Steep rise in ketamine and MDMA consumption reported in the latest wastewater analysis

The Home Office Wastewater Analysis Programme (WWAP) has reported a steep rise in ketamine and MDMA consumption between 2023 and 2024. The use of wastewater analysis to measure illicit drug consumption in the UK is an interesting and increasingly valuable tool in understanding substance use trends. Unlike surveys or police seizure data, which rely on self-reporting or enforcement outcomes, wastewater analysis provides a real-time snapshot of drug use. However, interpreting this data correctly requires an understanding of its strengths and limitations.

How wastewater analysis works

At the core of this approach is the collection of wastewater samples from treatment plants across different locations. These samples contain traces of substances that have been excreted by people or directly disposed of into the sewage system.

Interpreting the data and trends

Wastewater was sampled from 16 WWTPs (covering 18% of England’s population) between January and April 2023 and January and April 2024. Overall consumption estimates (measured in milligrams per 1,000 people per day) from these 2 periods in these areas have been compared to produce the following trends:

• cocaine consumption is estimated to have increased by 7%; his figure includes both powder and crack cocaine as it is currently not possible to produce individual estimates for these drugs; it is currently being explored whether this can be achieved in future outputs
• heroin consumption is estimated to have decreased by 11%
• ketamine consumption is estimated to have increased by 85%
• MDMA consumption is estimated to have increased by 52%
• amphetamine consumption is estimated to have decreased by 18%
• methamphetamine consumption is estimated to have decreased by 30%

Limitations and challenges

While wastewater analysis is a powerful tool, this study has several limitations:

1. Urban bias in sampling
   Since wastewater samples have predominantly been taken from urban areas, the data is skewed toward populations that tend to have higher drug-related harms. This means national-level extrapolations are limited.
2. Difficulty in distinguishing drug sources
   Some drugs, like MDMA, may be disposed of directly into the water system (e.g., flushing unused pills) rather than consumed. This can inflate estimates of consumption.
3. Medical use inclusion
   Drugs such as heroin (diamorphine) and amphetamines have legitimate medical uses, so some of the detected levels may not be from illicit consumption.
4. Synthetic opioids and emerging drugs
   Some substances, particularly synthetic opioids like nitazenes, are harder to detect due to their chemical properties and low quantities in wastewater. This makes monitoring emerging drug threats more challenging.

Conclusion

Wastewater analysis is a unique and valuable method for measuring drug consumption in the UK, providing insights that complement traditional data sources.  As technology advances, wastewater analysis is likely to become an even more refined and essential tool in public health efforts to understand and respond to drug use patterns. This study reports a steep rise in ketamine and MDMA consumption, and while consumption of other drugs, for example heroin, is reported to have decreased, the study identifies limitations in detection of synthetic opioids and emerging drugs which may be replacing heroin consumption rather than signifying a reduction in overall consumption amongst people using drugs. The overall message for services must be to continue to provide good harm reduction advice and to encourage access into treatment across the range of services available.