Schizophrenia Bulletin最新文献

Background and hypothesis: Sensory gating deficit is considered a pathophysiological feature of schizophrenia, which has been linked to N-methyl-d-aspartate receptor (NMDAR) hypofunction as one of the potential underlying mechanisms. Here, we hypothesize that higher levels of NMDAR antibody (Ab) may contribute to the sensory gating deficits in schizophrenia.

Study design: We enrolled 72 non-smoking inpatients with first-episode schizophrenia (FES), most of them with only a relatively short duration of exposure to antipsychotic medications, and 51 non-smoking healthy controls (HC). Sensory gating was measured by P50 evoked potentials ratio and the difference between the two stimuli in an auditory paired-stimuli paradigm and serum NMDAR Ab levels were quantified by enzyme-linked immunosorbent assay.

Study results: The FES group showed higher serum NMDAR Ab levels [(9.23 ± 4.15) ng/mL vs. (7.08 ± 2.83) ng/mL; P = .002], higher P50 ratio (P = .002), and less P50 difference (P = .001) than HC. In partial correlation analysis, serum NMDAR Ab levels were positively correlated with the P50 ratio (r = 0.36, P = .003) and negatively with the P50 difference (r = -0.39, P = .001) in the FES group. The NMDAR Ab levels mediated the diagnosis of schizophrenia and P50 sensory gating deficits (P50 ratio and P50 difference).

Conclusions: Autoimmunity targeting NMDAR is a crucial intermediate mechanism in impaired sensory gating in patients with schizophrenia. The findings support early intervention targeting NMDAR for patients with schizophrenia.

Background and hypothesis: Numerous studies have found that being born or raised in urban environments increases the odds of developing psychosis in Northern and Western Europe. However, available research from Southern Europe, Latin America, and Asia has reported null results. A limitation in most studies to date is the inadequate characterization of urban and rural life components that may contribute to varying psychosis risk across regions.

Study design: To deepen our understanding of the different concepts and measures of urbanicity and related factors in psychosis research, we conducted a qualitative systematic literature review extracting information from studies published between 2000 and 2024.

Study results: Sixty-one articles met the inclusion and exclusion criteria and were used in the thematic analysis. The analysis revealed that urbanicity lacked a single, coherent definition across studies and regions. Three major categories of themes were developed from the analysis: (1) Urbanicity comprises several interconnected constructs, (2) Urbanicity measurements vary between countries from the Global North and the Global South, and (3) Urbanicity operates through key neighborhood-level mechanisms.

Conclusions: Future research on urbanicity and psychosis should consider the potential limitations of urbanicity's conceptualization and operationalization and aim to address these limitations by focusing on contextual, historical, and community-level factors, utilizing locally validated measures, and employing mixed-method designs.

Background and hypothesis: The onset of schizophrenia occurs after the age of 40 in up to 20% of cases. We aim to depict risk factors for first-episode psychosis after the age of 40 by comparing late-onset psychosis (LOP) patients to healthy age-matched controls.

Study design: In this case-control study using electronic health records, 142 individuals aged 40-65 years with an encounter for a first episode of psychosis between 2013 and 2021 were included. Four controls (N = 568) were matched to each case on age, sex, race, and year of encounter. Potential risk factors for the primary analysis were captured via structured data and text-mining of medical notes. Conditional logistic regression models were used to assess the odds of LOP with potential risk factors.

Study results: After adjusting for all variables in the main analysis, odds for LOP were increased by immigration (OR 3.30, 95% CI, 1.56-6.98), depression (OR 3.58, 95% CI, 2.01-6.38), anxiety (OR 2.12, 95% CI, 1.20-3.75), cannabis use (OR 3.00, 95% CI, 1.36-6.61), alcohol use disorder (OR 5.46, 95% CI, 2.41-12.36), polysubstance use (OR 4.22, 95% CI, 1.30-13.7), severe trauma (OR 2.29, 95% CI, 1.08-4.48), and caregiver burden (OR 15.26, 95% CI, 3.85-60.48).

Conclusions: Life stressors along with the effects of substance use and other psychiatric conditions may confer some risk to the development of LOP. Replication is required in independent prospective studies. Further research is necessary to truly parse out which of these factors belong on the causal pathway.

Background/hypothesis: There is increasing awareness of interindividual variability in brain function, with potentially major implications for repetitive transcranial magnetic stimulation (rTMS) efficacy. We perform a secondary analysis using data from a double-blind randomized controlled 4-week trial of 20 Hz active versus sham rTMS to dorsolateral prefrontal cortex (DLPFC) during a working memory task in participants with schizophrenia. We hypothesized that rTMS would change local functional activity and variability in the active group compared with sham.

Study design: 83 participants were randomized in the original trial, and offered neuroimaging pre- and post-treatment. Of those who successfully completed both scans (n = 57), rigorous quality control left n = 42 (active/sham: n = 19/23), who were included in this analysis. Working memory-evoked activity during an N-Back (3-Back vs 1-Back) task was contrasted. Changes in local brain activity were examined from an 8 mm ROI around the rTMS coordinates. Individual variability was examined as the mean correlational distance (MCD) in brain activity pattern from each participant to others within the same group.

Results: We observed an increase in task-evoked left DLPFC activity in the active group compared with sham (F1,36 = 5.83, False Discovery Rate (FDR))-corrected P = .04). Although whole-brain activation patterns were similar in both groups, active rTMS reduced the MCD in activation pattern compared with sham (F1,36 = 32.57, P < .0001). Reduction in MCD was associated with improvements in attention performance (F1,16 = 14.82, P = .0014, uncorrected).

Conclusions: Active rTMS to DLPFC reduces individual variability of brain function in people with schizophrenia. Given that individual variability is typically higher in schizophrenia patients compared with controls, such reduction may "normalize" brain function during higher-order cognitive processing.