Brain Damage in Chronic Ketamine Users: A Multi-modal Imaging Study

• Other Authors: Lin, Yong (author.)
• Format: Others
• Language: English; Chinese
• Published: 2016
• Online Access: http://repository.lib.cuhk.edu.hk/en/item/cuhk-1292206

本研究的目的是探討長期氯胺酮使用者腦灰質容量減少與腦功能連接異常模式，以及評估腦部上述異常與認知損害的相關性。 === 181名受試者自2011年10月至2015年7月参加了本研究。他們分為2組：氯胺酮使用者組 （124名）和健康對照組 （57名）。所有受試者均完成了包括自評問卷篩查和面談的精神狀況評估，以及一套詳細的認知測試。該測試涵蓋一般智慧、詞語記憶、視覺記憶、執行功能和語言。然後他們均會接受腦部磁力共振掃描檢查。所獲得的結構磁共振和靜息態功能磁共振資料分別通過感興趣區域技術和獨立成分分析技術進行分析。 === 在氯胺酮使用者組中很多人曾經用過其他活性物質，如可卡因和大麻。在他們中，25%被診斷有抑鬱障礙，15.3%被診斷有焦慮症。氯胺酮使用者組在一般智慧、詞語記憶、視覺記憶和工作記憶、執行功能方面的測試表現也差於健康對照組。 === 氯胺酮使用者組右側眶額葉、右內側前額葉、左側蒼白球、左側海馬、右側伏隔核的灰質體積小於對照組，而左側尾狀核的體積則大於對照組。在氯胺酮使用者組中，右側眶額葉、右內側前額葉、右側伏隔核灰質體積與氯胺酮成癮嚴重程度呈負相關關係。右側眶額葉、右內側前額葉、左側尾狀核、左側蒼白球、左側海馬、和右側伏隔核也與認知測試表現呈相關關係。 === 與健康對照組相比，氯胺酮使用組靜息態功能網路連接在右側前額眶內部分、左側前扣帶回和半扣帶回部分、右側顳上回和雙側小腦vermic葉VI下降，而在左側枕中回增強。 === 本研究顯示長期氯胺酮使用對大腦損害有影像學依據。長期氯胺酮使用與特定腦區灰質體積下降、靜息態腦功能網絡連接改變有關。上述腦結構和腦功能異常可能也是氯胺酮使用與認知功能失調的精神病理學機制。氯胺酮所致的這些大腦結構及功能變化是否可逆轉尚需要縱向或前瞻性的研究來證實。 === The objectives of this study were to explore the pattern of grey matter volume reduction and functional connectivity abnormalities in the brain, and to assess the correlations between these brain abnormalities and cognitive impairment in chronic ketamine users. === One hundred and eighty-one participants took part in this study from October 2011 to July 2015. They were divided into two groups: ketamine users (n = 124) and healthy controls (n = 57). Each participant completed self-rated questionnaires and face-to-face interviews for psychiatric assessment, and took a detailed cognitive battery test that covered general intelligence, verbal and visual memory, executive function and language. All of the participants then underwent a magnetic resonance imaging (MRI) scan of the brain. The acquired structural MRI data and resting-state functional MRI data were analysed by region of interest technique and independent component analysis, respectively. === Many ketamine users used other substances, such as cocaine and cannabis. In the ketamine users group, 25% were diagnosed with a mood disorder and 15.3% with an anxiety disorder. The ketamine users performed worse than the healthy control group in tests of general intelligence, verbal memory, visual memory and working memory and executive function. === Grey matter volume was reduced in the right orbitofrontal cortex, right medial prefrontal cortex, left globus pallidus, left hippocampus, and right nucleus accumbens in the ketamine users group. In contrast, grey matter volume in the left caudate was larger in the ketamine users group than in the healthy control group. The grey matter volumes of the right orbitofrontal cortex, right medial prefrontal cortex, and right nucleus accumbens were negatively correlated with the severity of ketamine dependence. The right orbitofrontal cortex, right medial prefrontal cortex, left caudate, left globus pallidus, left hippocampus, and right nucleus accumbens volumes were also correlated with performance in the cognitive tests. === The ketamine users group showed significantly decreased functional connectivity of the default mode network in the orbital part of the right inferior frontal gyrus, left anterior cingulate and paracingulate gyri, right superior temporal gyrus and bilateral vermic lobule VI of cerebellum; and increased functional connectivity in the left middle occipital gyrus compared with the healthy control group. === This study found imaging evidence of brain damage in chronic ketamine users. Chronic ketamine use was associated with reduced grey matter volumes and altered functional connectivity of the default mode network in certain regions of the brain. These st === Lin, Yong. === Thesis Ph.D. Chinese University of Hong Kong 2016. === Includes bibliographical references (leaves ). === Abstracts also in Chinese. === Title from PDF title page (viewed on …). === Detailed summary in vernacular field only. === Detailed summary in vernacular field only. === Detailed summary in vernacular field only. === Detailed summary in vernacular field only. === Detailed summary in vernacular field only. === Detailed summary in vernacular field only.