A Novel Bio-Psychosocial-Behavioral Treatment Model in Schizophrenia

Effects of the mGlu2/3 receptor agonist LY379268 on two models of disturbed auditory evoked brain oscillations in mice

Cognitive impairment is a core feature of schizophrenia and is poorly addressed by currently available medication. This is partly because the underlying circuits are insufficiently understood, and available animal models for brain dysfunction do not adequately mimic human pathology. To improve the translatability of animal studies and complement behavioral data, EEG measurements are being increasingly used in preclinical research. Brain oscillations are similar across species and can be impaired via several means. In this study, we used two approaches to impair early sensory processing and cortical oscillations in mice: a pharmacological model targeting NMDA receptor function in the whole brain via systemic MK-801 application and an optogenetic model targeting parvalbumin-positive (PV+) interneurons locally in the medial prefrontal cortex (mPFC). We evoked brain activity using auditory stimulation, a tool with high translatability from mouse to human. We then investigated the effect of LY379268, an agonist of mGlu2/3 receptors, a potential therapeutic target for schizophrenia, on single neuron and EEG responses. LY379268 was able to rescue MK-801-induced deficits for a variety of clinically relevant early sensory EEG biomarkers. Single neuron recordings revealed a strong effect of LY379268 on the signal-to-noise ratio during auditory stimulation and optogenetic inhibition of PV+ interneurons. Our results contribute to a better understanding of how group II metabotropic glutamate receptors modulate neuronal population and network activity under sensory stimulation while challenged pharmacologically or optogenetically.

Network Analysis-Based Disentanglement of the Symptom Heterogeneity in Asian Patients with Schizophrenia: Findings from the Research on Asian Psychotropic Prescription Patterns for Antipsychotics

The symptom heterogeneity of schizophrenia is consistent with Wittgenstein's analogy of a language game. From the perspective of precision medicine, this study aimed to estimate the symptom presentation and identify the psychonectome in Asian patients, using data obtained from the Research on Asian Psychotropic Prescription Patterns for Antipsychotics. We constructed a network structure of the Brief Psychiatric Rating Scale (BPRS) items in 1438 Asian patients with schizophrenia. Furthermore, all the BPRS items were considered to be an ordered categorical variable ranging in value from 1-7. Motor retardation was situated most centrally within the BPRS network structure, followed by depressive mood and unusual thought content. Contrastingly, hallucinatory behavior was situated least centrally within the network structure. Using a community detection algorithm, the BPRS items were organized into positive, negative, and general symptom clusters. Overall, DSM symptoms were not more central than non-DSM symptoms within the symptom network of Asian patients with schizophrenia. Thus, motor retardation, which results from the unmet needs associated with current antipsychotic medications for schizophrenia, may be a tailored treatment target for Asian patients with schizophrenia. Based on these findings, targeting non-dopamine systems (glutamate, γ-aminobutyric acid) may represent an effective strategy with respect to precision medicine for psychosis.

Aberrant maturation and connectivity of prefrontal cortex in schizophrenia-contribution of NMDA receptor development and hypofunction

The neurobiology of schizophrenia involves multiple facets of pathophysiology, ranging from its genetic basis over changes in neurochemistry and neurophysiology, to the systemic level of neural circuits. Although the precise mechanisms associated with the neuropathophysiology remain elusive, one essential aspect is the aberrant maturation and connectivity of the prefrontal cortex that leads to complex symptoms in various stages of the disease. Here, we focus on how early developmental dysfunction, especially N-methyl-D-aspartate receptor (NMDAR) development and hypofunction, may lead to the dysfunction of both local circuitry within the prefrontal cortex and its long-range connectivity. More specifically, we will focus on an "all roads lead to Rome" hypothesis, i.e., how NMDAR hypofunction during development acts as a convergence point and leads to local gamma-aminobutyric acid (GABA) deficits and input-output dysconnectivity in the prefrontal cortex, which eventually induce cognitive and social deficits. Many outstanding questions and hypothetical mechanisms are listed for future investigations of this intriguing hypothesis that may lead to a better understanding of the aberrant maturation and connectivity associated with the prefrontal cortex.

NMDA receptor hypofunction for schizophrenia revisited: Perspectives from epigenetic mechanisms

Schizophrenia (SZ) is a neurodevelopmental disorder with cognitive deficits manifesting during early stages of the disease. Evidence suggests that genetic factors in combination with environmental insults lead to complex changes to glutamatergic, GABAergic, and dopaminergic systems. In particular, the N-methyl-d-aspartate receptor (NMDAR), a major glutamate receptor subtype, is implicated in both the disease progression and symptoms of SZ. NMDARs are critical for synaptic plasticity and cortical maturation, as well as learning and memory processes. In fact, any deviation from normal NMDAR expression and function can have devastating consequences. Surprisingly, there is little evidence from human patients that direct mutations of NMDAR genes contribute to SZ. One intriguing hypothesis is that epigenetic changes, which could result from early insults, alter protein expression and contribute to the NMDAR hypofunction found in SZ. Epigenetics is referred to as modifications that alter gene transcription without changing the DNA sequence itself. In this review, we first discuss how epigenetic changes to NMDAR genes could contribute to NMDAR hypofunction. We then explore how NMDAR hypofunction may contribute to epigenetic changes in other proteins or genes that lead to synaptic dysfunction and symptoms in SZ. We argue that NMDAR hypofunction occurs in early stage of the disease, and it may consequentially initiate GABA and dopamine deficits. Therefore, targeting NMDAR dysfunction during the early stages would be a promising avenue for prevention and therapeutic intervention of cognitive and social deficits that remain untreatable. Finally, we discuss potential questions regarding the epigenetic of SZ and future directions for research.

Insulin Resistance-Related Proteins Are Overexpressed in Patients and Rats Treated With Olanzapine and Are Reverted by Pueraria in the Rat Model

BACKGROUND

Olanzapine, a commonly used second-generation antipsychotic, causes severe metabolic adverse effects, such as elevated blood glucose and insulin resistance (IR). Previous studies have proposed that overexpression of CD36, GGPPS, PTP-1B, GRK2, and adipose triglyceride lipase may contribute to the development of metabolic syndrome, and Pueraria could eliminate the metabolic adverse effects. The study aimed to investigate the association between olanzapine-associated IR and IR-related proteins (IRRPs) and determine the role of Pueraria in protection against the metabolic adverse effects of olanzapine.

METHODS

The expression levels of IRRPs were examined in schizophrenia patients and rat models with long-term olanzapine treatment. The efficacy of Pueraria on anti-IR by reducing the expression of IRRPs was comprehensively evaluated.

RESULTS

Our study demonstrated that in schizophrenia patients chronically treated with olanzapine, the expression levels of IRRPs in patients with a high IR index significantly increased, and these phenomena were further confirmed in a rat model. The expression levels of IRRPs were reduced significantly in Pueraria-treated IR rat models. The body weight, blood glucose, and IR index were restored to levels similar to those of normal controls.

CONCLUSIONS

The IRRPs are closely related to IR induced by olanzapine, and Pueraria could interfere with olanzapine-associated IR and revert overexpressed IRRPs. These findings suggest that IRRPs are key players in olanzapine-associated IR and that Pueraria has potential as a clinical drug to prevent the metabolic adverse effects of olanzapine, further improving compliance of schizophrenia patients.

An Integrated Bio-psycho-social Approach to Psychiatric Disorders

The biopsychosocial approach is a model of eclecticism, which consists of multidisciplinary academic fields, reacting against the "neuroscientification" of psychiatry. The biopsychosocial approach was proposed by George Engel following Adolf Meyer's psychobiological and Roy R. Ginker's eclectic approach to psychiatry. Although the use of the biopsychosocial approach is increasing, it has several limitations: First, specific practices cannot be guided by the biopsychosocial approach because it is considered to be "boundless psychiatry." Second, unlike an initial intention, the symptomatic use of psychotropic medications may be justified by the biopsychosocial approach. Third, the economic forces to enhance biological psychiatry cannot be hindered by the biopsychosocial approach. Hence, to overcome the limitations of the current biopsychosocial approach, potential new paradigms including evolutionary psychiatry, pragmatism, integrationism, and pluralism have been proposed. Above all, Eric Kandel presented the link between neuroscience and psychiatry from the perspective of integrationism. In accordance with integrationism and/or pluralism, based on the paradigm shift of the theoretical construct from chemical imbalance to dysfunctional circuit, next-generation treatments for mental disorders have been proposed by Thomas Insel. Thus, a more integrated biopsychosocial approach to managing psychiatric disorders including schizophrenia and panic disorder may be proposed.

Comparative Efficacy and Safety of Long-acting Injectable and Oral Second-generation Antipsychotics for the Treatment of Schizophrenia: A Systematic Review and Meta-analysis

We aimed to compare the efficacy and safety of long-acting injectable (LAI) and oral second-generation antipsychotics (SGAs) in treating schizophrenia by performing a systematic review and meta-analysis. MEDLINE, EMBASE, PsycINFO, CINAHL, and the Cochrane Library, as well as five Korean databases, were systemically searched to identify studies published from 2000 to 16 April 2015, which compared the efficacy and safety of LAI and oral SGAs. Using data from randomized controlled trials (RCTs), meta-analyses were conducted. In addition, the GRADE (the Grading of Recommendations, Assessment, Development and Evaluation) approach was applied to explicitly assess the quality of the evidence. A total of 30 studies including 17 RCTs and 13 observational studies were selected. The group treated with LAI SGAs was characterized by significantly lower relapse rates, longer times to relapse and fewer hospital days, but also by a higher occurrence of extrapyramidal syndrome and prolactin-related symptoms than that in the group treated with oral SGAs. Our findings demonstrate that there is moderate to high level of evidence suggesting that in the treatment of schizophrenia, LAI SGAs have higher efficacy and are associated with higher rates of extrapyramidal syndrome and prolactin-related symptoms. Additionally, the use of LAI SGAs should be combined with appropriate measures to reduce dopamine D₂ antagonism-related symptoms.

Effectiveness of Traditional Chinese Medicineas as an Adjunct Therapy for Refractory Schizophrenia: A Systematic Review and Meta Analysis

Although recent studies focused on traditional Chinese medicine (TCM) for the treatment of refractory schizophrenia have reported that it may be beneficial, there is still lack of convincing evidence and critical meta-analytic work regarding its effectiveness as an adjunctive therapy. Therefore, we performed a meta-analysis to investigate the effectiveness of TCM in combination with antipsychotics for refractory schizophrenia. Fourteen articles involving 1725 patients published as of December 2016 were included which compared antipsychotic therapies to either TCM alone, or TCM as an adjunctive therapy. TCM was observed to have beneficial effects on aspects of the Positive and Negative Syndrome Scale (PANSS) including total score changes and negative score changes, as well as clinical effects estimated with PANSS or the Brief Psychiatric Rating Scale (BPRS). The changes in extrapyramidal side effects (RSESE) scores from baseline to the end of the treatment period were similar in two groups of related trials. TCM was also reported to mitigate some anti-psychotic related side-effects and overall, TCM adjuvant therapy was generally safe and well tolerated. While, the results indicated the potential utility of TCM as an alternative adjunctive therapeutic for refractory schizophrenia treatment, there remains a need for further high-quality studies.