Abstract：
Dopamine\'s role in addiction has been extensively studied, revealing disruptions in its functioning throughout all addiction stages. Neuromelanin in the substantia nigra (SN) may reflect dopamine auto-oxidation, and can be quantified using neuromelaninsensitive magnetic resonance imaging (neuromelanin-MRI) in a non-invasive manner.In this pre-registered systematic review, we assess the current body of evidence related to neuromelanin levels in substance use disorders, using both post-mortem and MRI examinations. The systematic search identified 10 relevant articles, primarily focusing on the substantia nigra. An early-stage meta-analysis (n = 6) revealed varied observations ranging from standardized mean differences of -3.55 to +0.62, with a pooled estimate of -0.44 (95 % CI = -1.52, 0.65), but there was insufficient power to detect differences in neuromelanin content among individuals with substance use disorders. Our gap analysis highlights the lack of sufficient replication studies, with existing studies lacking the power to detect a true difference, and a complete lack of neuromelanin studies on certain substances of clinical interest. We provide recommendations for future studies of dopaminergic neurobiology in addictions and related psychiatric comorbidities.
摘要：
多巴胺在成瘾中的作用已被广泛研究，揭示了它在所有成瘾阶段的功能中断。黑质（SN）中的神经黑色素可能反映了多巴胺的自动氧化，并且可以使用神经黑色素敏感磁共振成像（神经黑色素-MRI）以非侵入性方式进行定量。在这份预先登记的系统审查中，我们评估了目前与物质使用障碍中神经黑色素水平相关的证据，使用验尸和MRI检查。系统搜索确定了10篇相关文章，主要集中在黑质上。早期荟萃分析（n=6）显示了各种观察值，范围从-3.55到0.62的标准化平均差异，汇总估计值为-0.44（95％CI=-1.52，0.65），但是没有足够的力量来检测患有物质使用障碍的个体之间神经黑色素含量的差异。我们的差距分析强调缺乏足够的复制研究，现有的研究缺乏检测真正差异的能力，完全缺乏对某些临床感兴趣的物质的神经黑色素研究。我们为成瘾和相关精神病合并症中多巴胺能神经生物学的未来研究提供建议。
