Correspondence between Oral Fluid Drug Test Results and Self-Reported Illicit Drug Use among Music Festival Attendees

Abstract

Background: Use of illicit substances is often under-reported. Testing positive in oral fluid provides an objective confirmation of recent intake. Objectives: To examine the agreement between oral fluid test results and self-reported substance use among music festival attendees, and factors associated with reporting past 48 h drug use among users identified by drug testing. Methods: One thousand three hundred nine participants were recruited from six music festivals in Norway (June–August 2016). They completed a questionnaire and provided oral fluid samples analyzed for amphetamines, MDMA, tetrahydrocannabinol (cannabis), and cocaine. Additionally, their blood alcohol levels were measured. Results: Overall, 5.5% reported use of amphetamines, cannabis, cocaine, and/or MDMA during past 48 h in the questionnaire, whereas 10.8% tested positive in oral fluid. Only 16.7% of identified cocaine users and 31.1% of identified MDMA users reported past 48 h cocaine or MDMA use, respectively. Higher proportions of identified cannabis and amphetamine users reported past 48 h use (53.8% and 55.6%, respectively). Multivariable logistic regression analysis showed that among participants who tested positive, those reporting weekly illicit substance use (Adjusted Odds Ratio [AOR] 30.6; 95% Confidence Interval [CI] 6.3–147.9), and using such substances when younger than 18 years (AOR 5.0; 95% CI 1.9–13.4) were more likely to report past 48 h use. Conclusions/Importance: Oral fluid testing appears to be an important tool when studying illicit substance use among music festival attendees, as significant under-reporting was observed. Among those testing positive, regular, and experienced users were more likely to report recent use, compared to less regular and experienced users.

Keywords:

• Illicit drug use
• self-report
• oral fluid
• drug analysis
• music festivals

Acknowledgment

We would like to thank Jasmina Burdzovic Andreas, Norwegian Institute of Public Health, for comments and suggestions on the final draft of the article.

Declaration of interests

The authors report no conflicts of interest.

Additional information

Funding

This study was funded by The Norwegian Institute of Public Health and Oslo University Hospital with financial support from The Norwegian Health Directorate.