Overview of the paper

An assessment of the various harms of drugs used recreationally in the UK using multi-criteria decision analysis (MCDA) – a method that uses relevant experts’ knowledge and experience to assess the actual and relative harms.

Aims and Methodology

We wanted to assess drugs in terms of their known harms to individuals, those around them and more broadly, to domestic and international society. Showing drugs’ harms relative to each other also enables more objective and informed assessment of their harms individually and in relation to their current controls. This task is not easy because of the wide range of ways in which drugs can cause harm - from the intrinsic harms of the drugs to social and health-care costs.

To rectify these drawbacks we undertook a review of drug harms with a MCDA approach. This technology has been used successfully to lend support to decision makers facing complex issues characterised by many, conflicting objectives — e.g. appraisal of policies for disposal of nuclear waste. Sixteen harm criteria were identified by the UK Advisory Council on the Misuse of Drugs - nine relate to the harms that a drug produces in the individual and seven to the harms to others both in the UK and overseas.

Evaluation Criteria and their definitions

Drug-specific mortality
- Intrinsic lethality of the drug expressed as ratio of lethal dose and standard dose (for adults)

Drug-related mortality
- The extent to which life is shortened by the use of the drug (excludes drug-specific mortality) — e.g. road traffic accidents, lung cancers, HIV, suicide

Drug-specific damage
- Drug-specific damage to physical health — e.g. cirrhosis, seizures, strokes, cardiomyopathy, stomach ulcers

Drug-related damage
- Drug-related damage to physical health, including consequences of, for example, sexual unwanted activities and self-harm, blood-borne viruses, emphysema, and damage from cutting agents

- The extent to which a drug creates a propensity or urge to continue to use despite adverse consequences (ICD 10 or DSM IV)

Drug-specific impairment of mental functioning
- Drug-specific impairment of mental functioning — e.g. amfetamine-induced psychosis, ketamine intoxication

Drug-related impairment of mental functioning
- Drug-related impairment of mental functioning — e.g. mood disorders secondary to drug-user's lifestyle or drug use

Loss of tangibles
- Extent of loss of tangible things (e.g. income, housing, job, educational achievements, criminal record, imprisonment)

Loss of relationships
- Extent of loss of relationship with family and friends

- Extent to which the use of a drug increases the chance of injuries to others both directly and indirectly — e.g. violence (including domestic violence), traffic accident, fetal harm, drug waste, secondary transmission of blood-borne viruses

- Extent to which the use of a drug involves or leads to an increase in volume of acquisitive crime (beyond the use-of-drug act) directly or indirectly (at the population level, not the individual level)

Environmental damage
- Extent to which the use and production of a drug causes environmental damage locally — e.g. toxic waste from amfetamine factories, discarded needles

Family adversities
Extent to which the use of a drug causes family adversities — e.g. family breakdown, economic wellbeing, emotional wellbeing, future prospects of children, child neglect

International damage
- Extent to which the use of a drug in the UK contributes to damage internationally — e.g. deforestation, destabilisation of countries, international crime, new markets

Economic cost
Extent to which the use of a drug causes direct costs to the country (e.g. health care, police, prisons, social services, customs, insurance, crime) and indirect costs (e.g. loss of productivity, absenteeism)

- Extent to which the use of a drug creates decline in social cohesion and decline in the reputation of the community

ICD 10 = International Classification of Diseases, tenth revision. DSM IV = Diagnostic and Statistical Manual of Mental Disorders, fourth revision.

Drugs were point scored out of 100, with 100 assigned to the most harmful drug on a specific criterion, and subsequently weighted between criteria. For a full explanation and discussion of scoring and weighting, please download the full paper from the sidebar.

Watch Prof. David Nutt talk about the MCDA technique for analysing drug and nicotine product harm

Graduate Institute Geneva, Nov 2014

What does it show?

The report found heroin, crack cocaine, and methamphetamine to be the most harmful drugs to individuals (part scores 34, 37, and 32, respectively), with alcohol, heroin, and crack cocaine as the most harmful to others (46, 21, and 17, respectively). Overall, alcohol was the most harmful drug (overall harm score 72), with heroin (55) and crack cocaine (54) in second and third places. It also found the legal status of most drugs bears little relation to their harms.

What does it not show?

The report does not take the legal status of a drug into account. This will undeniably have some impact on levels of harm. Alcohol’s regulated availability means that many more people have access to it than most drugs, which will have an effect on its levels of harm. Conversely, the controlled status of many drugs elevates their harm profile - unregulated production leads to chemical contamination and their stigma to risky practices such as needle sharing. The user harm rankings are likely to be largely insensitive to universal criminalisation or decriminalisation as they are intrinsically linked to their effects on mind and body. Harms to society, however, could change were a drug’s legal status changed, as observed in Portugal.

What does this mean?

This paper represents a great step forward in our understanding of drug harms but is by no means an exhaustive answer. Further work should look to expand analysis to other countries, relevant social groups, the benefits of drugs and associated user motivation. In a similar study in 2015, forty drug experts from throughout the EU scored 20 drugs on the same 16 harm criteria, concluding:

... scores given by the EU experts in the current study were generally very similar to the UK scores assessed by the [DrugScience] group in 2010 ... Alcohol, heroin and crack emerged as the most harmful drugs (overall weighted harm score 72, 55 and 50, respectively). The remaining drugs had an overall weighted harm score of 38 or less, making them much less harmful than alcohol.