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Rawani NS, Chan AW, Dursun SM, Baker GB. The Underlying Neurobiological Mechanisms of Psychosis: Focus on Neurotransmission Dysregulation, Neuroinflammation, Oxidative Stress, and Mitochondrial Dysfunction. Antioxidants (Basel) 2024; 13:709. [PMID: 38929148 PMCID: PMC11200831 DOI: 10.3390/antiox13060709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 05/16/2024] [Accepted: 05/28/2024] [Indexed: 06/28/2024] Open
Abstract
Psychosis, defined as a set of symptoms that results in a distorted sense of reality, is observed in several psychiatric disorders in addition to schizophrenia. This paper reviews the literature relevant to the underlying neurobiology of psychosis. The dopamine hypothesis has been a major influence in the study of the neurochemistry of psychosis and in development of antipsychotic drugs. However, it became clear early on that other factors must be involved in the dysfunction involved in psychosis. In the current review, it is reported how several of these factors, namely dysregulation of neurotransmitters [dopamine, serotonin, glutamate, and γ-aminobutyric acid (GABA)], neuroinflammation, glia (microglia, astrocytes, and oligodendrocytes), the hypothalamic-pituitary-adrenal axis, the gut microbiome, oxidative stress, and mitochondrial dysfunction contribute to psychosis and interact with one another. Research on psychosis has increased knowledge of the complexity of psychotic disorders. Potential new pharmacotherapies, including combinations of drugs (with pre- and probiotics in some cases) affecting several of the factors mentioned above, have been suggested. Similarly, several putative biomarkers, particularly those related to the immune system, have been proposed. Future research on both pharmacotherapy and biomarkers will require better-designed studies conducted on an all stages of psychotic disorders and must consider confounders such as sex differences and comorbidity.
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Affiliation(s)
| | | | | | - Glen B. Baker
- Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2G3, Canada; (N.S.R.); (A.W.C.); (S.M.D.)
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Lv Y, Wen L, Hu WJ, Deng C, Ren HW, Bao YN, Su BW, Gao P, Man ZY, Luo YY, Li CJ, Xiang ZX, Wang B, Luan ZL. Schizophrenia in the genetic era: a review from development history, clinical features and genomic research approaches to insights of susceptibility genes. Metab Brain Dis 2024; 39:147-171. [PMID: 37542622 DOI: 10.1007/s11011-023-01271-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 07/27/2023] [Indexed: 08/07/2023]
Abstract
Schizophrenia is a devastating neuropsychiatric disorder affecting 1% of the world population and ranks as one of the disorders providing the most severe burden for society. Schizophrenia etiology remains obscure involving multi-risk factors, such as genetic, environmental, nutritional, and developmental factors. Complex interactions of genetic and environmental factors have been implicated in the etiology of schizophrenia. This review provides an overview of the historical origins, pathophysiological mechanisms, diagnosis, clinical symptoms and corresponding treatment of schizophrenia. In addition, as schizophrenia is a polygenic, genetic disorder caused by the combined action of multiple micro-effective genes, we further detail several approaches, such as candidate gene association study (CGAS) and genome-wide association study (GWAS), which are commonly used in schizophrenia genomics studies. A number of GWASs about schizophrenia have been performed with the hope to identify novel, consistent and influential risk genetic factors. Finally, some schizophrenia susceptibility genes have been identified and reported in recent years and their biological functions are also listed. This review may serve as a summary of past research on schizophrenia genomics and susceptibility genes (NRG1, DISC1, RELN, BDNF, MSI2), which may point the way to future schizophrenia genetics research. In addition, depending on the above discovery of susceptibility genes and their exact function, the development and application of antipsychotic drugs will be promoted in the future.
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Affiliation(s)
- Ye Lv
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, 116044, China
| | - Lin Wen
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, 116044, China
| | - Wen-Juan Hu
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, 116044, China
| | - Chong Deng
- Department of Neurosurgery, The Second Affiliated Hospital of Dalian Medical University, Dalian, 116027, China
| | - Hui-Wen Ren
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, 116044, China
| | - Ya-Nan Bao
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, 116044, China
| | - Bo-Wei Su
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, 116044, China
| | - Ping Gao
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, 116044, China
| | - Zi-Yue Man
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, 116044, China
| | - Yi-Yang Luo
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, 116044, China
| | - Cheng-Jie Li
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, 116044, China
| | - Zhi-Xin Xiang
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, 116044, China
| | - Bing Wang
- Department of Endocrinology and Metabolism, The Central hospital of Dalian University of Technology, Dalian, 116000, China.
| | - Zhi-Lin Luan
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, 116044, China.
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Khan MM, Parikh V. Prospects for Neurotrophic Factor-Based Early Intervention in Schizophrenia: Lessons Learned from the Effects of Antipsychotic Drugs on Cognition, Neurogenesis, and Neurotrophic Factors. CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2023; 22:289-303. [PMID: 35366786 DOI: 10.2174/1871527321666220401124151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 02/13/2022] [Accepted: 02/18/2022] [Indexed: 12/16/2022]
Abstract
Although reducing psychotic symptoms in schizophrenia has been a major focus of therapeutic interventions for decades, improving cognition is considered a better predictor of functional outcomes. However, the most commonly prescribed antipsychotic drugs (APDs) show only marginal beneficial effects on cognition in patients with schizophrenia. The neural mechanisms underlying cognitive disturbances in schizophrenia remain unknown that making drug development efforts very challenging. Since neurotrophic factors are the primary architects of neurogenesis, synaptic plasticity, learning, and memory, the findings from preclinical and clinical studies that assess changes in neurogenesis and neurotrophic factors and their relationship to cognitive performance in schizophrenia, and how these mechanisms might be impacted by APD treatment, may provide valuable clues in developing therapies to combat cognitive deficit in schizophrenia. Numerous evidence produced over the years suggests a deficit in a wide spectrum of neurotrophic factors in schizophrenia. Since schizophrenia is considered a neurodevelopmental disorder, early intervention with neurotrophic factors may be more effective in ameliorating the cognitive deficits and psychopathological symptoms associated with this pathology. In this context, results from initial clinical trials with neurotrophic factors and their future potential to improve cognition and psychosocial functioning in schizophrenia are discussed.
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Affiliation(s)
- Mohammad M Khan
- Laboratory of Translational Neurology and Molecular Psychiatry, Department of Biotechnology, Era\'s Lucknow Medical College and Hospital, and Faculty of Science, Era University, Lucknow, UP, India
| | - Vinay Parikh
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA, USA
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Abstract
Schizophrenia is a severe and clinically heterogenous mental disorder
affecting approximately 1% of the population worldwide. Despite
tremendous achievements in the field of schizophrenia research, its
precise aetiology remains elusive. Besides dysfunctional neuronal
signalling, the pathophysiology of schizophrenia appears to involve
molecular and functional abnormalities in glial cells, including
astrocytes. This article provides a concise overview of the current
evidence supporting altered astrocyte activity in schizophrenia, which
ranges from findings obtained from post-mortem immunohistochemical
analyses, genetic association studies and transcriptomic
investigations, as well as from experimental investigations of
astrocyte functions in animal models. Integrating the existing data
from these research areas strongly suggests that astrocytes have the
capacity to critically affect key neurodevelopmental and homeostatic
processes pertaining to schizophrenia pathogenesis, including
glutamatergic signalling, synaptogenesis, synaptic pruning and
myelination. The further elucidation of astrocytes functions in health
and disease may, therefore, offer new insights into how these glial
cells contribute to abnormal brain development and functioning
underlying this debilitating mental disorder.
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Affiliation(s)
- Tina Notter
- Tina Notter, Institute of
Pharmacology and Toxicology, University of Zurich-Vetsuisse, Zurich,
Switzerland. Emails: ;
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Mei YY, Wu DC, Zhou N. Astrocytic Regulation of Glutamate Transmission in Schizophrenia. Front Psychiatry 2018; 9:544. [PMID: 30459650 PMCID: PMC6232167 DOI: 10.3389/fpsyt.2018.00544] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 10/12/2018] [Indexed: 01/19/2023] Open
Abstract
According to the glutamate hypothesis of schizophrenia, the abnormality of glutamate transmission induced by hypofunction of NMDA receptors (NMDARs) is causally associated with the positive and negative symptoms of schizophrenia. However, the underlying mechanisms responsible for the changes in glutamate transmission in schizophrenia are not fully understood. Astrocytes, the major regulatory glia in the brain, modulate not only glutamate metabolism but also glutamate transmission. Here we review the recent progress in understanding the role of astrocytes in schizophrenia. We focus on the astrocytic mechanisms of (i) glutamate synthesis via the glutamate-glutamine cycle, (ii) glutamate clearance by excitatory amino acid transporters (EAATs), (iii) D-serine release to activate NMDARs, and (iv) glutamatergic target engagement biomarkers. Abnormality in these processes is highly correlated with schizophrenia phenotypes. These findings will shed light upon further investigation of pathogenesis as well as improvement of biomarkers and therapies for schizophrenia.
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Affiliation(s)
- Yu-Ying Mei
- Translational Medicine Research Center, China Medical University Hospital, Taichung, Taiwan.,Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan
| | - Dong Chuan Wu
- Translational Medicine Research Center, China Medical University Hospital, Taichung, Taiwan.,Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan
| | - Ning Zhou
- Translational Medicine Research Center, China Medical University Hospital, Taichung, Taiwan.,Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan
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