Greater clinical and cognitive improvement with clozapine and risperidone associated with a thinner cortex at baseline in first-episode schizophrenia

Resting-state functional MRI in treatment-resistant schizophrenia

BACKGROUND

Abnormalities in brain regions involved in the pathophysiology of schizophrenia (SCZ) may present insight into individual clinical symptoms. Specifically, functional connectivity irregularities may provide potential biomarkers for treatment response or treatment resistance, as such changes can occur before any structural changes are visible. We reviewed resting-state functional magnetic resonance imaging (rs-fMRI) findings from the last decade to provide an overview of the current knowledge on brain functional connectivity abnormalities and their associations to symptoms in treatment-resistant schizophrenia (TRS) and ultra-treatment-resistant schizophrenia (UTRS) and to look for support for the dysconnection hypothesis.

METHODS

PubMed database was searched for articles published in the last 10 years applying rs-fMRI in TRS patients, i.e., who had not responded to at least two adequate treatment trials with different antipsychotic drugs.

RESULTS

Eighteen articles were selected for this review involving 648 participants (TRS and control cohorts). The studies showed frontal hypoconnectivity before the initiation of treatment with CLZ or riluzole, an increase in frontal connectivity after riluzole treatment, fronto-temporal hypoconnectivity that may be specific for non-responders, widespread abnormal connectivity during mixed treatments, and ECT-induced effects on the limbic system.

CONCLUSION

Probably due to the heterogeneity in the patient cohorts concerning antipsychotic treatment and other clinical variables (e.g., treatment response, lifetime antipsychotic drug exposure, duration of illness, treatment adherence), widespread abnormalities in connectivity were noted. However, irregularities in frontal brain regions, especially in the prefrontal cortex, were noted which are consistent with previous SCZ literature and the dysconnectivity hypothesis. There were major limitations, as most studies did not differentiate between TRS and UTRS (i.e., CLZ-resistant schizophrenia) and investigated heterogeneous cohorts treated with mixed treatments (with or without CLZ). This is critical as in different subtypes of the disorder an interplay between dopaminergic and glutamatergic pathways involving frontal, striatal, and hippocampal brain regions in separate ways is likely. Better definitions of TRS and UTRS are necessary in future longitudinal studies to correctly differentiate brain regions underlying the pathophysiology of SCZ, which could serve as potential functional biomarkers for treatment resistance.

Clozapine's multiple cellular mechanisms: What do we know after more than fifty years? A systematic review and critical assessment of translational mechanisms relevant for innovative strategies in treatment-resistant schizophrenia

Almost fifty years after its first introduction into clinical care, clozapine remains the only evidence-based pharmacological option for treatment-resistant schizophrenia (TRS), which affects approximately 30% of patients with schizophrenia. Despite the long-time experience with clozapine, the specific mechanism of action (MOA) responsible for its superior efficacy among antipsychotics is still elusive, both at the receptor and intracellular signaling level. This systematic review is aimed at critically assessing the role and specific relevance of clozapine's multimodal actions, dissecting those mechanisms that under a translational perspective could shed light on molecular targets worth to be considered for further innovative antipsychotic development. In vivo and in vitro preclinical findings, supported by innovative techniques and methods, together with pharmacogenomic and in vivo functional studies, point to multiple and possibly overlapping MOAs. To better explore this crucial issue, the specific affinity for 5-HT₂R, D1R, α_2c, and muscarinic receptors, the relatively low occupancy at dopamine D2R, the interaction with receptor dimers, as well as the potential confounder effects resulting in biased ligand action, and lastly, the role of the moiety responsible for lipophilic and alkaline features of clozapine are highlighted. Finally, the role of transcription and protein changes at the synaptic level, and the possibility that clozapine can directly impact synaptic architecture are addressed. Although clozapine's exact MOAs that contribute to its unique efficacy and some of its severe adverse effects have not been fully understood, relevant information can be gleaned from recent mechanistic understandings that may help design much needed additional therapeutic strategies for TRS.

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.

Present and future antipsychotic drugs: a systematic review of the putative mechanisms of action for efficacy and a critical appraisal under a translational perspective

Antipsychotics represent the mainstay of schizophrenia pharmacological therapy, and their role has been expanded in the last years to mood disorders treatment. Although introduced in 1952, many years of research were required before an accurate picture of how antipsychotics work began to emerge. Despite the well-recognized characterization of antipsychotics in typical and atypical based on their liability to induce motor adverse events, their main action at dopamine D2R to elicit the "anti-psychotic" effect, as well as the multimodal action at other classes of receptors, their effects on intracellular mechanisms starting with receptor occupancy is still not completely understood. Significant lines of evidence converge on the impact of these compounds on multiple molecular signaling pathways implicated in the regulation of early genes and growth factors, dendritic spine shape, brain inflammation, and immune response, tuning overall the function and architecture of the synapse. Here we present, based on PRISMA approach, a comprehensive and systematic review of the above mechanisms under a translational perspective to disentangle those intracellular actions and signaling that may underline clinically relevant effects and represent potential targets for further innovative strategies in antipsychotic therapy.

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.

Impact cérébral structurel et fonctionnel de la Clozapine chez les patients souffrant de schizophrénie : revue systématique des études longitudinales en neuroimagerie

OBJECTIF

L'objectif de cette revue est d'identifier les corrélats anatomo-fonctionnels cérébraux lors d'un traitement par clozapine (CLZ) ainsi que les marqueurs anatomo-fonctionnels prédictifs de la réponse à la CLZ.

MÉTHODES

Nous avons réalisé une revue systématique de la littérature avec les bases de données MEDLINE et Web of Science afin d'identifier et d'examiner toutes les études longitudinales en neuroimagerie investiguant l'impact cérébral de la CLZ.

RÉSULTATS

30 études ont été incluses et analysées. La CLZ induit une diminution du volume et de la perfusion dans les noyaux gris centraux chez les patients répondeurs. Un plus grand volume de substance grise et perfusion dans ces structures avant l'instauration de la CLZ étaient associés à une meilleure réponse au traitement. La diminution de volume et de perfusion au niveau du cortex préfrontal (CPF) est observée malgré l'instauration de CLZ mais de façon moins importante chez les patients sous CLZ que chez les patients sous antipsychotiques typiques. Un plus grand volume au niveau du CPF avant l'instauration de la CLZ est associé à une meilleure réponse clinique dans la majorité des études. Enfin, la CLZ semble induire une réduction des altérations au niveau de la substance blanche.

CONCLUSION

Les corrélats anatomo-fonctionnels de la CLZ différent de ceux des autres antipsychotiques avec une action spécifique de la CLZ au niveau des ganglions de la base et du CPF pouvant participer à sa supériorité en termes de réponse clinique. Plusieurs données cliniques et d'imagerie conduisent à l'hypothèse d'un meilleur pronostic associé à une instauration plus rapide de la CLZ.

Thalamus Radiomics-Based Disease Identification and Prediction of Early Treatment Response for Schizophrenia

Background

Emerging evidence suggests structural and functional disruptions of the thalamus in schizophrenia, but whether thalamus abnormalities are able to be used for disease identification and prediction of early treatment response in schizophrenia remains to be determined. This study aims at developing and validating a method of disease identification and prediction of treatment response by multi-dimensional thalamic features derived from magnetic resonance imaging in schizophrenia patients using radiomics approaches.

Methods

A total of 390 subjects, including patients with schizophrenia and healthy controls, participated in this study, among which 109 out of 191 patients had clinical characteristics of early outcome (61 responders and 48 non-responders). Thalamus-based radiomics features were extracted and selected. The diagnostic and predictive capacity of multi-dimensional thalamic features was evaluated using radiomics approach.

Results

Using radiomics features, the classifier accurately discriminated patients from healthy controls, with an accuracy of 68%. The features were further confirmed in prediction and random forest of treatment response, with an accuracy of 75%.

Conclusion

Our study demonstrates a radiomics approach by multiple thalamic features to identify schizophrenia and predict early treatment response. Thalamus-based classification could be promising to apply in schizophrenia definition and treatment selection.

Divergent Alterations of Structural-Functional Connectivity Couplings in First-episode and Chronic Schizophrenia Patients

Emerging evidence suggests that the coupling relating the structural connectivity (SC) of the brain to its functional connectivity (FC) exhibits remarkable changes during development, normal aging, and diseases. Although altered structural-functional connectivity couplings (SC-FC couplings) have been previously reported in schizophrenia patients, the alterations in SC-FC couplings of different illness stages of schizophrenia (SZ) remain largely unknown. In this study, we collected structural and resting-state functional MRI data from 73 normal controls (NCs), 61 first-episode (FeSZ) and 78 chronic (CSZ) schizophrenia patients. Positive and negative syndrome scale (PANSS) scores were assessed for all patients. Structural and functional brain networks were constructed using gray matter volume (GMV) and resting-state magnetic resonance imaging (rs-fMRI) time series measurements. At the connectivity level, the CSZ patients showed significantly increased SC-FC coupling strength compared with the FeSZ patients. At the node strength level, significant decreased SC-FC coupling strength was observed in the FeSZ patients compared to that of the NCs, and the coupling strength was positively correlated with negative PANSS scores. These results demonstrated divergent alterations of SC-FC couplings in FeSZ and CSZ patients. Our findings provide new insight into the neuropathological mechanisms underlying the developmental course of SZ.

Verbal memory measurement towards digital perspectives in first-episode psychosis: A review

BACKGROUND

Even in the early phases of psychotic spectrum illnesses such as schizophrenia, patients can experience cognitive decline or deficits prior to the onset of psychotic symptoms such as delusions and hallucinations. In this systematic review, we assessed which verbal memory assessments are most widely used in first-episode psychosis and may be applied via digital technologies (smartphone applications, etc.) for use in early detection.

METHODS

In November 2019, we searched for studies measuring verbal memory in first episode psychosis or schizophrenia over the past 10 years on PubMed and PsycINFO. We screened abstracts of these studies and excluded review studies. Full-texts of included studies were used to identify the verbal memory measurement tests, follow-up frequencies, and sample sizes.

RESULTS

We screened 233 reports and found that 120 original research studies measured verbal memory in first episode psychosis over the past 10 years. Four of these studies specified using a computer, 24 (20%) used a paper-pen format, 1(1%) used both, and 91 (76%) studies did not specify their administration tools or suggest there were offered in digital formats. Thirty-five (30%) studies had follow-up measurements of verbal memory, while 85 (70%) had only a single verbal memory measurement.

DISCUSSION

While many scales are commonly used to measure verbal memory in first episode psychosis, they are not often administered via digital technology. There is an emerging opportunity to administer these and other tests via digital technologies for expanding access to early detection of cognitive decline in clinical high risk and first-episode psychosis.

Progressive subcortical volume loss in treatment-resistant schizophrenia patients after commencing clozapine treatment

The association of antipsychotic medication with abnormal brain morphometry in schizophrenia remains uncertain. This study investigated subcortical morphometric changes 6 months after switching treatment to clozapine in patients with treatment-resistant schizophrenia compared with healthy volunteers, and the relationships between longitudinal volume changes and clinical variables. In total, 1.5T MRI images were acquired at baseline before commencing clozapine and again after 6 months of treatment for 33 patients with treatment-resistant schizophrenia and 31 controls, and processed using the longitudinal pipeline of Freesurfer v.5.3.0. Two-way repeated MANCOVA was used to assess group differences in subcortical volumes over time and partial correlations to determine association with clinical variables. Whereas no significant subcortical volume differences were found between patients and controls at baseline (F(8,52) = 1.79; p = 0.101), there was a significant interaction between time, group and structure (F(7,143) = 52.54; p < 0.001). Corrected post-hoc analyses demonstrated that patients had significant enlargement of lateral ventricles (F(1,59) = 48.89; p < 0.001) and reduction of thalamus (F(1,59) = 34.85; p < 0.001), caudate (F(1,59) = 59.35; p < 0.001), putamen (F(1,59) = 87.20; p < 0.001) and hippocampus (F(1,59) = 14.49; p < 0.001) volumes. Thalamus and putamen volume reduction was associated with improvement in PANSS (r = 0.42; p = 0.021, r = 0.39; p = 0.033), SANS (r = 0.36; p = 0.049, r = 0.40; p = 0.027) and GAF (r = -0.39; p = 0.038, r = -0.42; p = 0.024) scores. Reduced thalamic volume over time was associated with increased serum clozapine level at follow-up (r = -0.44; p = 0.010). Patients with treatment-resistant schizophrenia display progressive subcortical volume deficits after switching to clozapine despite experiencing symptomatic improvement. Thalamo-striatal progressive volumetric deficit associated with symptomatic improvement after clozapine exposure may reflect an adaptive response related to improved outcome rather than a harmful process.

Identificacion of MRI-based psychosis subtypes: Replication and refinement

The identification of the cerebral substrates of psychoses such as schizophrenia and bipolar disorder is likely hampered by its biological heterogeneity, which may contribute to the low replication of results in the field. In this study we aimed to replicate in a completely new sample and supplement the results of a previous study with additional data on this topic. In the aforementioned study we identified a schizophrenia cluster characterized by high mean cortical curvature and low cortical thickness, subcortical hypometabolism and progressive negative symptoms. Here, we have used magnetic resonance images from 61 schizophrenia and 28 bipolar patients, as well as 51 healthy controls and a cluster analysis to search for possible subgroups primarily characterized by cerebral structural data. Diffusion tensor imaging (fractional anisotropy, FA), cognition, clinical data and electroencephalographic (EEG) modulation during a P300 task were used to validate the possible clusters. Two clusters of patients were identified. The first cluster (29 schizophrenia and 18 bipolar patients) showed decreased cortical thickness and area values, as well as lower subcortical volumes and higher cortical curvature in some regions, as compared to the second cluster. This first cluster also showed decreased FA in frontal lobe connections and worse cognitive performance. Although this cluster also showed longer illness duration, there were first episode patients in both clusters and treatment doses and types were not different between clusters. Both clusters of patients showed decreased EEG task-related modulation. In conclusion, our data give additional support to a distinct biologically based cluster encompassing schizophrenia and bipolar disorder patients with cortical and subcortical alterations, hampered cortical connectivity and lower cognitive performance.

Characteristics of gray matter alterations in never-treated and treated chronic schizophrenia patients

Though gray matter deficits have been consistently revealed in chronic treated schizophrenia, it is still not clear whether there are different brain alterations between chronic never treated and treated patients. To explore the different patterns of gray matter alterations among chronic never treated patients and those treated with monotherapy, we recruited 35 never-treated chronic schizophrenia patients with illness durations ranging from 5 to 48 years, 20 illness duration-matched risperidone monotherapy and 20 clozapine monotherapy patients, and 55 healthy controls. GM (surface area, cortical thickness, and cortical volume) measures were extracted and compared using ANCOVA across the four groups followed by post hoc tests. Relative to controls, both treated and never-treated chronic schizophrenia patients showed reduced GM mainly involving the bilateral medial and rostral middle frontal, left banks superior temporal sulcus, left fusiform, and left pericalcarine cortex and increased in the left cuneus. Compared with the untreated patient group, the two treated groups showed reductions mainly in the bilateral prefrontal, temporal, and left inferior parietal lobules. The clozapine monotherapy patients demonstrated more severe decreases in the bilateral prefrontal cortex and left cuneus and less severe decreases in the left ventral temporal lobe than risperidone monotherapy patients. These findings provide new insights into the long-term effects of antipsychotic treatment on gray matter alterations in schizophrenia patients. Furthermore, the characteristic findings of reductions in the inferior parietal lobule might be specific for long-term antipsychotic treatment, which could be a possible target for medication development in the future.

Effect of aerobic exercise combined with cognitive remediation on cortical thickness and prediction of social adaptation in patients with schizophrenia

Aerobic exercise is a promising intervention for patients with schizophrenia, but structural neuroplastic effects on brain regions relevant to the pathophysiology of the disease remain unclear. This study aimed to elucidate longitudinal changes in cortical thickness after aerobic exercise intervention in schizophrenia patients and the relationship of these changes to clinical correlates. We investigated 21 schizophrenia patients and 23 healthy controls who performed aerobic exercise and 21 schizophrenia patients who played table soccer. The 12-week exercise intervention was combined with computer-assisted cognitive remediation training from week 6 to week 12. Magnetic resonance imaging (MRI) scans were acquired at baseline and weeks 6, 12, and 24. The thickness of the entorhinal, parahippocampal, and lateral and medial prefrontal cortices was assessed with FreeSurfer 6.0. The schizophrenia aerobic exercise group showed a significant increase of cortical thickness in the right entorhinal cortex at week 6, and we found a significant correlation between the cortical thickness of the right lateral prefrontal cortex at baseline and improvement of social adaptation at week 12. In the schizophrenia table soccer and healthy control groups, we found no significant longitudinal change in cortical thickness through the intervention and follow-up period and no correlation of cortical thickness at baseline with clinical measures. Our results suggest that aerobic exercise in schizophrenia modulates the thickness of the entorhinal cortex, a structure adjacent to the hippocampus. Greater cortical thickness of the right lateral prefrontal cortex appears to predict better clinical response to an aerobic exercise intervention in patients with schizophrenia.

Disparate effects of first and second generation antipsychotics on cognition in schizophrenia - Findings from the randomized NeSSy trial

Cognitive impairment represents a core feature of schizophrenia. Uncertainty about demonstrable benefits of available antipsychotics on cognition remains an important clinical question relevant to patients' quality of life. The aim of our multi-center, randomized, double-blind "Neuroleptic Strategy Study" (NeSSy) was to compare the effectiveness of selected antipsychotics, conventionally classified as second- (SGAs) (haloperidol, flupentixol) and first generation antipsychotics (FGAs) (aripiprazole, olanzapine, quetiapine), on quality of life in schizophrenia. The effects on cognitive deficits represented a secondary outcome. We used an innovative double randomization for assignment of treatment group, and followed the patients with a neurocognitive test-battery upon six and 24 weeks of treatment. Psychopathology and quality of life were assessed using CGI, PANSS and SF-36. Assessment of cognitive performance was conducted in 114 of the 136 randomized patients. The SGA group (N = 62) showed beneficial effects of small to moderate effect size on cognition during the initial six weeks of treatment (executive functions, verbal fluency) and at 24 weeks (executive functions, working memory). In contrast, the FGA group (N = 52) showed moderately improved executive function, but a decline in verbal fluency at six weeks, with significant declines of moderate to large effect size in executive function, verbal learning and memory, and verbal fluency at 24 weeks. Our study indicates that SGAs present an advantage over FGAs regarding cognitive function during a medium-term treatment for schizophrenia. The results further emphasize a distinction between progression to detrimental effects of FGAs with prolonged treatment in contrast to more persistent cognitive benefits with SGA treatment.

Prediction of early response to overall treatment for schizophrenia: A functional magnetic resonance imaging study

INTRODUCTION

Treatment response at an early stage of schizophrenia is of considerable value with regard to future management of the disorder; however, there are currently no biomarkers that can inform physicians about the likelihood of response.

OBJECTS

We aim to develop and validate regional brain activity derived from functional magnetic resonance imaging (fMRI) as a potential signature to predict early treatment response in schizophrenia.

METHODS

Amplitude of low-frequency fluctuation (ALFF) was measured at the start of the first/single episode resulting in hospitalization. Inpatients were included in a principal dataset (n = 79) and a replication dataset (n = 44). Two groups of healthy controls (n = 87; n = 106) were also recruited for each dataset. The clinical response was assessed at discharge from the hospital. The predictive capacity of normalized ALFF in patients by healthy controls, ALFF_ratio , was evaluated based on diagnostic tests and clinical correlates.

RESULTS

In the principal dataset, responders exhibited increased baseline ALFF in the left postcentral gyrus/inferior parietal lobule relative to non-responders. ALFF_ratio of responders before treatment was significantly higher than that of non-responders (p < 0.001). The area under the receiver operating characteristic curve was 0.746 for baseline ALFF_ratio to distinguish responders from non-responders, and the sensitivity, specificity, and accuracy were 72.7%, 68.6%, and 70.9%, respectively. Similar results were found in the independent replication dataset.

CONCLUSIONS

Baseline regional activity of the brain seems to be predictive of early response to treatment for schizophrenia. This study shows that psycho-neuroimaging holds promise for influencing the clinical treatment and management of schizophrenia.

Development of Neuroimaging-Based Biomarkers in Psychiatry

This chapter presents an overview of accumulating neuroimaging data with emphasis on translational potential. The subject will be described in the context of three disease states, i.e., schizophrenia, bipolar disorder, and major depressive disorder, and for three clinical goals, i.e., disease risk assessment, subtyping, and treatment decision.

Biological Predictors of Clozapine Response: A Systematic Review

Background: Clozapine is the recommended antipsychotic for treatment-resistant schizophrenia (TRS) but there is significant variability between patients in the degree to which clozapine will improve symptoms. The biological basis of this variability is unknown. Although clozapine has efficacy in TRS, it can elicit adverse effects and initiation is often delayed. Identification of predictive biomarkers of clozapine response may aid initiation of clozapine treatment, as well as understanding of its mechanism of action. In this article we systematically review prospective or genetic studies of biological predictors of response to clozapine. Methods: We searched the PubMed database until 20th January 2018 for studies investigating "clozapine" AND ("response" OR "outcome") AND "schizophrenia." Inclusion required that studies examined a biological variable in relation to symptomatic response to clozapine. For all studies except genetic-studies, inclusion required that biological variables were measured before clozapine initiation. Results: Ninety-eight studies met the eligibility criteria and were included in the review, including neuroimaging, blood-based, cerebrospinal fluid (CSF)-based, and genetic predictors. The majority (70) are genetic studies, collectively investigating 379 different gene variants, however only three genetic variants (DRD3 Ser9Gly, HTR2A His452Tyr, and C825T GNB3) have independently replicated significant findings. Of the non-genetic variables, the most consistent predictors of a good response to clozapine are higher prefrontal cortical structural integrity and activity, and a lower ratio of the dopamine and serotonin metabolites, homovanillic acid (HVA): 5-hydroxyindoleacetic acid (5-HIAA) in CSF. Conclusions: Recommendations include that future studies should ensure adequate clozapine trial length and clozapine plasma concentrations, and may include multivariate models to increase predictive accuracy.

Duration of untreated psychosis and neurocognitive functioning in first-episode psychosis: a systematic review and meta-analysis

BACKGROUND

Previous reviews suggest there is minimal evidence for an association between duration of untreated psychosis (DUP) and neurocognition. This is based on tallied findings of studies with small samples and neurocognition viewed as a single construct. We aimed to conduct a systematic review and meta-analysis examining the association between DUP and individual neurocognitive domains and tests in first-episode psychosis (FEP).

METHOD

MOOSE and PRISMA guidelines were followed. Forty-three studies involving 4647 FEP patients were included. For studies providing correlations between DUP and neurocognition, 12 separate meta-analyses were performed based on neurocognitive domains/indices. The influence of demographic/clinical variables was tested using weighted linear meta-regression analyses.

RESULTS

The relationship between DUP and most neurocognitive domains/indices was not significant. Longer DUP was associated with a larger cognitive deterioration index, i.e. current minus premorbid intellectual functioning (N = 4; mean ES -0.213, 95% confidence interval (CI) (-0.344 to -0.074), p = 0.003). Findings were homogeneous, with no evidence of publication bias or significant influence from moderators. For studies providing mean and standard deviations for neurocognitive measures and DUP, 20 meta-regressions were performed on individual neurocognitive tests. One significant finding emerged showing that longer DUP was associated with fewer Wisconsin Card Sorting Test-perseverative errors (mean ES -0.031, 95% CI (-0.048 to -0.013), p < 0.001). Exploratory meta-regressions in studies with mean DUP <360 days showed longer DUP was significantly associated with poorer performance on Trail Making Test A and B and higher Full-Scale IQ.

CONCLUSION

There may not be a generalised association between DUP and neurocognition, however, specific cognitive functions may be associated with longer DUP or delayed help-seeking.

Neuroimaging markers of antipsychotic treatment response in schizophrenia: An overview of magnetic resonance imaging studies

Antipsychotic drugs are the primary treatment for psychosis, yet individual response to their administration remains variable. At present, no biological predictors of response exist to guide clinicians as they select treatments for patients, and our understanding of the neurobiology underlying the heterogeneity of outcomes remains limited. Magnetic Resonance Imaging (MRI) has been applied by numerous studies to examine the response to antipsychotic treatment, though a large gap remains between their results and our clinical practice. To advance patient care with precision medicine approaches, prior work must be accounted for and built upon with future studies. This review provides an overview of studies that relate treatment outcome to various MRI-related measures, including structural, spectroscopic, diffusion tensor, and functional imaging. Knowledge derived from these studies will be discussed along with future directions for the field.

Positive symptoms associate with cortical thinning in the superior temporal gyrus via the ENIGMA Schizophrenia consortium

OBJECTIVE

Based on the role of the superior temporal gyrus (STG) in auditory processing, language comprehension and self-monitoring, this study aimed to investigate the relationship between STG cortical thickness and positive symptom severity in schizophrenia.

METHOD

This prospective meta-analysis includes data from 1987 individuals with schizophrenia collected at seventeen centres around the world that contribute to the ENIGMA Schizophrenia Working Group. STG thickness measures were extracted from T1-weighted brain scans using FreeSurfer. The study performed a meta-analysis of effect sizes across sites generated by a model predicting left or right STG thickness with a positive symptom severity score (harmonized SAPS or PANSS-positive scores), while controlling for age, sex and site. Secondary models investigated relationships between antipsychotic medication, duration of illness, overall illness severity, handedness and STG thickness.

RESULTS

Positive symptom severity was negatively related to STG thickness in both hemispheres (left: β_std = -0.052; P = 0.021; right: β_std = -0.073; P = 0.001) when statistically controlling for age, sex and site. This effect remained stable in models including duration of illness, antipsychotic medication or handedness.

CONCLUSION

Our findings further underline the important role of the STG in hallmark symptoms in schizophrenia. These findings can assist in advancing insight into symptom-relevant pathophysiological mechanisms in schizophrenia.

Correlates of Clozapine Use after a First Episode of Schizophrenia: Results From a Long-term Prospective Study

BACKGROUND

Earlier commencement of clozapine has been related to a better response in treatment-resistant schizophrenia.

OBJECTIVES

To identify variables that predict clozapine use after a first episode of schizophrenia (FES).

METHODS

Patients with FES and ≤15 days of lifetime antipsychotic treatment were followed up during naturalistic treatment, and the patients who were initiated on clozapine were compared with those receiving non-clozapine antipsychotics for ≥24 months regarding demographic and clinical baseline characteristics, adherence, and relapse patterns during follow-up. Treatment-resistant schizophrenia was defined as two or more antipsychotic trials of adequate dose for ≥6 weeks.

RESULTS

Twenty-eight patients who used clozapine and 77 non-clozapine antipsychotic users were included. Clozapine was initiated after a mean of 2.5 ± 1.1 adequate antipsychotic trials. Eight of the 28 clozapine-treated patients (28.6 %) began their clozapine treatment during the first 12 months of follow-up (mean 7.1 ± 3.3 months) and their premorbid childhood adjustment was significantly worse than those who started clozapine later (mean 78.5 ± 43.0 months). Compared with non-clozapine users, patients who started clozapine had significantly more relapses in the first 6 months of follow-up prior to clozapine use (35.7 vs. 11.7 %, p = 0.005), and were significantly more likely to have a first relapse despite treatment adherence (38.1 vs. 73.3 %, p = 0.01). In the multivariate analyses, antipsychotic polypharmacy and first relapse despite adherence to antipsychotic treatment independently predicted subsequent clozapine use.

CONCLUSIONS

Clozapine use after a FES was predicted by a first relapse while being adherent to non-clozapine antipsychotics, especially if the first relapse occurred within the first 6 months. Developmental childhood difficulties predicted significantly earlier clozapine use.

Improvement in social and cognitive functioning associated with paliperidone extended-release treatment in patients with schizophrenia: a 24-week, single arm, open-label study

PURPOSE

This single-arm, open-label study aimed to explore the effects of extended-release paliperidone on social and cognitive function in patients with schizophrenia.

METHODS

Paliperidone extended-release (flexible dose ranging from 3 to 12 mg/day orally) was administered for 24 weeks in patients with schizophrenia. Patient function was assessed using the personal and social performance scale, measurement and treatment research to improve cognition in schizophrenia initiative-consensus cognitive battery, positive and negative syndrome scale, and clinical global impression-severity.

RESULTS

Ninety patients were included in the full analysis set, while 72 patients were included in the per protocol set. The personal and social performance score was 54.3±14.3 at baseline, and significantly increased to 73.4±12.6 at week 24 (P<0.001). For the measurement and treatment research to improve cognition in schizophrenia initiative-consensus cognitive battery assessment, six of the nine individual subtests, six of the seven cognitive domains, and total cognitive scores improved significantly (P<0.05) between baseline and endpoint. positive and negative syndrome scale total scores and clinical global impression-severity scores decreased gradually (P<0.001) from week 4 to the conclusion of the study.

CONCLUSION

Paliperidone extended-release treatment significantly improves social and neurocognitive function as well as symptoms in Chinese patients with schizophrenia.