Abstract
Objective: 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. Method: 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. Results: 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), THC-COOH, THCCOOH-glucuronide (times of use: r > .48–.61, all p < .05; grams: r > .40–.49, all p < .05). Conclusions: 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.
Original language | English (US) |
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Pages (from-to) | 441-446 |
Number of pages | 6 |
Journal | Journal of studies on alcohol and drugs |
Volume | 79 |
Issue number | 3 |
DOIs | |
State | Published - May 2018 |
Funding
Support for this work was provided by the Warren Wright Adolescent Center at Northwestern Medicine’s Stone Institute of Psychiatry; the Department of Psychiatry and Behavioral Sciences at Northwestern University Fein-berg School of Medicine; and Chemistry and Drug Metabolism, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health.The authors wish to acknowledge research staff at the Warren Wright Adolescent Center for data collection and database management, the staff at the National Institute on Drug Abuse’s Chemistry and Drug Metabolism branch for processing the blood samples, and the staff at the United States Drug Testing Laboratories for processing urine samples. Support for this work was provided by the Warren Wright Adolescent Center at Northwestern Medicine’s Stone Institute of Psychiatry; the Department of Psychiatry and Behavioral Sciences at Northwestern University Feinberg School of Medicine; and Chemistry and Drug Metabolism, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health. The authors wish to acknowledge research staff at the Warren Wright Adolescent Center for data collection and database management, the staff at the National Institute on Drug Abuse’s Chemistry and Drug Metabolism branch for processing the blood samples, and the staff at the United States Drug Testing Laboratories for processing urine samples.
ASJC Scopus subject areas
- Health(social science)
- Psychiatry and Mental health
- Toxicology