Development of a rational scale to assess the harm of drugs of potential misuse -The Lancet 2007; 369:1047-1053 23rd March 2007
Prof David Nutt , Leslie A King PhD , William Saulsbury & Prof Colin Blakemore
The capacity of humans to harm themselves with self medicated drugs, legal or illegal is remarkable. In response their use is regulated by a byzantine system that is somewhat like Topsy .. it er ... just growed.
Harmful drugs are now regulated in the UK and eslewhere according to statutory classification systems that purport to relate to the perceived harms and risks of each drug. It is evident that the system in use is not systematic. It is not evidence based. It is illogical and irrational.
e.g Evidence to the House of Commons Science and Technology Committee. Para 83
On the matter of why psilocin, one of the hallucinogenic compounds found in magic mushrooms, was in Class A, Sir Michael told us: "it is there because it is there […] there have been very few publications on psilocin. It has hardly been investigated at all"
Drug misuse is a major social, legal, and public-health problem and it places a huge burden on cash, resources and manpower. In the UK this is estimated at £10-16 Bn a year.
Current methods to counter drug misuse are;
1. Interdiction of supply (Police / Customs / NHS monitoring)
2. Education - although it is not directly the responsibility or function of any department of State - much of it is done by private charities.
3. Treatment - which is handled by a mix of NHS, Social Services, prisons, and private charities.
Currently all illegal drugs are classified under the Misuse of Drugs Act of 1971 A, B, and C— intended to indicate the dangers of each drug, class A being the most harmful and class C the least. The consequences of this affect both the determining of the legal penalties for importation, supply, and possession, but the degree of police / prison effort targeted at restricting its use.
Elsewhere drug classification systems are used that purport to be structured according to the relative risks and dangers of illicit drugs. The process of classification is unclear ill-defined, opaque, and apparently arbitrary.
The authors have attempted to arrive at a novel, logical, consistent ascending/descending classification for the most frequently used drugs in Western Society.
First they identify 3 principal factors -
Damage to organs or systems— effect on physiological functions—eg, respiratory and cardiac—is a major determinant of physical harm. The mrthod of administration is relevant intravenous use —eg, heroin—carry a high risk of causing sudden death from respiratory depression. Tobacco and alcohol cause illness and death as a result of chronic long term use. Long-term cigarette smoking reduces life expectancy, on average, by 10 years. Tobacco and alcohol together account for about 90% of all drug-related deaths in the UK.
The pleasure induced by drugs has essentially 2 components - the initial, rapid effect (the rush) and the euphoria that follows this, often extending over several hours (the high). The rush's intesity is directly realted to the speed the drug hits the brain - hence the street response to formulate drugs in ways that allow them to be injected intravenously or smoked - so the hit only takes 30 seconds. The nasal mucosa provides an amazing rapid response for cocaine. Medically many drugs are supplied as anal suppositories as the rectum is rich in blood vessels and provides fast uptake (often used for Valium) - there doesn't appear to be any such formulations in use ...yet.
Intoxication, however induced damages the person, their ability to work, their family and has widespread effects and costs borne by health care, social care, and police.
Drug use leads to accidental damage to the user, to others, and to property directly or indirectly by driving motor vehicles, using machinery. Addiction leads to criminal activity to fund the habit and has secondaru effects on family life, nutrition and ability to work.
Use of drugs causes immense health-care costs. Tobacco is estimated to cause up to 40% of all hospital illness and 60% of drug-related fatalities. Alcohol is involved in over half of all visits to accident and emergency departments and orthopaedic admissions.
Intravenous use of drugs helps also spread needle borne diseases, HIV, MDRTB, and Hepatitis with further consequences and costs for society.
Designing the system
Assessment of harm
The authors designed a straightforward2 dimensional matrix with 12 risk factors - created by dividing each of the three major categories of harm into four subgroups, described above. A four-point scale, with 0 being no risk, 1 some, 2 moderate, and 3 extreme risk is 4 .
Experts were then asked to score the drugs surveyed and a remarkably coherent view was reached, which although to a degree subjective and arbitrary was undertaken by a standard route. The average of the results obtained is given.
The results show that the current system in use in the UK is not consistent - as the authors conclude -
"The results of this study do not provide justification for the sharp A, B, or C divisions of the current classifications in the UK Misuse of Drugs Act. Distinct categorisation is, of course, convenient for setting of priorities for policing, education, and social support, as well as to determine sentencing for possession or dealing. But neither the rank ordering of drugs nor their segregation into groups in the Misuse of Drugs Act classification is supported by the more complete assessment of harm described here."There three charts provided, that are the most useful way to understand their method and results.
1 Mean harm scores for 20 substances
2. Mean independent group scores in each of the three categories of harm, for 20 substances, ranked by their overall score, and mean scores for each of the three subscales
3. The 20 substances assessed, showing their current status under the Misuse of Drugs Act
Other organisations (eg, the European Monitoring Centre for Drugs and Drug Addiction (A) and the CAM committee of the Dutch government(B) are currently exploring other risk assessment systems, some of which are also numerically based.
Let us hope that this will lead to a more rational understanding of the problems drug use, both legal and illegal, and bring to the discussion of public policy and the associated plans for dealing with it, by the law, health, prison and educational systems.
(A) EMCDDA. Guidelines for the risk assessment of new synthetic drugs. Luxembourg: EMCDDA, Office for Official Publications of the European Communities, 1999.
(B) van Amsterdam JDC, Best W, Opperhuizen A, de Wolff FA. Evaluation of a procedure to assess the adverse effects of illicit drugs. Regul Pharmacol Toxicol 2004; 39: 1-4.
This paper was prepared as Appendix 10 to the House of Commons Science and Technology Committee. Drug classification: making a hash of it? Fifth Report of Session 2005–06, 2006 (see also here Nick at the Scientist Activist)