Insight into the reliability of self-report of substance use in nightlife populations: a breath sampling study

The prevalence of drug use is often studied using self-report data. However, the reliability of self-reported illicit drug use can be uncertain due to under- or over-reporting.

In the present study, self-reported drug use was compared with biological samples among nightlife populations in Sweden and Belgium. Microparticles in the participants' breath were collected through a validated filter-device and analysed afterwards in a laboratory for the presence of 69 different drugs. Through comparison between self-reported data on drug use during the past 48 hours and the drug test results, the reliability of self-reported data of drug use can be estimated and compared between the countries.