Is Hair Analysis Useful in Postmortem Cases?

In postmortem cases, detection of drugs in blood is most relevant with regard to determining cause of death. However, it is sometimes also of interest to gain as much information as possible regarding the deceased's use of drugs in the period before death. The aim of this study was to compare results from analyses of a repertoire of psychoactive medicinal drugs in blood and hair samples from a larger material of postmortem cases. Hair samples in addition to blood were collected from 55 forensic autopsies and analyzed for a repertoire of 39 medicinal drugs (benzodiazepines, antidepressants and antipsychotics) using av fully validated liquid chromatography-tandem mass spectrometry method. In total, hair analyses gave information of the use of drugs not detected in blood in 47 of the 55 cases (85%). The most frequent single drugs detected in hair, but absent in blood, were benzodiazepines (64%), followed by antidepressants (35%). In each case, 1-10 (median two) single drugs were detected in hair, but absent in blood. In only two cases (4%), benzodiazepines were detected in blood and no benzodiazepines were detected in hair. In conclusion, hair analyses in addition to blood frequently indicate prior use of drugs that could yield important information about for instance unknown psychiatric diagnoses. In only a small number of cases lack of detections from the same drug class in hair might indicate reduced tolerance to drug effects.