The Forensic Implications of Cocaine

Introduction

Cocaine use in the UK is on the increase, particularly in London and the South East, and is mirroring the situation in the US. Cocaine is often thought of as a ‘safe’ drug, but more and more evidence is becoming available suggesting that this is not the case. This report aims to consider the forensic aspects of cocaine abuse, from the point of view of the Forensic Medical Examiner (FME) in terms of clinical signs and symptoms; the Forensic Psychiatrist in terms of the psychiatric effects of cocaine intoxication and chronic abuse (with a discussion of the phenomenon of ‘excited delirium’) and the forensic pathologist in terms of investigating the death of a suspected cocaine abuser, including findings at the scene of death and at autopsy. A description is also given of the basic pharmacology of cocaine and it’s most important metabolites (including cocaethylene), the analysis of samples taken for forensic investigation and the epidemiology of cocaine abuse.

Cocaine and ‘Crack’ Cocaine

Cocaine (benzoylmethylecgonine, C₁₇H₂₁NO₄) is an alkaloid prepared from the leaves of the Erythroxylon coca plant, which grows mainly in South Africa, and to a lesser extent in Africa, the Far East and India.

For centuries, the large Indian population of Peru have chewed coca leaves, and they have been found in the tombs of their ancestors dating back to 600 AD.

Coca leaves were first used in medicine in 1596, but it was not until the mid 1800’s that cocaine was extracted. Freud reported the effects of cocaine in 1884, and it was subsequently utilised in ophthalmology and dentistry as a local anaesthetic. (Cregler et al (1986) pp.1495-6).

Cocaine hydrochloride is prepared by dissolving the alkaloid in hydrochloric acid, forming a water soluble salt. It is sold illicitly as a white powder, or as crystals or granules. 

Street names include ‘coke’, ‘charlie’, ‘nose-candy’, ‘snow’ and ‘wash’. This form of cocaine can be ‘freebased’, prior to smoking, in which it is dissolved in ether or ammonia. The ‘freebase’ remains after the volatile substance has evaporated. Although this form of cocaine was popular in the late 1970s, a further refinement of this process became more prominent in the US during the 1980s, in which ‘crack’ cocaine was produced.

Crack cocaine is produced when cocaine hydrochloride is mixed with sodium bicarbonate (baking soda) and water, and then heated. On cooling, ‘rocks’ are precipitated, and these are smoked in crack pipes, or are heated on foil with the vapour inhaled. Crack is an extremely ‘pure’ form of an already ‘pure’ substance (in comparison with other drugs of abuse such as amphetamines). 

Cocaine can be administered as a drug of abuse in the following ways,

In the UK, cocaine is classified as a Class A controlled drug, by virtue of Schedule 2 of the Misuse of Drugs Act 1971 (as amended by the Misuse of Drugs Regulations 1985). It is a criminal offence to ‘unlawfully possess’ (with or without intent to supply), to import or export the drug, or produce it, and the police have extensive ‘stop and search’ powers to enforce these offences.

Cocaine addicts are required to be notified by doctors to the Chief Medical Officer under Regulation 3 of the Misuse of Drugs (Notification of and supply to Addicts) Regulations 1973, and Regulation 4 prevents doctors from prescribing cocaine unless they are licensed to do so by the Home Secretary. However, this does not apply to those treating organic disease or injury.

Epidemiology

Epidemiological data of drug misuse in the UK is not freely available in the same way that it is in the US because there is no ‘National Drugs Survey’ or ‘National Household Drugs Survey’. However, data have been collated by the Health Education Authority (1995), and as part of the 2 yearly British Crime Survey (most recently in 1998). The Four Cities Study (1992), and the Youth Lifestyle Survey (1993) also provided useful data on drug misuse in the populations covered by the study. (BMA 1997 pp,13-27, Institute for the Study of Drug Dependence, British Crime Survey 1998).

The following points of note can be extracted from the data,

In terms of cocaine and crack use, the data is often grouped with heroin use, and is not always easy to separate out,

American data indicate that 23.7 million people used cocaine between 1990-1, nearly 4 million of which were using crack. (Cone 1993). Mortality from cocaine abuse has also risen, and cocaine accounts for the most frequent substance related deaths. (Karch 1991(a) p.126).