I have a problem with this graph, from a 2007 Lancet article by David Nutt. I actually like David Nutt, he was fired from his position in the UK government for criticizing the decision to reclassify cannabis to Class B from C. That's right, a scientist who was working for the UK equivalent of the NIDA actually bucked the orthodoxy of "drugs are bad, mmkay," of course he was sacked for it. You will notice that heroin scores the highest on both dependence and physical harm. This the criteria used to evaluate physical harms in the lancet article:
Assessment of the propensity of a drug to cause physical harm—ie, damage to organs or systems—involves a systematic consideration of the safety margin of the drug in terms of its acute toxicity, as well as its likelihood to produce health problems in the long term. The effect of a drug on physiological functions—eg, respiratory and cardiac—is a major determinant of physical harm. The route of administration is also relevant to the assessment of harm. Drugs that can be taken intravenously—eg, heroin—carry a high risk of causing sudden death from respiratory depression, and therefore score highly on any metric of acute harm. Tobacco and alcohol have a high propensity to cause illness and death as a result of chronic use. Recently published evidence shows that long-term cigarette smoking reduces life expectancy, on average, by 10 years.9 Tobacco and alcohol together account for about 90% of all drug-related deaths in the UK.My main problem with the lancet article is they compare legal drugs, alcohol and tobacco, with illegal ones like heroin. Black market heroin is a dangerous drug because of its unknown purity and possibility of being adulterated with any number of substances, assuming you're even getting heroin and some some obscure fentanyl analog. Some basic information would go a long way to making heroin a less dangerous drug. For one combining opiates with CNS depressants dramatically increases the chance of overdose. Easy access to naloxone (narcan) nasal sprays could save countless lives, without having to call 911 and risk arrest in states without "good samaritan" laws. Disseminating information on safe injecting practices would go a long way to improving users health. Instead we get PSAs with a teenage girl destroying her kitchen in an apparently heroin-fueled rage. Furthermore due to the social stigma of using heroin, most users hide their drug use making it more likely no one will be around to save their life should they OD.
This is comparing apples to oranges. To compare apples to apples one would have to look at a quasi-legal system. One option would be to compare the physical harms of individuals on heroin prescriptions or physician opiate users. Both use pharmaceutically pure opiates and sterile injecting equipment. In the heroin assisted therapy trials in Vancouver there were ODs, but medical staff quickly revived them. Most importantly there were no opiate-related fatalities. Putting aside the potential for an opiate overdose, just how bad for the body is heroin? Dr. Arnold Trebach, writing in "The Heroin Solution," informs us that "putting aside the problem of addiction, the chemical heroin seems almost a neutral or benign substance. Taken in stable, moderate doses, it does not seem to cause organic injury, as does alcoholism over time." Interesting, so if heroin were administered in an environment where the chance of ODs were minimized, and with a readily available narcotic antagonist (antidote), heroin would score below alcohol and tobacco, probably just above cannabis. Heroin is the poster child for prohibition making drug use far more dangerous than it would be in a legal, regulated market.
Rob Arthur writing in his article, "Heroin Is Harmless?" breaks it down the harms further:
Three aspects of an ingestible substance that can be considered harmful are (1) its potential to debilitate, (2) its effects on one’s health, and (3) its potential to kill via an overdose.
(1) Like the stimulants, caffeine and cocaine, heroin is not a debilitating drug. That is, moderate usage does not interfere with one’s functioning, e.g. driving ability. This is in contrast to alcohol, in which one’s performance is directly hampered. Extreme usage can interfere just like with caffeine and cocaine, e.g. too much of a stimulant can make it difficult to focus and even cause hallucinations. However, even heroin addicts can moderate their usage so that they can work unimpaired and avoid withdrawal symptoms. For this reason, heroin addicts can and do have successful professional lives in such diverse fields as surgery and law enforcement.
(2) Long-term heroin addiction is relatively harmless to one’s health. Like caffeine addicts who “need” their coffee in the morning, the side-effects are minimal. Heroin’s long-term side-effects can include constipation and impotency. This is in contrast to alcohol and tobacco which destroy the liver and the lungs respectively.
(3) Like caffeine, it is difficult to fatally overdose on heroin by itself. (It is easy to overdose when using heroin and alcohol in combination.) The popular image of a dead heroin user with the needle still in his or her arm is misleading. A fatal heroin overdose is usually a long process that takes over an hour and it can be countered within minutes by an antidote.