A new UK study suggests that the current UK drug classification system of A, B, and C of the Misuse of Drugs Act is flawed and should be replaced by an evidence-based system of potential harm that would place alcohol and tobacco higher than cannabis and ecstasy.

The study is published in The Lancet.

Professor David Nutt from the University of Bristol, Professor Colin Blakemore, Chief Executive of the Medical Research Council, and two colleagues developed a new drug ranking system that would class socially acceptable tobacco and alcohol as more harmful than cannabis, and considerably more dangerous than Class A drugs such as ecstasy and LSD.

They say the current classification system used in the UK is flawed and should be scrapped.

Their proposed system of classification asesses harm in an “evidence-based fashion”. They use three main factors to determine the potential harm that a substance causes:

(1) Physical harm to the user,
(2) Tendency to induce dependence in the user, and
(3) The effect of its use on families, communities and society in general.

Within each factor there are three sub-categories which altogether made up a nine-category “matrix of harm”. Each category attracts a score of between 0 and 3, with 3 representing the most harm. An overall mean harm score of between 0 and 3 is then calculated for each drug.

They asked two independent expert panels to score 20 different substances using this new system. The 20 drugs included five legal potentially misused substances (alcohol, khat, solvents, alkyl nitrites, and tobacco) and one recently classified one (ketamine) so that the league table showed some familiar “benchmarks”.

The two panels found the method easy to use and came up with very similar harm scores for each drug.

In order of overall harm, the 20 drugs were given the following ranking (the most harmful, heroin at number 1 scored nearly 3, while the least harmful khat at number 20 scored less than 1):

(1) Heroin (most harmful).
(2) Cocaine.
(3) Barbiturates.
(4) Street Methodone.
(5) Alcohol.

(6) Ketamine.
(7) Benzodiazepines.
(8) Amphetamine.
(9) Tobacco.
(10) Buprenorphine.

(11) Cannabis.
(12) Solvents.
(13) 4-MTA (para-methylthioamphetamine).
(14) LSD.
(15) Methylphenidate (ritalin).

(16) Anabolic steroids.
(17) GHB (gamma hydroxybutyric acid).
(18) Ecstasy.
(19) Alkyl nitrites.
(20) Khat (least harmful).

Prof Nutt who led the study said, “Drug misuse and abuse are major health problems. Our methodology offers a systematic framework and process that could be used by national and international regulatory bodies to assess the harm of current and future drugs of abuse”.

Prof Blackmore said that while drug policy is aimed at reducing harm to users, their families and society as a whole, the present system was not a “Rational, evidence-based method for assessing the harm of drugs”. He said the system they have devised, on the other hand, is.

“We hope that policy makers will take note of the fact that the resulting ranking of drugs differs substantially from their classification in the Misuse of Drugs Act and that alcohol and tobacco are judged more harmful than many illegal substances,” he added.

Under the current system in the UK, which is regulated by the Misuse of Drugs Act, drugs are classified in three groups, A, B and C. The heaviest conviction penalties are applied for possession of Class A drugs (up to 7 years in prison or unlimited fine or both), while Class C drugs are liable to the lowest penalties (up to two years in prison, unlimited fine or both).

Class A drugs include: Ecstasy, LSD, heroin, cocaine, crack, magic mushrooms (if prepared for use) amphetamines (if prepared for injection).

Class B drugs include: Amphetamines, Methylphenidate, Pholcodine.

Class C drugs include: Cannabis, tranquillisers, some painkillers, GHB, ketamine.

(Crystal meth is pending classification as a Class A drug.)

Profs Nutt, Blackmore and colleagues criticized the current Class A, B, C system saying it was too arbitrary, put too much emphasis on unusual reactions that affect very few users, and did not specify the relative risks of a drug.

In their conclusions they comment on what they see as its most glaring deficiencies:

“The fact that the two most widely used legal drugs lie in the upper half of the ranking of harm is surely important information that should be taken into account in public debate on illegal drug use. Discussions based on a formal assessment of harm rather than on prejudice and assumptions might help society to engage in a more rational debate about the relative risks and harms of drugs”.

“Development of a rational scale to assess the harm of drugs of potential misuse.”
David Nutt, Leslie A King, William Saulsbury, Colin Blakemore.
The Lancet 2007; 369:1047-1053

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Written by: Catharine Paddock
Writer: Medical News Today