A scientific assessment of the harmfulness of the 16 most commonly used drugs


November 3, 2010

One of the more interesting news items of the last week came from the release of the Independent Scientific Committee on Drugs’ first piece of research – Drug harms in the UK: a multi-criteria decision analysis. The findings of the committee, based on wide ranging criteria, apply scientific methodology to answering the perpetually vexing question of exactly how much harm certain drugs do to their users and those around them.

The accompanying table summarizes the findings and the full paper is available free on the web, where you’ll see just how complex the equation actually is. Most interesting of all was that without government meddling and industry lobbying, alcohol was rated more harmful than any other drug, while tobacco (the only other taxed legal drug on the list), is more harmful than cannabis.

The Independent Scientific Committee on Drugs was set up after British Home Secretary Alan Johnson sacked Professor Nutt from his role as the head of the Advisory Council on the Misuse of Drugs (ACMD) in 2009. ACMD is the UK's official drugs advisory body and Johnson sacked Professor Nutt for saying cannabis was less harmful than alcohol.

The Independent Scientific Committee on Drugs was founded to investigate and review the scientific evidence relating to drugs, free from political concerns.

Nutt is not pro- or anti-anything – he is a scientist and science is our only true friend when it comes to making informed decisions on any subject, but particularly about the effects of one of mankind's greatest problems and its effects on society. The Committee’s aim is to provide accessible information on drugs, drug harms, benefits, regulation, education, prevention, treatment and recovery.

According to the report, which is available free (once you have registered at the Lancet), the most harmful drugs to users are crack cocaine (37), heroin (34) and metamfetamine (32), whereas the most harmful drugs to others are alcohol (46), heroin (21) and crack cocaine (17). When the two-part scores were combined, alcohol was the most harmful drug by a huge margin, followed by heroin and crack cocaine.

Professor David Nutt's has just launched a new blog. This is recommended reading for anyone with an open mind to finding a better way.

About the Author
Mike Hanlon Mike grew up thinking he would become a mathematician, accidentally started motorcycle racing, got a job writing road tests for a motorcycle magazine while at university, and became a writer. As a travelling photojournalist during his early career, his work was published in a dozen languages across 20+ countries. He went on to edit or manage over 50 print publications, with target audiences ranging from pensioners to plumbers, many different sports, many car and motorcycle magazines, with many more in the fields of communication - narrow subject magazines on topics such as advertising, marketing, visual communications, design, presentation and direct marketing. Then came the internet and Mike managed internet projects for Australia's largest multimedia company, (Australia's largest Telco), (Australia's largest employment site),,, and a dozen other internet start-ups before founding Gizmag in 2002. Now he writes and thinks. All articles by Mike Hanlon

What a pile of crap. Of course I can twist and turn any statistics in a way that it produces an outcome that I want. I cant see any 13 year olds prostituting themselves for alcohol, but plenty doing the same for heroin. Of course that spreads HIV (which I am sure was discarded as a means to hurt others). I am also wondering whether the crimes commited to get the money for a certain drug were rated in \"harms others\"... Whatever, just another stupid study with no connection to reality whatsoever. And people are wondering why scientists get a bad rep. I for my part dont want to be associated with these people.


It would be helpful to know how the number of users of a drug influence the level of harm in the chart published. Ie are the high results for alcohol predominantly due to the number of users? If there are a large number of alcohol related vehicle accidents, this will create more harm to society generally than a small number of \"13 year olds prostituing themselves\"


Dear Skipjack, could we see the methodology, criteria and numbers you used in YOUR study? Or was it tea leaves?

Facebook User

What a huge shame that petrol-sniffing isn\'t on the list - this is a huge problem - it would be awesome to see how it rates: my guess is it would outrank the lot on both counts?


I am interested to read the methodology and criteria,e specially in the `harmful to others\' category. A large number of the farm workers with the cocaine industries are indentured (slave) labour... I\'d consider that pretty harmful too. But yeahnah, as a professional musician it doesn\'t surprise me at all that alcohol is rated the most harmful in both categories.

Earl Leonard

By just observing how booze lovers defend alcohol and don\'t seem to imagine any social gathering without it, it has long been obvious as far as I\'m concern that addiction is strong. Now, considering that someone drunk can bring violence into families, loose jobs or not perform well in business, can provoke dramatic road accidents... something which is not the case with - say, tobacco, such consequences on others have a cost for society.

This is something which has long been observed by numerous people, especially those not keen on booze who have a fair judgement. I\'m glad that a team of scientist has finally brought a demonstration. I hope it helps health authorities to reassess their priorities: stop pointing your finger constantly at smokers, alcohol should be targeted equally if not more.

Angelie Baral

It appears that methamphetamine is misspelled as "metamfetamine". [Ed note: That's how the graphic was supplied to us, although it does appear to be an alternate spelling:]


\"Interpretation: These findings lend support to previous work assessing drug harms, and show how the improved scoring and weighting approach of MCDA increases the differentiation between the most and least harmful drugs. However, the findings correlate poorly with present UK drug classification, which is not based simply on considerations of harm.\" (Quoted from the summary of this report).

Henry Rody

Back in the 60\'s (Remember or read about then??) I was a Broadcast journalist in New York. This was the time of the first wide public consciousness about drug use. I heard parents say, \"Why would someone take a drug they don\'t need??\" There was little real information and a lot of myth and rumor.

Consumer Reports came out with a well-researched, scientifically based book titled \"Licit and Illicit Drugs\". It was a major part of my research into the drug phenomenon and the drug scene on the street. The book was widely condemned by people who \"knew\" things like \"heroin destroys the brain within 6 months\" and \"Marijuana smoking almost always leads to hard drug addiction\".

By the time Woodstock got moved from Wallkill to White Lake and really happened (I got the posh accommodations: I slept on the floor in the Press trailer), I was able to identify and talk about the drug reality at that time and place.

Again, well-researched hard information will be attacked by the fearmongers and the moralists. You will hear \"by saying \"XXDRUG\" is not terribly harmful you will lead our children into drug addiction\".

MY kids heard all the discussion, and got my stories from the street dealers and the really bad stuff that went down, often to nice people. They knew what was what with drugs, and they and my 11 grandchildren have never had a lack of true knowledge about drugs or been seduced by the street/cultural myths about how great they are.

The best thing you can do for YOUR kids is to know the truth and the details about \"Licit and Illicit Drugs\".. If you don\'t know the difference between opiates and amphetamines and hallucinogens and their street names, you can\'t help your kids learn about all the good things in the world and the bad things, and which is which.

Regards, Terry King ..On the Red Sea at

Terry King

What about all those pharmaceuticals that have a chance for the side effect of \"death\" or other serious health conditions, especially if mixed with other Pharmaceuticals. So many people are addicted to pills. My pastor\'s wife is afraid someone is going to break into her house and steal her pain meds, and has constant freak outs when she is away from her home that someone is breaking it right that second. Pharmacies are on every corner. Include pharmaceuticals in your study.

Stephen Owens

\"Marijuana smoke contains 50 to 70 percent more carcinogenic hydrocarbons than does tobacco smoke. It also induces high levels of an enzyme that converts certain hydrocarbons into their carcinogenic form - levels that may accelerate the changes that ultimately produce malignant cells. Marijuana users usually inhale more deeply and hold their breath longer than tobacco smokers do, which increases the lungs\' exposure to carcinogenic smoke. These facts suggest that, puff for puff, smoking marijuana may be more harmful to the lungs than smoking tobacco.\"

\"Depression, anxiety, and personality disturbances have been associated with chronic marijuana use. Because marijuana compromises the ability to learn and remember information, the more a person uses marijuana the more he or she is likely to fall behind in accumulating intellectual, job, or social skills. Moreover, research has shown that marijuana%u2019s adverse impact on memory and learning can last for days or weeks after the acute effects of the drug wear off.\"

\"Research has shown that some babies born to women who abused marijuana during their pregnancies display altered responses to visual stimuli, increased tremulousness, and a high-pitched cry, which may indicate neurological problems in development. During the preschool years, marijuana-exposed children have been observed to perform tasks involving sustained attention and memory more poorly than nonexposed children do. In the school years, these children are more likely to exhibit deficits in problem-solving skills, memory, and the ability to remain attentive.\"

\"An abuser\'s risk of heart attack more than quadruples in the first hour after smoking marijuana. The researchers suggest that such an effect might occur from marijuana\'s effects on blood pressure and heart rate and reduced oxygen-carrying capacity of blood.\"

Oh yes. Completely harmless.

Racqia Dvorak

Racqia, please check your \"facts\" before posting erroneous information and misleading people.


@Racqui Dvorak: Got an axe to grind against cannabis, we got it. But if you\'re going to pull some random quotes out of the air, at least have the integrity to cite the sources. After all, you may be citing out of date info, which it seems you are. Time to update your facts:


Do I think recreation drugs can be legalised?.

Yes, they can, just like alcohol started of as moonhine, and was to potent at 100% proof, and known to make certain people blind. These days with better control on its strength, it can e enjoyed as a socialising tool. Unfortunately, its effects vary dependant on person, thus, is classified as more harmfull to society with its ability to cause some to fight, be hospitalised, or have organ failure.

Now, one must ask themselves, why would smoking ciggarettes be more dangerous to your health, than cannabis users that don\'t use any filter element? ... answers on a postcard!.

Personally, I think people should have some kind of blood/medical test, that ascertains of how much alcohol and certain drug types will effect there body and mind. With this information, an individual will know what and how much they can take... after all just like a drugs prescription, you wouldn\'t take more than is prescribed by the Doc!

Take Care on your dosage... what ever is your DRUG.

Harpal Sahota

I\'d like to know the consumption methods and doses of all these. You can consume almost any drug that you can take orally, anally. Most people smoke marijuana, but there are far less harmful ways of consuming it. You can smoke mushrooms, but that does harm to your brain, eating them leaves no side effects. I\'ve never consumed them but have studied them a lot and find it all pretty fascinating. I think this article is pretty biased and vague. Another test to manipulate the public for someone else\'s agenda. One shot of alcohol is less harmful than one shot of heroin, regardless of the alcohol content. One hit of LSD versus one cannabis filled space brownie is much more harmful to the one taking the hit and the ones around them. I\'d like to see a fair argument with detailed tests. Drug content, methods used, dosage, surrounding environment. This is a good concept, just poorly and unfairly executed in my opinion.

Joe Apperson

WOW..... I have not seen so many people offended by a scientific study.. LOL

It appears it is news to most of the commenter that drugs actually do have a negative impact on the users and society as a whole.

This or course is obvious to all those not using drugs..

I think it is very interesting in terms of affects to others, pot is more harmful then cocaine.

Michael Mantion

Making drugs illegal has not stemmed the tide of abuse, then why would legalization be any different? Laws can not change people.


To any of the idiots that think that there was no science in the study there is a full report on the findings.... It is the illegality that creates the crimes! Read the full report and educate yourself.

Mark Mercieca

I just read the study, and I am not sure how this is called Science. I guess when you put 20 people in a room and ask them to rank criteria, this passes for Science these days. I know these people are experts and all, but my bullshit meter goes off when I see meth get a score less than 5 for \"harmful to others\".


The number of users should not have been a variable in assessing the dangers of the drug.

Vaughan Galustian

it would be interesting to know if these numbers are scaled by usage, in other words how many harmed versus how many regular users.

Curt Puszykowski

Surprise! All these drugs are harmful. No matter which ones you do, you're hurting yourself & others.

Post a Comment

Login with your Gizmag account:

Related Articles
Looking for something? Search our articles