Current Concepts and Treatments of Schizophrenia

SchizoLMNet: a modified lightweight MobileNetV2- architecture for automated schizophrenia detection using EEG-derived spectrograms

Schizophrenia (SZ) is a chronic neuropsychiatric disorder characterized by disturbances in cognitive, perceptual, social, emotional, and behavioral functions. The conventional SZ diagnosis relies on subjective assessments of individuals by psychiatrists, which can result in bias, prolonged procedures, and potentially false diagnoses. This emphasizes the crucial need for early detection and treatment of SZ to provide timely support and minimize long-term impacts. Utilizing the ability of electroencephalogram (EEG) signals to capture brain activity dynamics, this article introduces a novel lightweight modified MobileNetV2- architecture (SchizoLMNet) for efficiently diagnosing SZ using spectrogram images derived from selected EEG channel data. The proposed methodology involves preprocessing of raw EEG data of 81 subjects collected from Kaggle data repository. Short-time Fourier transform (STFT) is applied to transform pre-processed EEG signals into spectrogram images followed by data augmentation. Further, the generated images are subjected to deep learning (DL) models to perform the binary classification task. Utilizing the proposed model, it achieved accuracies of 98.17%, 97.03%, and 95.55% for SZ versus healthy classification in hold-out, subject independent testing, and subject-dependent testing respectively. The SchizoLMNet model demonstrates superior performance compared to various pretrained DL models and state-of-the-art techniques. The proposed framework will be further translated into real-time clinical settings through a mobile edge computing device. This innovative approach will serve as a bridge between medical staff and patients, facilitating intelligent communication and assisting in effective SZ management.

Repositioning of aripiprazole, an anti‑psychotic drug, to sensitize the chemotherapy of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy with limited therapeutic options. Cisplatin is a primary chemotherapeutic agent utilized in combination with other drugs or radiotherapy for PDAC treatment. However, the severe side effects of cisplatin often necessitate discontinuation of therapy and drug resistance in tumor cells poses significant clinical challenges. Therefore, the development of effective therapeutic strategies is imperative. The present study investigated whether repositioning of the antipsychotic drug aripiprazole could sensitize the anticancer activity of cisplatin in pancreatic cancer at doses calculated by the combination index. The findings indicated that aripiprazole combined with cisplatin to suppress pancreatic cancer cell growth. Notably, the combination notably increased the expression of apoptosis markers, including cleaved caspase‑3, compared with cisplatin alone. Additionally, this combination effectively decreased XIAP and MCL‑1 expression via mitochondrial membrane potential change as revealed by JC‑1 assay, thereby inducing apoptosis. Furthermore, in fluid shear stress assay, the combination of aripiprazole and cisplatin notably inhibited cell adhesion and tumor spheroid formation. Mechanistically, phospho‑kinase array profiles showed that the enhanced anticancer efficacy of the combination treatment could be attributed to the inhibition of STAT3 signaling, which led to a significant reduction in tumor growth in a pancreatic cancer animal model. The results showed that the repositioning of aripiprazole inhibits cancer cell growth by blocking the STAT3 signaling pathway and effectively enhancing cisplatin‑induced apoptosis, thereby suggesting that the combination of aripiprazole and cisplatin may be a potent chemotherapeutic strategy for the treatment of pancreatic cancer.

Speech Mismatch Negativity (MMN) in Schizophrenia with Auditory Verbal Hallucinations

Auditory verbal hallucinations (AVH) are experienced by many individuals with schizophrenia (SZ), a neurodevelopmental disease that encumbers the quality of life and psychosocial outcome of those afflicted by it. While many hypotheses attempt to better define the etiology of AVHs in SZ, their neural profile and its moderation by current neuroleptics remains limited. The Mismatch Negativity (MMN) is an event related potential (ERP) measured from electroencephalographic (EEG) activity during the presentation of a deviance detection auditory paradigm. The neural regions and activity underlying the generation of the MMN include the primary auditory cortex and the prefrontal cortex which are regions also found to be activated during the experience of AVHs. Decreased MMN amplitudes have been robustly noted in SZ patients during the presentation of MMN tasks using auditory tones. However, the MMN generation to speech stimuli has not been extensively examined in SZ nor in relation to AVHs. The primary objective of this study was to examine the MMN to five speech-based deviants in SZ patients and healthy controls. Second, we assessed MMN features with AVH characteristics in 19 SZ patients and 21 HC. While AVH features did not correlate with measures of MMN, we found decreased MMN amplitudes to speech-based frequency and vowel change deviants in SZ patients compared to HC potentially reflecting deficiencies in basic speech processing mechanisms.

MicroRNA dysregulation in glutamate and dopamine pathways of schizophrenia: From molecular pathways to diagnostic and therapeutic approaches

Schizophrenia is a complex psychiatric disorder, and genetic and environmental factors have been implicated in its development. Dysregulated glutamatergic and dopaminergic transmission pathways are involved in schizophrenia development. Besides genetic mutations, epigenetic dysregulation has a considerable role in dysregulating molecular pathways involved in schizophrenia. MicroRNAs (miRNAs) are small, non-coding RNAs that target specific mRNAs and inhibit their translation into proteins. As epigenetic factors, miRNAs regulate many genes involved in glutamate and dopamine signaling pathways; thereby, their dysregulation can contribute to the development of schizophrenia. Secretion of specific miRNAs from damaged cells into body fluids can make them one of the ideal non-invasive biomarkers in the early diagnosis of schizophrenia. Also, understanding the molecular mechanisms of miRNAs in schizophrenia pathogenesis can pave the way for developing novel treatments for patients with schizophrenia. In this study, we reviewed the glutamatergic and dopaminergic pathophysiology and highlighted the role of miRNA dysregulation in schizophrenia development. Besides, we shed light on the significance of circulating miRNAs for schizophrenia diagnosis and the recent findings on the miRNA-based treatment for schizophrenia.

Sex difference in alexithymia and cognitive impairment in chronic schizophrenia: a large sample study based on Chinese Han population

Sex differences in schizophrenia have been noted across domains such as alexithymia and cognitive function; however, how they interact remains unclear. This study aimed to explore sex differences in the relationship between alexithymia and cognitive function in patients with chronic schizophrenia. A total of 695 patients (464 males and 231 females) who met the DSM-IV diagnostic criteria for schizophrenia were recruited in this cross-sectional study. Demographic and clinical data were collected using self-reported questionnaires. We assessed alexithymia using the Toronto Alexithymia Scale (TAS-20), cognitive function using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), and psychiatric symptoms using the Positive and Negative Syndrome Scale (PANSS). Male schizophrenic patients have to read 56.7% of the alexithymia rate, and higher scores on the RBANS visuospatial/constructional, language and total score than female patients (all P < 0.05).Alexithymia patients had lower language than non-alexithymia patients(P = 0.001). In addition, there were significant differences of the correlation scores for men and women in immediate memory and delayed memory (P < 0.001). Our results indicate that there are sex differences in the prevalence comorbid alexithymia symptoms, as well as their association with cognitive function, in patients with schizophrenia. However, a cross-sectional design could not establish definitive causative associations between sex and alexithymia or cognitive function.

Relevance of diet in schizophrenia: a review focusing on prenatal nutritional deficiency, obesity, oxidative stress and inflammation

Background/Objectives

Schizophrenia is a complex mental disorder influenced by genetic and environmental factors, including dietary habits. Oxidative stress and inflammation play a crucial role in the pathophysiology of schizophrenia. Emerging research suggests that diet may affect schizophrenia through different biological mechanisms beyond oxidative stress and inflammation. In particular, epigenetic changes may alter the expression of genes related to neurodevelopment and neurotransmitter systems, while neuroplasticity plays a crucial role in brain adaptation and resilience to psychiatric disorders.

Methods

The literature search included the main available databases (Science Direct, PubMed and Google Scholar), considering the English language, and our screening was performed based on several words such as "schizophrenia", "diet", "nutrients", "obesity", "oxidative stress", "inflammation", "antioxidants" and "prenatal nutritional deficiency". The review focused specifically on studies examining the relevance of diet in schizophrenia, as well as prenatal nutritional deficiency, obesity, oxidative stress, and inflammation associated with this disorder.

Results

Following a review of the literature, it was found that nutritional deficiencies, including lack of omega-3 fatty acids, vitamins D, and B, during the prenatal and postnatal periods can have a negative impact on neurodevelopment and increase the risk of schizophrenia. Patients with schizophrenia have imbalances in antioxidant enzymes, such as glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), and reduced levels of antioxidants (vitamin E, vitamin C). These biochemical changes lead to an increase in markers of oxidative stress, including malondialdehyde (MDA). In addition, cytokine-mediated inflammation, microglial activation, and intestinal dysbiosis are associated with the onset of schizophrenia and the severity of schizophrenia symptoms. Currently, there is no universally accepted dietary regimen for control. However, various diets and nutritional methods are being researched and applied to alleviate the symptoms of schizophrenia and improve the overall health of patients, including the Mediterranean diet, the ketogenic diet, the gluten-free diet, and the DASH (Dietary Approaches to Stop Hypertension) diet.

Conclusion

A healthy diet, rich in anti-inflammatory nutrients and antioxidants, may help manage schizophrenia by reducing oxidative stress, preventing complications, and improving quality of life. Omega-3 fatty acids, vitamin D, and B vitamins are particularly important for brain development and function. In this review, we aim to analyze the literature on the influence of diet on schizophrenia, focusing on the role of prenatal nutritional deficiencies, obesity, oxidative stress, and inflammation.

Crocus sativus (saffron) adjunct to risperidone for negative symptoms of schizophrenia: a randomized, double-blind, placebo-controlled trial

Current treatments for schizophrenia encounter resistance, limited efficacy, and limiting complications, necessitating novel approaches. The effects of saffron on negative symptoms were investigated as it has shown neuroprotective and antipsychotic properties. Fifty-six clinically stable chronic schizophrenic outpatients were equally assigned to saffron 15 mg q12hr or placebo groups while continuing risperidone. The Positive and Negative Syndrome Scale (PANSS) was used to assess schizophrenia-related symptoms in weeks 4 and 8. Also, the patients were assessed for the Hamilton depression rating scale (HDRS) and adverse effects. The baseline characteristics of the groups were comparable (Ps > 0.05). There were significant time-treatment interaction effects on negative ( = 0.137), general psychopathology ( = 0.193), and total ( = 0.113) PANSS scores. Affirmatively, their reductions were significantly greater in the saffron group until weeks 4 (Cohen's ds = 0.922, 0.898, and 0.759, respectively) and 8 (Cohen's ds = 0.850, 1.047, and 0.705, respectively). Regarding the negative symptoms, a better 25% response rate was obtained in the saffron group until the endpoint (P = 0.003). The HDRS scores, extrapyramidal symptom rating scale scores, and side effect frequencies were comparable between the groups (Ps > 0.05). Saffron was beneficial for primary negative symptoms of chronic schizophrenia in a safe and tolerable manner. It also outperformed placebo in improving general psychopathology and total symptoms.

Recognition of schizophrenia and quality of treatment during the COVID-19 pandemic: A Danish nationwide study

BACKGROUND

The COVID-19 pandemic may have exacerbated the state of ill-health among patients with schizophrenia. We examined the number of patients diagnosed with schizophrenia, the number of hospital admissions and outpatient contacts and the quality of treatment during the pandemic in comparison with the previous years.

METHODS

We identified patients ≥18 years old registered in the Danish Schizophrenia Registry from 2016 to 2022. Using a generalized linear model, we estimated prevalence ratios (PR) and 95 % confidence intervals (CI) for each variable of interest.

RESULTS

A minor reduction in the number of new cases, admissions and outpatient contacts was seen during the first lockdown; however, there was no overall change across the pandemic period compared with the pre-pandemic period. We found no change in the proportion of patients who were interviewed using a diagnostic tool (37.0 % during pandemic vs 37.9 % pre-pandemic; PR = 0.87; 95 % CI 0.68-1.12) or received family intervention (57.7 % vs 57.1 %; PR = 0.97; 95 % CI 0.81-1.15), and no decrease was observed in the proportion of patients assessed for social support. Furthermore, no change in the proportion of patients re-admitted within 30 days (35.9 % vs 35.0 %; PR = 0.96; 95 % CI 0.88-1.07) or screened for suicide risk in relation to discharge (55.2 % vs 56.8 %; PR = 0.96; 95 % CI 0.97-1.09) was observed.

CONCLUSIONS

Recognition and treatment of schizophrenia was minimally affected during the first lockdown, but across the pandemic period no overall change was observed. The quality of treatment of schizophrenia was unchanged.

EPO Deficiency Upregulates GADD45b/p38 MAPK Axis, Mediating Schizophrenia-Related Synaptic and Cognitive Impairments

Schizophrenia (SZ) is a chronic and severe mental illness associated with psychiatric symptoms, cognitive deficits, and social dysfunction. Current clinical interventions only limit relief of psychiatric symptoms and have minimal impact on cognitive impairments. Erythropoietin (EPO), known for its role in neurogenesis and synaptic plasticity, is significantly low in SZ patients. However, the role of EPO deficiency in SZ-associated cognitive deficits remains unclear. In this study, we used the MK801-induced SZ rat model to show that EPO levels were significantly decreased, correlating with cognitive impairments. EPO supplementation mitigated apoptosis, synaptic damage, and cognitive impairments caused by MK801. RNA-sequencing and Western blot analysis revealed increased expression of growth arrest and DNA damage 45b (GADD45b) in MK801-treated rats, reversed by EPO supplementation. Moreover, overexpression of GADD45b exacerbated neuronal loss and cognitive impairments in male Sprague-Dawley rats, while downregulation of GADD45b rescued these SZ-related pathologies. Notably, the benefits of EPO supplementation on SZ pathology were blocked by GADD45b overexpression. Inhibition of p38 MAPK, a GADD45b target, reduced MK801-induced apoptosis and synaptic damage. These findings uncover a novel etiopathogenic mechanism of SZ-related cognitive impairments, driven by EPO deficiency and the activation of the GADD45b/p38 MAPK axis.

Discovering functional interactions among schizophrenia-risk genes by combining behavioral genetics with cell biology

Despite much progress in identifying risk genes for polygenic brain disorders, their core pathogenic mechanisms remain poorly understood. In particular, functions of many proteins encoded by schizophrenia risk genes appear diverse and unrelated, complicating the efforts to establish the causal relationship between genes and behavior. Using various mouse lines, recent studies indicate that alterations of parvalbumin-positive (PV+) GABAergic interneurons can lead to schizophrenia-like behavior. PV+ interneurons display fast spiking and contribute to excitation-inhibition balance and network oscillations via feedback and feedforward inhibition. Here, we first summarize different lines of genetically modified mice that display motor, cognitive, emotional, and social impairments used to model schizophrenia and related mental disorders. We highlight ten genes, encoding either a nuclear, cytosolic, or membrane protein. Next, we discuss their functional relationship in regulating fast spiking and other aspects of PV+ interneurons and in the context of other domains of schizophrenia. Future investigations combining behavioral genetics and cell biology should elucidate functional relationships among risk genes to identify the core pathogenic mechanisms underlying polygenic brain disorders.

Ancestral retrovirus envelope protein ERVWE1 upregulates circ_0001810, a potential biomarker for schizophrenia, and induces neuronal mitochondrial dysfunction via activating AK2

BACKGROUND

Increasingly studies highlight the crucial role of the ancestral retrovirus envelope protein ERVWE1 in the pathogenic mechanisms of schizophrenia, a severe psychiatric disorder affecting approximately 1% of the global population. Recent studies also underscore the significance of circular RNAs (circRNAs), crucial for neurogenesis and synaptogenesis, in maintaining neuronal functions. However, the precise relationship between ERVWE1 and circRNAs in the etiology of schizophrenia remains elusive.

RESULTS

This study observed elevated levels of hsa_circ_0001810 (circ_0001810) in the blood samples of schizophrenia patients, displaying a significant positive correlation with ERVWE1 expression. Interestingly, in vivo studies demonstrated that ERVWE1 upregulated circ_0001810 in neuronal cells. Circ_0001810, acting as a competing endogenous RNA (ceRNA), bound to miR-1197 and facilitated the release of adenylate kinase 2 (AK2). The bioinformatics analysis of the schizophrenia datasets revealed increased levels of AK2 and enrichment of mitochondrial dynamics. Notably, miR-1197 was reduced in schizophrenia patients, while AK2 levels were increased. Additionally, AK2 showed positive correlations with ERVWE1 and circ_0001810. Further studies demonstrated that AK2 led to mitochondrial dysfunction, characterized by loss of intracellular ATP, mitochondrial depolarization, and disruption of mitochondrial dynamics. Our comprehensive investigation suggested that ERVWE1 influenced ATP levels, promoted mitochondrial depolarization, and disrupted mitochondrial dynamics through the circ_0001810/AK2 pathway.

CONCLUSIONS

Circ_0001810 and AK2 were increased in schizophrenia and positively correlated with ERVWE1. Importantly, ERVWE1 triggered mitochondrial dysfunction through circ_0001810/miR-1197/AK2 pathway. Recent focus on the impact of mitochondrial dynamics on schizophrenia development had led to our discovery of a novel mechanism by which ERVWE1 contributed to the etiology of schizophrenia, particularly through mitochondrial dynamics. Moreover, these findings collectively proposed that circ_0001810 might serve as a potential blood-based biomarker for schizophrenia. Consistent with our previous theories, ERVWE1 is increasingly recognized as a promising therapeutic target for schizophrenia.

Manipulation of Lipid Nanocapsules as an Efficient Intranasal Platform for Brain Deposition of Clozapine as an Antipsychotic Drug

BACKGROUND/OBJECTIVES

The blood-brain barrier (BBB) significantly limits the treatment of central nervous system disorders, such as schizophrenia, by restricting drug delivery to the brain. This study explores the potential of intranasal clozapine-loaded lipid nanocapsules (IN LNCsClo) as a targeted and effective delivery system to the brain.

METHODS

LNCsClo were prepared using the phase inversion technique and characterized in terms of size, zeta potential, entrapment efficiency (EE%), and in vitro drug release. The pharmacokinetic, safety, and pharmacodynamic effects of LNCsClo were then evaluated in a rat model through intranasal (IN) administration and compared with those of oral and intravenous (IV) Clo solutions.

RESULTS

LNCsClo were prepared using a phase inversion technique, resulting in a nanocarrier with a particle size of 28.6 ± 3.6 nm, homogenous dispersion, and high EE% (84.66 ± 5.66%). Pharmacokinetic analysis demonstrated that IN LNCsClo provided enhanced Clo brain bioavailability, rapid CNS targeting, and prolonged drug retention compared to oral and intravenous routes. Notably, the area under the curve (AUC) for brain concentration showed more than two-fold and eight-fold increases with LNCsClo, compared to IV and oral solutions, respectively, indicating improved brain-targeting efficiency. Safety assessments indicated that LNCsClo administration mitigated Clo-associated metabolic side effects, such as hyperglycemia, insulin imbalance, and liver enzyme alterations. Additionally, pharmacodynamic studies showed that LNCsClo significantly improved antipsychotic efficacy and reduced schizophrenia-induced hyperactivity, while preserving motor function.

CONCLUSIONS

These results highlight the potential of IN LNCsClo as a novel drug delivery system, offering improved therapeutic efficacy, reduced systemic side effects, and better patient compliance in the treatment of schizophrenia and potentially other CNS disorders.

The effect of clozapine on immune-related biomarkers in schizophrenia patients

Globally, schizophrenia is one of the main causes of disability. Approximately 1 % of the general population suffers from schizophrenia, and 30 % of cases are unresponsive to therapy. Clozapine is the gold standard for therapy-resistant schizophrenia (TRS), yet it has limited effectiveness and serious adverse events in some patients. Because of the possibility of severe neutropenia, clozapine administration requires monthly hematological monitoring in the first four months. Previous investigations have demonstrated the immune system alteration after clozapine treatment in schizophrenia patients. Besides, it has been proposed that clozapine changes the cytokines profile in schizophrenia patients. These findings highlighted the need to learn more about the disease's etiology and investigate the relationship between peripheral immune system markers and clozapine response to support strategies for better treatment outcomes. The time decision-making to start clozapine could be significantly decreased if some biomarkers were developed to assist physicians in anticipating whether a particular patient will respond to the medication. Therefore, this study aimed to comprehensively review the effect of clozapine on immune-related biomarkers in schizophrenia patients.

Association of depressive symptoms and incident chronic kidney disease in middle-aged and older adults

BACKGROUND

Emerging evidence suggests that depressive symptoms may be a risk factor for the development of Chronic kidney disease (CKD). This study aimed to investigate the association between depressive symptoms and the incidence of CKD in middle-aged and older Chinese adults.

METHODS

We utilized data from the 2011-2020 China Health and Retirement Longitudinal Study (CHARLS). Depressive symptoms were assessed using the 10-item Center for Epidemiologic Studies Depression Scale (CES-D). Incident CKD was defined based on the estimated glomerular filtration rate ≤ 60 mL/min/m2 or self-reported. Cox proportional hazard models were used to estimate the hazard ratio (HR) and 95 % confidence intervals (95 % CI) for incident CKD, adjusting for potential confounders.

RESULTS

Among the 10,996 participants without baseline CKD, 890 developed CKD during a median follow-up of 9.0 years. After adjusting for potential covariates, participants with depressive symptoms had a significantly higher risk of developing CKD compared to those without depressive symptoms (HR: 1.450; 95 % CI: 1.249-1.682). The association remained statistically significant when the CES-D was scored according to the severity of depressive symptoms, i.e., quintiles. A linear positive association between total CES-D score and risk of incident CKD was also found using restricted cubic spline regression (Pfor non-linearity = 0.114).

CONCLUSIONS

Depressive symptoms are significantly associated with an increased risk of incident CKD in middle-aged and older Chinese adults. These findings underscore the importance of mental health screening and interventions in preventing CKD in this population.

Human stem cell-based models to study synaptic dysfunction and cognition in schizophrenia: A narrative review

Cognitive impairment is the strongest predictor of functional outcomes in schizophrenia and is hypothesized to result from synaptic dysfunction. However, targeting synaptic plasticity and cognitive deficits in patients remains a significant clinical challenge. A comprehensive understanding of synaptic plasticity and the molecular basis of learning and memory in a disease context can provide specific targets for the development of novel therapeutics targeting cognitive impairments in schizophrenia. Here, we describe the role of synaptic plasticity in cognition, summarize evidence for synaptic dysfunction in schizophrenia and demonstrate the use of patient derived induced-pluripotent stem cells for studying synaptic plasticity in vitro. Lastly, we discuss current advances and future technologies for bridging basic science research of synaptic dysfunction with clinical and translational research that can be used to predict treatment response and develop novel therapeutics.

Patient iPSC-derived neural progenitor cells display aberrant cell cycle control, p53, and DNA damage response protein expression in schizophrenia

BACKGROUND

Schizophrenia (SCZ) is a severe psychiatric disorder associated with alterations in early brain development. Details of underlying pathomechanisms remain unclear, despite genome and transcriptome studies providing evidence for aberrant cellular phenotypes and pathway deregulation in developing neuronal cells. However, mechanistic insight at the protein level is limited.

METHODS

Here, we investigate SCZ-specific protein expression signatures of neuronal progenitor cells (NPC) derived from patient iPSC in comparison to healthy controls using high-throughput Western Blotting (DigiWest) in a targeted proteomics approach.

RESULTS

SCZ neural progenitors displayed altered expression and phosphorylation patterns related to Wnt and MAPK signaling, protein synthesis, cell cycle regulation and DNA damage response. Consistent with impaired cell cycle control, SCZ NPCs also showed accumulation in the G2/M cell phase and reduced differentiation capacity. Furthermore, we correlated these findings with elevated p53 expression and phosphorylation levels in SCZ patient-derived cells, indicating a potential implication of p53 in hampering cell cycle progression and efficient neurodevelopment in SCZ.

CONCLUSIONS

Through targeted proteomics we demonstrate that SCZ NPC display coherent mechanistic alterations in regulation of DNA damage response, cell cycle control and p53 expression. These findings highlight the suitability of iPSC-based approaches for modeling psychiatric disorders and contribute to a better understanding of the disease mechanisms underlying SCZ, particularly during early development.

Efficacy of Horticultural Therapy on Positive, Negative, and Affective Symptoms in Individuals with Schizophrenia: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background/Objectives: Positive symptoms, negative symptoms, and emotional disturbances are core features of schizophrenia. Although horticultural therapy (HT) has shown promise as an adjunctive treatment, evidence supporting its effectiveness remains limited. This systematic review and meta-analysis aimed to assess the impact of HT on total symptoms, positive symptoms, negative symptoms, and emotional disturbances in individuals with schizophrenia. Methods: We conducted a search for randomized controlled trials (RCTs) published up to March 2024 across multiple databases, including PubMed, Embase, Cochrane Library, CINAHL, CEPS, CNKI, Wanfang, and Yiigle. A random-effects model was employed to calculate the standardized mean difference (SMD). Results: A total of 35 studies enrolling 2899 participants were included. Our results indicated that, in the short term (≦3 months), HT has moderate to large effect sizes on total symptoms (SMD = 0.690, 95% CI 0.463 to 0.916), positive symptoms (SMD = 0.695, 95% CI 0.038 to 1.351), negative symptoms (SMD = 0.681, 95% CI 0.395 to 0.967), depression (SMD = 0.646, 95% CI 0.334 to 0.959), and anxiety (SMD = 0.627, 95% CI 0.364 to 0.890), with more pronounced benefits for anxiety symptoms in patients with a shorter duration of illness. In the long term (>3 months), HT shows large effect sizes for total symptoms (SMD = 1.393, 95% CI 0.858 to 1.928), negative symptoms (SMD = 1.389, 95% CI 0.935 to 1.842), anxiety (SMD = 1.541, 95% CI 1.042 to 2.040), and moderate to large effect sizes for positive symptoms (SMD = 0.667, 95% CI 0.077 to 1.258) and depression (SMD = 0.707, 95% CI 0.198 to 1.217). Additionally, longer weekly treatment durations are associated with better outcomes for total symptoms and negative symptoms. Schizophrenia patients with more severe initial symptoms may be potential responders to HT. Conclusions: These findings support the efficacy of HT in improving symptoms and emotional well-being in schizophrenia patients. Further trials with more rigorous designs are warranted to confirm these benefits.

Multivariate QSAR, similarity search and ADMET studies based in a set of methylamine derivatives described as dopamine transporter inhibitors

The dopamine transporter (DAT), responsible for the regulation of dopaminergic neurotransmission, is implicated in the etiology of several neuropsychiatric disorders which, in turn, have contributed to high rates of disability and numerous deaths in recent years, significantly impacting the global health system. Although the research for new drugs for the treatment of neuropsychiatric disorders has evolved in recent years, the availability of DAT-selective drugs that do not generate the same psychostimulant effects observed in drugs of abuse remains scarce. Therefore, we performed a QSAR study based on a dataset of 36 methylamine derivatives described as DAT inhibitors. The model was obtained based only in descriptors derived from 2D structures, and it was validated and generated satisfactory results considering the metrics used for internal and external validation. Subsequently, a virtual screening step also based on 2D similarity was performed, where it was possible to identify a total of 1157 compounds. After a series of reductions of the set using toxicity filters, applicability domain evaluation, and pharmacokinetic properties in silico assessment, seven hit compounds were selected as the most promising to be used, in future studies, as new scaffolds for the development of new DAT inhibitors.

A Case of Clozapine-Induced Hepatotoxicity: Management Considerations and Future Direction

Clozapine is an atypical antipsychotic used for treatment-resistant schizophrenia. Its use is often limited due to its well-known association with a variety of side effects. Hepatotoxicity is a less common side effect and has been infrequently reported. Here, we present the case of a patient who developed abdominal discomfort and right upper quadrant pain after clozapine was initiated. Liver transaminases were found to be elevated and continued to rise despite cessation of another psychiatric medication more commonly associated with hepatotoxicity. Discontinuation of clozapine resulted in relief of symptoms and normalization of liver enzymes without any complications.

Exploring the acceptability, and feasibility of a modified virtual reality-based AVATAR therapy in schizophrenia spectrum disorders: A case series report

Schizophrenia spectrum disorder poses a complex challenge in psychiatric treatment due to its multifaceted symptomatology. Modified AVATAR therapy, an innovative virtual reality-based intervention integrating Cognitive Behavioral Therapy (CBT) techniques such as systematic desensitization, and Acceptance and Commitment Therapy (ACT) approach offers a promising avenue for addressing auditory verbal hallucinations (AVH). This case series report investigates the acceptability and feasibility of a modified AVATAR therapy in three patients diagnosed with schizophrenia spectrum disorder who experience distressing AVH. The study provides detailed demographic and clinical information, outlines the modified AVATAR therapy protocol, and presents outcomes measured through standardized assessments. The findings indicate a decrease in the severity of AVHs, along with enhancements in overall symptomatology after modified AVATAR therapy sessions. Moreover, qualitative perspectives from patients shed light on their favorable experiences and perceptions of this adapted intervention. Nonetheless, the results exhibited inconsistency across individual cases, underscoring challenges for future research and clinical applications in this domain. Nevertheless, in light of the hurdles accompanying the rehabilitation of schizophrenia patients, along with the evaluation and subsequent measurement of parameters affecting efficacy, modified AVATAR therapy could present a valuable addition to schizophrenia patient care.

Pharmacological Treatments of Negative Symptoms in Schizophrenia-An Update

Schizophrenia is a chronic psychotic disorder comprising positive symptoms, negative symptoms, and cognitive deficits. Negative symptoms are associated with stigma, worse functional outcomes, and a significant deterioration in quality of life. Clinical diagnosis is challenging despite its significance, and current treatments offer little improvement in the burden of negative symptoms. This article reviews current pharmacological strategies for treating negative symptoms. Dopaminergic, glutamatergic, serotonergic, noradrenergic, cholinergic, anti-inflammatory compounds, hormones, and psychostimulants are explored. Finally, we review pharmacological global treatment guidelines for negative symptoms. In general, switching to a second-generation antipsychotic seems to be most often recommended for patients with schizophrenia on first-generation antipsychotics, and an add-on antidepressant is considered when depression is also present. However, the treatment of negative symptoms remains an unmet need. Future, larger clinical studies and meta-analyses are needed to establish effective pharmacological agents for the effective treatment of negative symptoms.

Advances in Mood Disorder Pharmacotherapy: Evaluating New Antipsychotics and Mood Stabilizers for Bipolar Disorder and Schizophrenia

This article provides a narrative review of recent developments in mood-stabilizing drugs, considering their mechanism of action, efficacy, safety, and therapeutic potential in the treatment of mood disorders, particularly bipolar disorder and schizophrenia. The review focuses on the mechanism and clinical aspects of second-generation antipsychotic medications; aripiprazole, classified as a third-generation antipsychotic medication; lamotrigine, as a representative of antiepileptic drugs; and lurasidone, a novel second-generation antipsychotic medication. Moreover, the article refers to one of the newest and most highly effective normothymic drugs, cariprazine. The potential of new mood stabilizer candidates lumateperone and brexpiprazole is also presented. Covered topics include the clinical efficacy of new drugs in reducing manic and depressive symptoms during acute episodes, as well as their role in preventing relapse. In addition, we analyzed the incidence of adverse effects of each drug. Many of the new drugs have strong potential to be beneficial and safe in cases of many comorbidities, as they do not cause many adverse effects and do not require high doses of use. The results underscore the importance of ongoing and future research to better understand the action and efficacy of these mood stabilizers and their implications in the treatment of mood disorders, aiming to achieve euthymia and improve the quality of life of affected patients. In this article, we aim to review current drug treatments for the management of mood disorders, including bipolar disorder and schizophrenia.

Dysfunction of the NMDA Receptor in the Pathophysiology of Schizophrenia and/or the Pathomechanisms of Treatment-Resistant Schizophrenia

For several decades, the dopamine hypothesis contributed to the discovery of numerous typical and atypical antipsychotics and was the sole hypothesis for the pathophysiology of schizophrenia. However, neither typical nor atypical antipsychotics, other than clozapine, have been effective in addressing negative symptoms and cognitive impairments, which are indices for the prognostic and disability outcomes of schizophrenia. Following the development of atypical antipsychotics, the therapeutic targets for antipsychotics expanded beyond the blockade of dopamine D2 and serotonin 5-HT2A receptors to explore the partial agonism of the D2 receptor and the modulation of new targets, such as D3, 5-HT1A, 5-HT7, and metabotropic glutamate receptors. Despite these efforts, to date, psychiatry has not successfully developed antipsychotics with antipsychotic properties proven to be superior to those of clozapine. The glutamate hypothesis, another hypothesis regarding the pathophysiology/pathomechanism of schizophrenia, was proposed based on clinical findings that N-methyl-D-aspartate glutamate receptor (NMDAR) antagonists, such as phencyclidine and ketamine, induce schizophrenia-like psychotic episodes. Large-scale genome-wide association studies (GWASs) revealed that approximately 30% of the risk genes for schizophrenia (the total number was over one hundred) encode proteins associated with glutamatergic transmission. These findings supported the validation of the glutamate hypothesis, which was inspired by the clinical findings regarding NMDAR antagonists. Additionally, these clinical and genetic findings suggest that schizophrenia is possibly a syndrome with complicated pathomechanisms that are affected by multiple biological and genetic vulnerabilities. The glutamate hypothesis has been the most extensively investigated pathophysiology/pathomechanism hypothesis, other than the dopamine hypothesis. Studies have revealed the possibility that functional abnormalities of the NMDAR play important roles in the pathophysiology/pathomechanism of schizophrenia. However, no antipsychotics derived from the glutamatergic hypothesis have yet been approved for the treatment of schizophrenia or treatment-resistant schizophrenia. Considering the increasing evidence supporting the potential pro-cognitive effects of glutamatergic agents and the lack of sufficient medications to treat the cognitive impairments associated with schizophrenia, these previous setbacks cannot preclude research into potential novel glutamate modulators. Given this background, to emphasize the importance of the dysfunction of the NMDAR in the pathomechanism and/or pathophysiology of schizophrenia, this review introduces the increasing findings on the functional abnormalities in glutamatergic transmission associated with the NMDAR.

Aberrant glycosylation in schizophrenia: insights into pathophysiological mechanisms and therapeutic potentials

Schizophrenia (SCZ) is a severe neuropsychiatric disorder characterized by cognitive, affective, and social dysfunction, resulting in hallucinations, delusions, emotional blunting, and disordered thinking. In recent years, proteomics has been increasingly influential in SCZ research. Glycosylation, a key post-translational modification, can alter neuronal stability and normal signaling in the nervous system by affecting protein folding, stability, and cellular signaling. Recent research evidence suggests that abnormal glycosylation patterns exist in different brain regions in autopsy samples from SCZ patients, and that there are significant differences in various glycosylation modification types and glycosylation modifying enzymes. Therefore, this review explores the mechanisms of aberrant modifications of N-glycosylation, O-glycosylation, glycosyltransferases, and polysialic acid in the brains of SCZ patients, emphasizing their roles in neurotransmitter receptor function, synaptic plasticity, and neural adhesion. Additionally, the effects of antipsychotic drugs on glycosylation processes and the potential for glycosylation-targeted therapies are discussed. By integrating these findings, this review aims to provide a comprehensive perspective to further understand the role of aberrant glycosylation modifications in the pathophysiology of SCZ.

The Impact of Childhood Trauma on the Negative Symptoms of Schizophrenia

ABSTRACT

Schizophrenia is a debilitating mental health disorder that imposes profound economic, societal, and personal burdens. The negative symptoms of schizophrenia ( i.e. , blunted affect, alogia, anhedonia, asociality, and avolition) are highly prevalent and pervasive in the psychotic disorder and pose significant resistance to available treatment options. Traumatic childhood experiences are strongly linked with the risk of developing schizophrenia. Most prior studies have primarily focused on positive symptoms of schizophrenia ( e.g. , hallucinations and delusions), whereas less attention has been given to negative symptoms. The current study investigated the relationship between childhood trauma ( i.e. , physical abuse, sexual abuse, and emotional abuse and neglect) and negative symptoms in a sample of schizophrenia outpatients and healthy controls ( n = 159 participants, including 99 patients with schizophrenia). The observations from the current study revealed that schizophrenia patients experienced a significantly greater degree of childhood trauma and negative symptoms than the control individuals. The results of the current study also indicated that more severe experiences of total childhood trauma ( i.e. , summation of all trauma types), physical abuse, and emotional neglect may increase the risk of schizophrenia patients reporting negative symptoms. However, childhood sexual and emotional abuse was found to have no impact on the degree of negative symptoms experienced by schizophrenia patients. Implications and limitations of the current study are discussed. In conclusion, we found that the severity of overall childhood trauma, physical abuse, and emotional neglect may play an important role in increasing the likelihood of schizophrenia patients reporting negative symptoms.

Risperidone-cyclodextrin complex reservoir combined with hydrogel-forming microneedle array patches for enhanced transdermal delivery

Hydrogel-forming microneedle array patches (HFMAPs) are microneedles that create microconduits upon insertion and swelling in the skin, potentially allowing prolonged drug delivery without generating sharps waste. Delivering hydrophobic drugs using HFMAPs poses challenges, which can be addressed using solubility enhancers such as cyclodextrins (CDs). This study aimed to deliver risperidone (RIS) transdermally using HFMAPs. To enhance the aqueous solubility of RIS hydroxypropyl-beta-cyclodextrin (HP-β-CD) and hydroxypropyl-gamma-cyclodextrin (HP-γ-CD) were utilised and their performance was tested using phase solubility studies. The aqueous solubility of RIS was enhanced by 4.75-fold and 2-fold using HP-β-CD and HP-γ-CD, respectively. RIS-HP-β-CD complex (CX) and physical mixture (PM) directly compressed tablets were prepared and combined with HFMAPs. Among the tested formulations, RIS-HP-β-CD PM reservoirs with 11 x 11 PVA/PVP HFMAPs exhibited the best performance in ex vivo studies and were further evaluated in in vivo experiments using female Sprague Dawley rats. The extended wear time of the MAPs resulted in the sustained release of RIS and its active metabolite 9-hydroxyrisperidone (9-OH-RIS) in plasma samples, lasting from 3 to 5 days with a 1-day application and up to 10 days with a 5-day application. For a 1-day application, HFMAPs showed greater systemic exposure to RIS compared to intramuscular control (AUC0-t: 13330.05 ± 2759.95 ng/mL/hour versus 2706 ± 1472 ng/mL/hour). Moreover, RIS exposure was extended to 5 days (AUC0-t: 12292.37 ± 1801.94 ng/mL/hour). In conclusion, HFMAPs could serve as an alternative for delivering RIS in a sustained manner, potentially improving the treatment of schizophrenia.

Development of a simultaneous LC-MS/MS analytical method for plasma: 16 antipsychotics approved in Japan and 4 drug metabolites

The increased risk of adverse drug reactions due to the concomitant use of antipsychotics is problematic in the treatment of schizophrenia. Therefore, the simultaneous analysis of their plasma concentrations is required. In this study, we developed a simultaneous liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for analyzing plasma antipsychotics approved in Japan for therapeutic drug monitoring (TDM) applications. First, we counted the prescriptions for 16 antipsychotics and concomitant drugs used at the Tohoku University Hospital. LC-MS/MS was used for the simultaneous analysis of 16 antipsychotics and four drug metabolites. This analysis was conducted using a combination of selected reaction monitoring mode and reversed-phase chromatography. Following the examination of the MS/MS and LC conditions, an analytical method validation test was conducted. The developed method was used to analyze plasma antipsychotic levels in patients with schizophrenia. One-third of the patients received treatment with multiple antipsychotics. Under LC-MS/MS conditions, LC separation was performed using a combination of a C18 column and ammonium formate-based mobile phases with a gradient flow. The calibration curves were optimized by adjusting the ion abundance, and 11 compounds met the criteria for intra- and inter-day reproducibility tests. Some stability test results did not meet these criteria; therefore, further investigation is required. The developed method permitted the measurement of all the plasma parameters, including concentrations above the therapeutic range. Therefore, this method may be useful in the daily TDM practice of antipsychotics.

Human endogenous retroviruses type W (HERV-) activation and schizophrenia: A meta-analysis

OBJECTIVE

Human endogenous retroviruses (HERV) are the remnants of infections that occurred million years ago. They gradually integrated into the human genome, comprising 8 % of it. There are growing reports suggesting their potential role in various diseases, including schizophrenia. Schizophrenia, a serious psychiatric disorder, is caused by the interaction of genetic and environmental factors. In the present paper, we investigated studies focusing on the association between schizophrenia and HERV-W.

METHODS

We registered this study at PROSPERO (registration number: CRD42022301122). The entire steps of this study were based on the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. We searched PubMed, Scopus, Web of Science, and Google Scholar up to 1 August 2022. Heterogeneity was estimated through I2 statistics, and the association was measured using the first estimate and penalization methods.

RESULTS

Finally, 13 eligible studies were analyzed, including 698 cases and 728 controls. The overall odds ratio indicated a significant association in both the first estimate (OR = 9.34, 95 % CI = 4.92-17.75; P = 0.002) and penalization (OR = 7.38, 95 % CI = 4.15-13.10; P = 0.003) methods. In the subgroup analysis, among HERV-W fragments, the HERV-W envelope protein or RNA (OR = 11.41, 95 % CI: 5.67-22.97; P = 0.03) showed the strongest association with schizophrenia.

CONCLUSION

Our meta-analysis showed that HERV-W is significantly associated with schizophrenia. More studies are required to determine the pathophysiological mechanism and the diagnostic, prognostic, and therapeutic value of HERV-W in schizophrenia.

Second-generation antipsychotic quetiapine blocks voltage-dependent potassium channels in coronary arterial smooth muscle cells

Voltage-dependent K+ (Kv) channels play an important role in restoring the membrane potential to its resting state, thereby maintaining vascular tone. In this study, native smooth muscle cells from rabbit coronary arteries were used to investigate the inhibitory effect of quetiapine, an atypical antipsychotic agent, on Kv channels. Quetiapine showed a concentration-dependent inhibition of Kv channels, with an IC50 of 47.98 ± 9.46 μM. Although quetiapine (50 μM) did not alter the steady-state activation curve, it caused a negative shift in the steady-state inactivation curve. The application of 1 and 2 Hz train steps in the presence of quetiapine significantly increased the inhibition of Kv current. Moreover, the recovery time constants from inactivation were prolonged in the presence of quetiapine, suggesting that its inhibitory action on Kv channels is use (state)-dependent. The inhibitory effects of quetiapine were not significantly affected by pretreatment with Kv1.5, Kv2.1, and Kv7 subtype inhibitors. Based on these findings, we conclude that quetiapine inhibits Kv channels in both a concentration- and use (state)-dependent manner. Given the physiological significance of Kv channels, caution is advised in the use of quetiapine as an antipsychotic due to its potential side effects on cardiovascular Kv channels.

Beyond dopamine: Novel strategies for schizophrenia treatment

Despite extensive research efforts aimed at discovering novel antipsychotic compounds, a satisfactory pharmacological strategy for schizophrenia treatment remains elusive. All the currently available drugs act by modulating dopaminergic neurotransmission, leading to insufficient management of the negative and cognitive symptoms of the disorder. Due to these challenges, several attempts have been made to design agents with innovative, non-dopaminergic mechanisms of action. Consequently, a number of promising compounds are currently progressing through phases 2 and 3 of clinical trials. This review aims to examine the rationale behind the most promising of these strategies while simultaneously providing a comprehensive survey of study results. We describe the versatility behind the cholinergic neurotransmission modulation through the activation of M1 and M4 receptors, exemplified by the prospective drug candidate KarXT. Our discussion extends to the innovative approach of activating TAAR1 receptors via ulotaront, along with the promising outcomes of iclepertin, a GlyT-1 inhibitor with the potential to become the first treatment option for cognitive impairment associated with schizophrenia. Finally, we evaluate the 5-HT2A antagonist paradigm, assessing two recently developed serotonergic agents, pimavanserin and roluperidone. We present the latest advancements in developing novel solutions to the complex challenges posed by schizophrenia, offering an additional perspective on the diverse investigated drug candidates.

A Global, Regional, and National Burden and Quality of Care Index for Schizophrenia: Global Burden of Disease Systematic Analysis 1990-2019

BACKGROUND AND HYPOTHESIS

Schizophrenia is a mental disorder usually presented in adulthood that affects roughly 0.3 percent of the population. The disease contributes to more than 13 million years lived with disability the global burden of disease. The current study aimed to provide new insights into the quality of care in Schizophrenia via the implementation of the newly introduced quality of care index (QCI) into the existing data.

STUDY DESIGN

The data from the global burden of disease database was used for schizophrenia. Two secondary indices were calculated from the available indices and used in a principal component analysis to develop a proxy of QCI for each country. The QCI was then compared between different sociodemographic index (SDI) and ages. To assess the disparity in QCI between the sexes, the gender disparity ratio (GDR) was also calculated and analyzed in different ages and SDIs.

STUDY RESULTS

The global QCI proxy score has improved between 1990 and 2019 by roughly 13.5%. Concerning the gender disparity, along with a rise in overall GDR the number of countries having a GDR score of around one has decreased which indicates an increase in gender disparity regarding quality of care of schizophrenia. Bhutan and Singapore had 2 of the highest QCIs in 2019 while also showing GDR scores close to one.

CONCLUSIONS

While the overall conditions in the quality of care have improved, significant disparities and differences still exist between different countries, genders, and ages in the quality of care regarding schizophrenia.

The double-edged nature of nicotine: toxicities and therapeutic potentials

Nicotine is the primary addictive component of cigarette smoke and is associated with various smoking-related diseases. However, recent research has revealed its broader cognitive-enhancing and anti-inflammatory properties, suggesting its potential therapeutic applications in several conditions. This review aims to examine the double-edged nature of nicotine, encompassing its positive and negative effects. We provide a concise overview of the physiochemical properties and pharmacology of nicotine, including insights into nicotine receptors. Therefore, the article is divided into two main sections: toxicity and therapeutic potential. We comprehensively explored nicotine-related diseases, focusing on specific signaling pathways and the underlying mechanisms that contribute to its effects. Furthermore, we addressed the current research challenges and future development perspectives. This review aims to inspire future researchers to explore the full medical potential of nicotine, which holds significant promise for the clinical management of specific diseases.

Natural Product-Inspired Dopamine Receptor Ligands

Due to their evolutionary bias as ligands for biologically relevant drug targets, natural products offer a unique opportunity as lead compounds in drug discovery. Given the involvement of dopamine receptors in various physiological and behavioral functions, they are linked to numerous diseases and disorders such as Parkinson's disease, schizophrenia, and substance use disorders. Consequently, ligands targeting dopamine receptors hold considerable therapeutic and investigative promise. As this perspective will highlight, dopamine receptor targeting natural products play a pivotal role as scaffolds with unique and beneficial pharmacological properties, allowing for natural product-inspired drug design and lead optimization. As such, dopamine receptor targeting natural products still have untapped potential to aid in the treatment of disorders and diseases related to central nervous system (CNS) and peripheral nervous system (PNS) dysfunction.

Micro-Infusion of 5-HT1a Receptor Antagonists into the Ventral Subiculum Ameliorate MK-801 Induced Schizophrenia-Like Behavior in Rats

Recent studies have shown that the 5-HT1a receptor (5-HT1aR) in the central 5-HT (Serotonergic) system is involved in the pathophysiology of schizophrenia through its various receptors, and the dysfunction of the ventral hippocampus may be a key causative factor in schizophrenia. To date, whether the 5-HT1a receptor is involved in ventral hippocampal dysfunction and its internal mechanism remain unclear. In this study, schizophrenia-like animal model was induced by intraperitoneal injection of aspartate receptor antagonist MK-801 in male Sprague Dawley rats, and the role of 5-HT1aR in this animal model was investigated by bilaterally micro-infusing the 5-HT1aR antagonist WAY100635 into the ventral subiculum (vSub) of the hippocampus of rats. Behavioral experiments such as open field test (OFT) and prepulse inhibition (PPI) were performed. The results showed that MK-801 induced hyperactivity and impaired prepulse inhibition in rats, whereas, micro-infusion of 5-HT1aR antagonist WAY100635 into the vSub ameliorated these phenomena. Immunofluorescence analysis revealed that WAY100635 significantly increased the c-Fos expression in vSub. Western blot and immunohistochemical analysis showed that MK-801 induced up-regulation of 5-HT1aR and phospho-extracellular regulated protein kinase (p-ERK) pathway, while micro-infusion of the WAY100635 down-regulated 5-HT1aR and p-ERK in the vSub. Therefore, the results of the present study suggested that in vSub, the 5-HT1aR antagonist WAY100635 may attenuate MK-801-induced schizophrenia-like activity by modulating excitatory neurons and downregulating p-ERK.

Relationship between human oral microbiome dysbiosis and neuropsychiatric diseases: An updated overview

The role of the gut-brain axis in mental health disorders has been extensively studied. As the oral cavity is the starting point of the digestive tract, the role that the oral microbiota plays in mental health disorders has gained recent attention. Oral microbiota can enter the bloodstream and trigger inflammatory responses or translocate to the brain through the trigeminal nerve or olfactory system. Hence, the concept of the oral microbiota-brain axis has emerged. Several hypotheses have been suggested that the oral microbiota can enter the gastrointestinal tract and affect the gut-brain axis; however, literature describing oral-brain communication remains limited. This review summarizes the characteristics of oral microbiota and its mechanisms associated with mental health disorders. Through a comprehensive examination of the relationship between oral microbiota and various neuropsychiatric diseases, such as anxiety, depression, schizophrenia, autism spectrum disorder, epilepsy, Parkinson's disease, and dementia, this review seeks to identify promising avenues of future research.

Unlocking new avenues for neuropsychiatric disease therapy: the emerging potential of Peroxisome proliferator-activated receptors as promising therapeutic targets

RATIONALE

Peroxisome proliferator-activated receptors (PPARs) are transcription factors that regulate various physiological processes such as inflammation, lipid metabolism, and glucose homeostasis. Recent studies suggest that targeting PPARs could be beneficial in treating neuropsychiatric disorders by modulating neuronal function and signaling pathways in the brain. PPAR-α, PPAR-δ, and PPAR-γ have been found to play important roles in cognitive function, neuroinflammation, and neuroprotection. Dysregulation of PPARs has been associated with neuropsychiatric disorders like bipolar disorder, schizophrenia, major depression disorder, and autism spectrum disorder. The limitations and side effects of current treatments have prompted research to target PPARs as a promising novel therapeutic strategy. Preclinical and clinical studies have shown the potential of PPAR agonists and antagonists to improve symptoms associated with these disorders.

OBJECTIVE

This review aims to provide an overview of the current understanding of PPARs in neuropsychiatric disorders, their potential as therapeutic targets, and the challenges and future directions for developing PPAR-based therapies.

METHODS

An extensive literature review of various search engines like PubMed, Medline, Bentham, Scopus, and EMBASE (Elsevier) databases was carried out with the keywords "PPAR, Neuropsychiatric disorders, Oxidative stress, Inflammation, Bipolar Disorder, Schizophrenia, Major depression disorder, Autism spectrum disorder, molecular pathway".

RESULT & CONCLUSION

Although PPARs present a hopeful direction for innovative therapeutic approaches in neuropsychiatric conditions, additional research is required to address obstacles and convert this potential into clinically viable and individualized treatments.

The importance of oxidative biomarkers in diagnosis, treatment, and monitoring schizophrenia patients

INTRODUCTION

The etiology of schizophrenia (SCZ), an incredibly complex disorder, remains multifaceted. Literature suggests the involvement of oxidative stress (OS) in the pathophysiology of SCZ.

OBJECTIVES

Determination of selected OS markers and brain-derived neurotrophic factor (BDNF) in patients with chronic SCZ and those in states predisposing to SCZ-first episode psychosis (FP) and ultra-high risk (UHR).

MATERIALS AND METHODS

Determination of OS markers and BDNF levels by spectrophotometric methods and ELISA in 150 individuals (116 patients diagnosed with SCZ or in a predisposed state, divided into four subgroups according to the type of disorder: deficit schizophrenia, non-deficit schizophrenia, FP, UHR). The control group included 34 healthy volunteers.

RESULTS

Lower activities of analyzed antioxidant enzymes and GSH and TAC concentrations were found in all individuals in the study group compared to controls (p < 0.001). BDNF concentration was also lower in all groups compared to controls except in the UHR subgroup (p = 0.01). Correlations were observed between BDNF, R-GSSG, GST, GPx activity, and disease duration (p < 0.02). A small effect of smoking on selected OS markers was also noted (rho<0.06, p < 0.03).

CONCLUSIONS

OS may play an important role in the pathophysiology of SCZ before developing the complete clinical pattern of the disorder. The redox imbalance manifests itself with such severity in individuals with SCZ and in a state predisposing to the development of this psychiatric disease that natural antioxidant systems become insufficient to compensate against it completely. The discussed OS biomarkers may support the SCZ diagnosis and predict its progression.

Multi-omics analysis reveals the impact of gut microbiota on antipsychotic-induced weight gain in schizophrenia

Emerging evidence indicates that gut microbial dysbiosis is associated with the development of antipsychotic-induced weight gain in schizophrenia (SZ). However, the exact taxonomic composition and functionality that constitute the "obesogenic" microbial profile remain elusive. Our retrospective survey identified two groups of the SZ population separated by BMI, with 1/3 of patients developing overweight/obesity after chronic antipsychotic treatment. Based on multi-omics analysis, we observed altered gut microbiota in SZ patients with overweight/obesity, characterized by a reduction in several beneficial bacteria genera, including Bacteroides, Parabacteroides, Akkermansia, and Clostridium. This microbial dysbiosis was accompanied by disrupted energy expenditure and nutritional metabolism, worsened metabolic indices, and reduced levels of beneficial metabolites, e.g. indole-3-carboxylic acid and propionic acid. Moreover, leveraging data from first-episode drug-naïve schizophrenia (FSZ) patients at one-month and one-year follow-up, both artificial neural network and random forest classifier-based prediction models demonstrated a strong ability of microbial profiles to predict antipsychotic-induced weight gain. Importantly, FSZ patients with higher relative abundance of Parabacteria distasonis were less susceptible to antipsychotic-induced weight gain. Thus, gut microbiota could serve as a noninvasive approach to predict antipsychotic-induced weight gain, guiding clinical antipsychotics administration and developing novel therapeutic strategies for weight management in SZ.

Dietary interventions to improve metabolic health in schizophrenia: A systematic literature review of systematic reviews

AIM

This review of systematic reviews synthesised evidence on the impact of dietary interventions on anthropometric and biochemical measures associated with schizophrenia and metabolic syndrome. Secondly, an aim to identify intervention elements associated with greater dietary adherence and behaviour change.

METHODS

Five databases were searched from 2000-March 2023. Eligible reviews included adults, majority diagnosed with schizophrenia, dietary intervention components and at least one anthropometric or biochemical outcome related to metabolic syndrome. Two independent reviewers performed article selection, data extraction, and quality assessment.

RESULTS

Seven systematic reviews, consisting of 79 unique primary papers were included. No reviews exclusively examined dietary interventions. Nutrition education and counselling administered alongside physical activity were common. All reviews favoured intervention over the control to reduce body weight, body mass index, and waist circumference. Glycaemic control, blood pressure and triglycerides were not routinely reported with mixed effects following interventions. There was insufficient data to examine any trends for dropout rates, dietary adherence, and behaviour change. There was both low (n = 3/7) and high (n = 4/7) risk of bias and degree of study overlap was very high (16.4 %). The level of evidence was rated as suggestive (n = 2/7), weak (n = 2/7), non-significant (n = 1/7) and ungraded (n = 2/7).

CONCLUSION

Dietary interventions administered alongside lifestyle therapies can reduce anthropometric measurements for consumers living with schizophrenia and prescribed antipsychotic medications. Higher quality reviews with greater strength and credibility of evidence are required. Uniform reporting of intervention elements is also necessary for cross comparison of efficacious elements and synthesis of evidence at higher levels to advance dietetic practice and inform future policies.

Influence of antipsychotic drugs on microRNA expression in schizophrenia patients - A systematic review

Schizophrenia (SCZ) is a severe psychiatric disorder with unclear pathophysiology. Moreover, there is no specific biological marker to help clinicians to define a diagnosis, and medication is decided according to the psychiatrist's experience. In this scenario, microRNAs (miRNAs), which are small noncoding RNA molecules that regulate several genes, emerge as potential peripheral biomarkers to help not only the evaluation of the disease state but also the treatment response. Here, we systematically reviewed indexed literature and evaluated follow-up studies investigating the changes in miRNA expression due to antipsychotic treatment. We also assessed target genes and performed pathway enrichment analysis of miRNAs listed in this systematic review. A total of 11 studies were selected according to research criteria, and we observed that 28 miRNAs play a relevant role in schizophrenia pathogenesis or response to antipsychotic treatment, seven of those of extreme interest as possible biomarkers either for condition or treatment. Predicted targets of the miRNAs reviewed here were previously associated with schizophrenia in genome-wide studies, and pathway analysis showed enrichment for genes related to neural processes. With this review, we expect to highlight the importance of miRNAs in schizophrenia pathogenesis and its treatment and point out interesting miRNAs to future studies.

The effect of second-generation antipsychotics on anxiety/depression in patients with schizophrenia: A systematic review and meta-analysis

OBJECTIVE

Despite the high prevalence of anxiety in schizophrenia, no established guideline exists for the management of these symptoms. We aimed to synthesize evidence on the effect of second-generation antipsychotics (SGAs) on anxiety in patients with schizophrenia.

METHODS

We systematically searched Medline, Embase, PsycInfo, Web of Science, PubMed, and Cochrane library to identify randomized controlled trials of SGAs that reporting anxiety measures in schizophrenia. The search was limited to English-language articles published before February 2024. Data were pooled using a random-effects model.

RESULTS

Among 48 eligible studies, 29 (n = 7712) were included in the meta-analyses comparing SGAs to placebo, haloperidol, or another SGAs for their effect on anxiety/depression. SGAs had a small effect on anxiety/depression versus placebo (SMD = -0.28 (95 % CI [-0.34, -0.21], p < .00001, I2 = 47 %, n = 5576)) associated with efficacy for positive (z = 5.679, p < .001) and negative symptoms (z = 4.490, p < .001). Furthermore, SGAs were superior to haloperidol (SMD = -0.44, 95 % CI [-0.75, -0.13], p = .005, n = 1068) with substantial study-level heterogeneity (I2 = 85 %). Excluding one study of quetiapine in first-episode patients (SMD = -3.05, n = 73), SGAs showed a small effect on anxiety/depression versus haloperidol without heterogeneity (SMD = -0.23, 95 % CI [-0.35, -0.12], p = 01; I2 = %0). Risperidone's effect on anxiety/depression was comparable to olanzapine (SMD = -0.02, 95 % CI [-0.24,0.20], p = .87, I2 = 45 %, n = 753) and amisulpride (SMD = 0.27, 95 % CI [-1.08,0.61], p = .13, I2 = 50 %, n = 315).

CONCLUSION

While SGAs showed a small effect on anxiety/depression, the findings are inconclusive due to scarcity of research on comorbid anxiety in schizophrenia, heterogeneity of anxiety symptoms, and the scales used to measure anxiety. Further studies employing specific anxiety scales are required to explore antipsychotics, considering their receptor affinity and augmentation with serotonin/norepinephrine reuptake inhibitors or benzodiazepines for managing anxiety in schizophrenia.

What Remains to Be Discovered in Schizophrenia Therapeutics: Contributions by Advancing the Molecular Mechanisms of Drugs for Psychosis and Schizophrenia

Schizophrenia is a frequently debilitating and complex mental disorder affecting approximately 1% of the global population, characterized by symptoms such as hallucinations, delusions, disorganized thoughts and behaviors, cognitive dysfunction, and negative symptoms. Traditional treatment has centered on postsynaptic dopamine antagonists, commonly known as antipsychotic drugs, which aim to alleviate symptoms and improve functioning and the quality of life. Despite the availability of these medications, significant challenges remain in schizophrenia therapeutics, including incomplete symptom relief, treatment resistance, and medication side effects. This opinion article explores advancements in schizophrenia treatment, emphasizing molecular mechanisms, novel drug targets, and innovative delivery methods. One promising approach is novel strategies that target neural networks and circuits rather than single neurotransmitters, acknowledging the complexity of brain region interconnections involved in schizophrenia. Another promising approach is the development of biased agonists, which selectively activate specific signaling pathways downstream of receptors, offering potential for more precise pharmacological interventions with fewer side effects. The concept of molecular polypharmacy, where a single drug targets multiple molecular pathways, is exemplified by KarXT, a novel drug combining xanomeline and trospium to address both psychosis and cognitive dysfunction. This approach represents a comprehensive strategy for schizophrenia treatment, potentially improving outcomes for patients. In conclusion, advancing the molecular understanding of schizophrenia and exploring innovative therapeutic strategies hold promise for addressing the unmet needs in schizophrenia treatment, aiming for more effective and tailored interventions. Future research should focus on these novel approaches to achieve better clinical outcomes and improve the functional level and quality of life for individuals with schizophrenia.

Current Findings and Potential Mechanisms of KarXT (Xanomeline-Trospium) in Schizophrenia Treatment

Standard schizophrenia treatment involves antipsychotic medications that target D2 dopamine receptors. However, these drugs have limitations in addressing all symptoms and can lead to adverse effects such as motor impairments, metabolic effects, sedation, sexual dysfunction, cognitive impairment, and tardive dyskinesia. Recently, KarXT has emerged as a novel drug for schizophrenia. KarXT combines xanomeline, a muscarinic receptor M1 and M4 agonist, with trospium, a nonselective antimuscarinic agent. Of note, xanomeline can readily cross blood-brain barrier (BBB) and, thus, enter into the brain, thereby stimulating muscarinic receptors (M1 and M4). By doing so, xanomeline has been shown to target negative symptoms and potentially improve positive symptoms. Trospium, on the other hand, is not able to cross BBB, thereby not affecting M1 and M4 receptors; instead, it acts as an antimuscarinic agent and, hence, diminishes peripheral activity of muscarinic receptors to minimize side effects probably stemming from xanomeline in other organs. Accordingly, ongoing clinical trials investigating KarXT's efficacy in schizophrenia have demonstrated positive outcomes, including significant improvements in the Positive and Negative Syndrome Scale (PANSS) total score and cognitive function compared with placebo. These findings emphasize the potential of KarXT as a promising treatment for schizophrenia, providing symptom relief while minimizing side effects associated with xanomeline monotherapy. Despite such promising evidence, further research is needed to confirm the efficacy, safety, and tolerability of KarXT in managing schizophrenia. This review article explores the current findings and potential mechanisms of KarXT in the treatment of schizophrenia.

Striatal GDNF Neurons Chemoattract RET-Positive Dopamine Axons at Seven Times Farther Distance Than Medium Spiny Neurons

Glial cell line-derived neurotrophic factor (GDNF) is among the strongest dopamine neuron function- and survival-promoting factors known. Due to this reason, it has clinical relevance in dopamine disorders such as Parkinson's disease and schizophrenia. In the striatum, GDNF is exclusively expressed in interneurons, which make up only about 0.6% of striatal cells. Despite clinical significance, histological analysis of striatal GDNF system arborization and relevance to incoming dopamine axons, which bear its receptor RET, has remained enigmatic. This is mainly due to the lack of antibodies able to visualize GDNF- and RET-positive cellular processes; here, we overcome this problem by using knock-in marker alleles. We find that GDNF neurons chemoattract RET+ axons at least seven times farther in distance than medium spiny neurons (MSNs), which make up 95% of striatal neurons. Furthermore, we provide evidence that tyrosine hydroxylase, the rate-limiting enzyme in dopamine synthesis, is enriched towards GDNF neurons in the dopamine axons. Finally, we find that GDNF neuron arborizations occupy approximately only twelve times less striatal volume than 135 times more abundant MSNs. Collectively, our results improve our understanding of how endogenous GDNF affects striatal dopamine system function.

Decoding Clozapine-Induced Agranulocytosis: Unraveling Interactions and Mitigation Strategies

Agranulocytosis represents a severe complication associated with the administration of clozapine. Clozapine is an antipsychotic medication that has demonstrated substantial efficacy in remediating refractory schizophrenia and various other psychiatric disorders. Nonetheless, it is crucial to monitor patients for neutropenia regularly during clozapine therapy. Therefore, this article aimed to delve into the prevalence of agranulocytosis during clozapine treatment by scrutinizing the extant literature to discern trends and correlations. This review endeavored to explore factors such as drug interactions, dose-related factors, duration of treatment, and genetic predispositions that could potentially influence the likelihood of patients developing agranulocytosis while undergoing clozapine therapy. Moreover, this review enunciates the ramifications of agranulocytosis on both patients and healthcare providers and meticulously evaluates the strategies to mitigate this risk and ensure optimal patient outcomes.

Optogenetic inhibition of the limbic corticothalamic circuit does not alter spontaneous oscillatory activity, auditory-evoked oscillations, and deviant detection

Aberrant neuronal circuit dynamics are at the core of complex neuropsychiatric disorders, such as schizophrenia (SZ). Clinical assessment of the integrity of neuronal circuits in SZ has consistently described aberrant resting-state gamma oscillatory activity, decreased auditory-evoked gamma responses, and abnormal mismatch responses. We hypothesized that corticothalamic circuit manipulation could recapitulate SZ circuit phenotypes in rodent models. In this study, we optogenetically inhibited the mediodorsal thalamus-to-prefrontal cortex (MDT-to-PFC) or the PFC-to-MDT projection in rats and assessed circuit function through electrophysiological readouts. We found that MDT-PFC perturbation could not recapitulate SZ-linked phenotypes such as broadband gamma disruption, altered evoked oscillatory activity, and diminished mismatch negativity responses. Therefore, the induced functional impairment of the MDT-PFC pathways cannot account for the oscillatory abnormalities described in SZ.

Effects of Visual Art Therapy on Positive Symptoms, Negative Symptoms, and Emotions in Individuals with Schizophrenia: A Systematic Review and Meta-Analysis

Schizophrenia is characterized by psychiatric symptoms and emotional issues. While pharmacological treatments have limitations, non-pharmacological interventions are essential. Art therapy has the potential to enhance emotional expression, communication, and health; however, the effectiveness of visual art therapy remains uncertain. This systematic review and meta-analysis synthesizes the findings of randomized controlled trials (RCTs) of visual art therapy on positive symptoms, negative symptoms, and emotions in patients with schizophrenia. This study reviews RCTs published prior to February, 2024. The PubMed, Embase, Cochrane Library, CEPS, CNKI, Wanfang, and Yiigle databases were searched, and three independent researchers screened the studies. In this meta-analysis, standardized mean difference (SMD) was employed as a measure to calculate effect sizes for continuous variables using a random effects model, while the meta-regression and subgroup analyses were performed with patient and intervention characteristics. A total of 31 studies revealed visual art therapy had a significant small-to-moderate effect on positive symptoms (SMD = 0.407, 95% CI 0.233 to 0.581), a moderate effect on negative symptoms (SMD = 0.697, 95% CI 0.514 to 0.880), a moderate effect on depression (SMD = 0.610, 95% CI 0.398 to 0.821), and a large effect on anxiety (SMD = 0.909, 95% CI 0.386 to 1.433). The subgroup analysis revealed painting and handcrafts had significant effects on positive symptoms, negative symptoms, and emotions. Combined Chinese calligraphy and painting had significant effects on positive symptoms, depression, and anxiety. Better improvement was noted among the Asian population, and a longer weekly treatment duration was associated with better improvement in positive symptoms. Female participants tended to have more improvements in negative symptoms and anxiety through visual art therapy. The results indicate that visual art therapy has positive effects on the psychiatric symptoms and emotions of individuals with schizophrenia. We recommend future research further investigate art therapy modalities and durations.

A systematic chart review of pharmacological interventions in patients with clozapine-induced hypersalivation

OBJECTIVES

To investigate the efficacy and tolerability of medications, such as mouthwash use of 1 % atropine sulfate and tropicamide drops, oral amitriptyline and amisulpride used for clozapine-induced hypersalivation (CIH).

METHODS

The medical charts of inpatients with psychotic disorders between 2010 and 2022 were reviewed retrospectively. We detected 161 patients with eligible data who received or commenced clozapine. Primary outcome was defined as the percentage change in the diameter of a wet patch on the pillow (DWP) for improvements in CIH.

RESULTS

The frequency of CIH was 42 % (n = 68). The first step medications for CIH were tropicamide drops (49 %), atropine drops (43 %) and amitriptyline (3 %). After the first step, the median DWP significantly decreased by -33 %. During the index hospitalization, in 18 patients with persistent CIH, the median DWP significantly decreased by -42 % with the second step medications which also included amisulpride. There were no reported serious adverse events. The change in DWP was significantly correlated with the duration of clozapine treatment (r = 306) and clozapine serum level at discharge (r = 0.294). A linear regression model showed a link between the change in DWP and reduced Positive and Negative Syndrome Scale scores.

CONCLUSIONS

Our findings emphasize that mouthwash use of atropine or tropicamide drops has a satisfying and tolerable effect in treating CIH. Switching medications for CIH seems to be effective when CIH persists despite a first step agent. Controlled follow-up studies are needed to understand the relationship between CIH, clozapine serum levels, illness severity, and functioning.

Association of histone modification with the development of schizophrenia

Schizophrenia, influenced by genetic and environmental factors, may involve epigenetic alterations, notably histone modifications, in its pathogenesis. This review summarizes various histone modifications including acetylation, methylation, phosphorylation, ubiquitination, serotonylation, lactylation, palmitoylation, and dopaminylation, and their implications in schizophrenia. Current research predominantly focuses on histone acetylation and methylation, though other modifications also play significant roles. These modifications are crucial in regulating transcription through chromatin remodeling, which is vital for understanding schizophrenia's development. For instance, histone acetylation enhances transcriptional efficiency by loosening chromatin, while increased histone methyltransferase activity on H3K9 and altered histone phosphorylation, which reduces DNA affinity and destabilizes chromatin structure, are significant markers of schizophrenia.

The antipsychotic agent sulpiride microinjected into the ventral pallidum restores positive symptom-like habituation disturbance in MAM-E17 schizophrenia model rats

Dysfunction of subcortical D2-like dopamine receptors (D2Rs) can lead to positive symptoms of schizophrenia, and their analog, the increased locomotor activity in schizophrenia model MAM-E17 rats. The ventral pallidum (VP) is a limbic structure containing D2Rs. The D2R antagonist sulpiride is a widespread antipsychotic drug, which can alleviate positive symptoms in human patients. However, it is still not known how sulpiride can influence positive symptoms via VP D2Rs. We hypothesize that the microinjection of sulpiride into the VP can normalize hyperactivity in MAM-E17 rats. In addition, recently, we showed that the microinjection of sulpirid into the VP induces place preference in neurotypical rats. Thus, we aimed to test whether intra-VP sulpiride can also have a rewarding effect in MAM-E17 rats. Therefore, open field-based conditioned place preference (CPP) test was applied in neurotypical (SAL-E17) and MAM-E17 schizophrenia model rats to test locomotor activity and the potential locomotor-reducing and rewarding effects of sulpiride. Sulpiride was microinjected bilaterally in three different doses into the VP, and the controls received only vehicle. The results of the present study demonstrated that the increased locomotor activity of the MAM-E17 rats was caused by habituation disturbance. Accordingly, larger doses of sulpiride in the VP reduce the positive symptom-analog habituation disturbance of the MAM-E17 animals. Furthermore, we showed that the largest dose of sulpiride administered into the VP induced CPP in the SAL-E17 animals but not in the MAM-E17 animals. These findings revealed that VP D2Rs play an important role in the formation of positive symptom-like habituation disturbances in MAM-E17 rats.