From the Department of Psychiatry, Gifu University Graduate School of Medicine, Gifu, Japan (Ohi, Shioiri); the Department of General Internal Medicine, Kanazawa Medical University, Ishikawa, Japan (Ohi); and the School of Medicine, Gifu University, Gifu, Japan (Ishibashi, Torii, Hashimoto, Yano)
From the Department of Psychiatry, Gifu University Graduate School of Medicine, Gifu, Japan (Ohi, Shioiri); the Department of General Internal Medicine, Kanazawa Medical University, Ishikawa, Japan (Ohi); and the School of Medicine, Gifu University, Gifu, Japan (Ishibashi, Torii, Hashimoto, Yano).
J Psychiatry Neurosci. 2022 Mar 1;47(2):E77-E85. doi: 10.1503/jpn.210144. Print 2022 Mar-Apr.
Patients with schizophrenia and bipolar disorder have an overlapping polygenic architecture and clinical similarities, although the 2 disorders are distinct diagnoses with clinical dissimilarities. It remains unclear whether there are specific differences in subcortical volumes between schizophrenia and bipolar disorder, and whether the subcortical differences are affected by any clinical characteristics. We investigated differences in subcortical volumes bilaterally among patients with schizophrenia, patients with bipolar disorder and healthy controls. We also investigated the influences of clinical characteristics on specific subcortical volumes in these patient groups.
We collected 3 T -weighted MRI brain scans from 413 participants (157 with schizophrenia, 51 with bipolar disorder and 205 controls) with a single scanner at a single institute. We used FreeSurfer version 6.0 for processing the -weighted images to segment the following subcortical brain volumes: thalamus, caudate, putamen, globus pallidus, hippocampus, amygdala and nucleus accumbens. Differences in the 7 subcortical volumes were investigated among the groups. We also evaluated correlations between subcortical volumes and clinical variables in these patient groups.
Of 7 subcortical regions, patients with schizophrenia had significantly smaller volumes in the left thalamus (Cohen = -0.29, = 5.83 × 10), bilateral hippocampi (left, = -0.36, = 8.85 × 10; right, = -0.41, = 1.15 × 10) and left amygdala ( = -0.31, = 4.02 × 10) than controls. Compared with controls, patients with bipolar disorder had bilateral reductions only in the hippocampal volumes (left, = -0.52, = 1.12 × 10; right, = -0.58, = 0.30 × 10). We also found that patients with schizophrenia had significantly smaller volumes in the bilateral amygdalae (left, = -0.43, = 4.22 × 10; right, = -0.45, = 4.56 × 10) than patients with bipolar disorder. We did not find any significant volumetric differences in the other 6 subcortical structures between patient groups ( > 0.05). Smaller left amygdalar volumes were significantly correlated with younger onset age only in patients with schizophrenia ( = 0.22, = 5.78 × 10).
We did not evaluate the differences in subcortical volumes between patients stratified based on clinical bipolar disorder subtype and a history of psychotic episodes because our sample size of patients with bipolar disorder was limited.
Our findings suggest that volumetric differences in the amygdala between patients with schizophrenia and those with bipolar disorder may be a putative biomarker for distinguishing 2 clinically similar diagnoses.
精神分裂症和双相情感障碍患者具有重叠的多基因结构和临床相似性，尽管这两种疾病是具有临床差异的明确诊断。目前尚不清楚精神分裂症和双相情感障碍之间是否存在皮质下体积的特定差异，以及皮质下差异是否受到任何临床特征的影响。我们研究了精神分裂症患者、双相情感障碍患者和健康对照组之间双侧皮质下体积的差异。我们还研究了临床特征对这些患者组特定皮质下体积的影响。
我们在一个机构的一个扫描仪上收集了 3T T1 加权 MRI 脑扫描，共 413 名参与者（157 名精神分裂症患者、51 名双相情感障碍患者和 205 名对照组）。我们使用 FreeSurfer 版本 6.0 对 T1 加权图像进行处理，以分割以下皮质下脑体积：丘脑、尾状核、壳核、苍白球、海马体、杏仁核和伏隔核。我们研究了这 3 组之间 7 个皮质下体积的差异。我们还评估了这些患者组中皮质下体积与临床变量之间的相关性。
在 7 个皮质下区域中，精神分裂症患者的左侧丘脑（Cohen = -0.29， = 5.83×10）、双侧海马体（左侧， = -0.36， = 8.85×10；右侧， = -0.41， = 1.15×10）和左侧杏仁核（ = -0.31， = 4.02×10）体积明显小于对照组。与对照组相比，双相情感障碍患者仅双侧海马体体积减少（左侧， = -0.52， = 1.12×10；右侧， = -0.58， = 0.30×10）。我们还发现，精神分裂症患者双侧杏仁核体积明显小于双相情感障碍患者（左侧， = -0.43， = 4.22×10；右侧， = -0.45， = 4.56×10）。我们没有发现患者组之间其他 6 个皮质下结构的任何显著体积差异（>0.05）。精神分裂症患者中左侧杏仁核体积较小与发病年龄较小显著相关（ = 0.22， = 5.78×10）。
由于双相情感障碍患者的样本量有限，我们没有评估基于临床双相情感障碍亚型和精神病发作史的患者皮质下体积的差异。
我们的研究结果表明，精神分裂症患者和双相情感障碍患者之间杏仁核的体积差异可能是区分两种临床相似诊断的潜在生物标志物。
