Association of Lower Rostral Anterior Cingulate GABA+ and Dysregulated Cortisol Stress Response With Altered Functional Connectivity in Young Adults With Lifetime Depression: A Multimodal Imaging Investigation of Trait and State Effects.

OBJECTIVE: Preclinical work suggests that excess glucocorticoids and reduced cortical γ-aminobutyric acid (GABA) may affect sex-dependent differences in brain regions implicated in stress regulation and depressive phenotypes. The authors sought to address a critical gap in knowledge, namely, how stress circuitry is functionally affected by glucocorticoids and GABA in current or remitted major depressive disorder (MDD). METHODS: Multimodal imaging data were collected from 130 young adults (ages 18-25), of whom 44 had current MDD, 42 had remitted MDD, and 44 were healthy comparison subjects. GABA+ (γ-aminobutyric acid and macromolecules) was assessed using magnetic resonance spectroscopy, and task-related functional MRI data were collected under acute stress and analyzed using data-driven network modeling. RESULTS: Across modalities, trait-related abnormalities emerged. Relative to healthy comparison subjects, both clinical groups were characterized by lower rostral anterior cingulate cortex (rACC) GABA+ and frontoparietal network amplitude but higher amplitude in salience and stress-related networks. For the remitted MDD group, differences from the healthy comparison group emerged in the context of elevated cortisol levels, whereas the MDD group had lower cortisol levels than the healthy comparison group. In the comparison group, frontoparietal and stress-related network connectivity was positively associated with cortisol level (highlighting putative top-down regulation of stress), but the opposite relationship emerged in the MDD and remitted MDD groups. Finally, rACC GABA+ was associated with stress-induced changes in connectivity between overlapping default mode and salience networks. CONCLUSIONS: Lifetime MDD was characterized by reduced rACC GABA+ as well as dysregulated cortisol-related interactions between top-down control (frontoparietal) and threat (task-related) networks. These findings warrant further investigation of the role of GABA in the vulnerability to and treatment of MDD.

Use of remote centralized raters via live 2-way video in a multicenter clinical trial for schizophrenia.

Factors associated with clinician assessment may play a role in the increasing rate of failed trials. The use of centralized raters, a small group of highly skilled, tightly calibrated, and continuously monitored raters linked to the study sites through videoconferencing can address these issues by reducing the sheer number of raters involved, using rigorous calibration procedures not logistically feasible with a larger dispersed group of raters, and by blinding raters to visit and protocol. This phase 2 study was the first randomized controlled trial to use centralized raters in a study of treatments for schizophrenia. Subjects (N = 313) from 32 sites were randomly assigned to 6 weeks of treatment with 1 of 2 doses of an investigational antipsychotic, olanzapine 15 mg, or placebo. Subjects were evaluated weekly using the Positive and Negative Syndrome Scale. Data from the olanzapine (n = 68) and placebo (n = 68) arms were provided by the sponsor. The mean Positive and Negative Syndrome Scale change was significantly greater with olanzapine (-15.2) than placebo (-4.43), P = 0.002. The significant difference was apparent at week 1. The effect size was 0.48. Internal consistency was high throughout the study. Scores at screening were normally distributed and not skewed toward the cutoff score. Results found that hospitalized patients with schizophrenia were willing and able to participate in clinical trials using remote interviews conducted via videoconference. This methodology shows enormous promise for use in clinical trials, even with acutely psychotic patients.