Owing to the ability to accumulate drugs which, by converse, quickly disappear from biological fluids, hair is the matrix of choice for the assessment of past exposure to drugs, in terms of weeks to months preceding hair collection. In Italy, hair analysis for drugs of abuse is increasingly included among the clinical and laboratory tests that subjects with a history of drug abuse or suspected drug abusers have to undergo when applying for the issue/renewal of the driving licence. When hair tests positive, and anamnestic and clinical data support the diagnosis of past drug use, the driving licence is not issued or is withdrawn for a period of 6-12 months in order to prevent drug abusers from driving while under influence. The experience gained after several years of application demonstrates the efficacy of hair testing in detecting past exposure to drugs. Moreover, the combination of such a powerful and sensitive analytical tool with the adoption of restrictive measures (i.e. the withdrawal of the driving licence) acts as a strong deterrent, reducing the risk of relapse into drug use: two thirds of the positives for either opiates or cocaine, and more than 90% of the negatives, tested negative at a second control carried out 1-2 years later.
Abstract