Hair analysis in order to evaluate drug abuse in driver's license regranting procedures

In Italy, driving under the influence of drugs determines the suspension of the offender's driver's license. To regain the license the person must be drug free during an observation period. People whose license has been revoked or suspended can obtain, or re-obtain their driver's license subject to the judgment of a medical commission. The exclusion of illicit drug use is determined by means of toxicological analysis, mainly on urine or hair matrices. We reported the results of several years of experience of the forensic toxicology laboratory of the University of Macerata in the use of hair analysis for the assessment of past exposure to drugs in people suspected of driving under the influence of drugs. From 2004 to 2013, 8612 hair samples, were analyzed for opiates, cocaine and delta-9-tetrahydrocannabinol (Δ(9)-THC) using gas chromatography/mass spectrometry (GC/MS) method. We used a cutoff (SoHT or national guidelines) to determine the positive data, regardless of the hair sample concentrations. 1213 samples resulted positive, 71.7% were positive for cocaine and metabolites, 19.8% for morphine and metabolites, 8.5% for Δ(9)-THC. We also studied the timeframe of the abuse, as well as gender and age distribution of positive subjects. Moreover, we analyzed the possible deterrent effect of the hair analysis on driving under the influence of psychoactive substances.