School of Social Work, University of Michigan, Ann Arbor, Michigan.
Warren Wright Adolescent Center, Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois.
J Stud Alcohol Drugs. 2018 May;79(3):441-446. doi: 10.15288/jsad.2018.79.441.
Research typically characterizes cannabis use by self-report of cannabis intake frequency. In an effort to better understand relationships between measures of cannabis use, we evaluated if Δ-9-tetrahydrocannabinol (THC) and metabolite concentrations (biometrics) were associated with a calibrated timeline followback (TLFB) assessment of cannabis use.
Participants were 35 young adult male cannabis users who completed a calibrated TLFB measure of cannabis use over the past 30 days, including time of last use. The calibration required participants handling four plastic bags of a cannabis substitute (0.25, 0.5, 1.0, and 3.5 grams) to quantify cannabis consumed. Participants provided blood and urine samples for analysis of THC and metabolites, at two independent laboratories. Participants abstained from cannabis use on the day of sample collection. We tested Pearson correlations between the calibrated TLFB measures and cannabis biometrics.
Strong correlations were seen between urine and blood biometrics (all r > .73, all p < .001). TLFB measures of times of use and grams of cannabis consumed were significantly related to each biometric, including urine 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCCOOH) and blood THC, 11-hydroxy-THC (11-OH-THC), THCCOOH, THCCOOH-glucuronide (times of use: r > .48-.61, all p < .05; grams: r > .40-.49, all p < .05).
This study extends prior work to show TLFB methods significantly relate to an extended array of cannabis biometrics. The calibration of cannabis intake in grams was associated with each biometric, although the simple TLFB measure of times of use produced the strongest relationships with all five biometrics. These findings suggest that combined self-report and biometric data together convey the complexity of cannabis use, but allow that either the use of calibrated TLFB measures or biometrics may be sufficient for assessment of cannabis use in research.
研究通常通过自我报告的大麻摄入频率来描述大麻使用情况。为了更好地理解大麻使用的测量方法之间的关系，我们评估了 Δ-9-四氢大麻酚（THC）和代谢物浓度（生物标志物）是否与校准的时间线回溯（TLFB）评估大麻使用情况相关。
35 名年轻成年男性大麻使用者完成了过去 30 天内大麻使用的校准 TLFB 测量，包括最后一次使用时间。校准要求参与者处理四袋大麻替代品（0.25、0.5、1.0 和 3.5 克）以量化消耗的大麻。参与者在样本采集当天未使用大麻，并在两个独立的实验室提供血液和尿液样本进行 THC 和代谢物分析。
尿液和血液生物标志物之间存在很强的相关性（所有 r >.73，所有 p <.001）。TLFB 测量的使用时间和消耗的大麻克数与每种生物标志物均显著相关，包括尿液中 11-去甲-9-羧基-Δ9-四氢大麻酚（THCCOOH）和血液中的 THC、11-羟基-THC（11-OH-THC）、THCCOOH、THCCOOH-葡糖苷酸（使用时间：r >.48-.61，所有 p <.05；克数：r >.40-.49，所有 p <.05）。
本研究扩展了先前的工作，表明 TLFB 方法与广泛的大麻生物标志物显著相关。以克为单位校准的大麻摄入量与每种生物标志物均相关，尽管简单的 TLFB 测量使用时间与所有五种生物标志物的相关性最强。这些发现表明，结合自我报告和生物标志物数据可以共同描述大麻使用的复杂性，但也表明使用校准的 TLFB 测量或生物标志物可能足以评估研究中的大麻使用情况。
