Toxicological Investigations of Drug-Facilitated Sexual Assaults
LeBeau, Marc A., Forensic Science Communications
In past generations, alcohol and sedatives such as chloral hydrate were surreptitiously slipped into beverages to incapacitate an individual; typically, to commit robbery. In recent years, the idea of slipping someone a Mickey has taken a new twist with the use of drugs that are more difficult to detect, cause amnesia, and rapidly impair the victim (Andollo and Hearn 1997; Baselt 1998; Bismuth et al. 1997).
The victims in these cases tend to describe similar experiences. They often admit to having had one or more alcoholic drinks with a friend. A drink is left unattended for a period of time, after which the victim describes losing track of events and then waking in an unfamiliar environment, inappropriately clothed, or with a sensation of having had sexual intercourse. They are often confused and sleepy for hours to days following the event.
Although the majority of cases involve spiking the victim's drink, other scenarios exist that should also be considered as drug-facilitated sexual assault. For instance, a victim may voluntarily consume recreational drugs that lead to impairment. At other times a victim may lose consciousness after mixing prescription or over-the-counter medications with ethanol. If an individual takes advantage of such a situation and has unconsensual sexual relations with the victim, it should be considered a case of drug-facilitated sexual assault.
Difficulties Surrounding the Investigation of Drug-Facilitated Sexual Assault
Anyone who has dealt with cases of drug-facilitated sexual assault recognizes the difficulties surrounding these investigations. Problems include the vast number of drugs that can be used to commit the crime, the reporting of the crime, the collection of proper specimens, and the lack of findings in the forensic toxicology laboratory. Interestingly, many of the obstacles encountered in these investigations are directly related to the drugs used in these crimes.
Although the media has labeled drugs such as Rohypnol[R] and gamma hydroxybutyrate (GHB) as the date-rape drugs of the 1990s, in actuality, these are only two of the many drugs that have been used in recent years to incapacitate an unknowing victim (El Sohly et al. 1998). Table 1 lists drugs that have reportedly been detected or suspected in cases of drug-facilitated sexual assault (LeBeau et al. 1999). Of those listed, ethanol is the most common finding in investigations of drug-facilitated sexual assault. Although no other one drug is as prevalent as ethanol, benzodiazepines are present in a significant number of drug-facilitated sexual assault cases (El Shohly et al. 1998; LeBeau et al. 1999).
A number of the drugs listed are considered low-dose preparations and have synergistic effects when mixed with ethanol. Because such small amounts of the drug are required to cause sedation in an individual, it is difficult to detect the presence of the drug in a biological specimen unless sensitive methodologies are used in the forensic toxicology laboratory.
Achieving the lowest level of detection needed for these cases often requires the use of targeted analyses in which testing focuses on only one drug at a time. Needless to say, the analysis of a specimen for all of the drugs in Table 1 would prove to be a very time-consuming challenge.
The pharmacological properties of these drugs can present another problem for the toxicologist. Many of the drugs listed in Table 1 are quickly absorbed after oral administration, resulting in a rapid onset of effects. Depending on the drug or drugs used, these effects can include strong sedation with loss of consciousness, lowered inhibitions, amnesia, or combinations of these effects.
Many of these drugs are rapidly biotransformed into numerous inactive metabolites that may be conjugated. Some have very short half-lives, whereas others remain in the body for a fairly long period of time. …