Neural Substrates of Psychotic Depression: Findings From the Global ECT-MRI Research Collaboration.

Psychotic major depression (PMD) is hypothesized to be a distinct clinical entity from nonpsychotic major depression (NPMD). However, neurobiological evidence supporting this notion is scarce. The aim of this study is to identify gray matter volume (GMV) differences between PMD and NPMD and their longitudinal change following electroconvulsive therapy (ECT). Structural magnetic resonance imaging (MRI) data from 8 independent sites in the Global ECT-MRI Research Collaboration (GEMRIC) database (n = 108; 56 PMD and 52 NPMD; mean age 71.7 in PMD and 70.2 in NPMD) were analyzed. All participants underwent MRI before and after ECT. First, cross-sectional whole-brain voxel-wise GMV comparisons between PMD and NPMD were conducted at both time points. Second, in a flexible factorial model, a main effect of time and a group-by-time interaction were examined to identify longitudinal effects of ECT on GMV and longitudinal differential effects of ECT between PMD and NPMD, respectively. Compared with NPMD, PMD showed lower GMV in the prefrontal, temporal and parietal cortex before ECT; PMD showed lower GMV in the medial prefrontal cortex (MPFC) after ECT. Although there was a significant main effect of time on GMV in several brain regions in both PMD and NPMD, there was no significant group-by-time interaction. Lower GMV in the MPFC was consistently identified in PMD, suggesting this may be a trait-like neural substrate of PMD. Longitudinal effect of ECT on GMV may not explain superior ECT response in PMD, and further investigation is needed.

有假设认为，伴精神病性症状的重度抑郁症（PMD）是与非精神病性重度抑郁症（NPMD）不同的一种临床疾病实体。然而，支持这一观点的神经生物学证据却很匮乏。本研究旨在明确PMD与NPMD之间灰质体积（GMV）的差异，以及在电休克治疗（ECT）后两者灰质体积的纵向变化。对全球ECT - MRI研究协作组（GEMRIC）数据库中8个独立站点的结构磁共振成像（MRI）数据进行了分析（n = 108；其中PMD患者56例，NPMD患者52例；PMD患者平均年龄71.7岁，NPMD患者平均年龄70.2岁）。所有参与者在ECT治疗前后均接受了MRI检查。首先，在两个时间点分别对PMD和NPMD进行全脑体素层面的横断面GMV比较。其次，采用灵活的析因模型，分别检验时间的主效应以及组间与时间的交互作用，以确定ECT对GMV的纵向影响，以及ECT在PMD和NPMD之间的纵向差异效应。与NPMD相比，PMD在ECT治疗前，其前额叶、颞叶和顶叶皮质的GMV较低；ECT治疗后，PMD在内侧前额叶皮质（MPFC）的GMV较低。尽管在PMD和NPMD中，多个脑区的GMV均存在显著的时间主效应，但未发现显著的组间与时间的交互作用。在PMD中始终发现MPFC的GMV较低，这表明这可能是PMD一种类似特质的神经基础。ECT对GMV的纵向影响可能无法解释PMD对ECT的更佳反应，还需要进一步研究。