Department of Family Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
Exp Clin Psychopharmacol. 2012 Oct;20(5):430-5. doi: 10.1037/a0029210. Epub 2012 Aug 6.
Treatment responses of placebo groups in addiction medicine trials have important implications for research methodology and clinical practice, however studies examining placebo group responses in addiction medicine are scarce. Extant data suggest the importance of early treatment responsiveness for long-term outcomes. Among methamphetamine-(MA) dependent individuals randomized to placebo pill plus behavioral support conditions in pharmacotherapy development trials, we hypothesized that immediate abstinence would be a necessary but insufficient predictor for end-of-trial (EOT) abstinence. The study is a secondary analysis of participants (n = 184; 36% female) in the placebo condition of three randomized, placebo-controlled methamphetamine dependence pharmacotherapy trials. Receiver operating characteristic (ROC) curve analyses assessed the predictive power of initial abstinence, assessed by thrice weekly urine samples, for EOT abstinence. Sixty percent of individuals with complete abstinence in the first two weeks of treatment were abstinent at EOT, while 18% of people who failed to meet this standard were abstinent at EOT. Early response was related to retention at EOT and 12-month follow-up. Findings suggest that the inability to achieve at least three MA negative screenings in the first two weeks is associated with greater than 90% likelihood of treatment failure. A third week of screening added minimally to the prediction of EOT outcomes. The prediction of treatment failure was more precise than the prediction of treatment success. The absence of a clinical response in the first two weeks of treatment among participants in the placebo group signals high risk of treatment failure. The majority of information regarding response in the placebo group from a 12-week trial is obtained early in the trial.
在药物成瘾医学试验中，安慰剂组的治疗反应对研究方法学和临床实践具有重要意义，然而，目前关于药物成瘾医学中安慰剂组反应的研究却很少。现有数据表明，早期治疗反应对长期结局至关重要。在药物治疗开发试验中，我们假设，对于接受美沙酮（MA）治疗的依赖个体，立即戒断将是预测试验结束（EOT）戒断的必要但不充分条件。这项研究是对三个随机、安慰剂对照的美沙酮依赖药物治疗试验中安慰剂组的 184 名参与者（36%为女性）进行的二次分析。通过每周三次的尿液样本进行评估，接受治疗的头两周内完全戒断的个体中，有 60%在 EOT 时保持戒断，而未达到这一标准的个体中有 18%在 EOT 时保持戒断。早期反应与 EOT 时的保留率和 12 个月随访相关。研究结果表明，在治疗的头两周内无法达到至少三次 MA 阴性检测结果的个体，其治疗失败的可能性大于 90%。在 EOT 结果的预测中，增加第三周的检测结果并没有明显的帮助。治疗失败的预测比治疗成功的预测更准确。在安慰剂组的参与者中，治疗的前两周内没有出现临床反应，这表明治疗失败的风险很高。在 12 周的试验中，安慰剂组反应的大部分信息都是在试验早期获得的。
