Drug Science response to Ketamine Harms Assessment

By Anne Katrin Schlag, David Nutt and Celia Morgan

Drug Science responded to the Advisory Council on the Misuse of Drugs’ (ACMD’s) call on Ketamine use, harms and interventions. We hope that our evidence can help to develop rational debate, policy making and scheduling about Ketamine.

Ketamine harms

Populations in the community predominantly affected by Ketamine use  tend to be young drug users (16-24 years old) - here ketamine use is most common, and the chance of ketamine addiction is the highest. Ketamine addiction has increased such that numbers presenting for treatment are higher and are typically of a younger age – data suggest here was also an increase in the proportion of adults entering treatment in 2023 to 2024 to 3,609 is now over 8 times higher than it was in 2014 to 2015, when the number was 426 (OHID, 2025).

Short-term effects acutely are disorientation, detachment, enhanced chance of accidental death; chronic effects from those who use recreationally (less than four times per week) are limited (Morgan et al., 2008) but in those with dependence predominantly are bladder and kidney damage leading longer term to organ failure (Harding et al., 2025). Psychological effects of heavy use can include memory impairment and in a minority of users, psychosis (Morgan et al., 2010; 2009). Social harms reported by users include damage to family relationships, delayed employment – however, most harms are to the individual.

Our research suggests that individuals who are addicted were unaware of the addictive potential (Harding et al., 2025) but aware of the acute effects.

The need for harm reduction

It is vital to improve methods of harm reduction. These should include information campaigns at festivals users attend, and earlier information in secondary schools as our survey suggests some users are starting using as early as 12 years old. Schools need more funding to be able to offer high quality drug education - at present, this is often outsourced to companies with varied standards.

More research is needed on ketamine use so that clear harm reduction advice may be provided about relatively safe levels of ketamine use. Many young people now use small amounts of ketamine instead of alcohol as it is perceived as less harmful and is cheaper so clear evidence on this question would be able to advise users on the relative harms related to this behaviour.

Raising awareness more broadly in the population of the health risks and harms along with the potential for dependence will signal to users that caution is warranted. Many users surveyed in our work were oblivious to the potential for ketamine addiction and the associated health consequences and were surprised when their use spiralled out of control (Harding et al., 2025). Providing specialist ketamine treatment in addiction services for this younger group who have specific needs due to their urological problems, for example the need for frequent breaks to pee, will enable users to be better served if they develop ketamine use disorders. Destigmatising the issues associated with ketamine use disorder as much as possible will better enable ketamine users to engage with treatment services, as research suggests that shame may be particularly high around urological problems amongst the group, which delay people seeking help. Providing age-appropriate specialist urological advice for people suffering from ketamine induced ulcerative cystitis and similarly for those who need to undergo cystectomies or e.g. nephrostomy tubes to enable better post-operative management. At present, individuals with ketamine use disorder or related health issues only have limited options for care and support, as highlighted in the 2013 ACMD Ketamine review.

Legal classification

Evidence suggests that when ketamine moved from class C to class B in 2014 the use of the drug increased exponentially, and indeed it doubled when ketamine was first classified under the Misuse of Drugs Act in 2006 – highlighting the fact that re-classifying Ketamine into a higher class actually seems to increase, rather than decrease use, counter to the argument that the legal status might prohibit increased use.

The proposed change in legal status from Class B to Class A would be a politically driven response rather than being based on the latest scientific evidence. National and international evidence consistently shows that increasing criminal penalties does not significantly deter drug use, and reducing penalties does not increase use either- but the latter might positively impact users’ willingness to seek help and access treatment.

There is no evidence to suggest that raising Ketamine to Class A status would increase cost, deter use or impact availability. Increasing criminal punishments do not prevent use.

Moreover, making ketamine Class A would have a negative impact on the growing use of ketamine as a therapy for mental illnesses for patients who have not responded to other treatments.

There is long standing evidence that harsher criminalisation can worsen both health and social outcomes. Increasing penalties will likely delay/deter people from seeking help; criminalisation itself is a public health harm with a criminal record having serious long term consequences; the burden of criminalisation will disproportionally fall on vulnerable/marginalised populations; and increased punitive enforcement diverts valuable public resources away from public health interventions.

As such, the proposed reclassification of Ketamine is likely to undermine the health and well-being of the people it is supposed to protect. Rather than further criminalising users and making Ketamine use disorder/drug addiction a criminal issue, we need to offer a public health centred approach to be able to positively impact problematic use and users.