As the khat ban approached, DrugScience commissioned a review of khat harms, following the detailed and rigorous report from the UK Government Advisory Council on the Misuse of Drugs earlier that year. DrugScience's review provided independent corroboration of the ACMD’s findings that the harms of khat cannot justify a ban and that community measures should be used instead of criminalisation to address khat harms. The review was also used to launch DrugScience's own journal - Drug Science, Policy and Law. Regrettably, the UK Government elected to ignore the evidence-based opinions of both its own Advisory Council and DrugScience - as it had done with both mephedrone and drug-driving legislation. Khat was banned in the UK in June 2014.

The review used a different approach to the ACMD that helps put the harms of khat in context. Our review structured its analysis of the evidence using a model that evaluates a drug on 16 criteria which collectively encapsulate the ways in which drugs do harm - a "multi-criteria decision analysis". The criteria were defined by the ACMD in 2009, then developed further in later work by DrugScience - Drug Harms in the UK and Harms of Nicotine Products. By scoring the harm a drug does in each category, it is easier to compare their dangers and come to rational decisions over how different drugs should be controlled.

This review on khat clearly shows that the evidence does not support a ban. If the government are serious about reducing the potential for damage from khat use then the recommendations of our review and those of the ACMD’s report should be put in place. What motivation does the government have to criminalise users when the evidence of harm is flimsy at best?

Dr Tim Williams
Co-author, addiction psychiatrist and co-author of the ACMD’s 2005 khat report

Results and Interpretation of Tables

The tables above/below use the scores given to alcohol and khat from DrugScience's Drug Harms in the UK paper, along with text derived from the findings of the ACMD and DrugScience reviews.

In the original multicriteria decision analysis research the scores for harm were weighted in accordance with their relative importance (i.e. littering matters less than death) and added up. Alcohol got a total score of 72, the highest of any drug. Khat scored 9.

Harms to user

Harms to society

It is vital that any work detailing drug harms acknowledges its limitations and caveats. Drug harms are multi-faceted and highly complex - please consider the points below as you evaluate the results tables:

• The tables show that the harms of khat are very much lower than the harms of alcohol. It should be noted that whilst alcohol is well researched, and therefore future study is unlikely to change the scores much, khat is poorly researched, so future work may result in changes in the evaluations given. However, enough is already known of its pharmacology to conclude that future research will not show that khat is harmless, nor will it turn out to be comparably harmful to alcohol. To take the first row of the table as an example, future research will not reveal khat to cause frequent overdose deaths as alcohol does.

• This method of evaluating drugs is by its nature conservative, because it only considers the harms associated with khat and alcohol, whereas it could be argued that these need balancing against benefits. For example the social harms of the drugs are evaluated but not any social benefits, their cost to the economy is evaluated but not the gains in tax.

• The first table shows the risks to users themselves, and so the harms of alcohol can be compared directly to the harms of khat. The second table depicts the risks that apply to UK society as a whole. Therefore, the total amount of harm is strongly influenced by the high prevalence of alcohol and low prevalence of khat. This means the figures cannot be compared in such a straightforward way. The harms for UK society from khat are all ‘negligible’, because they are scaled in proportion to the harms of alcohol and other drugs, and less than 0.2% percent of the UK population use khat. This is a 'bird's eye view' assessment of the UK situation and should not be mistaken as implying that within the small groups that use khat, the harms are all negligible. Some may not be.