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Background: Abnormalities in the anterior cingulate cortex (ACC) are thought to play an important role in the pathophysiology of schizophrenia. Given regional variations in ACC structure, the present study aimed to examine ACC structural subdivisions and their relationships to treatment resistance and glutamatergic levels in schizophrenia. Methods: This study included 100 patients with schizophrenia and 52 healthy controls from 2 cohorts. We applied non-negative matrix factorization to identify accurate and stable spatial components of ACC structure. Between groups, we compared ACC structural indices in each spatial component based on treatment resistance or response and tested relationships with ACC glutamate + glutamine levels. Results: We detected reductions in cortical thickness and increases in mean diffusivity in the spatial components on the surface of the cingulate sulcus, especially in patients with treatment-resistant and clozapine-resistant schizophrenia. Notably, mean diffusivity in these components was higher in patients who did not respond to clozapine compared to those who did. Furthermore, these ACC structural alterations were related to elevated ACC glutamate + glutamine levels but not related to symptomatology or antipsychotic dose. Limitations: Sample sizes, cross-sectional findings and mixed antipsychotic status were limitations of this study. Conclusion: This study identified reproducible abnormalities in ACC structures in patients with treatment-resistant and clozapine-resistant schizophrenia. Given that these spatial components play a role in inhibitory control, the present study strengthens the notion that glutamate- related disinhibition is a common biological feature of treatment resistance in schizophrenia., Introduction Current antipsychotics fail to alleviate clinical symptoms in approximately one-third of patients with schizophrenia. (1) This subtype is termed treatment-resistant schizophrenia, which is formally defined as having an inadequate [...]

Background and Hypothesis Given the heterogeneity and possible disease progression in schizophrenia, identifying the neurobiological subtypes and progression patterns in each patient may lead to novel biomarkers. Here, we adopted data-driven machine-learning techniques to identify the progression patterns of brain morphological changes in schizophrenia and investigate the association with treatment resistance. Study Design In this cross-sectional multicenter study, we included 177 patients with schizophrenia, characterized by treatment response or resistance, with 3D T1-weighted magnetic resonance imaging. Cortical thickness and subcortical volumes calculated by FreeSurfer were converted into z scores using 73 healthy controls data. The Subtype and Stage Inference (SuStaIn) algorithm was used for unsupervised machine-learning analysis. Study Results SuStaIn identified 3 different subtypes: (1) subcortical volume reduction (SC) type (73 patients), in which volume reduction of subcortical structures occurs first and moderate cortical thinning follows, (2) globus pallidus hypertrophy and cortical thinning (GP-CX) type (42 patients), in which globus pallidus hypertrophy initially occurs followed by progressive cortical thinning, and (3) cortical thinning (pure CX) type (39 patients), in which thinning of the insular and lateral temporal lobe cortices primarily happens. The remaining 23 patients were assigned to baseline stage of progression (no change). SuStaIn also found 84 stages of progression, and treatment-resistant schizophrenia showed significantly more progressed stages than treatment-responsive cases (P  = .001). The GP-CX type presented earlier stages than the pure CX type (P  = .009). Conclusions The brain morphological progressions in schizophrenia can be classified into 3 subtypes, and treatment resistance was associated with more progressed stages, which may suggest a novel biomarker. [ABSTRACT FROM AUTHOR]

Background: To elucidate the neurobiology underlying alcohol's effect on the human brain, we examined the acute effects of moderate alcohol administration on levels of glutamatergic neurometabolites and N‐acetylaspartate, an amino acid found in neurons, may reflect disordered neuronal integrity. Methods: Eighteen healthy Japanese participants (7 males/11 females) aged 20–30 years who were heterozygous for an inactive allele of acetaldehyde dehydrogenase‐2 (ALDH/*1/*2) were included. Participants underwent an intravenous alcohol infusion using the clamp method at a target blood alcohol concentration (BAC) of 0.50 mg/mL for 90 min within a range of ±0.05 mg/mL. We examined glutamate + glutamine (Glx) and N‐acetylaspartate N‐acetylaspartylglutamate (NAA) levels in the midcingulate cortex (MCC) using 3 T 1H‐MRS PRESS at baseline, 90 min, and 180 min (i.e., 90 min after alcohol infusion was finished). A two‐way repeated‐measures analysis of variance was used to assess longitudinal changes in Glx and NAA levels, with time and sex as within‐ and between‐subject factors, respectively. Pearson's correlation coefficients were calculated among neurometabolite levels and BAC or blood acetaldehyde concentration (BAAC). Results: Both Glx (F(2,32) = 8.15, p = 0.004, η2 = 0.15) and NAA (F(2,32) = 5.01, p = 0.04, η2 = 0.07) levels were increased after alcohol injection. There were no sex or time × sex interaction effects observed. NAA levels were positively correlated with BAAC at 90 min (r(13) = 0.77, p = 0.01). There were no associations between neurometabolite levels and BAC. Conclusions: Both Glx and NAA levels in the MCC increased in response to the administration of moderate concentrations of alcohol. Given positive associations between NAA levels and BAAC and the hypothetical glutamate release via dopamine pathways, the effects of drinking on the MCC in the acute phase may be ascribed to acetaldehyde metabolized from alcohol. [ABSTRACT FROM AUTHOR]