The UK is grappling with a serious drug-related deaths crisis. All these tragic deaths are preventable, but well-meaning policies, treatment programs and educational campaigns will not have the desired impact unless the true scale of the problem is known – this underestimation will be leading to underfunding.
Senior author of the paper, Dr Caroline Copeland from the School of Cancer & Pharmaceutical Sciences and Director of the National Programme on Substance Use Mortality
16 September 2025
Opioid-related deaths in past decade 55% higher than recorded
Opioid-related deaths from 2011 to 2022 are 54.7% higher than recorded, according to new research by King’s. Analysis by researchers puts the estimated number of deaths at 39,232 compared to 25,364 deaths previously reported.
Deaths following opioid use in England and Wales have nearly doubled in the last decade, with 22.9 deaths per million people in 2012, and 43.8 deaths per million people in 2023. But the true number is likely higher because of a constraint of the data provided by coroners to The Office for National Statistics (ONS).
In a study published today in the International Journal of Drug Policy, researchers from the Faculty of Life Sciences & Medicine used data from coroners’ reports submitted to the National Programme on Substance Use Mortality data (NPSUM) based at the university to triangulate and better estimate the number of opioid-related deaths.
Whilst the total number of drug deaths is accurate, the count for deaths due to specific substances is limited by the fact the ONS does not have access to post-mortem reports or toxicology results.
Instead, the accuracy of figures depends on the information provided by the coroner on the death certificate. If that is missing information, such as when an individual dies from using multiple drugs at the same time – known as polydrug use – and it is recorded with ambiguous terms such as ‘multidrug overdose’, the ONS cannot determine the individual substances involved. As a result of this incomplete information, the ONS warns that figures for drug misuse for specific substances are underestimates.
Researchers found the number of unaccounted deaths has grown in the past decade. The ONS recorded 574 heroin/morphine-related deaths in 2011 but by using NPSUM data, researchers found there were a likely 239 further unaccounted deaths – underestimated by 29%. This gap grew to 34% by 2022, with the ONS recording 1,264 deaths but the researchers projected there were 1,980.
She added: “The increase of users taking more than one drug increases the likelihood of accidental overdose and also adds to the reporting problem. We need to alert coroners to the impact that not naming specific drugs as the cause of death has on the planning and funding of public health policies.”
The rate of underestimation in the recorded data has increased over time for heroin/morphine, methadone, tramadol, dihydrocodeine and fentanyl.
The authors say it is likely ONS data reporting deaths due to other specified substances – such as cocaine – are likely underestimated too. Researchers at King’s are extending this study to provide estimates for the number of deaths due to other specified substances that ONS provides.
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Senior Lecturer in Pharmacology & Toxicology