Alcohol most harmful drug based on multicriteria analysis (Update)

November 1, 2010, Imperial College London

( -- A new system that ranks drugs on the basis of harm caused to both the user and others places alcohol as the most harmful drug, above heroin and crack. The scale, developed by drug experts led by Professor David Nutt of Imperial College London, is published online today in The Lancet.

Drugs including alcohol and tobacco products are a major cause of harms to individuals and society. To provide better guidance to policy makers in health, policing, and social care, the harms that drugs cause need to be properly assessed. This task is not easy because of the wide range of ways in which drugs can cause harm, the researchers say.

When Professor Nutt and colleagues attempted this assessment previously in 2007, they engaged experts to score each drug according to nine criteria of harm, ranging from the intrinsic harms of the drugs to social and healthcare costs. This analysis provoked major interest and public debate, although it raised concerns about the choice of the nine criteria and the absence of any differential weighting of them.

To rectify these drawbacks, the authors undertook a review of drug harms with the multicriteria decision analysis (MCDA) approach. MCDA technology has been used successfully to lend support to decision makers facing complex issues characterised by many, conflicting objectives, such as policies for disposal of nuclear waste.

Multicriteria decision analysis

The new analysis uses nine criteria that relate to the harms that a drug produces in the individual and seven to the harms to others both in the UK and overseas. These harms are clustered into five subgroups representing physical, psychological, and social harms.

Drugs were scored with points out of 100, with 100 assigned to the most harmful drug on a specific criterion. Zero indicated no harm. Explaining their model, the authors say: "In scaling of the drugs, care is needed to ensure that each successive point on the scale represents equal increments of harm. Thus, if a drug is scored at 50, then it should be half as harmful as the drug that scored 100." A zero means no harm is caused.

The criteria are weighted according to a judgement of their relative importance. "The issue of the weightings is crucial since they affect the overall scores,” the authors say. “The weighting process is necessarily based on judgement, so it is best done by a group of experts working to consensus."

The nine categories in harm to self are drug-specific mortality, drug-related mortality, drug-specific damage, drug-related damage, dependence, drug-specific impairment of mental function, drug-related impairment of mental functioning, loss of tangibles, loss of relationships, and injury. The harm to others categories are crime, environmental damage, family conflict, international damage, economic cost, and decline in community cohesion.

Overall, MCDA modelling showed alcohol was the most harmful drug (overall harm score 72), with heroin (55) and crack (54) in second and third places. Heroin, crack, and crystal meth were the most harmful drugs to the individual, whereas alcohol, heroin, and crack were the most harmful to others. The other drugs assessed followed in this order in terms of overall harm: Crystal meth (33), cocaine (27), tobacco (26), amphetamine/speed (23), cannabis (20), GHB (18), benzodiazepines (eg valium) (15), ketamine (also 15), methadone (14), mephedrone (13), butane (10), khat (9), ecstacy (9), anabolic steroids (9), LSD (7), buprenorphine (6), mushrooms (5).

Thus the new ISCD MCDA modelling showed that as well as being the most harmful drug overall, alcohol is almost three times as harmful as cocaine or tobacco. It also showed that alcohol is more than five times more harmful than mephedrone, which was recently a so-called legal high in the UK before it was made a class B controlled drug in April 2010. Ecstasy, which has had much harm-related media attention over the past two decades, is only one eighth as harmful as alcohol in this new analysis.

Implications for drug policy

The authors say that their work correlates with both the previous analysis by Nutt and colleagues and that of other such as the Dutch addiction medicine expert group. However, there is almost no relation between the results and the current UK drug classification system based on the UK Misuse of Drugs Act (1971).

Professor Nutt, from the Department of Medicine at Imperial College London, says: "What a new classification system might look like would depend on what set of harms - to self or others - you are trying to reduce. But if you take overall harm, then alcohol, heroin and crack are clearly more harmful than all others so perhaps drugs with a score of 40 or more could be class A; 39 to 20 class B; 19-10 class C and 10 or under class D."

The authors say the MCDA process provides a powerful means to deal with complex issues that drug misuse represents.

They conclude: "Our findings lend support to previous work in the UK and the Netherlands, confirming that the present drug classification systems have little relation to the evidence of harm. They also accord with the conclusions of previous expert reports that aggressively targeting alcohol harms is a valid and necessary public health strategy."

More information: Research paper online: … (10)61462-6/abstract

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5 / 5 (9) Nov 01, 2010
... And yet, alcohol remains widely available, widely advertised and socially acceptable, while cannabis remains at the top of the list of targets of the "War on Drugs". I'm sure that makes sense to someone in control of tax dollars.
2.1 / 5 (8) Nov 01, 2010
Just a minute - I guess a bullet to the heart is less harmful than a 3rd degree burn on the foot by this reasoning. The bullet will cause instant death and no additional harm, whereas the burn will cause pain and suffering, a need for medical care, etc. That's the logic being used here. Sure alcoholism is harmful, to self and others, but drugs are more harmful to self and if their harmful effects are minimized by society, this harm will spread like wildfire.
3 / 5 (2) Nov 01, 2010
As usual, the confound of usage is not mentioned. Alcohol is the most widely used drug, and therefore its associated costs are understandably much higher than something more illicit such as heroin. It cannot be said that alcohol is therefore more dangerous since its higher social costs could easily be attributed to its higher usage.
5 / 5 (4) Nov 01, 2010
[P] Sure alcoholism is harmful, to self and others, but drugs are more harmful to self and if their harmful effects are minimized by society, this harm will spread like wildfire.

Drugs? Oh, you mean stuff like aspirin and tums...

Getting permission to do something doesn't say anything about how safe it is nor does its legal status. It is pendantic to use such an ill defined label such as drugs to address all the substances that exist. Alcohol fits the category of drug by just about any standard you want to does a lot of food for that matter. The drug war has never been about safety. Wise up.
5 / 5 (2) Nov 01, 2010
And the war on candles is still to fought. More people die from candle fires than pot every single year. Why are candles legal?
not rated yet Nov 01, 2010
Good point on the tendency of not providing a solid definition when discussing "the drugs."

On that note, I was referring to psychoactive drugs and I assume that this study was too.

The update to the article addresses the issue I brought up earlier (kudos to physorg on that).
not rated yet Nov 01, 2010
i miss PCP on the list as a highly dangerous drug, also i wonder what would happen if lsd and shrooms were more widely used, we'd probably see shroomed drivers instead of drunkdrive accidents, good call on the ecstasy though wich DOES have a widespread use but seems highly overcriminilized in relation to damagings effect to the individual and soceity
not rated yet Nov 01, 2010
i am a cigarette smoker, i don't give up tabacco lightly, especially with its easy availlabillity, but from a pure rational standpoint i would have to agree that for the net impact better smoking be banned than fighting against mdma
5 / 5 (3) Nov 01, 2010
And the implications for drug policy are immense.....or would be if those making policy weren't insane. Also, evidently the fact that marijuana never killed a single person while most of the others kill regularly wasn't a factor. Marijuana does cause insanity though, just not in those that smoke it.
5 / 5 (1) Nov 02, 2010
We have been hoping for decades for rational drugs policies from our governments. Dr Nutt was sacked for telling a politically unwelcome truth. We should support his independence, and his ability to speak out on a subject which he has studied in depth.
5 / 5 (3) Nov 02, 2010
Dr Nutt was sacked

I hope this was intentional.
not rated yet Nov 08, 2010
What a bunch of stupid asses. This sort of statistical nonsense should be labeled as drivel and forgotten about.

Of course alcohol wound up at the top based on the ridiculous criteria that were used. It is the only one in the list that is not proscribed.

Fancy comparing damage actually caused instead of damaged caused per user so that their could be proper emphasis on which ones to control.

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