In German criminal court proceedings, the consumption of an illegal drug must be proved. In contrast, German driving licence authorities need only an indication of illegal drug abuse to order a medical psychological examination. Nevertheless, the chemical findings should be scientifically as well supported as in criminal court proceedings. Courts have often found that initially, only immunological examinations of urine samples have evidential value. It is thus important to support such chemical examinations with a second independent method. This paper gives examples of how this can be done through analysing hair samples. Hair grows about 1cm per month, and receives traces of any illegal drug through the hair roots; a hair generally retains the drug at the point in the hair where it was absorbed. Thus a picture can be obtained of the total time interval of drug elimination. Diagrams are shown to illustrate (1) the distribution of a drug in a hair or hair tuft after a single dose; (2) the distribution of drugs in hair after frequent drug abuse; (3) the distribution of opiates in hair after heroin substitution by codeine or dihydrocodeine; (4) typical concentrations in the hair of heroin addicts; (5) the theoretical distribution of drugs after the end of frequent drug abuse.
Abstract