Original communication
Toxicological findings in cases of alleged drug-facilitated sexual assault in the United Kingdom over a 3-year period

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Abstract

This paper outlines the toxicology results from 1014 cases of claimed drug-facilitated sexual assault (DFSA) analysed at the Forensic Science Service, London Laboratory between January 2000 and December 2002. Where appropriate, either a whole blood sample and/or a urine sample was analysed for alcohol, common drugs of abuse and potentially stupefying drugs. The results were interpreted with respect to the number of drugs detected and an attempt was made to distinguish between voluntary and involuntary ingestion from information supplied.

Alcohol (either alone or with an illicit and/or medicinal drug) was detected in 470 of all cases (46%). Illicit drugs were detected in 344 cases (34%), with cannabis being the most commonly detected (26% of cases), followed by cocaine (11%).

In 21 cases (2%), a sedative or disinhibiting drug was detected which had not been admitted and could therefore be an instance of deliberate spiking. This included three cases in which complainants were allegedly given Ecstasy (MDMA) without their knowledge. Other drugs detected included gammahydroxybutyrate (GHB) and the benzodiazepine drugs diazepam and temazepam. Another nine cases (1%) involved the complainant being either given or forced to ingest pharmaceutical tablets or an illicit drug.

Introduction

Cases of alleged drug facilitated sexual assault (DFSA) are encountered frequently in the United Kingdom (UK). The Forensic Science Service is the major provider of forensic services in the UK and nearly all of its work involves crime cases submitted by the police. It deals with approximately 500 cases of claimed DFSA annually. Generally, the Forensic Science Service, London Laboratory analyses toxicology samples submitted by Police forces in the southern half of England and Wales whereas the Forensic Science Service, Chorley Laboratory analyses toxicology samples submitted by Police forces in the northern half of England and Wales. Several papers have reported the incidence of alcohol and drugs in DFSA cases in the USA1, 2, 3, 4, 5 but none have been reported to date for the UK. A number of papers have also been published giving advice for the prevention and investigation of such crimes.6, 7

Over the past few years, the subject of DFSA has generated widespread media interest. The media have adopted the term ‘date-rape’ to describe such cases although many of these cases are clearly not ‘dates’. Toxicology practitioners generally prefer to use the term DFSA instead which can be defined as the use of a drug, noxious substance or chemical agent to facilitate sexual contact. In the media, there has been a particular association of the benzodiazepine drug flunitrazepam (Rohypnol®), and more recently GHB (gammahydroxy-butyrate) and ketamine, with the crime.2, 3, 8, 9, 10 The sedative properties of these drugs, which make them desirable as agents for this type of crime, have been well documented in the literature.1, 2, 3, 4, 5, 6, 7, 8 Alcohol will potentiate their sedative effects. There is, however, no strong scientific evidence that any one drug in particular is being used, although both Flunitrazepam11 and GHB12 have been reported to have been used in DFSA cases outside the UK. It is well known that a number of other sedative drugs could potentially be used, e.g., other benzodiazepine drugs, zopiclone and antihistamines.6, 7, 8 The majority of these are medicinal drugs with legitimate therapeutic properties.

The desired effect of administering a chemical agent in DFSA cases is to produce sedative and hypnotic (i.e., sleep-inducing) effects, to alter the victim’s behaviour and to cause anterograde amnesia so that the victim has no recollection of events.6, 8, 13 These effects can all increase the victim’s susceptibility to sexual assault. A typical scenario involves the victim having ingested a drink (often bought by an unknown individual) after which they had little, partial or no recollection of events for a period of time. The victim may have awoken many hours later in unfamiliar surroundings, sometimes in a state of undress or partial dress, and sometimes in the company of an unfamiliar person which consequently led them to fear that they had been raped or sexually assaulted in the intervening period. Occasionally, they may have had “flashbacks” to this incident at a later date. There may often be a considerable time delay before the victim reported the allegation to police as some may have been reluctant to do so until they had discussed the events with friends/relatives or until their memory had returned.

DFSA is not a new crime. In the UK, the Offences Against the Person Act 1861 and, more recently, the Sexual Offences Act 1956 and 2003, include legislation concerning such crimes. This legislation covers those people directly involved in administering the drug as well as those who take advantage of a person in that state. There has, however, been an increase in recent years in the number of claims of DFSA which may be as a consequence of heightened awareness following media interest.

Section snippets

Study protocol

In this study, we have recorded how many of the alleged DFSA cases analysed contained alcohol, illicit drugs and therapeutic drugs (whether potentially stupefying or not). However, the main interests of this study were twofold:

  • (a)

    Where a sedative or disinhibiting drug was detected, we were interested in trying to distinguish between voluntary use and involuntary ingestion of that drug. By using information provided by the investigating police officer (with follow up discussion where necessary), we

Samples recommended for toxicology analysis

The Forensic Science Service encouraged investigating police officers to submit blood and urine samples in all cases of alleged DFSA. Collection of urine samples does not require medical supervision and complainants should have been encouraged to supply a sample at the earliest opportunity. A urine sample was the most useful sample to be taken as it gives a much greater chance of any drugs being detected, especially if a rapidly eliminated drug such as GHB was suspected. It was also essential

Analytical protocol

The analytical protocol used in this laboratory for the investigation of DFSA cases was in agreement with the recommendations and guidelines published with regards to toxicological investigation of this type of crime.5, 6, 7 The analytical tests involved specific and sensitive methods using established techniques that looked for a wide range of drugs (not just GHB and Rohypnol®). These tests have been shown to be able to detect low concentrations of the relevant drugs (and/or their metabolites).

Samples analysed

All the cases in this study were analysed at the Forensic Science Service, London Laboratory between January 2000 and December 2002. Samples were submitted from 33 of the 43 police forces in England and Wales and two of the police forces in Scotland. Most of the urine samples were collected from the complainant at police stations, hospitals or specialist victim treatment centres. A few of the complainants collected their own samples at home. All the blood samples were collected by medical

Samples submitted

Of the 1014 cases examined, 879 (87%) had a urine sample submitted (with or without a whole blood sample). Of these, 635 (72%) were taken within 24 h of the alleged incident. The remaining 135 (13%) of the total cases were those in which only a whole blood sample was submitted. Of these, 113 (84%) were taken within 24 h of the alleged incident. A breakdown of the time intervals between the alleged incident and sampling is shown in Fig. 1.

Illicit drugs and alcohol

The results relating to alcohol and illicit drugs from

Discussion

Alcohol is clearly the most commonly used substance, being detected in 46% of the total samples. Since the vast majority of alleged DFSA cases take place in or following social situations, the presence of alcohol is not surprising. However, there were also a large number of cases (n = 344; 34%) in which illicit drugs were detected. In some cases (n = 87; 8%), more than one illicit drug was detected. The most commonly detected illicit drug was cannabis which was present in approximately a quarter of

Recommendations

The widespread media interest has generated a greater awareness of the issues surrounding DFSA, including good advice on how to avoid being spiked with a drug. However, attention could also be directed to giving advice regarding alcohol consumption, e.g., drinking steadily, not drinking on an empty stomach and the dangers of illicit drug use. Calls have been made for raising awareness of these concerns37. The results from this study suggest that if such advice were taken, there would almost

Conclusion

Only a few cases were found where a sedative drug was detected and its presence could not be attributed to voluntary use by the complainant (e.g., by taking the drug on prescription). This is in agreement with studies recently carried out in the United States. The low number of identified deliberate spiking cases (approximately 2%) may not necessarily reflect the true number of DFSA cases that have occurred. There could have been other cases in which a drug was not detected because the samples

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