Genetic predisposition of BDNF (rs6265) gene is susceptible to Schizophrenia: A prospective study and updated meta-analysis / Asociación entre el gen BDNF (rs6265) y predisposición a la esquizofrenia: estudio prospectivo y metaanálisis actualizado

Introduction: Genetic polymorphism in the BDNF gene has been found to cause neuronal alterations and has been identified as a causal factor for many neuropsychiatric disorders. Therefore, various neurological case–control studies and meta-analyses have been conducted to find the possible link between BDNF and susceptibility to schizophrenia. Method: This meta-analysis gathered data from 25 case–control studies including a total of 8384 patients with schizophrenia and 8821 controls in order to identify the relationship between the rs6265 single nucleotide polymorphism and the disease, evaluating the combined odds ratio and 95% confidence intervals under 5 different genetic models. Validation followed the “Leave one out” method, and we used the Egger test and Begg's funnel plot to identify publication bias. Results: Research into the rs6265 (G/A) polymorphism revealed a non-significant association with schizophrenia in all 5 genetic models; in the subgroup analysis, no association was found between white and Asian populations, with a p value > .05. Conclusions: Overall, the updated meta-analysis revealed that rs6265 exonic polymorphisms do not increase susceptibility to this disease. However, to better understand the pathogenesis of the disease, there is a need for further case–control studies into the BDNF polymorphism including larger sample sizes and different ethnic groups.(AU)

Introducción: Se sabe que los polimorfismos del gen BDNF provocan alteraciones neuronales y parecen ser un factor causal en muchos trastornos neuropsiquiátricos. Es por ello que se han llevado a cabo varios metaanálisis y estudios de casos y controles con el objetivo de evaluar la posible relación entre BDNF y la esquizofrenia. Método: Realizamos un metaanálisis de 25 estudios de casos y controles, que incluyó un total de 8.384 pacientes con esquizofrenia y 8.821 controles. Se analizó la relación entre el polimorfismo de nucleótido simple rs6265 y la esquizofrenia mediante odds ratios combinados y sus intervalos de confianza del 95% con 5 modelos genéticos diferentes. Utilizamos el método de validación cruzada dejando uno fuera («leave one out»), la prueba de Egger y el gráfico en embudo de Begg para identificar posibles sesgos de publicación. Resultados: Los estudios sobre el polimorfismo rs6265 (G/A) muestran una asociación no significativa con la esquizofrenia en los 5 modelos genéticos. En el análisis por subgrupos, no se encontró relación con las poblaciones caucásica y asiática (p > 0,05). Conclusiones: La presencia de polimorfismos rs6265 no aumenta la predisposición a desarrollar esquizofrenia. Sin embargo, se deben realizar más estudios de casos y controles sobre polimorfismos de BDNF, con muestras más numerosas y con individuos de diferentes grupos étnicos, para comprender mejor los mecanismos patogénicos de la enfermedad.(AU)

Functional myelin in cognition and neurodevelopmental disorders.

In vertebrates, oligodendrocytes (OLs) are glial cells of the central nervous system (CNS) responsible for the formation of the myelin sheath that surrounds the axons of neurons. The myelin sheath plays a crucial role in the transmission of neuronal information by promoting the rapid saltatory conduction of action potentials and providing neurons with structural and metabolic support. Saltatory conduction, first described in the peripheral nervous system (PNS), is now generally recognized as a universal evolutionary innovation to respond quickly to the environment: myelin helps us think and act fast. Nevertheless, the role of myelin in the central nervous system, especially in the brain, may not be primarily focused on accelerating conduction speed but rather on ensuring precision. Its principal function could be to coordinate various neuronal networks, promoting their synchronization through oscillations (or rhythms) relevant for specific information processing tasks. Interestingly, myelin has been directly involved in different types of cognitive processes relying on brain oscillations, and myelin plasticity is currently considered to be part of the fundamental mechanisms for memory formation and maintenance. However, despite ample evidence showing the involvement of myelin in cognition and neurodevelopmental disorders characterized by cognitive impairments, the link between myelin, brain oscillations, cognition and disease is not yet fully understood. In this review, we aim to highlight what is known and what remains to be explored to understand the role of myelin in high order brain processes.

The identification of novel schizophrenia-related metabolites using untargeted lipidomics.

Human lipidome still remains largely unexplored among Chinese schizophrenia patients. We aimed to identify novel lipid molecules associated with schizophrenia and cognition among schizophrenia patients. The current study included 96 male schizophrenia patients and 96 gender-matched healthy controls. Untargeted lipidomics profiling was conducted among all participants. Logistic regression models were used to assess metabolite associations with schizophrenia. We further assessed the incremental predictive value of identified metabolites beyond conventional risk factors on schizophrenia status. In addition, identified metabolites were tested for association with cognitive function among schizophrenia patients using linear regression models. A total of 34 metabolites were associated with schizophrenia. Addition of these identified metabolites to age, body mass index, smoking, and education significantly increased the risk reclassification of schizophrenia. Among the schizophrenia-related metabolites, 10 were further associated with cognition in schizophrenia patients, including four metabolites associated with immediate memory, two metabolites associated with delayed memory, three metabolites associated with visuospatial, four metabolites associated with language, one metabolite associated with attention, and two metabolites associated with the total score. Our findings provide novel insights into the biological mechanisms of schizophrenia, suggesting that lipid metabolites may serve as potential diagnostic or therapeutic targets of schizophrenia.

Novel α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAR) potentiator LT-102: A promising therapeutic agent for treating cognitive impairment associated with schizophrenia.

AIMS: We aimed to evaluate the potential of a novel selective α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAR) potentiator, LT-102, in treating cognitive impairments associated with schizophrenia (CIAS) and elucidating its mechanism of action. METHODS: The activity of LT-102 was examined by Ca2+ influx assays and patch-clamp in rat primary hippocampal neurons. The structure of the complex was determined by X-ray crystallography. The selectivity of LT-102 was evaluated by hERG tail current recording and kinase-inhibition assays. The electrophysiological characterization of LT-102 was characterized by patch-clamp recording in mouse hippocampal slices. The expression and phosphorylation levels of proteins were examined by Western blotting. Cognitive function was assessed using the Morris water maze and novel object recognition tests. RESULTS: LT-102 is a novel and selective AMPAR potentiator with little agonistic effect, which binds to the allosteric site formed by the intradimer interface of AMPAR's GluA2 subunit. Treatment with LT-102 facilitated long-term potentiation in mouse hippocampal slices and reversed cognitive deficits in a phencyclidine-induced mouse model. Additionally, LT-102 treatment increased the protein level of brain-derived neurotrophic factor and the phosphorylation of GluA1 in primary neurons and hippocampal tissues. CONCLUSION: We conclude that LT-102 ameliorates cognitive impairments in a phencyclidine-induced model of schizophrenia by enhancing synaptic function, which could make it a potential therapeutic candidate for CIAS.

Genetic predisposition of BDNF (rs6265) gene is susceptible to Schizophrenia: A prospective study and updated meta-analysis.

INTRODUCTION: Genetic polymorphism in the BDNF gene has been found to cause neuronal alterations and has been identified as a causal factor for many neuropsychiatric disorders. Therefore, various neurological case-control studies and meta-analyses have been conducted to find the possible link between BDNF and susceptibility to schizophrenia. METHOD: This meta-analysis gathered data from 25 case-control studies including a total of 8384 patients with schizophrenia and 8821 controls in order to identify the relationship between the rs6265 single nucleotide polymorphism and the disease, evaluating the combined odds ratio and 95% confidence intervals under 5 different genetic models. Validation followed the "Leave one out" method, and we used the Egger test and Begg's funnel plot to identify publication bias. RESULTS: Research into the rs6265 (G/A) polymorphism revealed a non-significant association with schizophrenia in all 5 genetic models; in the subgroup analysis, no association was found between white and Asian populations, with a p value>.05. CONCLUSIONS: Overall, the updated meta-analysis revealed that rs6265 exonic polymorphisms do not increase susceptibility to this disease. However, to better understand the pathogenesis of the disease, there is a need for further case-control studies into the BDNF polymorphism including larger sample sizes and different ethnic groups.

New role of platelets in schizophrenia: predicting drug response.

Background: Elevated platelet count (PLTc) is associated with first-episode schizophrenia and adverse outcomes in individuals with precursory psychosis. However, the impact of antipsychotic medications on PLTc and its association with symptom improvement remain unclear. Aims: We aimed to investigate changes in PLTc levels following antipsychotic treatment and assess whether PLTc can predict antipsychotic responses and metabolic changes after accounting for other related variables. Methods: A total of 2985 patients with schizophrenia were randomised into seven groups. Each group received one of seven antipsychotic treatments and was assessed at 2, 4 and 6 weeks. Clinical symptoms were evaluated using the positive and negative syndrome scale (PANSS). Additionally, we measured blood cell counts and metabolic parameters, such as blood lipids. Repeated measures analysis of variance was used to examine the effect of antipsychotics on PLTc changes, while structural equation modelling was used to assess the predictive value of PLTc on PANSS changes. Results: PLTc significantly increased in patients treated with aripiprazole (F=6.00, p=0.003), ziprasidone (F=7.10, p<0.001) and haloperidol (F=3.59, p=0.029). It exhibited a positive association with white blood cell count and metabolic indicators. Higher baseline PLTc was observed in non-responders, particularly in those defined by the PANSS-negative subscale. In the structural equation model, PLTc, white blood cell count and a latent metabolic variable predicted the rate of change in the PANSS-negative subscale scores. Moreover, higher baseline PLTc was observed in individuals with less metabolic change, although this association was no longer significant after accounting for baseline metabolic values. Conclusions: Platelet parameters, specifically PLTc, are influenced by antipsychotic treatment and could potentially elevate the risk of venous thromboembolism in patients with schizophrenia. Elevated PLTc levels and associated factors may impede symptom improvement by promoting inflammation. Given PLTc's easy measurement and clinical relevance, it warrants increased attention from psychiatrists. Trial registration number: ChiCTR-TRC-10000934.

Sulcal pits of the superior temporal sulcus in schizophrenia patients with auditory verbal hallucinations.

Auditory verbal hallucinations (AVHs) are among the most common and disabling symptoms of schizophrenia. They involve the superior temporal sulcus (STS), which is associated with language processing; specific STS patterns may reflect vulnerability to auditory hallucinations in schizophrenia. STS sulcal pits are the deepest points of the folds in this region and were investigated here as an anatomical landmark of AVHs. This study included 53 patients diagnosed with schizophrenia and past or present AVHs, as well as 100 healthy control volunteers. All participants underwent a 3-T magnetic resonance imaging T1 brain scan, and sulcal pit differences were compared between the two groups. Compared with controls, patients with AVHs had a significantly different distributions for the number of sulcal pits in the left STS, indicating a less complex morphological pattern. The association of STS sulcal morphology with AVH suggests an early neurodevelopmental process in the pathophysiology of schizophrenia with AVHs.

Systematic Review of the Link Between Social Cognition and Suicidal Ideation and Behavior in People With Serious Mental Illness.

Background and Hypothesis: People with serious mental illness (SMI; psychotic and affective disorders with psychosis) are at an increased risk of suicide, yet there is limited research on the correlates of suicide in SMI. Social cognitive impairments are common among people with SMI and several studies have examined social cognition and suicidal ideation (SI) and behavior. This systematic review aims to evaluate the links between various domains of social cognition, SI, and suicidal behavior in SMI. Study Design: Electronic databases (PubMed and PsycInfo) were searched through June 2023. Records obtained through this search (N = 618) were screened by 2 independent reviewers according to inclusion criteria. Relevant data were extracted, and study quality was assessed. Study Results: Studies (N = 16) from 12 independent samples were included in the systematic review (N = 2631, sample sizes ranged from N = 20 to N = 593). Assessments of social cognition and SI and behavior varied widely between studies. Broadly, effects were mixed. Better emotion recognition of negative affect was linked to SI and a history of suicide attempts, though there is little consistent evidence for the relationship of emotion recognition and SI or behavior. On the other hand, better theory of mind ability was linked to SI and a history of suicide attempts. Furthermore, negative attributional bias was linked to current SI, but not a history of SI or attempt. Conclusions: This review suggests mixed associations between social cognition, SI, and behavior in SMI. Future research should evaluate additional mediators and moderators of social cognition and suicide, employing prospective designs.

Simultaneous EEG-fMRI Investigation of Rhythm-Dependent Thalamo-Cortical Circuits Alteration in Schizophrenia.

Schizophrenia is accompanied by aberrant interactions of intrinsic brain networks. However, the modulatory effect of electroencephalography (EEG) rhythms on the functional connectivity (FC) in schizophrenia remains unclear. This study aims to provide new insight into network communication in schizophrenia by integrating FC and EEG rhythm information. After collecting simultaneous resting-state EEG-functional magnetic resonance imaging data, the effect of rhythm modulations on FC was explored using what we term "dynamic rhythm information." We also investigated the synergistic relationships among three networks under rhythm modulation conditions, where this relationship presents the coupling between two brain networks with other networks as the center by the rhythm modulation. This study found FC between the thalamus and cortical network regions was rhythm-specific. Further, the effects of the thalamus on the default mode network (DMN) and salience network (SN) were less similar under alpha rhythm modulation in schizophrenia patients than in controls ([Formula: see text]). However, the similarity between the effects of the central executive network (CEN) on the DMN and SN under gamma modulation was greater ([Formula: see text]), and the degree of coupling was negatively correlated with the duration of disease ([Formula: see text], [Formula: see text]). Moreover, schizophrenia patients exhibited less coupling with the thalamus as the center and greater coupling with the CEN as the center. These results indicate that modulations in dynamic rhythms might contribute to the disordered functional interactions seen in schizophrenia.

Multimorbidity and the Etiology of Schizophrenia.

PURPOSE OF REVIEW: A global study of multimorbidity in schizophrenia, especially of the association with physical conditions, might offer much needed etiological insights. RECENT FINDINGS: Our review suggests that life-style factors and medication related to schizophrenia are only part of the explanation of the increase in risk for cardiovascular, metabolic, pulmonary disorders, and some cancers. Positive associations with autoimmune disorders (with the exception of rheumatoid arthritis) and epilepsy are promising avenues of research but to date have not been fully exploited. The same holds for the negative comorbidity seen for rheumatoid arthritis and some cancers (e.g., prostate). As a whole, our review suggests that most of the explored conditions have a different prevalence in schizophrenia than in the general population. Several hypotheses emerged from this review such as the role of immune and genetic factors, of sex hormones, and of more general variability factors.

Pharmacogenetic intervention improves treatment outcomes in Chinese adult men with schizophrenia.

To investigate the clinical application value of pharmacogenetic testing in individualized drug therapy for adult male patients with schizophrenia. A total of 186 adult patients with schizophrenia were enrolled and randomised into the pharmacogenetic (PGx) intervention group and the standard care group. In the PGx intervention group, PGx testing was performed, and the medication regimen was adjusted according to the results of the pharmacogenomic analysis. In contrast, in the standard care group, patients were treated according to the physician's medication experience. Differences in the primary indicator of schizophrenia, the Positive and Negative Symptom Scale (PANSS), and the secondary efficacy measures, the Clinical Global Impressions-Severity of Illness scale (CGI-SI) and Clinical Global Impressions-Global Improvement (CGI-GI) scale, were compared between the intervention and standard care groups. At baseline, the PGx intervention group consisted of 109 individuals, while the standard care group had 77 participants. After 12 weeks of treatment, 49 individuals withdrew from the PGx group (a dropout rate of 45.0%), and 34 withdrew from the standard care group (a dropout rate of 44.2%), with no significant difference in dropout rates between the two groups. The PANSS score reduction rate in the PGx intervention group significantly exceeded that of the standard care group during weeks 3, 6, and 12 of follow-up (P < 0.05). At the 12th week, the PGx intervention group achieved a treatment response rate of 81.7%, significantly surpassing the 48.8% of the standard care group (odds ratio of 4.67, 95% confidence interval of 1.96-11.41; P = 0.001). Furthermore, the PGx intervention was significantly more effective than standard care regardless of whether the patient had a first episode or a relapse (P < 0.05). Furthermore, the Global Assessment of Functioning (GAF) scores and the Personal and Social Performance Scale (PSP) score changes in the PGx intervention group were both significantly different from those in the standard care group (P < 0.05). It is noteworthy that the PGx intervention similarly improves the prognostic outcomes for patients with and without a family history of mental disorders. In conclusion, the application of a PGx intervention treatment model based on PGx testing can significantly improve medication efficacy and shorten the time to achieve the effects of medication in schizophrenia.

Liraglutide 3.0 mg once daily for the treatment of overweight and obesity in patients hospitalised at a forensic psychiatric department: A 26-week open-label feasibility study.

INTRODUCTION: Overweight and obesity constitute a major concern among patients treated at forensic psychiatric departments. The present clinical feasibility study aimed at investigating the extent to which glucagon-like peptide 1 receptor agonist (GLP-1RA) treatment with once-daily liraglutide 3.0 mg could be a feasible pharmacological treatment of these conditions in patients with schizophrenia spectrum disorders hospitalised in forensic psychiatry. METHODS: The 26-week, open-label feasibility study included participants aged 18-65 years diagnosed with a severe mental illness and hospitalised at a forensic psychiatric department. At the time of inclusion, all participants fulfilled the indication for using liraglutide as a treatment for overweight and obesity. Participants' baseline examinations were followed by a 26-week treatment period with liraglutide injection once daily according to a fixed uptitration schedule of liraglutide, with a target dose of 3.0 mg. Each participant attended seven visits to evaluate the efficacy and adverse events. The primary endpoint was the number of "completers", with adherence defined as >80% injections obtained in the period, weeks 12-26. Determining whether liraglutide is a feasible treatment was pre-defined to a minimum of 75% completers. RESULTS: Twenty-four participants were included in the study. Sex, male = 19 (79.2%). Mean age: 42.3 [25th and 75th percentiles: 39.1; 48.4] years; body mass index (BMI): 35.7 [31.7; 37.5] kg/m2; glycated haemoglobin (HbA1c): 37 [35; 39] mmol/mol. Eleven out of 24 participants (46%) completed the study. For the completers, the median net body weight loss after 26 weeks of participation was -11.4 kg [-15.4; -5.9]. The net difference in HbA1C and BMI was -2.0 mmol/mol [-4; -1] and -3.6 kg/m2 [-4.7; -1.8], respectively. The weight change and reduction in HbA1c and BMI were all statistically significant from baseline. CONCLUSION: The study did not confirm our hypothesis that liraglutide is a feasible treatment for a minimum of 75% of the patients initiating treatment with liraglutide while hospitalised in a forensic psychiatric department. The high dropout rate may be due to the non-naturalistic setting of the clinical trial. For the proportion of patients compliant with the medication, liraglutide 3.0 mg was an efficient treatment for overweight.

Postnatal hypofunction of N-methyl-D-aspartate receptors alters perforant path synaptic plasticity and filtering and impairs dentate gyrus-mediated spatial discrimination.

BACKGROUND AND PURPOSE: Transient hypofunction of the NMDA receptor represents a convergence point for the onset and further development of psychiatric disorders, including schizophrenia. Although the cumulative evidence indicates dysregulation of the hippocampal formation in schizophrenia, the integrity of the synaptic transmission and plasticity conveyed by the somatosensorial inputs to the dentate gyrus, the perforant pathway synapses, have barely been explored in this pathological condition. EXPERIMENTAL APPROACH: We identified a series of synaptic alterations of the lateral and medial perforant paths in animals postnatally treated with the NMDA antagonist MK-801. This dysregulation suggests decreased cognitive performance, for which the dentate gyrus is critical. KEY RESULTS: We identified alterations in the synaptic properties of the lateral and medial perforant paths to the dentate gyrus synapses in slices from MK-801-treated animals. Altered glutamate release and decreased synaptic strength precede an impairment in the induction and expression of long-term potentiation (LTP) and CB1 receptor-mediated long-term depression (LTD). Remarkably, by inhibiting the degradation of 2-arachidonoylglycerol (2-AG), an endogenous ligand of the CB1 receptor, we restored the LTD in animals treated with MK-801. Additionally, we showed for the first time, that spatial discrimination, a cognitive task that requires dentate gyrus integrity, is impaired in animals exposed to transient hypofunction of NMDA receptors. CONCLUSION AND IMPLICATIONS: Dysregulation of glutamatergic transmission and synaptic plasticity from the entorhinal cortex to the dentate gyrus has been demonstrated, which may explain the cellular dysregulations underlying the altered cognitive processing in the dentate gyrus associated with schizophrenia.

Function and mechanism exploring of icariin in schizophrenia through network pharmacology.

This study aims to explore the therapeutic effect and possible mechanisms of icariin in schizophrenia. SD rats were divided into five groups, a control group, a MK801-induced schizophrenia model group, and three icariin treatment groups, with twelve rats in each group. Morris water maze and open field were used to observe the spatial learning and memory ability of rats. Compared with the control group, rats in the MK801-induced model group showed an increase in stereotypic behavior score, distance of spontaneous activities, escape latency, malondialdehyde (MDA) content, and IL-6, IL-1ß, TNF-α expression, but a decrease in platform crossing times and superoxide dismutase (SOD) activity (P < 0.05). Furthermore, all the above changes of the model group were reversed after icariin treatment in a dose-dependent manner (P < 0.05). Network pharmacology found that icariin can exert anti-schizophrenic effects through some signaling pathways, such as relaxin, estrogen, and TNF signaling pathways. MAPK1, MAPK3, FOS, RELA, TNF, and JUN were the key targets of icariin on schizophrenia, and their expression was detected in animal models, which was consistent with the predicted results of network pharmacology. Icariin treatment may improve the spatial learning and memory ability of schizophrenic rats through TNF signaling pathway.

Role of the Cerebellum in Bipolar Disorder: A Systematic Literature Review.

The aim of this systematic literature review was to investigate the role of the cerebellum in the affective symptoms observed in patients with bipolar disorder. The present systematic literature review included clinical studies conducted from 2013-2023 among adult populations with bipolar I and II disorders, along with their specifiers. With regard to cerebellar pathology, it was found that those with bipolar disorder performed worse than their healthy counterparts in their ability to comprehend the mental states of others and in identifying negative mental states. Additionally, individuals with bipolar disorder had reduced gray matter loss in regions such as lobules I-IX, crus I, and crus II, different functional activation patterns of the thalamus, striatum, and hippocampus on functional magnetic resonance imaging (fMRI), and increased cortical thickness. Cerebro-cerebellar functional connectivities were altered in patients with bipolar disorder. The effects of lamotrigine and lithium on cerebellar volume and abnormalities are also discussed in this paper. The present systematic literature review illustrates the emerging involvement of the cerebellum in bipolar disorder and its affective symptoms and paves the way for future research and a better understanding of bipolar disorder.

The patient journey project in Italian mental health services: results from a co-designed survey on clinical interventions and current barriers to improve the care of people living with schizophrenia.

Introduction: The Patient Journey Project aimed to analyze the scenario among Italian Mental Health Services (MHS) to understand the clinical interventions that are properly implemented and the ones deserving further implementation to design an effective treatment plan for patients living with schizophrenia (PLWS). Methods: The 60-items survey was co-designed with all the stakeholders (clinicians, expert patients and caregivers) involved in the Patient Journey and focused on three phases of schizophrenia course: early detection and management, acute phase management, long-term management/continuity of care. Respondents were Heads of the Mental Health Departments and Addiction Services (MHDAS) or facilities directors throughout Italian MHS. For each statement, respondents expressed the consensus on the importance and the degree of implementation in clinical practice. Results: Considering the importance of the statement, strong consensus was reached for most of the statements. Good levels of implementation were found on 2/17 statements of early detection and management, on 3/16 statements for acute phase management and on 1/27 statements of long-term management/continuity of care. Poor levels of implementation were found on 1/17 statements of early detection and management, none of acute phase management, and 4/27 statements for long-term management/continuity of care. Moderate levels of implementation were found on 14/17 statements for early detection and management, on 13/16 statements of acute phase management, and on 22/27 statements of long-term management/continuity of care. Thus, among Italian MHDAS, most interventions for PLWS were moderately implemented in clinical practice. Discussion: Italian MHS have to provide new strategies and structural actions to overcome these current limitations and barriers to effectively improve the journey of PLWS. The areas that deserve most implementation include interventions during the early stage (especially the continuity of care between Child and Adolescent Mental Health Services and Adult Mental Health Services), the evidence-based psychosocial interventions during the chronic stages of the disorder, and the continuity of care after acute hospitalization.

Adaptive coding of reward in schizophrenia, its change over time and relation to apathy.

Adaptive coding of reward is the process by which neurons adapt their response to the context of available compensations. Higher rewards lead to a stronger brain response, but the increase of the response depends on the range of available rewards. A steeper increase is observed in a narrow range, and a more gradual slope in a wider range. In schizophrenia, adaptive coding appears affected in different domains, and in the reward domain in particular. Here we tested adaptive coding of reward in a large group of patients with schizophrenia (N = 86) and controls (N = 66). We assessed 1) the association between adaptive coding deficits and symptoms; 2) the longitudinal stability of deficits (the same task was performed three months apart); 3) the stability of results between two experimental sites. We used fMRI and the Monetary Incentive Delay task to assess participant' adaptation to two different reward ranges: a narrow and a wide range. We used a region of interest analysis, evaluating adaptation within striatal and visual regions. Patients and controls underwent a full demographic and clinical assessment. We found reduced adaptive coding in patients, due to a decreased slope in the narrow reward range, with respect to that of control participants in striatal but not visual regions. This pattern was observed at both research sites. Upon re-test, patients increased their narrow range slopes, showing improved adaptive coding, whereas controls slightly reduced them. At re-test, patients with overly steep slopes in the narrow range also showed higher levels of negative symptoms. Our data confirm deficits in reward adaptation in schizophrenia and reveal a practice effect in patients, leading to improvement, with steeper slopes upon retest. However, in some patients, an overly steep slope may result in poor discriminability of larger rewards, due to early saturation of the brain response. Together, the loss of precision of reward representation in new (first exposure, underadaptation) and more familiar (re-test, overadaptation) situations may contribute to the multiple motivational symptoms in schizophrenia.

The MATRICS consensus cognitive battery for the assessment of cognitive impairment in schizotypal personality disorder.

Cognitive deficits are a core impairment across the range of schizophrenia (SZ) spectrum disorders, including schizotypal personality disorder (SPD). The MATRICS Consensus Cognitive Battery (MCCB) was developed to be a robust, specific, and valid cognitive assessment battery to assess cognition in clinical trials for treating cognitive impairments in SZ. Despite the similarity of cognitive impairments shown in SPD and SZ and the clear relevance of uniform assessment across a diagnostic spectrum, the MCCB has yet to be validated in SPD. As such, this is the first study to evaluate the sensitivity of the MCCB for the assessment of cognitive function in individuals with SPD. Participants were 30 individuals with SPD and 54 healthy controls (HC) assessed with the MCCB and supplemental neurocognitive assessments (Trails B, DOT test, Paced Auditory Serial Addition Test (PASAT), AX Continuous Performance Task (AX-CPT), and N-back). Individuals with SPD performed worse than HC participants on all MCCB subtests, as well as on converging supplemental tasks including Trails B, DOT test, PASAT, AX-CPT, and N-back. These results indicate that the MCCB was sensitive to cognitive impairment in SPD compared to controls. SPD participants demonstrate impairments similar to data of SZ participants within the literature, although to a slightly lesser degree of severity. Taken together, these results highlight the generalizability of using the MCCB across SZ spectrum diagnostic groups to assess cognition. Such findings allow for further comparison across disorders, greater understanding of the cognitive characteristics in the spectrum, and use of uniform assessment within cognitive intervention research.

Effort-cost decision-making associated with negative symptoms in schizophrenia and bipolar disorder.

Motivational deficits and reduced goal-directed behavior for external rewards have long been considered an important features of negative symptoms in patients with schizophrenia (SCZ). Negative symptoms have also a high prevalence in bipolar disorder (BP). We used a transdiagnostic approach in order to examine association between negative symptoms and effort allocation for monetary rewards. 41 patients with SCZ and 34 patients with BP were enrolled in the study along with 41 healthy controls (HC). Effort-Expenditure for Rewards Task (EEfRT) was used to measure subjects' effort allocation for monetary rewards. Generalized estimating equation models were used to analyze EEfRT choice behavior. Negative symptoms were assessed using the Brief Negative Symptom Scale (BNSS). SCZ and BP groups expended lower effort to obtain a monetary rewards compared to HC. Severity of negative symptoms was negatively correlated with EEfRT performance in both diagnostic groups. Each diagnostic group showed lower effort allocation for monetary rewards compared to HC suggesting reduced motivation for monetary rewards. In addition, our results suggest that abnormal effort-based decision-making might be a transdiagnostic factor underlying negative symptoms.