Schizophrenia Research

Background and Hypothesis: Environmental exposures linked to schizophrenia may play a role in shaping long-term clinical outcomes among individuals with psychotic disorders. This study examined whether the Maudsley Environmental Risk Score (ERS), a cumulative measure of five established environmental risk factors, predicts trajectories of symptoms, cognition, and psychosocial functioning over 25 years following first hospitalization for psychosis. Study Design: Participants were drawn from the Suffolk County Mental Health Project, a longitudinal cohort of individuals with first-admission psychosis assessed six times over two decades. A total of 516 participants had sufficient ERS data and repeated assessments of symptoms (SAPS, SANS), cognitive ability, and functioning (GAF). Study Results: Linear mixed-effects models showed that higher ERS was significantly associated with lower global functioning ({beta} = -0.104, p = 0.008), an effect that remained consistent over time. ERS also predicted more severe and worsening reality distortion ({beta} = 0.082, p = 0.023 for intercept; {beta} = 0.005, p = 0.032 for slope of time). No significant associations were observed between ERS and cognitive ability, disorganization, or negative symptoms. Conclusions: These findings highlight the contribution of environmental risk to functional impairment and persistent positive symptoms across the course of psychotic illness. Incorporating ERS into clinical risk models may aid the identification of individuals likely to experience a more severe illness trajectory, and inform long-term treatment planning.

Weak inhibition of mitochondrial complex I (mtCI) has been shown to have neuroprotective effects in cellular and animal models of Alzheimers and Huntingtons diseases, at least in part by enhancing mitochondrial biogenesis and function. Mitochondrial dysfunction has also been demonstrated in schizophrenia patients and mouse models of schizophrenia. We tested whether weak inhibition of mtCI would ameliorate mitochondrial and behavioral phenotypes in a mouse model of schizophrenia. In mice with four copies of the Gldc gene, 8 weeks of treatment with the weak mtCI inhibitor, the small-molecule tricyclic pyrone compound CP2, reversed spontaneous alternation deficits in the Y maze, startle habituation deficits, and social novelty deficits in the three-chamber social interaction test. Consistent with the mechanism of action, Western blots revealed that CP2 reverses the reduced expression of PGC-1, a master regulator of mitochondrial biogenesis, and of the VDAC1, a primary gatekeeper for the exchange of metabolites, ions, and ATP between mitochondria and the cytosol. These findings suggest that the improvement of mitochondrial function may represent a novel strategy to reverse pathophysiological and behavioral deficits in schizophrenia.

Working memory depends on gamma oscillations generated across sensory and prefrontal cortices. In sensory cortices such as primary visual cortex (V1), stimulus-locked gamma oscillations encode stimulus information, while in prefrontal cortex (PFC), persistent gamma oscillations maintain this information after the stimulus is removed. In schizophrenia (SZ), gamma power is reduced in both V1 and PFC, consistent with deficits in sensory encoding and working memory maintenance in the illness. These two regimes of gamma oscillations arise from a canonical microcircuit involving pyramidal neurons (PNs) and parvalbumin-expressing interneurons (PVIs). Yet, whether stimulus-locked and persistent gamma oscillations are similarly or differentially vulnerable to synaptic alterations within this circuit in SZ remains unknown. To investigate this question, we used a mean-field model of the PN-PVI circuit generating either stimulus-locked or persistent gamma oscillations. We then assessed the effects of three synaptic alterations found in SZ: lower excitatory drive to PVIs (E[->]I), lower inhibitory drive to PNs (I[->]E), and greater variability in E[->]I synaptic strength. Each alteration produced larger gamma power deficits in the persistent regime than in the stimulus-locked regime. When applied together, these alterations interacted synergistically to reduce gamma power in both regimes, with the persistent regime exhibiting a more pronounced deficit. Among the three parameters, E[->]I synaptic strength was the strongest contributor to the synergistic loss of gamma power. Two-dimensional bifurcation analyses further revealed that this differential vulnerability arises from a narrower margin of oscillatory stability in the persistent regime, where the parameter values producing maximum gamma power sit closer to the Hopf bifurcation boundary. Together, these findings identify the persistent regime as intrinsically more fragile than the stimulus-locked regime, with the implications for understanding regional patterns of synaptic pathology and cortical gamma oscillations with distinct dynamics in SZ. Author summaryWorking memory depends on stimulus-locked gamma oscillations in sensory cortices such as primary visual cortex (V1) for encoding stimulus information, and persistent gamma oscillations in prefrontal cortex (PFC) for maintaining this information after stimulus offset. In schizophrenia (SZ), gamma power is reduced in both V1 and PFC, and postmortem human brain studies suggest that the underlying synaptic alterations are more severe in V1 than in PFC. Our computational modeling results suggest that this regional pattern arises because persistent gamma oscillations are intrinsically more fragile than stimulus-locked gamma oscillations, so that smaller synaptic alterations are sufficient to disrupt gamma oscillations in PFC while larger alterations are required to produce comparable disruption in V1. Together, these findings give rise to a differential vulnerability model of cortical gamma oscillations in SZ, linking the regional patterns of synaptic pathology to the deficits in gamma oscillations observed across sensory and prefrontal cortices in the illness.

Background: Psychotic disorders such as schizophrenia have been associated with older-appearing brain structure, commonly quantified using the brain-age paradigm. However, it remains unclear whether these alterations are present at illness onset and whether antipsychotic treatment modifies their trajectory. Methods: In this study, 61 (28 females and 33 males) antipsychotic-naive people with first-episode psychosis were randomised to receive either a second-generation antipsychotic (risperidone or paliperidone) or placebo over a 6-month treatment period, alongside intensive psychosocial therapy. A healthy control group (n = 27, 17 females, 10 males) was also recruited. Structural MRI scans were collected at baseline, 3 months, and 12 months. Brain age was estimated using two pretrained and validated models (Pyment and CentileBrain). Results: Brain-predicted age difference (brain-PAD) did not differ between patients and healthy controls at baseline (F(1,80) = 1.30; p = 0.26). There were also no significant effects of time, treatment group (antipsychotic, placebo, healthy control), or their interaction on brain-PAD across the first year (all p > 0.26). Findings were consistent across both brain-age models, and brain-PAD was not associated with clinical and lifestyle measures. Conclusion: These findings suggest that altered structural brain ageing is not evident during the earliest stages of psychosis and is not modified by early antipsychotic exposure over the first year of illness. Longer follow-up and approaches that account for illness heterogeneity may be needed to clarify when brain-age alterations emerge in psychotic disorders.

BackgroundSchizophrenia (SCZ) is a severe neurodevelopmental disorder with numerous genetic risk loci. However, little is known about the molecular alterations that occur during brain development in SCZ, particularly regarding the role of microRNA (miRNA) mediated regulatory mechanisms. This gap in knowledge is largely due to the limited availability of developing human brain tissue. Patient-derived brain organoids offer a promising alternative model. Here we use 3D dorsal forebrain organoids (DFOs) to investigate miRNA dysregulation in SCZ. MethodsDFOs were generated from human induced pluripotent stem cells (hiPSCs) derived from six SCZ patients and five matched controls and cultured for 120 days. Multi-omics analyses, immunohistochemistry, and in situ hybridization were employed to characterize molecular and spatial features. ResultsDFOs recapitulated key molecular hallmarks of human cortical development. Nineteen miRNAs were differentially expressed in SCZ: nine associated with neural progenitor proliferation were downregulated and ten linked to neuronal differentiation and synaptic maturation were upregulated, reflecting a compressed developmental timeline. Among 77 dysregulated mRNAs, 55 were predicted miRNA targets. SCZ DFOs exhibited significant upregulation of GABAergic pathway genes accompanied by altered expression of their regulatory miRNAs, indicating premature GABAergic lineage specification. The disrupted miRNA-mRNA network converged on glutamatergic and dopaminergic development, synaptic organization, and extracellular matrix remodeling. ConclusionDysregulated miRNAs in SCZ DFOs disrupt neuronal differentiation, excitatory-inhibitory balance, and early circuit formation, implicating miRNA-mediated post-transcriptional regulation as a key mechanism linking molecular alterations to cellular and network-level deficits in SCZ.

Background: Tobacco use is prevalent in clinical high risk for psychosis (CHR-P) population and has widespread negative health consequences, but understanding of its neural substrates is limited. Abnormal default mode network (DMN) may underlie tobacco dependence in CHR-P. We investigated how tobacco use relates to DMN connectivity and how CHR-P status impacts this relationship. Methods: We used baseline substance use and resting-state functional magnetic resonance imaging data from the North American Prodrome Longitudinal Study (NAPLS2; CHR-P: n=211, mean age 19.2, 37.9% female; healthy control: n=132, mean age 19.9, 47.7% female). Voxel-wise connectivity was calculated from the left lateral parietal (LLP) node of the DMN to the rest of the brain. We regressed LLP-brainwide connectivity against tobacco use frequency in the past month to generate a spatial map of how connectivity relates to current tobacco use. Results: Brainwide connectivity analysis identified two clusters in R hippocampus (peak voxel at MNI [+30,-12,-27]) and in L parahippocampus (peak voxel at MNI [-27,-27,-27]), where higher LLP-cluster connectivity was associated with more frequent tobacco use. LLP - R hippocampus connectivity was higher in current tobacco users compared to non-tobacco users (t=-3.5466, df=101.88, p=0.0006), and higher in CHR-P than controls (t=-2.8651, df=279.47, p=0.0049). Among current tobacco users, there was a significant tobacco-by-diagnosis interaction on LLP - R hippocampus connectivity (estimate=0.306, SE=0.149, t=2.051, p=0.045) such that heavier tobacco use predicted hyperconnectivity only in CHR. Conclusions: More frequent tobacco use was associated with higher DMN-hippocampal connectivity in both CHR-P and controls. CHR-P diagnosis enhanced this relationship.

Background. Something in discourse with a person experiencing psychosis often "feels off" before formal assessment is completed, yet this disturbance has not been quantified at the level of ongoing dyadic conversation. Prior work has largely treated patient speech in isolation, limiting our capacity to measure how communicative disruption emerges within clinical exchange. Methods. We applied a three-level decomposition of conversational alignment in 109 patients with psychotic disorders (26 female) and 60 healthy controls (22 female) at baseline and 12 months (n = 115). Register divergence (dAUCnorm) captured lexical distance between interviewer and patient; embedding-based synchrony (rembed) measured semantic trajectory coupling; within-speaker coherence was computed separately for each speaker. We used linear mixed-effects models adjusted for timepoint and participant clustering. Results. Patients showed significantly greater lexical-semantic divergence from the interviewer (d = 0.48, p < .001) and reduced embedding-based synchrony (d = -0.59, p < .001), both effects replicating at each time point. Critically, the interviewer's within-speaker coherence was reduced during conversations with patients (d = -0.33, p = .016), indicating that the disruption extends beyond the patient to the interaction itself. Register divergence tracked impoverished thinking and synchrony tracked disorganized thinking (both FDR-corrected q = .038). Group differences were persistent at 12 months, indicating a partially stable profile. Conclusions. Conversational alignment in psychosis reveals a dyadic failure of semantic coordination that destabilizes the interviewing clinician's coherence even when patient narrative continuity is preserved. These transcript-derived alignment metrics offer a scalable approach to quantifying interpersonal communicative function from routine clinical encounters.

Social withdrawal is a key component of the negative symptom domain of schizophrenia, and pharmacological blockade of the N-methyl-D-aspartate receptor (NMDAR) is widely used to model schizophrenia-relevant phenotypes in animals. However, findings on social behaviour are inconsistent across paradigms and laboratories. We therefore conducted a systematic review and meta-analysis to synthesise the effects of dizocilpine, ketamine, and phencyclidine on social interaction and social preference, to evaluate whether clinically approved antipsychotics modify these outcomes, and to examine locomotor activity measured within the same social tests to aid interpretation. We searched Embase, PubMed and Web of Science without language or date restrictions. Controlled in vivo studies in laboratory animals administering an eligible NMDAR antagonist and reporting social interaction and/or social preference outcomes were included. Two reviewers independently screened records, extracted data and assessed risk of bias. Effect sizes were computed as standardised mean differences and synthesised using correlated multilevel random-effects models with cluster-robust variance estimation. In total, 264 studies met the inclusion criteria. Overall, NMDAR antagonists were associated with reduced social interaction and reduced social preference relative to controls, although the social preference literature appeared vulnerable to small-study effects and imprecision. Locomotor activity measured during social interaction tests tended to be higher following NMDAR antagonists, whereas during social preference no consistent overall change was observed. In animals exposed to NMDAR antagonists, antipsychotics increased social behaviour, but these changes commonly co-occurred with reduced locomotion during social interaction tests, suggesting that improvements in social measures may partly reflect altered behavioural competition and time allocation rather than selective restoration of social functioning. Taken together, the evidence supports an overall link between NMDAR antagonism and reduced social behaviour, but the strength and interpretability of this signal depend on the paradigm and are constrained by heterogeneity and limitations in reporting.

In the past two decades, the focus on genome-wide association studies in large samples of unrelated patients has overshadowed family genetic studies. Therefore, little is still known about the levels and effects of the transmission of polygenic risk scores (PRS) among familial cases of schizophrenia (SZ) or bipolar disorder (BD) and their unaffected relatives. Prior research has shown that PRS are elevated in both patients and young individuals at familial risk for BD and SZ. We sought to study the transmission of PRS in affected multigenerational families and non-affected adult relatives (NAARs) with or without other non-mood nonpsychotic DSM-IV diagnoses and unrelated non-affected individuals from the same population. We genotyped 1,117 participants divided in 48 families from the Eastern Quebec Schizophrenia and Bipolar Disorder Kindreds. PRSs for both SZ and BD were computed using Multivariate Lassosum. For both SZ PRS and BD PRS, SZ and BD cases present higher PRS compared to controls, replicating previous findings. Regardless of a diagnosis of other non-psychotic and non-mood conditions, NAARs presented higher PRS than the unrelated cohort. Crucially, a subset of families presented consistently low PRS transmission profiles across generations, falling below expectations from our polygenic inheritance model. When the effect of individual PRs is accounted for, we observed sex-specific associations between familial PRS and patients' symptom dimensions. Our results clearly demonstrate that polygenic inheritance alone does not adequately explain disease transmission in families. Such an approach may also clarify why some families exhibit dense clustering of cases despite minimal polygenic burden.

Background. There is growing evidence to suggest a clinically significant overlap between autism spectrum conditions and psychotic disorders. Preliminary evidence suggest that autism diagnoses and autistic traits are associated with poorer outcomes following a first episode of psychosis. Methods. This study used data from the Cambridgeshire and Peterborough National Health Service Foundation Trust (CPFT) Research Database to examine clinical outcomes in autistic and non-autistic people following a first episode of psychosis. We describe patterns of community and inpatient service use, using descriptive statistics , Cox regression, binomial logistic regression, and negative binomial regression. Results. Data from 282 autistic and 7127 non-autistic people with psychosis were analysed. Autism was associated with greater community service use (use of mental health emergency lines, mental health detentions by police), as well as greater likelihood of psychiatric hospital admission (adjusted hazard ratio 1.34, 95% confidence interval 1.05 -1.7, p<0.05) and longer inpatient stays (median 111 versus 48 days, p<0.0001). Learning disability played a significant role in the utilisation of community and inpatient services, with lower rates of community service use but longer inpatient admissions. Conclusions. This study indicates a differing pattern of service use between autistic and non-autistic people following psychosis that warrants further research into how best to support autistic people with psychosis.

BackgroundWhile resting-state fMRI demonstrated that brain networks are spatially dynamic (expanding, shrinking, and changing complexity over time), understanding the transient spatial network interactions that remain poorly characterized is critical for revealing the mechanisms underlying brain disorders. MethodsWe introduce DESINE (Dynamic Estimation of Spatially Interactive Networks), a novel framework using joint density distributions (2D histograms) of voxel-wise activity to quantify 4D spatial network interactions across sliding windows. We analysed transient deviations from the average functional state using root-mean-square error (RMSE) and mean absolute deviation (MAD), and characterized recurring interaction patterns using k-means clustering. We applied DESINE to 91 network pairs (14 networks) in a cohort of 508 subjects (315 healthy controls; 193 patients with schizophrenia, SZ). ResultsSZ is characterized by a significantly "constrained dynamic repertoire" of network interactions. SZ patients showed markedly lower means and standard deviations for both RMSE and MAD metrics across network pairs, particularly in regions of high activity, indicating systematic rigidity. Cluster analysis revealed significant alterations in state affinity metrics, suggesting a global breakdown in the brains capacity to preserve diverse, high-fidelity spatial configurations. Critically, these interaction metrics were associated with cognitive performance, symptom scores on the positive and negative syndrome scale, and chlorpromazine equivalent drug scores. ConclusionsThis work introduces DESINE as a global, voxel-agnostic framework for characterizing time-varying spatial interactions. Our findings highlight spatial rigidity as a fundamental feature of psychopathology, suggesting that the inability to express a diverse range of spatial interactions is a factor underlying cognitive deficits in schizophrenia.

Forensic patients often have complex and costly healthcare needs, even following discharge from secure care. However, little is known about their health and justice outcomes after community reintegration. To address this gap in the literature, we conducted a systematic review and meta-analysis to estimate the incidence of key post-discharge outcomes among community-discharged forensic patients, including any reoffending, violent reoffending, reconvictions, readmissions, all-cause mortality, and suicide. We systematically searched PsycINFO, Embase, CINAHL, Medline, PubMed, and ProQuest Dissertations from database inception to May 2025 (PROSPERO CRD42024529265). Random-effect meta-analyses were used to generate pooled incidence estimates, with heterogeneity quantified using prediction intervals. A total of 49 studies met inclusion criteria (total patient n = 18,871) and contributed to the meta-analyses. The pooled incidence rate per 100,000 person-years was: any reoffending 3,889 (95% CI 2,055, 7,359; 95% PI 290, 52,136); violent reoffending 1,851 (95% CI 1,229, 2,789; 95% PI 201, 17,068); reconvictions 3,291 (95% CI 2,591, 4,179; 95% PI 950, 11,394); readmissions 7,945 (95% CI 5,507, 11,463; 95% PI 1,225, 51,548); all-cause mortality 1,789 (95% CI 1,341, 2,388; 95% PI 673, 4,756); and suicide 407 (95% CI 319, 519; 95% PI 225, 735). Overall, the reoffending rate for forensic patients discharged to the community was lower than that reported for other cohorts of people charged with general and violent offences. However, despite typically receiving long admission periods, discharged forensic patients continue to experience high rates of readmission, all-cause mortality, and suicide relative to other psychiatric patient groups in the community. Together, our findings highlight a need for enhanced post-discharge suicide support for forensic patients living in the community to better facilitate successful, long-term reintegration.

Schizophrenia is a severe psychiatric disorder associated with altered dopaminergic signaling and hippocampal circuit dysfunction. Although antipsychotic medications remain the standard treatment, many are limited by incomplete efficacy and adverse effects. Cariprazine, a dopamine D2/D3 receptor partial agonist, has a favorable clinical profile, but its effects on neuronal excitability and network activity remain incompletely understood. Here, we integrated nationwide real-world clinical data with in vitro electrophysiology, computational modeling, and molecular analyses to define the neuronal actions of cariprazine. Among Hungarian patients diagnosed with schizophrenia and receiving index-drug monotherapy with one of the three prespecified D2/D3 targeting antipsychotics, haloperidol was associated with worse survival and a higher cumulative incidence of first registered suicide attempt than cariprazine or aripiprazole in matched observational cohorts. In primary mouse hippocampal cultures, multielectrode array recordings showed that acute cariprazine treatment moderately reduced spontaneous firing in a dose-dependent manner and prolonged burst intervals while largely preserving network synchronization. These effects were milder than those of haloperidol and aripiprazole. Whole-cell patch-clamp recordings revealed cell-type-dependent effects, with reduced intrinsic excitability and increased firing irregularity mainly in regular- and stuttering-type neurons. Conductance-based modeling identified enhanced Kv1-mediated D-type potassium currents as sufficient to reproduce these effects. Consistent with this mechanism, chronic cariprazine treatment altered Kv1.2 protein distribution without changing Kcna2/Kcna3 or Drd1/Drd2/Drd3 transcript expression. These findings identify modulation of intrinsic excitability via Kv1/D-type potassium currents as a candidate cellular mechanism of cariprazine and provide a translational link between real-world evidence and circuit-level drug effects.

Background: Childhood adversity (CA) is recognized as a distal risk-factor for suicide attempts (SA) in individuals with psychiatric disorders. However, not all individuals with experiences of CA will engage in SA. Contributing to this relationship may be proximal factors such as impulsivity, inward anger and self-aggression. However, these factors are often conceptually blended and measured in different samples. We sought to clarify association among CA and personality factors in persons with SA. Methods: Participants from two studies comprised individuals with a diagnosed psychiatric disorder and history of SA (n= 139) and individuals with depressive disorder (clinical controls, CC; n= 24). We investigated self-reported levels of CA, impulsivity, inward anger, and self-aggression between the SA and CC (pcorr< .012). We tested the relationship among the factors using regression (pcorr<.017) and mediation model (indirect effects, p<.05) within the SA group. Sensitivity models were run controlling for age, gender, symptom severity, trait anger, and externally oriented aggression. Results: SA group had higher impulsivity (pcorr=.067) in a model controlled for age and gender. Other factors did not differ among groups. Within the SA group the analyses revealed positive association among CA and personality factors (pcorr<.06) in basic and model with age and gender, however the association was not specific for internally (self) oriented factors (coefficient comparison, p<.07). Parallel mediation model indicated that CA had indirect effect on self-aggression through impulsivity (p=.001) and to a lesser extent through inward anger (p=.066). Generally, models controlling for cognitive depression symptoms showed less prominent effects (pcorr>.1). Limitations: The study was cross-sectional and did not include behavioral tasks (state) measures of proximal factors. Conclusions: CA and personality factors showed similar severity levels among the SA and CC groups suggesting they may relate to broader psychopathologies, rather than specifically to SA. The association of CA with anger and aggression was unspecific to internally oriented factors indicating the need for more precise measuring instruments developed specifically for individuals with SA. Overall, the study highlights personality factors as being associated with risk in broader vulnerable populations.

Abstract Schizophrenia (SCZ) and bipolar disorder (BPD) are highly heritable psychiatric disorders with complex polygenic architectures. Genome-wide association studies (GWASs) have identified numerous common variant associations, but rarer variants detectable through whole-genome sequencing (WGS) remain underexplored. We conducted rare variant association analysis using WGS data from the Portuguese Island Collection (PIC), including 28 families with SCZ (n = 53) and 41 families with BPD (n = 83) cases, and population controls (n = 62). Following ANNOVAR and CADD annotation, burden analysis of deleterious variants showed that both affected and unaffected family members from SCZ and BPD pedigrees had significantly higher burdens of rare deleterious variants compared to controls (p < 0.0001), with no significant differences observed between affected and unaffected relatives, consistent with shared familial genetic liability. Polygenic Risk Score (PRS) analysis confirmed significant genetic contributions to both disorders within PIC. Association analyses were subsequently performed using SAIGE-GENE+ identifying 483 and 583 nominally significant (suggestive associations) gene sets (p-value [&le;] 0.05; FDR > 0.05) for SCZ and BPD, respectively, including gene sets related to neurotransmission, synaptic function and structure, neurodevelopment, and neuroinflammation as well as major signaling pathways. Cross disorder overlaps also identified shared suggestive enrichment of GABA and glutamate signaling, synaptic signaling, and Wnt signaling gene sets in both SCZ and BPD. These findings support shared rare variant burden within multiplex psychiatric families and highlight the role of gene-set based rare variant analysis in identifying neurobiological pathways relevant to SCZ and BPD. Keywords: WGS, Rare Variants, Schizophrenia, Bipolar Disorder

Schizophrenia is a severe neuropsychiatric disorder that affects the behavioral, emotional and cognitive state of patients. Despite its substantial heritability, the molecular etiology of the disease remains poorly understood. Many schizophrenia-associated genetic variants reside in non-coding regions, and exert their effects through distal regulatory elements of the genome. In this context, the three-dimensional organization of the genome is expected to play a decisive role in establishing contacts between these regulatory elements and their target genes, thereby mediating schizophrenia-associated dysregulation of gene expression. Here, we present a novel Hi-C dataset providing an unprecedented view of three-dimensional genome organization in post-mortem schizophrenia brain samples. Our findings indicate that most changes occur at long-range genomic distances while local architecture of topologically-associated domains remains largely intact. However, neurons display localized and functionally relevant loop differences, particularly in regulatory regions associated with neurodevelopmental processes. Global characteristics of higher-order chromatin organization show accelerated aging alteration pattern in schizophrenia, and downstream analysis of transcriptomic data in schizophrenia brain samples further confirms that schizophrenia is associated with accelerated aging.

IntroductionThe anterior limb of the internal capsule (ALIC) is a major white matter highway connecting prefrontal cortical (PFC) regions to the thalamus, brainstem, and subthalamic nucleus. Structural and functional abnormalities within the ALIC circuit have been associated with many neuropsychiatric disorders, including obsessive-compulsive disorder (OCD) and depression, and deep brain stimulation (DBS) may provide effective treatment to some of these patients. However, it remains unclear whether the well-characterized topographic organization of the ALIC observed in healthy individuals and preclinical models is preserved in treatment-resistant psychiatric populations. MethodsWe first used diffusion tractography to evaluate the topography of PFC and subcortical fibers through the ALIC in patients with treatment-resistant OCD (n=18) and depression (n=5). In depression patients, we also evaluated ALIC topography using cerebro-cerebral evoked potentials (CCEPs) elicited by single-pulse electrical stimulation (SPES) of DBS leads in the ALIC and recordings in the ventral PFC (vPFC). ResultsThe topographic organization of PFC and subcortical projections is preserved in the ALIC among treatment-resistant psychiatric patients, consistent with patterns observed in healthy individuals and preclinical models. CCEP recordings in the ventral PFC showed a ventral ALIC to medial vPFC/dorsal ALIC to lateral vPFC response pattern in the left hemisphere, but not in the right. ConclusionOur findings confirm that topographic patterns within the ALIC previously identified using preclinical models and healthy controls are preserved in treatment-resistant psychiatric patients. Furthermore, by linking white matter topography to stimulation effects, this work supports more precise and individualized neuromodulatory strategies for neuropsychiatric disorders.

The glutamate delta 1 receptor (GluD1) represents a unique subtype of ionotropic glutamate receptors that is strongly expressed in the mammalian striatum. Disruptions of the GRID1 gene, which encodes GluD1, have been associated with neuropsychiatric disorders, including schizophrenia and autism spectrum disorder; however, the role of GluD1 in the brain remains poorly understood. Previous studies in mice have demonstrated that the knockout of striatal GluD1 led to fear-conditioning deficits and depressive-like behaviors. Furthermore, these mice exhibited reduced excitatory input to the striatum due to a loss of thalamostriatal innervation, whereas corticostriatal innervation was unaffected. In this study, we examined whether changes in synapse morphology contribute to the observed functional deficits. We found that the ablation of GluD1 does not affect synaptic targeting patterns of corticostriatal and thalamostriatal terminals, using transmission electron microscopy. We further utilized three-dimensional reconstruction to obtain quantitative data on synapse ultrastructure and found no significant changes in corticostriatal and thalamostriatal synaptic components, including the presynaptic terminal volume, postsynaptic density area and morphology, and postsynaptic dendritic spine volume. These findings support a model in which GluD1 regulates input-specific circuit organization and synaptic connectivity rather than the structural morphology of individual synapses.

Introduction: Engagement with mental health services (MHCS) during the first episode of psychosis (FEP) is critical for symptom control, quality of life, and relapse prevention. However, disengagement rates remain high in Uganda with severe consequences for patients and caregivers. This study protocol describes a mixed-methods investigation which aims to examine the relationship between patients and caregivers lived experiences and mental health service engagement during first-episode psychosis. Methods and Analysis. The mixed-methods study will recruit 82 patients with first-episode psychosis and their primary caregivers from Butabika National Referral Mental Hospital in Kampala, Uganda. Inclusion criteria are ages 18-60, less than 12 weeks on antipsychotic medications, living in the greater Kampala Metropolitan Area, with a consenting caregiver. Caregivers must be an adult (> 18years) providing full-time care for at least 6 months prior. Patients with substance use disorders will be excluded. Qualitative data on the lived experiences of patients and caregivers will be collected using the draw-write-and-tell method, while quantitative data on service engagement and associated factors will be collected using semi-structured questionnaires. The data will be analysed using Stata version 18, and participants will be reimbursed for their time. Ethics and Dissemination. Ethical clearance has been obtained from the School of Medicine Research and Ethics Committee (SOMREC) Ref: Mak-SOMREC-2024-1002 and institutional approval from Butabiika National Referral Mental Hospital. All participants will provide informed consent prior to participation. Data will be de-identified and securely stored, with results disseminated through peer-reviewed academic publications, conferences and community stakeholder workshops.

Background/ObjectivesPersistent cognitive impairments are prevalent in methamphetamine (meth) use disorder and contribute to maladaptive decision-making and increased relapse vulnerability. There are currently no effective treatments for meth-associative cognitive deficits, and their neurobiological underpinnings remain incompletely understood. This study investigated the effects of chronic meth self-administration on episodic-like recognition memory and evaluated whether pharmacological potentiation of metabotropic glutamate receptor subtype 2 (mGlu2) could rescue these deficits. MethodsAdult male Sprague-Dawley rats underwent 7 days of limited- (1h/day) followed by 14 days of extended-access (6h/day) meth self-administration, followed by 30 days of abstinence. Recognition memory was assessed using the object-in-place (OIP) task. A positive allosteric modulator of mGlu2 receptors, LY-487379 (25 mg/kg, s.c.), was administered prior to the memory test. In parallel, changes in total and surface mGlu2/3 protein levels in the prelimbic and perirhinal cortices were evaluated. ResultsRats with extended access to meth self-administration exhibited escalated drug intake and persistent deficits in OIP memory. Administration of LY-487379 reversed this deficit. Total mGlu2/3 protein levels were unaltered; however, meth exposure was associated with a significant increase in surface mGlu2/3 receptor expression in both cortical regions examined. ConclusionsThese results demonstrate that chronic meth produces persistent cognitive dysfunction that can be rescued by mGlu2 receptor potentiation. The observed increase in surface mGlu2/3 expression may represent a compensatory response to chronic glutamatergic dysregulation, but it appears to be insufficient to restore cognitive function alone, without pharmacological enhancement. The current data encourage further exploration of mGlu2 role in stimulant-associated cognitive dysfunction. HighlightsChronic methamphetamine self-administration produced persistent deficits in episodic-like recognition memory in male rats and dysregulation of mGlu2/3 receptors in the prelimbic and perirhinal cortices. Systemic pharmacological potentiation of mGlu2 receptors rescued meth-associated memory deficits. mGlu2 receptor potentiation may represent a promising therapeutic strategy for treating stimulant-associated cognitive dysfunction. Increased surface mGlu2/3 expression may represent a compensatory adaptation to post-methamphetamine glutamatergic dysfunction, but it is not sufficient to restore cognition alone, without pharmacological enhancement.