Forensic urinalysis of drug use in cases of alleged sexual assault.

The results of 3303 analyses of urine samples, collected in an independent testing programme from individuals who claimed to have been sexually assaulted and believed that drugs were involved, were examined in detail. Of the samples provided, 2026 (61.3%) proved positive for one or more substances. Alcohol, either alone or in combination with other drugs, was by far the commonest substance found, being present in 1358 samples (67.0% of positives). Cannabis was the second most prevalent drug, present in 613 samples, (30.3% of positives). Detailed examination of the testing results does not support the contention that any single drug, apart from alcohol, can be particularly identified as a 'date rape' drug. Rather, the alleged sexual assaults may often take place against a background of licit or recreational alcohol or drug use, where alcohol and other drugs are frequently taken together. The extensive forensic database examined here does not support the concept of a commonly occurring 'date rape' scenario, in which the victim's drink is covertly 'spiked' with a tablet, capsule or powder containing a sedative-hypnotic. This research highlights the need for the early collection of forensic samples in cases of alleged sexual assault. Law enforcement agencies and health professionals should establish guidelines and procedures to ensure that appropriate forensic samples (blood and urine) are collected in a timely manner following allegations of possible drug mediated sexual assault.