Study Finds Alcohol and Tobacco More Harmful than Marijuana, LSD, or Ecstasy (Revisited)

Blogging on Peer-Reviewed ResearchBack in August, I reported on an ACMD study buried in the back of a UK government report. The study gave strong evidence that the current drug classification scheme in the UK was fundamentally flawed and was not based on the actual danger of a given drug. The study has now been published in this week's issue of

The Lancet. The Guardian also has a nice piece on it today. The bottom line is that the current unscientific drug classifcations that the UK (and the US) currently rely on need to change. Now.

Here's what I originally wrote:

(1 August 2006) Yesterday, the House of Commons Science and Technology Committee released a report entitled Drug Classification: Making a Hash of It?, which challenges the logic behind current drug classifications in the UK, especially when tied to legal penalties. The report discusses specific cases where drugs were misclassified or their classifications were changed for political, rather than scientific, reasons. The report is particularly critical of the Advisory Council on the Misuse of Drugs (ACMD) for not doing enough to push for a more scientifically based drug classification system.

The conclusions of the report were based on findings from extensive observations and oral and written testimony. Of particular interest, though, is one of the sources, which can be found buried in the appendices of the report. The ACMD recently conducted a study on how well drug classification correlates to the actual health risks of those drugs. The findings are, frankly, astonishing and deserve quite a bit more publicity, since they turn current drug dogma on its head. Unfortunately, as far as I can tell, the only place this study has been published is in the back of the larger Science and Technology Committee report (specifically on pages Ev 110-Ev 117 of the pdf, although The Independent also published a nice summary of the rankings).

In the US, drugs are classified primarily by schedules, which divide up drugs into five schedules based on their relative medical utility compared to their potential for abuse and dependence. Drugs in Schedule I have "no currently accepted medical use in treatment" and are considered to be particularly dangerous. Drugs in Schedules II-V have accepted medical uses and decrease in danger as the schedule increases. This system is problematic, because it lumps together very different substances, including heroin, marijuana, ecstasy, LSD, psilocybin, into Schedule I.

The UK also uses drug schedules, but it additionally divides drugs into three classes strictly on their perceived health risks. Drugs in Class A are considered the most dangerous, those in Class C the least. Drug enforcement is carried out in accordance with these classifications, which makes sense, since hard drugs like heroin and cocaine are placed in Class A and treated distinctly from the softer drug marijuana, which was recently downgraded to Class C.

Still, drug classification has hitherto been less than scientific, and the recent ACMD study highlights just how out of whack some of the classifications are. In order to evaluate the current classification scheme, the ACMD had various addiction experts evaluate the danger of different drugs using nine parameters (acute harm, chronic harm, IV harm, intensity of pleasure, psychological dependence, physical dependence, intoxication, other social harms, and healthcare costs). The values from each parameter were combined, giving each drug a single rating. The results are pretty surprising:

i-3b49e3d17204db18b42306fb36d3e154-drug study bbc.gif

Image from the BBC

The Class of a drug appears to have little to no relation to its actual danger. Although heroin and cocaine, both Class A drugs, received the highest harm ratings, other Class A drugs (ecstasy, LSD, and 4-MTA (an amphetamine derivative)) were rated as being less harmful than alcohol or even tobacco. In fact, of the twenty substances surveyed, alcohol was (it pains me to say) ranked the fifth most harmful.

Now, I don't think anybody is saying we need to outlaw alcohol (come one, we're not Puritans here), but this is food for thought. The Science and Technology Committee report says it best:

In our view, it would be unfeasible to expect a penalty-linked classification system to include tobacco and alcohol but there would be merit in including them in a more scientific scale, decoupled from penalties, to give the public a better sense of the relative harms involved.

In particular, the onus is now on lawmakers to defend exactly why ecstasy, LSD, and 4-MTA belong in Class A, if experts judge them to be not particularly dangerous.

The good news for the UK's drug classification system is that the placement of marijuana in Class C appears appropriate. This is in line with the results of another recent study that found that smoking marijuana isn't as dangerous as once thought. Things aren't looking so good back in the US, though, where marijuana is still a Schedule I drug, despite potential medical uses. So, even though the UK's system isn't perfect, it's beats what we have in the US, where the war on drugs continues to spin out of control.

This study is a great example of the importance of taking science into account in formulating policy. Clearly, if science superseded politics (ha!), then the UK's drug classification system would be much different. Although the study at hand is a great start, though, it is still somewhat subjective, since it just relies basically on survey data. If anything, its results indicate the dire need for more studies in this area. That doesn't mean the results from the current study aren't compelling, or even conclusive, since, for example, a sample of psychiatrists were surveyed as well, and came up with very similar results to those of the addiction and drug experts, whose data is shown above.

Although magic mushrooms, or their active substance psilocybin, were not evaluated in the ACMD survey, the Science and Technology Committee report explored their classification as a Class A substance and found serious issues here. The government used a roundabout way of placing magic mushrooms in Class A, and did not appear to take scientific evidence into account in doing so. The report, though, places a lot of the blame on the ACMD for not speaking out against this, "despite the striking lack of evidence to suggest that the Class A status of magic mushrooms was merited on the basis of the harm associated with their misuse." The placement of magic mushrooms in Class A seems particularly absurd, considering that in addition to their relative lack of major side effects, a recent study (with very sound methodology) found that controlled usage of psilocybin can regularly induce intense and positive spiritual experiences.

One of the primary recommendations of the Science and Technology Committee reports is that, due to the inconsistencies in and the ephemeral nature of the classification system, penalties for drug possession should not be tied to a classification scheme. Beyond the fact that the report does not propose an alternative model, I would disagree with this assertion on principle. Especially if one has a scientifically valid classification system, why shouldn't that be tied to penalties. For example, I would certainly not expect one to have the same penalty for possession of marijuana as one would for heroin, and based on the results of the ACMD study, several other drugs should be downgraded to marijuana's status as well. When most major drugs are lumped into a single category, as in the US, many more problems can arise. A great example of this is the much higher penalty for possession of crack (a drug used more commonly by minorities and the less wealthy) as opposed to cocaine (a drug of choice for many upper class whites), despite both having the same active ingredient. Clearly, that's not based on science.

Of course, a good and comprehensive drug policy should rely on education and treatment over punishment, and when penalties come into play, they should be targeted toward dealers over users. Also, the need for legal penalties for the recreational use of soft drugs could also be debated. With that said, it appears that for the most part the UK's drug policy is heading in the right direction. Before it's acceptable, though, scientific studies such as the one by the ACMD need to be taken into account in determining drug classifications. After all, I'd much rather have a drug policy based on fact than on fiction.

Nutt, D., King, L., Saulsbury, W., Blakemore, C. (2007). Development of a rational scale to assess the harm of drugs of potential misuse. The Lancet, 369(9566), 1047-1053. DOI: 10.1016/S0140-6736(07)60464-4


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"In particular, the onus is now on lawmakers to defend exactly why ecstasy, LSD, and 4-MTA belong in Class A, if experts judge them to be not particularly dangerous."

Thats easy, it's because whenever anyone is harmed by one of these drugs the papers (usually mail/express/sun) start printing articles like mad talking about how everyone in Britain between the age of 15 and 25 spends all of their time going to nightclubs and taking ecstacy. Either that or that these drugs will definately kill you and anyone who says otherwise should be locked up. I can only imagine what the outcry would be if the government started to reclassify drugs based on their actual harm.

Maybe I've just had some extreme experiences in my lifetime, but based on personal experience, I find it REALLY hard to believe that LSD and ecstasy could be less harmful than cannabis. I had a friend in college who went into a coma after taking 1 pill of ecstasy. She missed an entire semester of school after the episode. I also have a friend who sporadically has 'acid flashbacks' from using LSD as a teenager, to the point where he can't function normally. Imagine having one of those flashbacks while driving on the highway...

I know people that have smoked cannabis for decades, and are healthy in both body and mind, including myself. I understand the long term effects of smoking are damaging to your lungs and heart, but that danger is nowhere near the immediate and potentially grave consequences of using ecstacy or acid.

@ gateman's nametag I totally agree with you.

It's really difficult for me to figure out how depending on these parameters "...(acute harm, chronic harm, IV harm, intensity of pleasure, psychological dependence, physical dependence, intoxication, other social harms, and healthcare costs)" give us this rank.
I believe tobacco and even cannabis could be considered MORE "harmful" than e.g. lsd or ecstasy as you say only in two categories: psycological dependence and psysical dependence. And I strongly doubt if these two categories can be used with the same weight (I don't know what weights or if any have been used) with the acute or chronic harm for example.
Indeed, the reasons why some drugs in Class A exist there have nothing to do with their harmness, but this result about tobacco/cannabis and lsd/ecstasy is weird.

By CastonjoFfF (not verified) on 23 Mar 2007 #permalink

@gateman's nametag

I tend to agree with you that long-term LSD usage can definitely cause problems but I find it hard to believe that a single pill of true ecstasy could send someone into a coma.

MDMA itself is a pretty safe chemical so it's far more likely that your friend took something that was sold as E but was actually a different chemical.

This is of the major problems with prohibition - people have now way of knowing what they are taking. During the US' experiment with prohibition of alcohol, many people were poisoned when they drank methyl (instead of ethyl) alcohols.

Nick, I recall a paper in Science maybe '90 or '91 by Avram Goldstein or one of the great neuropharmacologists that ranked the addictive potential/costs to society of legal/illegal CNS-acting agents. Again, alcohol and nicotine were far more dangerous and costly than marijuana or hallucinogens. Opioids (morphine, heroin) were ranked at the top of the addiction rating.

Cannabis is not physically addictive, or at least no more than sugar. Psychological dependence seems to be genetically based and rather independent of the substance being used. A person likely to be psychologically addicted to some drug is just as likely to have a gambling problem. As for fatalities, there are several noteworthy studies, two done by the DEA, that have found no cases of overdose due to cannabis use. THC, the active ingredient in cannabis has such a low toxicity that whatever your chosen vector for consuming cannabis is, it will kill you before the THC has a chance to reach lethal levels.

This is really interesting information. Thank you for doing all this hard work and sharing with all of us.

I would really like to see a bar-graph like the one you show for your harm rate, but for every one of the parameters, separately and then superimposed. Are there are any parameters that might be correlated? Which ones and in which way(s)?

And then I would like to see a dynamic model using something like Stella, showing all of the connections between the different parameters. It would be neat to see what happens when you change them. Perhaps as you change one of the parameters, your combined rating will change, and when it does, we can see how it changes too.

And we can take it from there.

Do you already have any of this information?

Cannabis is more harmful than LSD and X? This thing just lost its validity - across the freakin board. Bye-o! Eat me up, all of you. Ain't coming back here.

I'm 100% sure that the only reason marijuana is considered more dangerous than ecstasy is because of the long term damaging of the lungs, the lining of the mouth, and due to its high psychological dependence. Don't get me wrong, some people don't get addicted to it, and most of the time it's only the people with a high chance of becoming mentally addicted to anything that get addicted to it, however LSD and ecstasy are not addictive, mentally or physically. Ecstasy can raise your blood pressure and your temperature temporarily, but as long as you are a healthy adult that is responsibly taking it, then you WILL be safe. If you have underlying medical issues, then you take a gamble. Over the long run, ecstasy doesn't damage you in any way, shape, or form. LSD possibly can cause flashbacks in the future, however that's not considered a danger because it physically isn't endangering. In reality, the flashback could happen while you are driving, but driving the car is dangerous to begin with. If someone that has a flashback while they are driving dies, the LSD didn't harm them in any way, the crashing of the car did. See my point?

Marijuana has never been responsible for the death of anyone... tobacco kills tens of thousands every year....

No one ever beat up their wife (or vise versa) because they were stoned.... it's usually because they are drunk.

There are no recorded cases of anyone taking another person's life because they were stoned at the wheel...drunk drivers have taken FAR TOO MANY lives... or have destroyed the quality of life for people by putting them into a wheelchair for life. Oh .. and more people harm others in vehicle accidents because of prescription drugs! Even a TTC bus driver (Toronto) was recently busted for this!

Pot may cause cancer... but not at the rate tobacco does. At least if a person gets cancer because of pot - they are only harming themself... unlike drunk drivers, drunk spouse-beaters, bar fights, etc.........

Bottom line - if you choose to do whatever drug (booze, pot, cigarettes) because you can't handle life - at least don't harm another as a result.

Fantastic article, and intensive discussion that follows. Let me first address that some of the anecdotal evidence presented here that indicates Ecstasy's or LSD's danger over other substances (i.e marijuana). Both 3,4-Methylenedioxymethamphetamine and (6aR,9R)- N,N- diethyl- 7-methyl- 4,6,6a,7,8,9- hexahydroindolo- [4,3-fg] quinoline- 9-carboxamid - more commonly known as Ecstasy and LSD-25 respectively - as their scientific names would suggest, are synthesized compounds that are impossible to grow in your backyard (or closet), and extremely difficult to synthesize cleanly in your bathtub or kitchen. And since they are illegal - and nearly every precursor to their syntheses are also illegal - it's improbable that there are many chemists who posses the skills required to create and distribute quality product.

Most of what is available on the (black) market for these substances is horribly tainted with by-products and impurities, most of which are extremely toxic. It's harder to pass off bad marijuana since it's a more natural product, and other plants that look even remotely similar are not toxic either so... Most of these experiences that show the "danger" of synthesized drugs (and I have no doubt they are very real, and very bad experiences) have more to do with poor quality and toxic residues (due to the black market distribution required because of their illegality - there is no quality control) than it has to do with the drug itself. This is unfortunate when looked at from every angle - no one wins, not even the dealer (no one wants bad product).

It is clear that there is an obvious, deep, and wide gap between scientific evidence, public understanding, and governmental policy; and not only when it comes to the issue of scheduling drugs for regulation. This, however, is a whole other topic in and of itself.

But in this context, it is clear that the general, media-covered, information that is distributed is skewed. What leaks through to the general populous rarely tells the truth of the situation, because that would clearly lead people to question policies. When you couple prison statistics of those incarcerated for petty drug offenses vs. violent and abhorred crimes, it raises even more questions.

This is such an excellent article. I only wish that there were more writers willing to take the heat for shedding light on this (continually) debatable and opinionated subject!

Sorry, but to all those who say it so harmful to the lungs etc, you should read this article:…

I quote "The study, which tracked and tested over 5,000 men and women for twenty years between 1985 and 2006, found that marijuana users who smoke an entire joint a day for seven years, or one joint a week for twenty years did not exhibit any decrease in lung function as measured by lung airflow and lung volume. And get this: casual âpotâ users actually exhibited a small, but statistically significant increase in lung function."