging from gustatory detection to the maintenance of effort and, finally, mediated performance. Our results indicate that perturbations of the DISC-1 genetic locus lead to a reduction in the number of cells in the VTA → IC circuit. Behaviorally, VTA → IC circuitry does not influence gustatory detection or motivation to acquire sucrose reward; however, inactivation of this circuit differentially suppresses Pavlovian approach behavior in wild-type and DISC-1 transgenic mice during mediated performance testing. Moreover, under these testing conditions, inactivation of this circuit predisposes wild-type (but not DISC-1) mice to display impaired reality testing. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

OBJECTIVE: N-Methyl-d-aspartate receptor (NMDA-R) hypofunctioning has been hypothesized to be involved in circuit dysfunctions in schizophrenia (ScZ). Yet, it remains to be determined whether the physiological changes observed following NMDA-R antagonist administration are consistent with auditory gamma-band activity in ScZ which is dependent on NMDA-R activity.
METHODS: This systematic review investigated the effects of NMDA-R antagonists on auditory gamma-band activity in preclinical (n = 15) and human (n = 3) studies and compared these data to electro/magneto-encephalographic measurements in ScZ patients (n = 37) and 9 studies in early-stage psychosis. The following gamma-band parameters were examined: (1) evoked spectral power, (2) intertrial phase coherence (ITPC), (3) induced spectral power, and (4) baseline power.
RESULTS: Animal and human pharmacological data reported a reduction, especially for evoked gamma-band power and ITPC, as well as an increase and biphasic effects of gamma-band activity following NMDA-R antagonist administration. In addition, NMDA-R antagonists increased baseline gamma-band activity in preclinical studies. Reductions in ITPC and evoked gamma-band power were broadly compatible with findings observed in ScZ and early-stage psychosis patients where the majority of studies observed decreased gamma-band spectral power and ITPC. In regard to baseline gamma-band power, there were inconsistent findings. Finally, a publication bias was observed in studies investigating auditory gamma-band activity in ScZ patients.
CONCLUSIONS: Our systematic review indicates that NMDA-R antagonists may partially recreate reductions in gamma-band spectral power and ITPC during auditory stimulation in ScZ. These findings are discussed in the context of current theories involving alteration in E/I balance and the role of NMDA hypofunction in the pathophysiology of ScZ.

UNASSIGNED: The anticholinergic properties of medications are associated with poorer cognitive performance in schizophrenia. Numerous scales have been developed to assess anticholinergic burden and yet, there is no consensus indicating which anticholinergic burden scale is more relevant for patients with schizophrenia. We aimed to identify valid scales for estimating the risk of iatrogenic cognitive impairment in schizophrenia.
UNASSIGNED: We identified 27 scales in a literature review. The responses to neuropsychological tests of 839 individuals with schizophrenia or schizoaffective disorder in the FACE-SZ database were collected between 2010 and 2021. We estimated the association between objective global cognitive performance and the 27 scales, the number of psychotropic drugs, and chlorpromazine and lorazepam equivalents in bivariable regressions in a cross-sectional design. We then adjusted the bivariable models with covariates: the predictors significantly associated with cognitive performance in multiple linear regressions were considered to have good concurrent validity to assess cognitive performance.
UNASSIGNED: Eight scales, the number of psychotropic drugs, and drug equivalents were significantly associated with cognitive impairment. The number of psychotropic drugs, the most convenient predictor to compute, was associated with worse executive function (Standardized β = -0.12, p = .004) and reasoning (Standardized β = -0.08, p = .037).
UNASSIGNED: Anticholinergic burden, the number of psychotropic drugs, and drug equivalents were weakly associated with cognition, thus suggesting that cognitive impairment in schizophrenia and schizoaffective disorder is explained by factors other than medication. The number of psychotropic drugs was the most parsimonious method to assess the risk of iatrogenic cognitive impairment.

UNASSIGNED: In this study, we investigated the differences in clinical biochemical values and mitochondrial mass between schizophrenia patients with and without COVID-19, so as to provide assistance to the treatment and management of COVID-19 positive patients with schizophrenia.
UNASSIGNED: We undertook an exploratory, retrospective review of patient data from Dec. 6, 2022, to Jan. 31, 2023. A total of 1696 inpatients with psychosis (921 schizophrenia patients and 775 diagnosed with other mental diseases) during this period were identified. Finally, 60 schizophrenia patients were enrolled in our study, and 20 of them were infected with syndrome coronavirus 2 (SARS-CoV-2). The serum biochemical levels and single-cell mitochondrial mass (SCMM) of the T lymphocytes of all schizophrenia patients were analyzed.
UNASSIGNED: The serum levels of aspartate aminotransferase (AST), alkaline phosphatase (ALP), creatinine (Cr) and lactate dehydrogenase (LDH) were significantly higher in schizophrenia patients with COVID-19 (SCZ-C) group. In addition, the SCZ-C group showed lower CD3+, CD3+CD4+ and CD3+CD8+ cell counts and higher SCMM of T lymphocytes compared to SCZ group. Furthermore, positive correlations were found between the T-cell subpopulation counts and positive symptom scores on the Positive and Negative Syndrome Scale (PANSS).
UNASSIGNED: Our study findings showed that schizophrenia patients with COVID-19 have a phenotype of mitochondrial damage in T lymphocytes and higher serum levels of AST, ALP, Cr and LDH, which might provide evidence for treating individuals with schizophrenia during subsequent spread of infectious disease.

Data on reproductive safety of recently approved newer antipsychotics are limited. Here, we report a case vignette of a patient with schizophrenia treated with cariprazine during pregnancy. The patient became pregnant unexpectedly while taking medication. As a result of shared decision-making, the patient and her psychiatrist decided to continue the treatment, which proved to be protective against relapse and had no adverse effect either on the course of pregnancy or on the health of the newborn. Cariprazine maintenance treatment during pregnancy was found to be safe in our case.

TRPV1 channels are polymodal cation channels located predominantly on primary afferent neurons that are activated by inflammatory mediators, capsaicin (the active component in chili peppers), and noxious heat. TRPV1 channel antagonists are potential new analgesic agents, but their development has been hindered by the finding that they also produce loss of thermal homeostasis and response to noxious heat. Results from recent studies of the TRPV1 channel indicate that it might be possible to develop TRPV1 channel antagonists that inhibit pain without affecting noxious heat sensation. TRPV1 channels are also present in the central nervous system (CNS) and have been implicated in learning, memory, and behaviour. TRPV1 channel modulators have been proposed to have possible therapeutic potential in the treatment of neurological and psychiatric conditions. However, further understanding of the role of TRPV1 channels in the CNS is required before therapeutic advances in the treatment of neuropsychiatric conditions with TRPV1 channel modulators can be made.

Avatar therapy (AT) is a novel virtual reality-based psychotherapy that has been developed to treat auditory verbal hallucinations (AVH) in treatment-resistant schizophrenia. Various psychotherapeutic components, such as emotions and sense of presence, could contribute to clinical outcomes. However, the interplay between sense of presence, emotions, and clinical response has seldom been investigated. This study aimed to explore the relations between sense of presence, emotions, and clinical outcomes in AT. To conduct this investigation, data from previous and ongoing AT trials were used. Sense of presence and emotions were assessed using standardized questionnaires. AVH were evaluated using the Psychotic Symptom Rating Scales. While sense of presence was positively associated with positive emotions such as control and serenity, no significant associations were found for negative emotions. Moreover, a higher level of sense of presence was associated with a bigger decrease in AVH. Overall, positive emotions seem to be associated with sense of presence in AT. Sense of presence also seems to be involved in the therapeutic outcome, thereby suggesting that this could be an important component related to clinical response. More studies are needed to confirm these trends, which could be generalized to other virtual reality-based psychotherapies.

Background and Objectives: Radicalization, a complex and multifaceted phenomenon, has been a subject of increasing concern in recent years, particularly due to its potential connection to acts of mass violence and terrorism. This systematic review examines the intricate link between radicalization and psychotic disorders, utilizing various sources such as observational studies, case reports, and series. It aims to highlight the prevalence of schizophrenia spectrum and other psychotic disorders among radicalized individuals and to define the role of mental health professionals in dealing with this issue, contributing to the development of prevention and treatment strategies. Materials and Methods: The methodology involved an extensive literature search across PubMed, Scopus, and APA PsycINFO up to 1 February 2024, adhering to PRISMA guidelines. The study focused on radicalization and psychotic disorders as defined by DSM-5 criteria, excluding other mental disorders. A population sample of 41 radicalized individuals diagnosed with psychotic disorders was selected, among which schizophrenia was identified as the predominant condition. Results: It was observed that 24% of these individuals passed away soon after committing their crimes, leading the researchers to rely on retrospective data for their diagnoses. The use of diverse assessment tools for psychiatric diagnosis and the lack of a standardized method for diagnosing or assessing involvement in the radicalization process were also noted. Despite limitations like reliance on observational studies and case reports, which result in low evidence quality and varied methodologies, our work provides a valuable contribution to clarifying the relationship between radicalization and psychotic disorders. However, further clinical studies are needed to delve deeper into these aspects. Conclusions: In conclusion, our review points out that individuals with psychotic disorders do not have a higher crime rate than the general population and warns against associating crimes with mental illness due to the stigma it creates. The lack of uniform psychiatric diagnostic tools and radicalization assessment highlights the need for more standardized risk assessment tools and validated scales in psychiatric diagnosis to better understand the relationship between radicalization and psychotic disorders and to develop integrated protocols.

BACKGROUND: Schizophrenia is a mental disorder affecting approximately 0.32% of the global population, according to the World Health Organization. Antipsychotic medications are used to treat this condition by inhibiting D2 dopamine and 5HT2 serotonin receptors. The selection of the appropriate mode of delivery for these drugs is based on factors such as patient adherence, clinical presentation, and patient preferences. However, additional drivers of treatment selection are required in clinical practice. Mounting evidence suggests that neuroinflammation plays a crucial role in the pathogenesis of schizophrenia. NLR, a cost-effective biomarker of inflammation, has increased in several psychiatric conditions and may represent a valid method for studying the inflammatory stage in schizophrenia, relapse, and the first episode of psychosis. The aim of this study is to evaluate whether there are any variations in NLR values between patients given oral antipsychotics and those given long-acting antipsychotics.
METHODS: The study included 50 individuals with schizophrenia, either acute or in the follow-up phase. NLR was obtained by calculating the ratio of absolute neutrophil count (cells/μL) and absolute lymphocyte count (cells/μL).
RESULTS: Patients on long-acting antipsychotics exhibited significantly lower mean NLR scores (1.5 ± 0.7) compared to those on oral antipsychotics (2.2 ± 1.3) (p < 0.05).
CONCLUSIONS: NLR appears promising as a neuroinflammatory biomarker. This study reveals significantly lower NLR values in patients on long-acting antipsychotics, which may signify reduced systemic inflammation and improved adherence.