Drug risks and uncertainties
As of the 23rd May 2022 this website is archived and will receive no further updates.
understandinguncertainty.org was produced by the Winton programme for the public understanding of risk based in the Statistical Laboratory in the University of Cambridge. The aim was to help improve the way that uncertainty and risk are discussed in society, and show how probability and statistics can be both useful and entertaining.
Many of the animations were produced using Flash and will no longer work.
Reliable drug use figures are very difficult to find, and it is more difficult still to estimate accurately the associated risks. Some indication can be provided by drug use surveys combined with mortality figures, but there are many limitations to such data.
The table below displays survey data taken from Table 2.4 (page 18) of a report by the NHS Information Centre "Statistics on Drug Misuse: England, 2008"
This is combined with mortality data from Table 6 (page 258) of the Office for National Statistics report "Mortality statistics - Deaths registered in 2007"
HEJ: QUERY - Ecstasy and LSD deaths shown below are not from Table 6. Need to check these.
I've checked all the other figures. However, mortality data from the spreadsheet here might be preferred. See also the corresponding
report.
NB This shows total numbers of mentions on death certificates, so the figures will be higher. Need to be clear about which definition we're using.
| Drug | Estimated users (past month) | Estimated users (past year) | Estimated deaths caused | Micromorts per monthly user per year |
|---|---|---|---|---|
| Ecstasy | 255,000 | 567,000 | 57 | 224 |
| LSD | 28,000 | 77,000 | Close to 0 | 0 |
| Heroin | 31,000 | 41,000 | 171 | 5516 |
| Cocaine | 405,000 | 835,000 | 44 | 109 |
| Cannabis | 1,526,000 | 2,616,000 | 1 | 0.65 |
| Methadone | 25,000 | 37,000 | 112 | 4480 |
However, determining the true risk is difficult for several reasons. Firstly, it is not clear what time period should be used to define active drug use. Is it fair to say that someone who has used a drug in the past year but not in the past month is no longer an "active user"? Did everyone who replied that they had taken drugs become a "regular" user, or did the subsequent use of some dwindle? In addition, it is unclear how much the "average" user takes, or even if the respondents to the survey are being truthful, especially with the "harder" drugs.
There are problems with determining the number of deaths caused by drugs too. The ONS statistics only include those who died as a direct result of taking drugs, and where any inquiries had confirmed that drugs were one of the causes of death. Those who died through actions performed while under the influence or who died as a result of any impurities in drugs taken may not have been included. Drug users may be killed by conatimants in drugs, either directly (allergic reaction to something added to drug, taking a poison with the drug) or indirectly (person takes high dosages due to low purity of drug, then when they get a pure version of the drug they overdose). Injecting drug users can also be infected with sexually transmitted diseases such as HIV and hepatitis C, especially if in an epidemic area. Some figures may also include (or fail to include) mental issues that were made worse by drugs.
Finding the actual usage per user is also extremely difficult, due to the illegal nature of the drugs. However, the 2006 World Drug Report - Analysis (Sandeep Chawla, Thibault le Pichon, United Nations Office on Drugs and Crime, Research and Analysis Section) goes some way to estimating the total of cannabis - and explains the problem in reconciling supply and demand in Cannabis. The thing is, when you look at the estimated figures for cannabis production and cannabis consumption, you come to the conclusion that each Cannabis user must be using an average of 554 joints a year, at the cost of over $2000 - which is impossibly high. Even if you raise the estimated users this still does not help solve the problem. The Report suggests that whole plants, whilst theoretically psychoactive, are not salable, and generally only the flowering parts of the plants are used. This may bring consumption down to a more reasonable level, of around 200 per user (the vast majority of it used by daily or near constant users - possibly making an analysis of the "average" user meaningless.).
Several websites also quoted that:
"[A] dependent person use[s] between 150 - 250 milligrams [of heroin] per day. [This is] Divided into 3 doses."
However, I was unable to source this claim (the websites all failed to provide a citation, and some even had a citation that didn't match up to anything), so it remains difficult to say how many doses the "average" user takes, or even if it's actually meaningful to have an "average" user, due to the majority of drugs being taken by a core of very heavy users.
Another interesting thing to note from the statistics is that the methadone risk is similar to the risk of taking heroin, at least in terms of identified deaths. People may argue that using methadone in a safe environment prevents crime and infection, but it remains a very dangerous drug. It is sometimes used on the black market (due to cheap cost) but also sometimes used to treat heroin addiction, with questionable benefit. Many argue that taking methadone can be more successful than trying to beat heroin addiction "Cold Turkey", and leaves less chance of relapse. Studies are ongoing, and Methadone is certainly far from a panacea to Heroin addiction.
In conclusion, while it is possible to build up a picture of how likely someone is to overdose on a drug and die, any figures on this matter must be taken with a liberal supply of salt. It certainly doesn't take someone with an ulterior motive to make statistics unreliable.
