The influence of chronic exposure to antipsychotic medications on brain size before and after tissue fixation: a comparison of haloperidol and olanzapine in macaque monkeys

Schizophrenia, Off-Label Antipsychotics, and Dementia Risk in People With HIV

BACKGROUND

Comorbidities such as schizophrenia and medication such as antipsychotics may influence the risk of dementia among people living with HIV (PLWH). The objective of this article is to assess the associations among HIV patients with schizophrenia, off-label antipsychotics, and dementia risk.

SETTING

US Department of Veterans Affairs health care facilities from 2000 to September 2023.

METHODS

Retrospective cohort study of PLWH treated by the US Department of Veterans Affairs with history of schizophrenia, off-label antipsychotic use, and neither schizophrenia nor antipsychotic use. Propensity score-matched non-HIV controls were included for the respective HIV groups. The hazard of dementia is estimated using Cox proportional hazards models.

RESULTS

PLWH and schizophrenia, were found to have a 2.49 higher hazard of dementia than HIV patients with no history of schizophrenia or antipsychotic medication use (hazard ratio [HR] = 2.49, 95% confidence interval [CI]: 1.85 to 3.35). PLWH and off-label antipsychotic use were found to have a 1.77-fold higher hazard of dementia than HIV patients with no history of schizophrenia or antipsychotic medication use (HR = 1.77, 95% CI: 1.37 to 2.28). Propensity score-matched analysis reveals that, among patients with schizophrenia, those with HIV had a 1.65-fold higher hazard of dementia (HR = 1.65, 95% CI: 1.12 to 2.44). Among patients with no schizophrenia or antipsychotic medication, those with HIV had a 1.47-fold higher hazard of dementia (HR = 1.47, 95% CI: 1.33 to 1.63).

CONCLUSIONS

This study demonstrates that among PLWH, history of schizophrenia or off-label antipsychotic medication use are associated with substantial increases in dementia incidence. Furthermore, propensity score-matched control analysis reveals that HIV infection itself is independently and significantly associated with elevated dementia risk.

Brainwide Anatomical Connectivity and Prediction of Longitudinal Outcomes in Antipsychotic-Naïve First-Episode Psychosis

BACKGROUND

Disruptions of axonal connectivity are thought to be a core pathophysiological feature of psychotic illness, but whether they are present early in the illness, prior to antipsychotic exposure, and whether they can predict clinical outcome remain unknown.

METHODS

We acquired diffusion-weighted magnetic resonance images to map structural connectivity between each pair of 319 parcellated brain regions in 61 antipsychotic-naïve individuals with first-episode psychosis (15-25 years, 46% female) and a demographically matched sample of 27 control participants. Clinical follow-up data were also acquired in patients 3 and 12 months after the scan. We used connectome-wide analyses to map disruptions of inter-regional pairwise connectivity and connectome-based predictive modeling to predict longitudinal change in symptoms and functioning.

RESULTS

Individuals with first-episode psychosis showed disrupted connectivity in a brainwide network linking all brain regions compared with controls (familywise error-corrected p = .03). Baseline structural connectivity significantly predicted change in functioning over 12 months (r = 0.44, familywise error-corrected p = .041), such that lower connectivity within fronto-striato-thalamic systems predicted worse functional outcomes.

CONCLUSIONS

Brainwide reductions of structural connectivity exist during the early stages of psychotic illness and cannot be attributed to antipsychotic medication. Moreover, baseline measures of structural connectivity can predict change in patient functional outcomes up to 1 year after engagement with treatment services.

Preventing disease progression in schizophrenia: What are we waiting for

Despite research advances and progress in health care, schizophrenia remains a debilitating and costly disease. Onset occurs typically during youth and can lead to a relapsing and ultimately chronic course with persistent symptoms and functional impairment if not promptly and properly treated. Consequently, over time, schizophrenia causes substantial distress and disability for patients, their families and accrues to a collective burden to society. Recent research has revealed much about the pathophysiology that underlies the progressive nature of schizophrenia. Additionally, treatment strategies for disease management have been developed that have the potential to not just control psychotic symptoms but limit the cumulative morbidity of the illness. Given the evidence for their effectiveness and feasibility for their application, it is perplexing that this model of care has not yet become the standard of care and widely implemented to reduce the burden of illness on patients and society. This begs the question of whether the failure of implementation of a potentially disease-modifying strategy is due to the lack of evidence of efficacy (or belief in it) and readiness for implementation, or whether it's the lack of motivation and political will to support their utilization. To address this question, we reviewed and summarized the literature describing the natural history, pathophysiology and therapeutic strategies that can alleviate symptoms, prevent relapse, and potentially modify the course of schizophrenia. We conclude that, while we await further advances in mental health care from research, we must fully appreciate and take advantage of the effectiveness of existing treatments and overcome the attitudinal, policy, and infrastructural barriers to providing optimal mental health care capable of providing a disease-modifying treatment to patients with schizophrenia.

Antipsychotic Drugs: A Concise Review of History, Classification, Indications, Mechanism, Efficacy, Side Effects, Dosing, and Clinical Application

The introduction of the first antipsychotic drug, chlorpromazine, was a milestone for psychiatry. The authors review the history, classification, indications, mechanism, efficacy, side effects, dosing, drug initiation, switching, and other practical issues and questions related to antipsychotics. Classifications such as first-generation/typical versus second-generation/atypical antipsychotics are neither valid nor useful; these agents should be described according to the Neuroscience-based Nomenclature (NbN). Antipsychotic drugs are not specific for treating schizophrenia. They reduce psychosis regardless of the underlying diagnosis, and they go beyond nonspecific sedation. All currently available antipsychotic drugs are dopamine blockers or dopamine partial agonists. In schizophrenia, effect sizes for relapse prevention are larger than for acute treatment. A major unresolved problem is the implausible increase in placebo response in antipsychotic drug trials over the decades. Differences in side effects, which can be objectively measured, such as weight gain, are less equivocal than differences in rating-scale-measured (subjective) efficacy. The criteria for choosing among antipsychotics are mainly pragmatic and include factors such as available formulations, metabolism, half-life, efficacy, and side effects in previous illness episodes. Plasma levels help to detect nonadherence, and once-daily dosing at night (which is possible with many antipsychotics) and long-acting injectable formulations are useful when adherence is a problem. Dose-response curves for both acute treatment and relapse prevention follow a hyperbolic pattern, with maximally efficacious average dosages for schizophrenia of around 5 mg/day risperidone equivalents. Computer apps facilitating the choice between drugs are available. Future drug development should include pharmacogenetics and focus on drugs for specific aspects of psychosis.

Ketamine-dependent patients with persistent psychosis have higher neurofilament light chain levels than patients with schizophrenia

OBJECTIVES

Ketamine can induce persisting psychosis in a subset of individuals who use it chronically and heavily. Previously, we found that the psychopathology and cognitive impairments in patients with ketamine dependence (KD) exhibiting persistent psychosis (KPP) bear resemblances with schizophrenia, albeit with less severity in those with no persistent psychosis (KNP). Furthermore, we also showed that patients with KD had higher blood levels of neurofilament light chain (NFL), a biomarker for neuroaxonal injury, compared to healthy controls. In this study, we aimed to investigate the differences in NFL levels between patients with KPP and KNP while comparing the levels of individuals with schizophrenia and healthy controls.

METHODS

We enrolled 64 treatment-seeking ketamine-dependent patients (53 with KNP and 11 with KPP), 37 medication-free patients with schizophrenia, and 80 healthy controls. Blood NFL levels were measured by single molecule array immunoassay.

RESULTS

NFL levels were highest in the KPP subgroup, followed by the KNP subgroup, and then the schizophrenia and control groups (mean ± SD: 24.5 ± 24.7, 12.9 ± 10.9, 9.2 ± 12.2, and 6.2 ± 2.2 pg/mL, respectively), with no significant difference observed between the schizophrenia and control groups.

CONCLUSIONS

We found that KD is associated with higher NFL levels compared to schizophrenia, with the KPP subgroup showing the most consistent alterations. The observation of accentuated neuroaxonal pathology in individuals with KPP implies that this clinical manifestation is associated with a specific neurobiological phenotype, despite prior evidence suggesting syndromal similarity between schizophrenia and KPP.

Neurostructural, Neurofunctional, and Clinical Features of Chronic, Untreated Schizophrenia: A Narrative Review

Studies of individuals with chronic, untreated schizophrenia (CUS) can provide important insights into the natural course of schizophrenia and how antipsychotic pharmacotherapy affects neurobiological aspects of illness course and progression. We systematically review 17 studies on the neuroimaging, cognitive, and epidemiological aspects of CUS individuals. These studies were conducted at the Shanghai Mental Health Center, Institute of Mental Health at Peking University, and Huaxi MR Research Center between 2013 and 2021. CUS is associated with cognitive impairment, severe symptoms, and specific demographic characteristics and is different significantly from those observed in antipsychotic-treated individuals. Furthermore, CUS individuals have neurostructural and neurofunctional alterations in frontal and temporal regions, corpus callosum, subcortical, and visual processing areas, as well as default-mode and somatomotor networks. As the disease progresses, significant structural deteriorations occur, such as accelerated cortical thinning in frontal and temporal lobes, greater reduction in fractional anisotropy in the genu of corpus callosum, and decline in nodal metrics of gray mater network in thalamus, correlating with worsening cognitive deficits and clinical outcomes. In addition, striatal hypertrophy also occurs, independent of antipsychotic treatment. Contrasting with the negative neurostructural and neurofunctional effects of short-term antipsychotic treatment, long-term therapy frequently results in significant improvements. It notably enhances white matter integrity and the functions of key subcortical regions such as the amygdala, hippocampus, and striatum, potentially improving cognitive functions. This narrative review highlights the progressive neurobiological sequelae of CUS, the importance of early detection, and long-term treatment of schizophrenia, particularly because treatment may attenuate neurobiological deterioration and improve clinical outcomes.

Brain Age Gap in Early Illness Schizophrenia and the Clinical High-Risk Syndrome: Associations With Experiential Negative Symptoms and Conversion to Psychosis

BACKGROUND AND HYPOTHESIS

Brain development/aging is not uniform across individuals, spawning efforts to characterize brain age from a biological perspective to model the effects of disease and maladaptive life processes on the brain. The brain age gap represents the discrepancy between estimated brain biological age and chronological age (in this case, based on structural magnetic resonance imaging, MRI). Structural MRI studies report an increased brain age gap (biological age > chronological age) in schizophrenia, with a greater brain age gap related to greater negative symptom severity. Less is known regarding the nature of this gap early in schizophrenia (ESZ), if this gap represents a psychosis conversion biomarker in clinical high-risk (CHR-P) individuals, and how altered brain development and/or aging map onto specific symptom facets.

STUDY DESIGN

Using structural MRI, we compared the brain age gap among CHR-P (n = 51), ESZ (n = 78), and unaffected comparison participants (UCP; n = 90), and examined associations with CHR-P psychosis conversion (CHR-P converters n = 10; CHR-P non-converters; n = 23) and positive and negative symptoms.

STUDY RESULTS

ESZ showed a greater brain age gap relative to UCP and CHR-P (Ps < .010). CHR-P individuals who converted to psychosis showed a greater brain age gap (P = .043) relative to CHR-P non-converters. A larger brain age gap in ESZ was associated with increased experiential (P = .008), but not expressive negative symptom severity.

CONCLUSIONS

Consistent with schizophrenia pathophysiological models positing abnormal brain maturation, results suggest abnormal brain development is present early in psychosis. An increased brain age gap may be especially relevant to motivational and functional deficits in schizophrenia.

Deep Learning-based Brain Age Prediction in Patients With Schizophrenia Spectrum Disorders

BACKGROUND AND HYPOTHESIS

The brain-predicted age difference (brain-PAD) may serve as a biomarker for neurodegeneration. We investigated the brain-PAD in patients with schizophrenia (SCZ), first-episode schizophrenia spectrum disorders (FE-SSDs), and treatment-resistant schizophrenia (TRS) using structural magnetic resonance imaging (sMRI).

STUDY DESIGN

We employed a convolutional network-based regression (SFCNR), and compared its performance with models based on three machine learning (ML) algorithms. We pretrained the SFCNR with sMRI data of 7590 healthy controls (HCs) selected from the UK Biobank. The parameters of the pretrained model were transferred to the next training phase with a new set of HCs (n = 541). The brain-PAD was analyzed in independent HCs (n = 209) and patients (n = 233). Correlations between the brain-PAD and clinical measures were investigated.

STUDY RESULTS

The SFCNR model outperformed three commonly used ML models. Advanced brain aging was observed in patients with SCZ, FE-SSDs, and TRS compared to HCs. A significant difference in brain-PAD was observed between FE-SSDs and TRS with ridge regression but not with the SFCNR model. Chlorpromazine equivalent dose and cognitive function were correlated with the brain-PAD in SCZ and FE-SSDs.

CONCLUSIONS

Our findings indicate that there is advanced brain aging in patients with SCZ and higher brain-PAD in SCZ can be used as a surrogate marker for cognitive dysfunction. These findings warrant further investigations on the causes of advanced brain age in SCZ. In addition, possible psychosocial and pharmacological interventions targeting brain health should be considered in early-stage SCZ patients with advanced brain age.

Haloperidol, Olanzapine, and Risperidone Induce Morphological Changes in an In Vitro Model of Human Hippocampal Neurogenesis

BACKGROUND

Induced pluripotent stem cell (iPSC) based neuronal differentiation is valuable for studying neuropsychiatric disorders and pharmacological mechanisms at the cellular level. We aimed to examine the effects of typical and atypical antipsychotics on human iPSC-derived neural progenitor cells (NPCs).

METHODS

Proliferation and neurite outgrowth were measured by live cell imaging, and gene expression levels related to neuronal identity were analyzed by RT-QPCR and immunocytochemistry during differentiation into hippocampal dentate gyrus granule cells following treatment of low- and high-dose antipsychotics (haloperidol, olanzapine, and risperidone).

RESULTS

Antipsychotics did not modify the growth properties of NPCs after 3 days of treatment. However, the characteristics of neurite outgrowth changed significantly in response to haloperidol and olanzapine. After three weeks of differentiation, mRNA expression levels of the selected neuronal markers increased (except for MAP2), while antipsychotics caused only subtle changes. Additionally, we found no changes in MAP2 or GFAP protein expression levels as a result of antipsychotic treatment.

CONCLUSIONS

Altogether, antipsychotic medications promoted neurogenesis in vitro by influencing neurite outgrowth rather than changing cell survival or gene expression. This study provides insights into the effects of antipsychotics on neuronal differentiation and highlights the importance of considering neurite outgrowth as a potential target of action.

The contribution of first-episode illness characteristics and cumulative antipsychotic usage to progressive structural brain changes over a long-term follow-up in schizophrenia

Exposure to antipsychotics as well as certain first-episode illness characteristics have been associated with greater gray matter (GM) deficits in the early phase of schizophrenia. Whether the first-episode illness characteristics affect the long-term progression of the structural brain changes remain unexplored. We therefore assessed the role of first-episode illness characteristics and life-time antipsychotic use in relation to long-term structural brain GM changes in schizophrenia. Individuals with schizophrenia (SZ, n = 29) and non-psychotic controls (n = 61) from the Northern Finland Birth Cohort 1966 underwent structural MRI at the ages of 34 (baseline) and 43 (follow-up) years. At follow-up, the average duration of illness was 19.8 years. Voxel-based morphometry was used to assess the effects of predictors on longitudinal GM changes in schizophrenia-relevant brain areas. Younger age of onset (AoO), higher cumulative antipsychotic dose and severity of symptoms were associated with greater GM deficits in the SZ group at follow-up. None of the first-episode illness characteristics were associated with longitudinal GM changes during 9-year follow-up period. We conclude that a younger AoO and high life-time antipsychotic use may contribute to progression of structural brain changes in schizophrenia. Apart from AoO, other first-episode illness characteristics may not contribute to longitudinal GM changes in midlife.

Antipsychotics and structural brain changes: could treatment adherence explain the discrepant findings?

Progressive structural brain changes are well documented in schizophrenia and have been linked to both illness progression and the extent of antipsychotic treatment exposure. Literature reporting longitudinal changes in brain structure in individuals with schizophrenia is selectively reviewed to assess the roles of illness, antipsychotic treatment, adherence and other factors in the genesis of these changes. This narrative review considers literature investigating longitudinal changes in brain structure in individuals with schizophrenia. The review focusses on structural changes in the cortex, basal ganglia and white matter. It also examines effects of medication non-adherence and relapse on the clinical course of the illness and on structural brain changes. Studies investigating structural magnetic resonance imaging changes in patients treated with long-acting injectable antipsychotics are reviewed. Temporal changes in brain structure in schizophrenia can be divided into those that are associated with antipsychotic treatment and those that are not. Changes associated with treatment include increases in basal ganglia and white matter volumes. Relapse episodes may be a critical factor in illness progression and brain volume reductions. Medication adherence may be an important factor that could explain the findings that brain volume reductions are associated with poor treatment response, higher intensity of antipsychotic treatment exposure and more time spent in relapse. Improved adherence via long-acting injectable antipsychotics and adherence focussed psychosocial interventions could maximize protective effects of antipsychotics against illness progression.

Cortical and subcortical brain morphometry abnormalities in youth at clinical high-risk for psychosis and individuals with early illness schizophrenia

Neuroimaging studies have documented morphometric brain abnormalities in schizophrenia, but less is known about them in individuals at clinical high-risk for psychosis (CHR-P), including how they compare with those observed in early schizophrenia (ESZ). Accordingly, we implemented multivariate profile analysis of regional morphometric profiles in CHR-P (n = 89), ESZ (n = 93) and healthy controls (HC; n = 122). ESZ profiles differed from HC and CHR-P profiles, including 1) cortical thickness: significant level reduction and regional non-parallelism reflecting widespread thinning, except for entorhinal and pericalcarine cortex, 2) basal ganglia volume: significant level increase and regional non-parallelism reflecting larger caudate and pallidum, and 3) ventricular volume: significant level increase with parallel regional profiles. CHR-P and ESZ cerebellar profiles showed significant non-parallelism with HC profiles. Regional profiles did not significantly differ between groups for cortical surface area or subcortical volume. Compared to CHR-P followed for ≥18 months without psychosis conversion (n = 31), CHR-P converters (n = 17) showed significant non-parallel ventricular volume expansion reflecting specific enlargement of lateral and inferolateral regions. Antipsychotic dosage in ESZ was significantly correlated with frontal cortical thinning. Results suggest that morphometric abnormalities in ESZ are not present in CHR-P, except for ventricular enlargement, which was evident in CHR-P who developed psychosis.

The Effects of Antipsychotics in Experimental Models of Krabbe Disease

The role of altered myelin in the onset and development of schizophrenia and changes in myelin due to antipsychotics remains unclear. Antipsychotics are D₂ receptor antagonists, yet D₂ receptor agonists increase oligodendrocyte progenitor numbers and limit oligodendrocyte injury. Conflicting studies suggest these drugs promote the differentiation of neural progenitors to oligodendrocyte lineage, while others report antipsychotics inhibit the proliferation and differentiation of oligodendrocyte precursors. Here, we utilised in-vitro (human astrocytes), ex-vivo (organotypic slice cultures) and in-vivo (twitcher mouse model) experimental study designs of psychosine-induced demyelination, a toxin that accumulates in Krabbe disease (KD), to investigate direct effects of antipsychotics on glial cell dysfunction and demyelination. Typical and atypical antipsychotics, and selective D₂ and 5HT_2A receptor antagonists, attenuated psychosine-induced cell viability, toxicity, and morphological aberrations in human astrocyte cultures. Haloperidol and clozapine reduced psychosine-induced demyelination in mouse organotypic cerebellar slices. These drugs also attenuated the effects of psychosine on astrocytes and microglia and restored non-phosphorylated neurofilament levels, indicating neuroprotective effects. In the demyelinating twitcher mouse model of KD, haloperidol improved mobility and significantly increased the survival of these animals. Overall, this study suggests that antipsychotics directly regulate glial cell dysfunction and exert a protective effect on myelin loss. This work also points toward the potential use of these pharmacological agents in KD.

Antipsychotic treatment effects and structural MRI brain changes in schizophrenia

BACKGROUND

Progressive brain structural MRI changes are described in schizophrenia and have been ascribed to both illness progression and antipsychotic treatment. We investigated treatment effects, in terms of total cumulative antipsychotic dose, efficacy and tolerability, on brain structural changes over the first 24 months of treatment in schizophrenia.

METHODS

A prospective, 24-month, single-site cohort study in 99 minimally treated patients with first-episode schizophrenia, schizophreniform and schizoaffective disorder, and 98 matched healthy controls. We treated the patients according to a fixed protocol with flupenthixol decanoate, a long-acting injectable antipsychotic. We assessed psychopathology, cognition, extrapyramidal symptoms and BMI, and acquired MRI scans at months 0, 12 and 24. We selected global cortical thickness, white matter volume and basal ganglia volume as the regions of interest.

RESULTS

The only significant group × time interaction was for basal ganglia volumes. However, patients, but not controls, displayed cortical thickness reductions and increases in white matter and basal ganglia volumes. Cortical thickness reductions were unrelated to treatment. White matter volume increases were associated with lower cumulative antipsychotic dose, greater improvements in psychopathology and cognition, and more extrapyramidal symptoms. Basal ganglia volume increases were associated with greater improvements in psychopathology, greater increases in BMI and more extrapyramidal symptoms.

CONCLUSIONS

We provide evidence for plasticity in white matter and basal ganglia associated with antipsychotic treatment in schizophrenia, most likely linked to the dopamine blocking actions of these agents. Cortical changes may be more closely related to the neurodevelopmental, non-dopaminergic aspects of the illness.

Altered expression of microglial markers of phagocytosis in schizophrenia

BACKGROUND

Cognitive disturbances in schizophrenia have been linked to a lower density of dendritic spines on pyramidal neurons in the prefrontal cortex (PFC). Complement component C4, which has previously been found at higher levels in schizophrenia, marks synapses for phagocytosis by microglia. Thus, elevated consumption of dendritic spines by microglia mediated through excessive complement activity may play a role in lower spine density in schizophrenia. However, it is unclear if microglia themselves have the molecular capacity for enhanced phagocytosis of spines in schizophrenia.

METHODS

Transcript levels for complement components and microglia-specific phagocytic markers were quantified using quantitative PCR in the PFC of 62 matched pairs of schizophrenia and unaffected comparison subjects and in antipsychotic-exposed monkeys.

RESULTS

Relative to comparison subjects, schizophrenia subjects had higher mRNA levels for C4 (+154 %); C1q (+69 %), which initiates the classical complement pathway that includes C4; and for microglia-specific markers that enable phagocytic activity including TAM receptor tyrosine kinases Axl (+27 %) and MerTK (+27 %) and lysosome-associated glycoprotein CD68 (+27 %) (all p ≤ .042). Transcript levels for microglial phagocytic markers were correlated with C4 mRNA levels in schizophrenia subjects (all r ≥ 0.31, p ≤ .015). We also found further evidence consistent with microglial activation in schizophrenia, including higher mRNA levels for THIK1 (TWIK-related halothane-inhibited potassium channel: +30 %) and lower mRNA levels for the purinergic receptor P2Y12 (-27 %) (all p ≤ .016). Transcript levels were unchanged in antipsychotic-exposed monkeys.

CONCLUSIONS

These results are consistent with the presence of increased complement activity and an elevated molecular capacity of microglia for phagocytosis in the same schizophrenia subjects.

Glutamatergic dysfunction in Schizophrenia

The NMDA-R hypofunction model of schizophrenia started with the clinical observation of the precipitation of psychotic symptoms in patients with schizophrenia exposed to PCP or ketamine. Healthy volunteers exposed to acute low doses of ketamine experienced mild psychosis but also negative and cognitive type symptoms reminiscent of the full clinical picture of schizophrenia. In rodents, acute systemic ketamine resulted in a paradoxical increase in extracellular frontal glutamate as well as of dopamine. Similar increase in prefrontal glutamate was documented with acute ketamine in healthy volunteers with 1H-MRS. Furthermore, sub-chronic low dose PCP lead to reductions in frontal dendritic tree density in rodents. In post-mortem ultrastructural studies in schizophrenia, a broad reduction in dendritic complexity and somal volume of pyramidal cells has been repeatedly described. This most likely accounts for the broad, subtle progressive cortical thinning described with MRI in- vivo. Additionally, prefrontal reductions in the obligatory GluN1 subunit of the NMDA-R has been repeatedly found in post-mortem tissue. The vast 1H-MRS literature in schizophrenia has documented trait-like small increases in glutamate concentrations in striatum very early in the illness, before antipsychotic treatment (the same structure where increased pre-synaptic release of dopamine has been reported with PET). The more recent genetic literature has reliably detected very small risk effects for common variants involving several glutamate-related genes. The pharmacological literature has followed two main tracks, directly informed by the NMDA-R hypo model: agonism at the glycine site (as mostly add-on studies targeting negative and cognitive symptoms); and pre-synaptic modulation of glutamatergic release (as single agents for acute psychosis). Unfortunately, both approaches have failed so far. There is little doubt that brain glutamatergic abnormalities are present in schizophrenia and that some of these are related to the etiology of the illness. The genetic literature directly supports a non- specific etiological role for glutamatergic dysfunction. Whether NMDA-R hypofunction as a specific mechanism accounts for any important component of the illness is still not evident. However, a glutamatergic model still has heuristic value to guide future research in schizophrenia. New tools to jointly examine brain glutamatergic, GABA-ergic and dopaminergic systems in-vivo, early in the illness, may lay the ground for a next generation of clinical trials that go beyond dopamine D2 blockade.

Improving Cavalieri volume estimation based on non-equidistant planar sections: The trapezoidal estimator

The Cavalieri estimator allows one to infer the volume of an object from area measurements in equidistant planar sections. It is known that applying this estimator in the non-equidistant case may inflate the coefficient of error considerably. We therefore consider a newly introduced variant, the trapezoidal estimator, and make it available to practitioners. Its typical variance behaviour for natural objects is comparable to the equidistant case. We state this unbiased estimator, describe variance estimates and explain how the latter can be simplified under rather general but realistic models for the gaps between sections. Simulations and an application to a synthetic area function based on parietal lobes of 18 monkeys illustrate the new methods.

The role of hypothalamic endoplasmic reticulum stress in schizophrenia and antipsychotic-induced weight gain: A narrative review

Schizophrenia (SCZ) is a serious mental illness that affects 1% of people worldwide. SCZ is associated with a higher risk of developing metabolic disorders such as obesity. Antipsychotics are the main treatment for SCZ, but their side effects include significant weight gain/obesity. Despite extensive research, the underlying mechanisms by which SCZ and antipsychotic treatment induce weight gain/obesity remain unclear. Hypothalamic endoplasmic reticulum (ER) stress is one of the most important pathways that modulates inflammation, neuronal function, and energy balance. This review aimed to investigate the role of hypothalamic ER stress in SCZ and antipsychotic-induced weight gain/obesity. Preliminary evidence indicates that SCZ is associated with reduced dopamine D2 receptor (DRD2) signaling, which significantly regulates the ER stress pathway, suggesting the importance of ER stress in SCZ and its related metabolic disorders. Antipsychotics such as olanzapine activate ER stress in hypothalamic neurons. These effects may induce decreased proopiomelanocortin (POMC) processing, increased neuropeptide Y (NPY) and agouti-related protein (AgRP) expression, autophagy, and leptin and insulin resistance, resulting in hyperphagia, decreased energy expenditure, and central inflammation, thereby causing weight gain. By activating ER stress, antipsychotics such as olanzapine activate hypothalamic astrocytes and Toll-like receptor 4 signaling, thereby causing inflammation and weight gain/obesity. Moreover, evidence suggests that antipsychotic-induced ER stress may be related to their antagonistic effects on neurotransmitter receptors such as DRD2 and the histamine H1 receptor. Taken together, ER stress inhibitors could be a potential effective intervention against SCZ and antipsychotic-induced weight gain and inflammation.

Layer III pyramidal cells in the prefrontal cortex reveal morphological changes in subjects with depression, schizophrenia, and suicide

Brodmann Area 46 (BA46) has long been regarded as a hotspot of disease pathology in individuals with schizophrenia (SCH) and major depressive disorder (MDD). Pyramidal neurons in layer III of the Brodmann Area 46 (BA46) project to other cortical regions and play a fundamental role in corticocortical and thalamocortical circuits. The AutoCUTS-LM pipeline was used to study the 3-dimensional structural morphology and spatial organization of pyramidal cells. Using quantitative light microscopy, we used stereology to calculate the entire volume of layer III in BA46 and the total number and density of pyramidal cells. Volume tensors estimated by the planar rotator quantified the volume, shape, and nucleus displacement of pyramidal cells. All of these assessments were carried out in four groups of subjects: controls (C, n = 10), SCH (n = 10), MDD (n = 8), and suicide subjects with a history of depression (SU, n = 11). SCH subjects had a significantly lower somal volume, total number, and density of pyramidal neurons when compared to C and tended to show a volume reduction in layer III of BA46. When comparing MDD subjects with C, the measured parameters were inclined to follow SCH, although there was only a significant reduction in pyramidal total cell number. While no morphometric differences were observed between SU and MDD, SU had a significantly higher total number of pyramidal cells and nucleus displacement than SCH. Finally, no differences in the spatial organization of pyramidal cells were found among groups. These results suggest that despite significant morphological alterations in layer III of BA46, which may impair prefrontal connections in people with SCH and MDD, the spatial organization of pyramidal cells remains the same across the four groups and suggests no defects in neuronal migration. The increased understanding of pyramidal cell biology may provide the cellular basis for symptoms and neuroimaging observations in SCH and MDD patients.

Testing Equality of Multiple Population Means under Contaminated Normal Model Using the Density Power Divergence

This paper considers the problem of comparing several means under the one-way Analysis of Variance (ANOVA) setup. In ANOVA, outliers and heavy-tailed error distribution can seriously hinder the treatment effect, leading to false positive or false negative test results. We propose a robust test of ANOVA using an M-estimator based on the density power divergence. Compared with the existing robust and non-robust approaches, the proposed testing procedure is less affected by data contamination and improves the analysis. The asymptotic properties of the proposed test are derived under some regularity conditions. The finite-sample performance of the proposed test is examined via a series of Monte-Carlo experiments and two empirical data examples-bone marrow transplant dataset and glucose level dataset. The results produced by the proposed testing procedure are favorably compared with the classical ANOVA and robust tests based on Huber's M-estimator and Tukey's MM-estimator.

Altered Neuroanatomical Signatures of Patients With Treatment-Resistant Schizophrenia Compared to Patients With Early-Stage Schizophrenia and Healthy Controls

Background

The relationship between brain structural changes and cognitive dysfunction in schizophrenia is strong. However, few studies have investigated both neuroanatomical abnormalities and cognitive dysfunction in treatment-resistant schizophrenia (TRS). We examined neuroanatomical markers and cognitive function between patients with TRS or early-stage schizophrenia (ES-S) and healthy controls (HCs). Relationships between neuroanatomical markers and cognitive function in the patient groups were also investigated.

Methods

A total of 46 and 45 patients with TRS and ES-S and 61 HCs underwent structural magnetic resonance imaging (MRI) brain scanning and comprehensive cognitive tests. MRI scans were analyzed using the FreeSurfer to investigate differences in cortical surface area (CSA), cortical thickness (CT), cortical volume (CV), and subcortical volume (SCV) among the groups. Four cognitive domains (attention, verbal memory, executive function, and language) were assessed. Comparisons of neuroanatomical and cognitive function results among the three groups were performed.

Results

A widespread reduction in CT was observed in patients with TRS compared to HCs, but differences in cortical thinning between TRS and ES-S patients were mainly limited to the inferior frontal gyrus and insula. Several subcortical structures (accumbens, amygdala, hippocampus, putamen, thalamus and ventricles) were significantly altered in TRS patients compared to both ES-S patients and HCs. Performance in the verbal memory domain was significantly worse in TRS patients compared to ES-S patients. A positive relationship between the thickness of the left middle temporal gyrus and the composite score for language was identified in patients with ES-S.

Conclusions

Our findings suggest significant cognitive impairment and reductions in CT and SCV in individuals with TRS compared to those with ES-S and HCs. These abnormalities could act as biomarkers for earlier identification of TRS.

Schizophrenia: A developmental disorder with a risk of non-specific but avoidable decline

The onset of schizophrenia is determined by biological and social risk factors operating predominantly during development. These result in subtle deviations in brain structure and cognitive function. Striatal dopamine dysregulation follows, causing abnormal salience and resultant psychotic symptoms. Most people diagnosed as having schizophrenia do not progressively deteriorate; many improve or recover. However, poor care can allow a cycle of deterioration to be established, stress increasing dopamine dysregulation, leading to more stress consequent on continuing psychotic experiences, and so further dopamine release. Additionally, long-term antipsychotics can induce dopamine supersensitivity with resultant relapse and eventually treatment resistance. Some patients suffer loss of social and cognitive function, but this is a consequence of the hazards that afflict the person with schizophrenia, not a direct consequence of genetic predisposition. Thus, brain health and cognition can be further impaired by chronic medication effects, cardiovascular and cerebrovascular events, obesity, poor diet, and lack of exercise; drug use, especially of tobacco and cannabis, are likely to contribute. Poverty, homelessness and poor nutrition which become the lot of some people with schizophrenia, can also affect cognition. Regrettably, the model of progressive deterioration provides psychiatry and its funders with an alibi for the effects of poor care.

The effect of first- and second-generation antipsychotics on brain morphology in schizophrenia: A systematic review of longitudinal magnetic resonance studies with a randomized allocation to treatment arms

Schizophrenia manifests as loss of brain volume in specific areas in a progressive nature and an important question concerns whether long-term treatment with medications contributes to this. The aim of the current PRISMA systematic review was to search for prospective studies involving randomization to treatment. PROSPERO ID: CRD42020197874. The MEDLINE/PUBMED was searched and it returned 2638 articles; 3 were fulfilling the inclusion criteria. A fourth was published later; they included 359 subjects, of whom 86 were healthy controls, while the rest were first-episode patients, with 91 under olanzapine, 93 under haloperidol, 48 under risperidone, 5 under paliperidone, 6 under ziprasidone, and 30 under placebo. Probably one-third of patients were suffering from a psychotic disorder other than schizophrenia. The consideration of their results suggested that there is no significant difference between these medications concerning their effects on brain structure and also in comparison to healthy subjects. There does not seem to be any strong support to the opinion that medications that treat psychosis cause loss of brain volume in patients with schizophrenia. On the contrary, the data might imply the possible presence of a protective effect for D2, 5-HT2, and NE alpha-2 antagonists (previously called SGAs). However, the literature is limited and focused research in large study samples is essential to clarify the issue, since important numerical differences do exist. The possibility of the results and their heterogeneity to be artifacts secondary to a modification of magnetic resonance imaging (MRI) signal by antipsychotics should not be easily rejected until relevant data are available.

Subcortical volume reduction and cortical thinning 3 months after switching to clozapine in treatment resistant schizophrenia

The neurobiological effects of clozapine are under characterised. We examined the effects clozapine treatment on subcortical volume and cortical thickness and investigated whether macrostructural changes were linked to alterations in glutamate or N-acetylaspartate (NAA). Data were acquired in 24 patients with treatment-resistant schizophrenia before and 12 weeks after switching to clozapine. During clozapine treatment we observed reductions in caudate and putamen volume, lateral ventricle enlargement (P < 0.001), and reductions in thickness of the left inferior temporal cortex, left caudal middle frontal cortex, and the right temporal pole. Reductions in right caudate volume were associated with local reductions in NAA (P = 0.002). None of the morphometric changes were associated with changes in glutamate levels. These results indicate that clozapine treatment is associated with subcortical volume loss and cortical thinning and that at least some of these effects are linked to changes in neuronal or metabolic integrity.

Mechanisms underlying dorsolateral prefrontal cortex contributions to cognitive dysfunction in schizophrenia

Kraepelin, in his early descriptions of schizophrenia (SZ), characterized the illness as having "an orchestra without a conductor." Kraepelin further speculated that this "conductor" was situated in the frontal lobes. Findings from multiple studies over the following decades have clearly implicated pathology of the dorsolateral prefrontal cortex (DLPFC) as playing a central role in the pathophysiology of SZ, particularly with regard to key cognitive features such as deficits in working memory and cognitive control. Following an overview of the cognitive mechanisms associated with DLPFC function and how they are altered in SZ, we review evidence from an array of neuroscientific approaches addressing how these cognitive impairments may reflect the underlying pathophysiology of the illness. Specifically, we present evidence suggesting that alterations of the DLPFC in SZ are evident across a range of spatial and temporal resolutions: from its cellular and molecular architecture, to its gross structural and functional integrity, and from millisecond to longer timescales. We then present an integrative model based upon how microscale changes in neuronal signaling in the DLPFC can influence synchronized patterns of neural activity to produce macrocircuit-level alterations in DLPFC activation that ultimately influence cognition and behavior. We conclude with a discussion of initial efforts aimed at targeting DLPFC function in SZ, the clinical implications of those efforts, and potential avenues for future development.

The effects of cumulative antipsychotic dose on brain structures in patients with schizophrenia: Observational study of multiple CT scans over a long-term clinical course

Multiple lines of evidence indicate that antipsychotic agents could affect brain structures of schizophrenia patients. However, the effect of antipsychotic dosage or type on brain structure is uncertain. The present study retrospectively analyzed brain computed tomography (CT) images from a psychiatric hospital to examine the relationship between cumulative dose of antipsychotics and brain volume reduction in schizophrenia patients. A total of 43 patients with repeated relapse episode of psychosis were included and CT scans that were performed an average of 3.2 times per patient during nearly 13 years of follow-up were analyzed. The results revealed significant positive relationships of expansion of cerebrospinal fluid space with cumulative dosage of all antipsychotics and that of typical antipsychotics. Patients treated with antipsychotics including typical antipsychotics exhibited a greater volume reduction compared to patients treated with only atypical antipsychotics. The present study was one of the longest longitudinal studies examining the effects of antipsychotics on brain volume in schizophrenia patients. These results suggest a relation between cumulative lifetime antipsychotic dosage and progressive brain volume reduction in patients with schizophrenia. However, the effects of specific agent on brain structure are still uncertain, and more detailed analysis is needed.

Large-Scale Transcriptomics Studies Provide Insight Into Sex Differences in Depression

Major depressive disorder (MDD) is a leading cause of disability, affecting more than 300 million people worldwide. We first review the well-known sex difference in incidence of MDD, with women being twice as likely to be diagnosed as men, and briefly summarize how the impact of MDD varies between men and women, with sex differences in symptoms, severity, and antidepressant drug response. We then attempt to deconstruct the biological bases for MDD and discuss implications for sex differences research. Next, we review findings from human postmortem studies, both from selected candidate gene studies and from well-powered, unbiased transcriptomics studies, which suggest distinct, and possibly opposite, molecular changes in the brains of depressed men and women. We then discuss inherent challenges of research on the human postmortem brain and suggest paths forward that rely on thoughtful cohort design. Although studies indicate that circulating gonadal hormones might underlie the observed sex differences in MDD, we discuss how additional sex-specific factors, such as genetic sex and developmental exposure to gonadal hormones, may also contribute to altered vulnerability, and we highlight various nuances that we believe should be considered when determining mechanisms underlying observed sex differences. Altogether, this review highlights not only how various sex-specific factors might influence susceptibility or resilience to depression, but also how those sex-specific factors might result in divergent pathology in men and women.

A meta-analysis of deep brain structural shape and asymmetry abnormalities in 2,833 individuals with schizophrenia compared with 3,929 healthy volunteers via the ENIGMA Consortium

Schizophrenia is associated with widespread alterations in subcortical brain structure. While analytic methods have enabled more detailed morphometric characterization, findings are often equivocal. In this meta-analysis, we employed the harmonized ENIGMA shape analysis protocols to collaboratively investigate subcortical brain structure shape differences between individuals with schizophrenia and healthy control participants. The study analyzed data from 2,833 individuals with schizophrenia and 3,929 healthy control participants contributed by 21 worldwide research groups participating in the ENIGMA Schizophrenia Working Group. Harmonized shape analysis protocols were applied to each site's data independently for bilateral hippocampus, amygdala, caudate, accumbens, putamen, pallidum, and thalamus obtained from T1-weighted structural MRI scans. Mass univariate meta-analyses revealed more-concave-than-convex shape differences in the hippocampus, amygdala, accumbens, and thalamus in individuals with schizophrenia compared with control participants, more-convex-than-concave shape differences in the putamen and pallidum, and both concave and convex shape differences in the caudate. Patterns of exaggerated asymmetry were observed across the hippocampus, amygdala, and thalamus in individuals with schizophrenia compared to control participants, while diminished asymmetry encompassed ventral striatum and ventral and dorsal thalamus. Our analyses also revealed that higher chlorpromazine dose equivalents and increased positive symptom levels were associated with patterns of contiguous convex shape differences across multiple subcortical structures. Findings from our shape meta-analysis suggest that common neurobiological mechanisms may contribute to gray matter reduction across multiple subcortical regions, thus enhancing our understanding of the nature of network disorganization in schizophrenia.

Chronic Polypharmacy with Increasing Drug Burden Index Exacerbates Frailty and Impairs Physical Function, with Effects Attenuated by Deprescribing, in Aged Mice

Polypharmacy (use of ≥5 medications) and increasing Drug Burden Index (DBI) score (measure of person's total exposure to anticholinergic/sedative medications) are associated with impaired physical function in observational studies of older adults. Deprescribing, the supervised withdrawal of medications for which harms outweigh benefits for an individual, may be a useful intervention. Current knowledge is limited to clinical observational studies that are unable to determine causality. Here, we establish a preclinical model that investigates the effects of chronic polypharmacy, increasing DBI, and deprescribing on global health outcomes in aging. In a longitudinal study, middle-aged (12 months) male C57BL/6J (B6) mice were administered control feed or feed and/or water containing polypharmacy or monotherapy with different DBI scores. At 21 months, each treatment group was subdivided (stratified by frailty at 21 months) to either continue on treatment for life or to have treatment withdrawn (deprescribed). Frailty and physical function were evaluated at 12, 15, 18, and 24 months, and were analyzed using a mixed modeling approach. Polypharmacy with increasing DBI and monotherapy with citalopram caused mice to become frailer, less mobile, and impaired their strength and functional activities. Critically, deprescribing in old age reversed a number of these outcomes. This is the first preclinical study to demonstrate that chronic polypharmacy with increasing DBI augments frailty and impairs function in old age, and that drug withdrawal in old age reversed these outcomes. It was not the number of drugs (polypharmacy) but the type and dose of drugs (DBI) that caused adverse geriatric outcomes.

Subtyping Schizophrenia Patients Based on Patterns of Structural Brain Alterations

Schizophrenia is a complex and heterogeneous syndrome. Whether quantitative imaging biomarkers can identify discrete subgroups of patients as might be used to foster personalized medicine approaches for patient care remains unclear. Cross-sectional structural MR images of 163 never-treated first-episode schizophrenia patients (FES) and 133 chronically ill patients with midcourse schizophrenia from the Bipolar and Schizophrenia Network for Intermediate Phenotypes (B-SNIP) consortium and a total of 403 healthy controls were recruited. Morphometric measures (cortical thickness, surface area, and subcortical structures) were extracted for each subject and then the optimized subtyping results were obtained with nonsupervised cluster analysis. Three subgroups of patients defined by distinct patterns of regional cortical and subcortical morphometric features were identified in FES. A similar three subgroup pattern was identified in the independent dataset of patients from the multi-site B-SNIP consortium. Similarities of classification patterns across these two patient cohorts suggest that the 3-group typology is relatively stable over the course of illness. Cognitive functions were worse in subgroup 1 with midcourse schizophrenia than those in subgroup 3. These findings provide novel insight into distinct subgroups of patients with schizophrenia based on structural brain features. Findings of different cognitive functions among the subgroups support clinical differences in the MRI-defined illness subtypes. Regardless of clinical presentation and stage of illness, anatomic MR subgrouping biomarkers can separate neurobiologically distinct subgroups of schizophrenia patients, which represent an important and meaningful step forward in differentiating subtypes of patients for studies of illness neurobiology and potentially for clinical trials.

Lithium as a Neuroprotective Agent for Bipolar Disorder: An Overview

Lithium (Li⁺) is a first option treatment for adult acute episodes of Bipolar Disorder (BD) and for the prophylaxis of new depressed or manic episodes. It is also the preferred choice as maintenance treatment. Numerous studies have shown morphological abnormalities in the brains of BD patients, suggesting that this highly heritable disorder may exhibit progressive and deleterious changes in brain structure. Since treatment with Li⁺ ameliorates these abnormalities, it has been postulated that Li⁺ is a neuroprotective agent in the same way atypical antipsychotics are neuroprotective in patients diagnosed with schizophrenia spectrum disorders. Li⁺'s neuroprotective properties are related to its modulation of nerve growth factors, inflammation, mitochondrial function, oxidative stress, and programmed cell death mechanisms such as autophagy and apoptosis. Notwithstanding, it is not known whether Li⁺-induced neuroprotection is related to the inhibition of its putative molecular targets in a BD episode: the enzymes inositol-monophosphatase, (IMPase), glycogen-synthase-kinase 3β (GSK3), and Protein kinase C (PKC). Furthermore, it is uncertain whether these neuroprotective mechanisms are correlated with Li⁺'s clinical efficacy in maintaining mood stability. It is expected that in a nearby future, precision medicine approaches will improve diagnosis and expand treatment options. This will certainly contribute to ameliorating the medical and economic burden created by this devastating mood disorder.

Antipsychotics Effects on Network-Level Reconfiguration of Cortical Morphometry in First-Episode Schizophrenia

Cortical thickness reductions are evident in schizophrenia (SZ). Associations between antipsychotic medications (APMs) and cortical morphometry have been explored in SZ patients. This raises the question of whether the reconfiguration of morphological architecture by APM plays potential compensatory roles for abnormalities in the cerebral cortex. Structural magnetic resonance imaging was obtained from 127 medication-naive first-episode SZ patients and 133 matched healthy controls. Patients received 12 weeks of APM and were categorized as responders (n = 75) or nonresponders (NRs, n = 52) at follow-up. Using surface-based morphometry and structural covariance (SC) analysis, this study investigated the short-term effects of antipsychotics on cortical thickness and cortico-cortical covariance. Global efficiency was computed to characterize network integration of the large-scale structural connectome. The relationship between covariance and cortical thinning was examined by SC analysis among the top-n regions with thickness reduction. Widespread cortical thickness reductions were observed in pre-APM patients. Post-APM patients showed more reductions in cortical thickness, even in the frontotemporal regions without baseline reductions. Covariance analysis revealed strong cortico-cortical covariance and higher network integration in responders than in NRs. For the NRs, some of the prefrontal and temporal nodes were not covariant between the top-n regions with cortical thickness reduction. Antipsychotic effects are not restricted to a single brain region but rather exhibit a network-level covariance pattern. Neuroimaging connectomics highlights the positive effects of antipsychotics on the reconfiguration of brain architecture, suggesting that abnormalities in regional morphology may be compensated by increasing interregional covariance when symptoms are controlled by antipsychotics.

Differentiating the effect of antipsychotic medication and illness on brain volume reductions in first-episode psychosis: A Longitudinal, Randomised, Triple-blind, Placebo-controlled MRI Study

Changes in brain volume are a common finding in Magnetic Resonance Imaging (MRI) studies of people with psychosis and numerous longitudinal studies suggest that volume deficits progress with illness duration. However, a major unresolved question concerns whether these changes are driven by the underlying illness or represent iatrogenic effects of antipsychotic medication. In this study, 62 antipsychotic-naïve patients with first-episode psychosis (FEP) received either a second-generation antipsychotic (risperidone or paliperidone) or a placebo pill over a treatment period of 6 months. Both FEP groups received intensive psychosocial therapy. A healthy control group (n = 27) was also recruited. Structural MRI scans were obtained at baseline, 3 months and 12 months. Our primary aim was to differentiate illness-related brain volume changes from medication-related changes within the first 3 months of treatment. We secondarily investigated long-term effects at the 12-month timepoint. From baseline to 3 months, we observed a significant group x time interaction in the pallidum (p < 0.05 FWE-corrected), such that patients receiving antipsychotic medication showed increased volume, patients on placebo showed decreased volume, and healthy controls showed no change. Across the entire patient sample, a greater increase in pallidal grey matter volume over 3 months was associated with a greater reduction in symptom severity. Our findings indicate that psychotic illness and antipsychotic exposure exert distinct and spatially distributed effects on brain volume. Our results align with prior work in suggesting that the therapeutic efficacy of antipsychotic medications may be primarily mediated through their effects on the basal ganglia.

Strucutural brain imaging at the onset of schizophrenia:What have we learned and what have we missed

Over the past 50 years, the application of structural neuroimaging techniques to schizophrenia research has added relevant information about the pathophysiology of the disorder. Several lines of investigation gave strong evidence that schizophrenia is associated with multiple subtle brain abnormalities that involve both cerebral grey and white matter volumes and structure. The time of onset and longitudinal course of brain morphological abnormalities support the notion that brain pathology of schizophrenia has a neurodevelopmental component and a progressive course, although several confounders of brain changes should be carefully taken into account. Brain anomalies detected before and close to the onset of schizophrenia are likely to be unrelated to confounders of brain changes such as antipsychotic drug treatment, duration of illness or illicit substance abuse, i.e. they related to the pathological process of the disorder per se. Nonetheless, clinically useful diagnostic or prognostic biomarkers have not derived from neuroimaging studies and this is likely related to the neurobiological heterogeneity of the disorder. Thus, there is the compelling need to set new methodological standards for developing innovative hypothesis-driven studies to overcome what we have missed to date in neuroimaging research in schizophrenia.

Increased Glutamate Plus Glutamine in the Right Middle Cingulate in Early Schizophrenia but Not in Bipolar Psychosis: A Whole Brain 1H-MRS Study

Proton magnetic resonance spectroscopy (1H-MRS) studies have examined glutamatergic abnormalities in schizophrenia and bipolar-I disorders, mostly in single voxels. Though the critical nodes remain unknown, schizophrenia and bipolar-I involve brain networks with broad abnormalities. To provide insight on the biochemical differences that may underlie these networks, the combined glutamine and glutamate signal (Glx) and other metabolites were examined in patients in early psychosis with whole brain 1H-MRS imaging (1H-MRSI). Data were acquired in young schizophrenia subjects (N = 48), bipolar-I subjects (N = 21) and healthy controls (N = 51). Group contrasts for Glx, as well as for N-acetyl aspartate, choline, myo-inositol and creatine, from all voxels that met spectral quality criteria were analyzed in standardized brain space, followed by cluster-corrected level alpha-value (CCLAV ≤ 0.05) analysis. Schizophrenia subjects had higher Glx in the right middle cingulate gyrus (19 voxels, CCLAV = 0.05) than bipolar-I subjects. Healthy controls had intermediate Glx values, though not significant. Schizophrenia subjects also had higher N-acetyl aspartate (three clusters, left occipital, left frontal, right frontal), choline (two clusters, left and right frontal) and myo-inositol (one cluster, left frontal) than bipolar-I, with healthy controls having intermediate values. These increases were likely accounted for by antipsychotic medication effects in the schizophrenia subgroup for N-acetyl aspartate and choline. Likewise, creatine was increased in two clusters in treated vs. antipsychotic-naïve schizophrenia, supporting a medication effect. Conversely, the increments in Glx in right cingulate were not driven by antipsychotic medication exposure. We conclude that increments in Glx in the cingulate may be critical to the pathophysiology of schizophrenia and are consistent with the NMDA hypo-function model. This model however may be more specific to schizophrenia than to psychosis in general. Postmortem and neuromodulation schizophrenia studies focusing on right cingulate, may provide critical mechanistic and therapeutic advancements, respectively.

Basic quantitative morphological methods applied to the central nervous system

Generating numbers has become an almost inevitable task associated with studies of the morphology of the nervous system. Numbers serve a desire for clarity and objectivity in the presentation of results and are a prerequisite for the statistical evaluation of experimental outcomes. Clarity, objectivity, and statistics make demands on the quality of the numbers that are not met by many methods. This review provides a refresher of problems associated with generating numbers that describe the nervous system in terms of the volumes, surfaces, lengths, and numbers of its components. An important aim is to provide comprehensible descriptions of the methods that address these problems. Collectively known as design-based stereology, these methods share two features critical to their application. First, they are firmly based in mathematics and its proofs. Second and critically underemphasized, an understanding of their mathematical background is not necessary for their informed and productive application. Understanding and applying estimators of volume, surface, length or number does not require more of an organizational mastermind than an immunohistochemical protocol. And when it comes to calculations, square roots are the gravest challenges to overcome. Sampling strategies that are combined with stereological probes are efficient and allow a rational assessment if the numbers that have been generated are "good enough." Much may be unfamiliar, but very little is difficult. These methods can no longer be scapegoats for discrepant results but faithfully produce numbers on the material that is assessed. They also faithfully reflect problems that associated with the histological material and the anatomically informed decisions needed to generate numbers that are not only valid in theory. It is within reach to generate practically useful numbers that must integrate with qualitative knowledge to understand the function of neural systems.

Biological and anthropogenic influences on macrophage aggregates in white perch Morone americana from Chesapeake Bay, USA

The response of macrophage aggregates in fish to a variety of environmental stressors has been useful as a biomarker of exposure to habitat degradation. Total volume of macrophage aggregates (MAV) was estimated in the liver and spleen of white perch Morone americana from Chesapeake Bay using stereological approaches. Hepatic and splenic MAV were compared between fish populations from the rural Choptank River (n = 122) and the highly urbanized Severn River (n = 131). Hepatic and splenic MAV increased with fish age, were greater in females from the Severn River only, and were significantly greater in fish from the more polluted Severn River (higher concentrations of polycyclic aromatic hydrocarbons, organochlorine pesticides, and brominated diphenyl ethers). Water temperature and dissolved oxygen had a significant effect on organ volumes, but not on MAV. Age and river were most influential on hepatic and splenic MAV, suggesting that increased MAV in Severn River fish resulted from chronic exposures to higher concentrations of environmental contaminants and other stressors. Hemosiderin was abundant in 97% of spleens and was inversely related to fish condition and positively related to fish age and trematode infections. Minor amounts of hemosiderin were detected in 30% of livers and positively related to concentrations of benzo[a]pyrene metabolite equivalents in the bile. This study demonstrated that hepatic and splenic MAV were useful indicators in fish from the 2 tributaries with different land use characteristics and concentrations of environmental contaminants. More data are needed from additional tributaries with a wider gradient of environmental impacts to validate our results in this species.

A 16-week randomized placebo-controlled trial investigating the effects of omega-3 polyunsaturated fatty acid treatment on white matter microstructure in recent-onset psychosis patients concurrently treated with risperidone

We examined the impact of treatment with fish oil (FO), a rich source of omega-3 polyunsaturated fatty acids (n-3 PUFA), on white matter in 37 recent-onset psychosis patients receiving risperidone in a double-blind placebo-controlled randomized clinical trial. Patients were scanned at baseline and randomly assigned to receive 16-weeks of treatment with risperidone + FO or risperidone + placebo. Eighteen patients received follow-up MRIs (FO, n = 10/Placebo, n = 8). Erythrocyte levels of n-3 PUFAs eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and docosapentaenoic acid (DPA) were obtained at both time points. We employed Free Water Imaging metrics representing the extracellular free water fraction (FW) and fractional anisotropy of the tissue (FA-t). Analyses were conducted using Tract-Based-Spatial-Statistics and nonparametric permutation-based tests with family-wise error correction. There were significant positive correlations of FA-t with DHA and DPA among all patients at baseline. Patients treated with risperidone + placebo demonstrated reductions in FA-t and increases in FW, whereas patients treated with risperidone + FO exhibited no significant changes in FW and FA-t reductions were largely attenuated. The correlations of DPA and DHA with baseline FA-t support the hypothesis that n-3 PUFA intake or biosynthesis are associated with white matter abnormalities in psychosis. Adjuvant FO treatment may partially mitigate against white matter alterations observed in recent-onset psychosis patients following risperidone treatment.

Rationale and neurobiological effects of treatment with antipsychotics in patients with chronic schizophrenia considering dopamine supersensitivity

The long-term treatment of patients with schizophrenia often involves the management of relapses for most patients and the development of treatment resistance in some patients. To stabilize the clinical course and allow as many patients as possible to recover, clinicians need to recognize dopamine supersensitivity, which can be provoked by administration of high dosages of antipsychotics, and deal with it properly. However, no treatment guidelines have addressed this issue. The present review summarized the characteristics of long-acting injectable antipsychotics, dopamine partial agonists, and clozapine in relation to dopamine supersensitivity from the viewpoints of receptor profiles and pharmacokinetics. The potential merits and limitations of these medicines are discussed, as well as the risks of treating patients with established dopamine supersensitivity with these classes of drugs. Finally, the review discussed the biological influence of antipsychotic treatment on the human brain based on findings regarding the relationship between the hippocampus and antipsychotics.

Emerging therapeutic targets for schizophrenia: a framework for novel treatment strategies for psychosis

Introduction: Antipsychotic drugs are central to the treatment of schizophrenia, but their limitations necessitate improved treatment strategies. Multiple lines of research have implicated glutamatergic dysfunction in the hippocampus as an early source of pathophysiology in schizophrenia. Novel compounds have been designed to treat glutamatergic dysfunction, but they have produced inconsistent results in clinical trials. Areas covered: This review discusses how the hippocampus is thought to drive psychotic symptoms through its influence on the dopamine system. It offers the reader an evaluation of proposed treatment strategies including direct modulation of GABA or glutamate neurotransmission or reducing the deleterious impact of stress on circuit development. Finally, we offer a perspective on aspects of future research that will advance our knowledge and may create new therapeutic opportunities. PubMed was searched for relevant literature between 2010 and 2020 and related studies. Expert opinion: Targeting aberrant excitatory-inhibitory neurotransmission in the hippocampus and its related circuits has the potential to alleviate symptoms and reduce the risk of transition to psychosis if implemented as an early intervention. Longitudinal multimodal brain imaging combined with mechanistic theories generated from animal models can be used to better understand the progression of hippocampal-dopamine circuit dysfunction and heterogeneity in treatment response.

Spinophilin expression in postmortem prefrontal cortex of schizophrenic subjects: Effects of antipsychotic treatment

Schizophrenia has been associated with alterations in neurotransmission and synaptic dysfunction. Spinophilin is a multifunctional scaffold protein that modulates excitatory synaptic transmission and dendritic spine morphology. Spinophilin can also directly interact with and regulate several receptors for neurotransmitters, such as dopamine D₂ receptors, which play a role in the pathophysiology of schizophrenia and are targets of antipsychotics. Several studies have thus suggested an implication of spinophilin in schizophrenia. In the present study spinophilin protein expression was determined by western blot in the postmortem dorsolateral prefrontal cortex of 24 subjects with schizophrenia (12 antipsychotic-free and 12 antipsychotic-treated subjects) and 24 matched controls. Experiments were performed in synaptosomal membranes (SPM) and in postsynaptic density fractions (PSD). As previously reported, two specific bands for this protein were observed: an upper 120-130 kDa band and a lower 80-95 kDa band. The spinophilin lower band showed a significant decrease in schizophrenia subjects compared to matched controls, both in SPM and PSD fractions (-15%, p = 0.007 and -15%, p = 0.039, respectively). When schizophrenia subjects were divided by the presence or absence of antipsychotics in blood at death, the lower band showed a significant decrease in antipsychotic-treated schizophrenia subjects (-24%, p = 0.003 for SPM and -26%, p = 0.014 for PSD), but not in antipsychotic-free subjects, compared to their matched controls. These results suggest that antipsychotics could produce alterations in spinophilin expression that do not seem to be related to schizophrenia per se. These changes may underlie some of the side effects of antipsychotics.

Translation-Focused Approaches to GPCR Drug Discovery for Cognitive Impairments Associated with Schizophrenia

There are no effective therapeutics for cognitive impairments associated with schizophrenia (CIAS), which includes deficits in executive functions (working memory and cognitive flexibility) and episodic memory. Compounds that have entered clinical trials are inadequate in terms of efficacy and/or tolerability, highlighting a clear translational bottleneck and a need for a cohesive preclinical drug development strategy. In this review we propose hippocampal-prefrontal-cortical (HPC-PFC) circuitry underlying CIAS-relevant cognitive processes across mammalian species as a target source to guide the translation-focused discovery and development of novel, procognitive agents. We highlight several G protein-coupled receptors (GPCRs) enriched within HPC-PFC circuitry as therapeutic targets of interest, including noncanonical approaches (biased agonism and allosteric modulation) to conventional clinical targets, such as dopamine and muscarinic acetylcholine receptors, along with prospective novel targets, including the orphan receptors GPR52 and GPR139. We also describe the translational limitations of popular preclinical cognition tests and suggest touchscreen-based assays that probe cognitive functions reliant on HPC-PFC circuitry and reflect tests used in the clinic, as tests of greater translational relevance. Combining pharmacological and behavioral testing strategies based in HPC-PFC circuit function creates a cohesive, translation-focused approach to preclinical drug development that may improve the translational bottleneck currently hindering the development of treatments for CIAS.

Antipsychotic ffects on ortical Morphology in chizophrenia and ipolar isorders

Background: Previous studies of atypical antipsychotic effects on cortical structures in schizophrenia (SZ) and bipolar disorder (BD) have findings that vary between the short and long term. In particular, there has not been a study exploring the effects of atypical antipsychotics on age-related cortical structural changes in SZ and BD. This study aimed to determine whether mid- to long-term atypical antipsychotic treatment (mean duration = 20 months) is associated with cortical structural changes and whether age-related cortical structural changes are affected by atypical antipsychotics. Methods: Structural magnetic resonance imaging images were obtained from 445 participants consisting of 88 medicated patients (67 with SZ, 21 with BD), 84 unmedicated patients (50 with SZ, 34 with BD), and 273 healthy controls (HC). Surface-based analyses were employed to detect differences in thickness and area among the three groups. We examined the age-related effects of atypical antipsychotics after excluding the potential effects of illness duration. Results: Significant differences in cortical thickness were observed in the frontal, temporal, parietal, and insular areas and the isthmus of the cingulate gyrus. The medicated group showed greater cortical thinning in these regions than the unmediated group and HC; furthermore, there were age-related differences in the effects of atypical antipsychotics, and these effects did not relate to illness duration. Moreover, cortical thinning was significantly correlated with lower symptom scores and Wisconsin Card Sorting Test (WCST) deficits in patients. After false discovery rate correction, cortical thinning in the right middle temporal gyrus in patients was significantly positively correlated with lower HAMD scores. The unmedicated group showed only greater frontotemporal thickness than the HC group. Conclusion: Mid- to long-term atypical antipsychotic use may adversely affect cortical thickness over the course of treatment and ageing and may also result in worsening cognitive function.

Diagnosis- and Cell Type-Specific Mitochondrial Functional Pathway Signatures in Schizophrenia and Bipolar Disorder

OBJECTIVE

The shared risk factors and clinical features in schizophrenia and bipolar disorder may be linked via mitochondrial dysfunction. However, the severity of mitochondrial dysfunction, and/or the specific mitochondrial functional pathways affected, may differ between diagnoses, especially at the level of individual cell types.

METHODS

Transcriptomic profiling data for a gene set indexing mitochondrial functional pathways were obtained for dorsolateral prefrontal cortex (DLPFC) gray matter and layer 3 and layer 5 pyramidal neurons of subjects with schizophrenia or bipolar disorder. Analyses were conducted using a dual strategy: identification of differentially expressed genes (DEGs) and their functional pathway enrichment, and application of weighted gene coexpression network analysis. These analyses were repeated in monkeys chronically exposed to antipsychotic drugs to determine their effect on mitochondrial-related gene expression.

RESULTS

In DLPFC gray matter, 41% of mitochondrial-related genes were differentially expressed in the schizophrenia group, whereas 8% were differentially expressed in the bipolar group. In the schizophrenia group, 83% of DEGs showed lower expression, and these were significantly enriched for three functional pathways, each indexing energy production. DEGs in the bipolar disorder group were not enriched for functional pathways. This disease-related pattern of findings was also identified in pyramidal neurons. None of the gene expression alterations disrupted coexpression modules, and DEGs were not attributable to antipsychotic medications.

CONCLUSIONS

Schizophrenia and bipolar disorder do not appear to share similar mitochondrial alterations in the DLPFC. The selective and coordinated down-regulation of energy production genes in schizophrenia is consistent with the effects of chronic reductions in pyramidal neuron firing, and enhancement of this activity may serve as a therapeutic target.

N-acetylcysteine prevents olanzapine-induced oxidative stress in mHypoA-59 hypothalamic neurons

Olanzapine is a second-generation antipsychotic (AP) drug commonly prescribed for the treatment of schizophrenia. Recently, olanzapine has been found to cause brain tissue volume loss in rodent and primate studies; however, the underlying mechanism remains unknown. Abnormal autophagy and oxidative stress have been implicated to have a role in AP-induced neurodegeneration, while N-acetylcysteine (NAC) is a potent antioxidant, shown to be beneficial in the treatment of schizophrenia. Here, we investigate the role of olanzapine and NAC on cell viability, oxidative stress, mitochondrial mass and mitophagy in hypothalamic cells. Firstly, cell viability was assessed in mHypoA-59 and mHypoA NPY/GFP cells using an MTS assay and flow cytometric analyses. Olanzapine treated mHypoA-59 cells were then assessed for mitophagy markers and oxidative stress; including quantification of lysosomes, autophagosomes, LC3B-II, p62, superoxide anion (O₂^–) and mitochondrial mass. NAC (10 mM) was used to reverse the effects of olanzapine (100 µM) on O₂⁻, mitochondrial mass and LC3B-II. We found that olanzapine significantly impacted cell viability in mHypoA-59 hypothalamic cells in a dose and time-dependent manner. Olanzapine inhibited mitophagy, instigated oxidative stress and prompted mitochondrial abnormalities. NAC was able to mitigate olanzapine-induced effects. These findings suggest that high doses of olanzapine may cause neurotoxicity of hypothalamic neurons via increased production of reactive oxygen species (ROS), mitochondrial damage and mitophagy inhibition. This could in part explain data suggesting that APs may reduce brain volume.

Rethinking the risks and benefits of long-term maintenance in schizophrenia

This review addresses the risks and benefits of long-term maintenance antipsychotic treatment for patients that extends beyond two years. It focuses on framing discussions with patients who are recovering from a first episode. For these patients the evidence strongly supports the benefits over the risk for the first two years. However, both the clinical side effects of antipsychotics and the possible long-term effects of dopamine blocking drugs on the brain require a more nuanced discussion beyond this initial period. In most cases, the decision will be to continue antipsychotics but to consider strategies for mitigating the risks of drugs. This review provides information about the relative risks of dose reduction and intermittent treatment.