Nail analysis for the assessment of caffeine abuse in Northwest China: A population-based study.

Caffeine is the most widely consumed psychoactive agent worldwide and has the potential for abuse, but studies monitoring caffeine abuse in China are scarce. This study aims to estimate the prevalence of caffeine abuse in northwest China and investigate the correlation between caffeine and other drugs in hair and nails using an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Fingernail clippings were collected from 376 participants in northwest China to detect caffeine and 13 other illicit psychoactive drugs and their metabolites. Paired hair and nail samples were collected from 39 participants to investigate the correlation between caffeine and other drugs in hair and nails. The samples were decontaminated, pulverized, and extracted by a high-throughput nail sample preparation method and analyzed by UPLC-MS/MS. The results showed a risk of caffeine abuse in northwest China, with concentrations ranging from 0.43 to 10.6 ng/mg for healthy volunteers, 0.49-246 ng/mg for caffeine abusers, and 0.25-363 ng/mg for drug addicts in community rehabilitation centers. Caffeine was detected together with other illicit psychoactive drugs and their metabolites. Furthermore, positive detection correlations were found between hair and nail samples. This study provides a current perspective on caffeine abuse in northwest China and demonstrates the practical use of UPLC-MS/MS for the simultaneous detection of caffeine and 13 illicit psychoactive drugs and their metabolites in hair and nails. The results highlight the potential of nails as a supplementary matrix when hair samples are unavailable and emphasize the need for handling caffeine carefully given its potential for abuse.

Pathway of effects of adverse childhood experiences on the poly-drug use pattern among adults using drugs: A structural equation modeling.

Introduction: Adverse childhood experiences (ACEs) are associated with an increased risk of poly-substance use among drug-using adults. However, there is a paucity of literature on a direct or indirect relationship between ACEs and drug use patterns. We thus aimed to identify the pathway of effects of ACEs on drug use patterns in adults by the structural equation model (SEM). Methods: A cross-sectional study was conducted by respondent-driving sampling and consecutive sampling among adult drug users in Southwest China in 2021. Descriptive, univariate, and SEM analyses were performed by R software 4.2.1. Results: Of 406 participants recruited from a drug abuse clinic, the average age was 34 years. The majority of the participants were male patients (98.3%) from ethnic minorities (79.6%), who were unmarried (71.6%) and employed (81.2%). Nearly 95.5% experienced ACEs with 46.6% of them reporting four or more ACEs. The median value of self-perception of drug abuse score, friend drug use score, and drug use score was 8.0 (3.0, 11.0), 1.0 (0.0, 1.0), and 1.0 (1.0, 2.0) respectively. In the confirmatory analysis part of SEM, the construct of latent variables fitted well with the data. Poly-drug use was significantly and directly affected by three predictors including monthly incomes (ß = 0.09), friend drug use (ß = 0.50), and ACEs (ß = 0.11). The indirect effect of ACEs passing through self-perception of drugs (ß = 0.09) was not significant. Discussion: ACEs have an independent and direct effect on the drug user for poly-drug use apart from the effect of drug-using friends and family income.