Department of Psychosis Studies, Institute of Psychiatry, King's College London, USA.
Am J Psychiatry. 2012 Mar;169(3):264-72. doi: 10.1176/appi.ajp.2011.11060940.
Striatal dopamine transporter abnormalities are thought to underlie the pathophysiology and psychostimulant treatment of attention deficit hyperactivity disorder (ADHD). However, individual studies using single photon emission tomography (SPECT) or positron emission tomography (PET) have yielded inconsistent results, i.e., both high and low striatal dopamine transporter levels.
Nine SPECT and PET studies investigating striatal dopamine transporter density in ADHD patients (N=169) and age-, gender-, and IQ-matched healthy comparison subjects (N=173) were included in a quantitative meta-analysis. Binding potentials in the striatum and demographic, clinical, and methodological variables were extracted from each publication or obtained directly from authors. Hedges' g was used as a measure of effect size in an analysis using Comprehensive Meta-Analysis software. Publication bias was assessed with funnel plots and Egger's intercept. Heterogeneity was addressed with the Q statistic and I2 index.
Striatal dopamine transporter density was 14% higher on average in the ADHD group than in the healthy comparison group. However, heterogeneity across studies was large and statistically significant. Meta-regression analyses showed that the percentage of subjects without exposure to psychostimulants was negatively correlated with dopamine transporter density; density was higher in patients with previous medication exposure and lower in medication-naive patients. There was no moderating effect for age, comorbidity, gender, year of publication, or imaging technique. There was no publication bias, and sensitivity analysis confirmed robustness of the results.
Striatal dopamine transporter density in ADHD appears to depend on previous psychostimulant exposure, with lower density in drug-naive subjects and higher density in previously medicated patients.
纹状体多巴胺转运体异常被认为是注意力缺陷多动障碍（ADHD）的病理生理学和精神兴奋剂治疗的基础。然而，使用单光子发射断层扫描（SPECT）或正电子发射断层扫描（PET）的个别研究得出了不一致的结果，即纹状体多巴胺转运体水平既高又低。
纳入了 9 项 SPECT 和 PET 研究，这些研究调查了 ADHD 患者（N=169）和年龄、性别和智商匹配的健康对照受试者（N=173）的纹状体多巴胺转运体密度。从每个出版物中提取纹状体和人口统计学、临床和方法变量的结合潜能，或直接从作者处获得。使用 Comprehensive Meta-Analysis 软件，使用 Hedges'g 作为效应量的衡量标准进行分析。使用漏斗图和 Egger 的截距评估发表偏倚。使用 Q 统计量和 I2 指数解决异质性。
ADHD 组的纹状体多巴胺转运体密度平均高出 14%。然而，研究之间的异质性很大且具有统计学意义。元回归分析表明，未暴露于精神兴奋剂的受试者百分比与多巴胺转运体密度呈负相关；有既往药物暴露的患者密度较高，而未用药的患者密度较低。年龄、合并症、性别、发表年份或成像技术均无调节作用。不存在发表偏倚，敏感性分析证实了结果的稳健性。
ADHD 患者的纹状体多巴胺转运体密度似乎取决于先前的精神兴奋剂暴露，未用药的患者密度较低，而先前用药的患者密度较高。
