[Use of psychotropic substances by the elderly and driving accidents]

In the context of a study for the Federal Highway Research Institute (Bundesanstalt für Strassenwesen), a database containing almost 40,000 toxicological blood analysis results from drivers with various traffic offences (time frame 1998-2001) from throughout Germany was evaluated. The database contains the results of 25 laboratories in Germany performing toxicological blood analysis of driving offences. Of these laboratories, 23 gave information about their methodology for toxicological analysis by questionnaire. This database and the results from 10,000 toxicological blood analyses of traffic offences in Hamburg (time frame 2003-2008) were evaluated. The number of elderly driver cases, the spectrum of detectable substances, the type of offence and the medical findings were compared to the results of the total sample in the corresponding period. The number of traffic offences with elderly drivers has risen in recent years but to a much smaller degree than the total number of traffic offences. The relative frequency of detection decreased from 2% in 1998 to 1.1% in 2001 (Germany wide) and from 2.3% (2003) to 1.4% (2008) in Hamburg. In the group of elderly drivers, only 39% (43% in Hamburg) of the sample showed positive results for medical drugs or drugs of abuse (73.9% of all samples). The medical diagnosis on the symptomatic level of intoxication, which had been assigned by medical doctors after blood sampling, did not correlate with the actual presence of therapeutic drugs in the blood. This demonstrates the interactions of senso-motor and physical frailties with potential additive, substance-related effects when driving skills appear to be compromised in the elderly. Drugs of abuse were detected in 5.6% (10.6% in Hamburg) among the senior drivers. Benzodiazepines were detected in 24.5% (23% in Hamburg) of the cases with a high frequency of detection in traffic accidents compared to traffic offences without accident. The type of offence was given in 87 of benzodiazepine-positive cases (20 in Hamburg), 59 of them (11 in Hamburg) were traffic accidents. Keeping the increasing percentage of senior drivers in mind, the results show that most of the elderly drivers are very careful with medical therapy and driving. However traffic-related safety advice including pharmaceutical side effects on driving ability given by general practitioners is important and necessary.