Emergency department toxicology: ASSIST

Between March and May 2024, the ‘A Surveillance Study of Illicit Substance Toxicity’ (ASSIST) emergency department project made 563 detections of 43 different illicit drugs, in samples from 116 patients. The most commonly detected drug category was depressants (60% of detections), followed by stimulants (17%). The most commonly detected individual drug was cocaine (13%), followed by temazepam (10%) and desmethyldiazepam (9%).

Background

The ASSIST study is conducted by the emergency department (ED) at the Queen Elizabeth University Hospital (QEUH) in NHS Greater Glasgow and Clyde (GGC). This project has been funded by the Scottish Government since August 2022.

The aim of the study is to monitor drug trends and associated clinical features through the use of prospective surveillance of ED attendances due to acute illicit drug toxicity. For the most unwell patients, the study performs full toxicological analysis through the biorepository-approved surplus sampling.

The study allows drug profiling and the identification of emerging drugs or changing trends to inform appropriate harm reduction measures and public health responses.

Data collection

The study collects anonymised data through the analysis of standard-of-care clinical data for patients attending QEUH ED due to illicit drug toxicity and surplus serum sample toxicology testing. Surplus serum samples are leftover blood samples, which were taken as part of usual care.

Each ED attendance is counted once in these data. If the same person presented more than once, each attendance would be a separate data point.

Drug detections presented here are of ‘illicit drugs’ only and were not prescribed to the individual.

Illicit drug definition

The use of the term 'illicit drug' encompasses any substance that is controlled. It excludes:

• legal substances, such as alcohol, nicotine, caffeine and paracetamol
• medications recently prescribed to the individual (e.g. if methadone is detected but the individual is prescribed methadone, it will not be included)
• drugs administered to the individual as part of treatment (by ambulance staff or in hospital).

Toxicology analysis of surplus serum samples

Detections presented are for the substance only. If a metabolite (compound produced when a drug breaks down in the body) is detected, it will be presented as the substance only.

If the metabolite and substance are detected, it will also be presented as the substance only.

However, if a drug and a metabolite are both detected and the metabolite could also be a drug, the metabolite is included as it is not possible to say which has been used, if not both.

Data from the study are presented in quarters, based on the date of ED presentation, and are provided in the table below.

Results

The first chart shows the most common drug categories detected in toxicology analysis of surplus serum samples between 17 August 2022 and 16 May 2024 (Q1 to Q7).

The results are shown as the total number of detections. They are broken down by the top five drug categories and presented by study quarter.

This stacked bar chart shows the percentage of detections of drug types within QEUH ED across seven quarters - Q1 to Q7. The drugs are grouped into five categories (depressant, opioid, stimulant, cannabinoid and other (including dissociative and psychedelic drugs)). Percentage of detections by category is on the y axis and the time period is on the x axis. The most common category was depressants with 57%, 62%, 60%, 64%, 66%, 67% and 60% across the time series. The second most common across quarters 1 to 6 was opioids with 17%, 18%, 16%, 16%, 15% and 13% across the time series and in quarter 7, stimulants (17%).

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ASSIST hospital toxicology analysis: drug categories by study quarter

Summary

Historic trend

Between 17 August 2022 and 16 February 2024:

• The most commonly detected drug type was depressants, making up 63% of all detections, followed by opioids (16%). The most commonly detected individual drug was cocaine (11%).
• 72% of attendances were male and 28% were female.
• 76% of attendances were aged 44 and under. The most common age category was 25 to 34 years (29%), followed by 35 to 44 (28%) and 16 to 24 (19%).
• The most common outcomes were discharged to home (40%), ward (28%) and police custody (12%).

Update

For the most recent period (17 February to 16 May 2024):

• 297 individual ED attendances related to illicit drug use were identified.
• 116 surplus serum samples were analysed for toxicology (as they were categorised as having a higher clinical severity of toxicity as per research inclusion criteria).

Drug type and category

Among the 116 samples analysed:

• There were 563 detections of 43 individual substances (found through the biological detection of the drug or its metabolite).
• The average number of drugs detected per sample was five.

Of the 563 detections, the following drugs were the most common:

• cocaine: 75 (13% of detections, 65% of samples)
• temazepam: 54 (10% of detections, 47% of samples)
• desmethyldiazepam: 53 (9% of detections, 46% of samples)
• etizolam: 41 (7% of detections, 35% of samples)
• bromazolam: 38 (7% of detections, 33% of samples)
• diazepam: 29 (5% of detections, 25% of samples)
• oxazepam: 29 (5% of detections, 25% of samples)
• pregabalin: 29 (5% of detections, 25% of samples)
• morphine: 22 (4% of detections, 19% of samples)
• cannabis (tetrahydrocannabinol): 21 (4% of detections, 18% of samples)

Please note: desmethyldiazepam, temazepam and oxazepam are all benzodiazepine drugs but can also be found as a metabolite of diazepam and other benzodiazepines.

The chart below shows the most common depressant drug detected in toxicology analysis of surplus serum samples between 17 August 2022 and 16 May 2024 (Q1 to Q7). The percentages are of all detections.

This line chart shows the percentage of detections of specific depressant drugs within QEUH ED across seven quarters - Q1 to Q7. Percentage of detections is on the y axis and the time period is on the x axis. The most common depressant drug in Q1, Q2, Q5, Q6 and Q7 was desmethyldiazepam (Q1; 10%, Q2; 8%, Q5; 11%, Q6; 10%); Q7: 9%). The most common depressant drug in Q4 was bromazolam (Q4; 10%). This was the fourth quarter in which xylazine was detected.

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ASSIST hospital toxicology analysis: depressant drugs by study quarter

Depressants were the most common drug category, making up 60% of detections (338).

• Benzodiazepines were detected 291 times (52% of all detections):
  • In total, 16 different types of benzodiazepines were detected, including temazepam (10%), desmethyldiazepam (9%), etizolam (7%), clonazolam (3%), gidazepam (2%) and flubromazepam (2%).
  • Bromazolam made up 7% of all detections, down from 10% in Q6.
• Gabapentinoids were detected 40 times (7% of all detections, from 6% in Q6). Of these detections, 11 were gabapentin and 29 were pregabalin.
• There were four detections of xylazine (1%), the same as in the previous quarter.

Stimulants were the second most common drug category, making up 17% of detections (93).

• The most common stimulant was cocaine, making up 13% of detections (75).

Opioids were the third most common drug category, making up 14% of detections (90).

• There were 23 detections of heroin/morphine (4%), 15 for methadone (3%) and 11 for codeine (2%).
• There were six detections of nitazenes (1%), down from eight detections in the previous quarter.

This line chart shows the percentage of detections of specific opioid drugs within QEUH ED across seven quarters - Q1 to Q7. Percentage of detections is on the y axis and the time period is on the x axis. The most common opioid drug across the time series was heroin/morphine (Q1: 4%, Q2: 5%, Q3: 6%, Q4: 5%, Q5: 5%, Q6; 4% and Q7; 4%). Nitazenes were detected for the first time in Q4 (seven detections) and increased to 2% of detections (16 detections) in Q5. They were detected 8 times in Q6 and 6 times in Q7. Detections of noscapine decreased from 3% in Q1 to 0 in Q5 and increased to 1% in Q6 and 2% in Q7.

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ASSIST hospital toxicology analysis: opioid drugs by study quarter

Further findings

Complete clinical data were available for 297 attendances for the most recent period (17 February to 16 May 2024):

• 72% of attendees were male (213) and 28% were female (84).
• 19% (57) of attendees were aged 16 to 24 years and 25% (74) were aged 25 to 34.
• 55% of attendees were aged 35 years and over, with 34% (101) aged 35 to 44, 15% (44) aged 45 to 54 and 6% (18) aged 55 years or older. Age was unknown for three attendances.

This stacked bar chart shows the percentage of QEUH ED ASSIST attendees by age group across seven time periods - Q1 to Q7. Percentage of attendees is on the y axis and the time period is along the x axis. The most common age group in Q1, Q2 and Q4 was 25 to 34 years (34%, 34% and 29% respectively). In Q3, patients aged 25 to 34 years and 35 to 44 were equally common (both 29%). The most common age group in Q5, Q6 and Q6 was 35 to 44 years (30%, 34% and 34% respectively).

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Attendances by age

ED outcome records show:

• 96 (32%) patients were admitted to a ward – this is the highest proportion observed throughout the study (quarterly average – 28%)
• 94 (32%) patients were discharged home
• 42 (14%) were taken into police custody
• 37 (9%) self-discharged
• 14 (6%) were admitted to an intensive care unit, high-dependency unit, critical care unit or died
• 14 were recorded as ‘unknown’ or ‘other’.

Clinical severity outcome (after 28 days) recorded:

• 278 (94%) patients were discharged following the attendance
• five patients either died or remained an inpatient following the attendance
• outcomes for 14 patients were ‘unknown’.

Additional information

Public Health Scotland (PHS) was provided with these data by QEUH, NHS GGC.

The ASSIST trial is registered with Clinical Trials UK (ID: NCT05329142).

Ethical approval has been granted by the West of Scotland Research Ethics Service (IRAS ref: 313616, REC ref: 22/WS/0047) and surplus sampling methodology through Biorepository Ethics (ref: 22/WS/0020).

The West of Scotland Safe Haven research database hosts the electronic clinical data under IRAS ref: 321198 or REC ref: 22/WS/0163.

This study is sponsored by NHS GGC Research and Innovation and is funded by the Scottish Government.

The testing has been carried out by the LGC group (external website). LGC analyse pseudonymised samples using mass spectrometry and screen against a database of over 3,500 analytes. This testing can detect drugs and metabolites, but this analysis does not imply that specific drugs were implicated in harms.

Further information on the study can be found at Clinical Trials (external website).

Post-mortem toxicology testing for controlled substances

In Q1 of 2024, the most common drug types detected in post-mortem toxicology were opioids (72%) and benzodiazepines (60%). The percentage of deaths where cocaine was detected remained stable (36%). It continued to be the most commonly detected individual substance, followed by heroin/morphine (31%), diazepam (30%) and methadone (28%).

Background

All sudden or unexpected deaths in Scotland are subject to investigation by the Crown Office and Procurator Fiscal Service (COPFS) to determine the cause of death and the need for criminal proceedings. In order to inform these decisions, the COPFS commissions post-mortem toxicology and pathology services.

This analysis is based on data from toxicology testing conducted at post-mortem for sudden and unexplained deaths, or where there was suspicion of involvement of controlled drugs.

Post-mortem toxicology testing is carried out by two services in Scotland:

• The Scottish Police Authority Forensic Services (SPA FS) covers deaths occurring in the west, east and parts of the north of Scotland.
• The Department of Clinical Biochemistry at NHS Grampian covers deaths in the far north and north-east of Scotland.

This report presents data on deaths covering the whole of Scotland, which became available from January 2022. It includes new data for the period from 1 January to 31 March 2024, representing Q1 of 2024.

The range of substances routinely analysed is extensive and includes the detection of alcohol, prescribed medicines and controlled drugs. The data within this report will develop further as other new or emerging drugs are added to toxicology screening.

The charts below show the prevalence of controlled substances detected in deaths which were subject to post-mortem toxicology screening. Drug detections were assigned to specific time periods based on the calendar year quarter of death. Throughout the series, the sum of the percentages for each quarter exceeds 100%, due to the widespread detection of multiple substances in deaths (multiple controlled drugs were detected in 95% of deaths in Q1 of 2024).

The first chart below provides an indication of controlled drugs detected at post-mortem, in deaths occurring between 1 January 2022 and 31 March 2024.

The chart shows the percentage of forensic toxicology cases testing positive for controlled substances (opioids, benzodiazepines, gabapentin and pregabalin, cocaine). The percentage of cases is on the y axis and the calendar year and quarter of death, between Q1 of 2022 and Q1 of 2024 is on the x axis. The most commonly detected drug types were opioids and benzodiazepines. The percentage of deaths where opioids, benzodiazepines, and gabapentin and pregabalin were detected has remained relatively stable throughout the time series averaging 71% for opioids, 58% for benzodiazepines and 31% for gabapentin and pregabalin. The percentage of deaths where cocaine was detected was relatively stable until Q1 of 2023 (averaging 29%). Detections increased to 36% in Q2 of 2023, after which they remained stable.

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Forensic toxicology cases testing positive for controlled substances

The following charts provide an indication of specific opioids and benzodiazepines detected at post-mortem, in deaths occurring between 1 January 2022 and 31 March 2024.

The chart shows the percentage of forensic toxicology cases testing positive for specific opioids (heroin/morphine, fentanyls, methadone, buprenorphine and nitazenes). The percentage of cases is on the y axis and the calendar year and quarter of death, between Q1 of 2022 and Q1 of 2024 is on the x axis. Heroin/morphine has been the most commonly detected opioid throughout the series; however, detections have been gradually decreasing from 36% in Q1 of 2022 to 31% in Q1 of 2024. Methadone detections decreased to 23% in Q3 of 2022 (from 32% in Q1 of 2022). Since then, methadone detections have increased slightly to 28% in Q1 of 2024. Deaths with buprenorphine present remained relatively low and stable throughout the time series (averaging 5%). There was a gradual increase in the percentage of cases where fentanyl-type opioids were detected, from 1% in Q1 of 2022, to 7% in Q4 of 2023. Nitazene-type opioid substances were first detected in Q1 of 2022 and, have continued to increase, being detected in 4% of deaths in Q1 of 2024.

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Forensic toxicology cases testing positive for specific opioids

The chart shows the percentage of forensic toxicology cases testing positive for specific benzodiazepines (diazepam, etizolam, clonazolam and bromazolam). The percentage of cases is on the y axis and the calendar year and quarter of death, between Q1 of 2022 and Q1 of 2024 is on the x axis. Diazepam has been the most commonly detected benzodiazepine since Q2 of 2022. Since then, detections have fluctuated between 25% and 35%. Bromazolam detections increased sharply between Q3 of 2022 (1%) and Q3 of 2023 (24%). Detections of bromazolam then decreased to 20% in Q1 of 2024. Etizolam was the most common benzodiazepine detected in Q1 of 2022 (31%), after which detections have followed a decreasing trend to 7% of deaths in Q1 of 2024. The percentage of temazepam detections have remained broadly stable throughout the time series, detected in an average of 8% of deaths. Clonazolam detections remained low and stable throughout the time series, detected in an average of 2% of deaths.

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Forensic toxicology cases testing positive for specific benzodiazepines

Summary

• The most commonly detected drug types were opioids and benzodiazepines, averaging 71% and 58% respectively between January 2022 to March 2024.
• The most commonly detected individual drug in the last year was cocaine (averaging 36%). Before Q2 of 2023, the most common individual drug was heroin/morphine.
• Multiple controlled drugs were detected in 662 of 694 deaths (95%) in Q1 of 2024.
• The following drugs or drug types were the most commonly detected in deaths in Q1 of 2024:
  • opioids: 499 (72%)
  • benzodiazepines: 418 (60%)
  • cocaine: 248 (36%)
  • heroin/morphine: 214 (31%)
  • diazepam: 209 (30%)
  • gabapentin and pregabalin: 198 (29%)
  • methadone: 197 (28%)
  • codeine: 155 (22%)

Stimulants

• For the fourth quarter in a row, the most commonly detected drug was cocaine.
• The percentage of deaths where cocaine was detected was relatively stable until Q1 of 2023 (averaging 29%). Detections increased in Q2 of 2023 to 36% and have remained stable since.

Opioids

• The percentage of deaths where opioids were detected has remained relatively stable throughout the time series, averaging 71%.
• Heroin/morphine detections have been gradually decreasing from 36% in Q1 of 2022 to 31% in Q1 of 2024.
• Methadone detections decreased from 32% in Q1 2022 to 23% in Q3 of 2022. Since then, detections have increased slightly (28% in Q1 of 2024).
• Buprenorphine detections remained low and stable throughout the time series, detected in an average of 5% of deaths.
• Fentanyl-type opioid detections increased, from 1% in Q1 of 2022 to 6% in Q1 of 2023. Since then, detections have remained stable averaging 5% in the last four quarters.
• Nitazene-type opioid detections increased, from 2% of deaths (12) in Q4 of 2023 to 4% (25) in Q1 of 2024. Metonitazene was the most common nitazene detected, followed by protonitazene. Two nitazenes were detected in 17 deaths.

Depressants

• Benzodiazepines have remained broadly stable throughout the time series, detected in an average of 58% of deaths.
• Diazepam has been the most commonly detected benzodiazepine since Q2 of 2022. Since then, detections have fluctuated between 25% and 35%.
• Detections of bromazolam increased sharply between Q3 of 2022 and Q3 of 2023, replacing etizolam as the most commonly detected ‘street’ benzodiazepine from Q1 of 2023 onwards. Bromazolam was detected in 20% of deaths in Q1 of 2024.
• Etizolam was the most common benzodiazepine detected in Q1 of 2022, after which detections have followed a decreasing trend to 7% of deaths in Q1 of 2024.
• The percentage of temazepam detections have remained broadly stable throughout the series, detected in an average of 8% of deaths.
• Clonazolam detections remained low and stable throughout the series, detected in an average of 1% of deaths.
• Several other novel benzodiazepines were detected in deaths. Of note is gidazepam, which increased from <1% of deaths (6) in Q4 of 2023 to 1% of deaths (8) in Q1 of 2024.
• The percentage of deaths involving gabapentin and pregabalin has been relatively stable throughout the series, averaging 31%.
• Xylazine (detected for the first time in Q3 of 2023) detections increased, from <1% (3) in Q4 of 2023 to 1% of deaths (10) in Q1 of 2024.

More detailed descriptions of historical changes can be found within our previous reports.

Additional information

PHS was provided with post-mortem toxicology testing data for deaths occurring in the west, east and parts of the north of Scotland by Forensic Medicine and Science at the University of Glasgow and SPA FS.

In late 2022, post-mortem toxicology services for the west, east and parts of the north of Scotland were transferred from the University of Glasgow to the Scottish Police Authority Forensic Services (SPA FS). During the period of transition, tests were completed by other laboratory testing sites in the UK. Although testing has now been moved to SPA FS, these testing sites continued to provide support in 2023 and data from both SPA FS and outsourced sites have been included in this report.

Data on deaths occurring in the far north and north-east of Scotland, was supplied by the Department of Clinical Biochemistry at NHS Grampian.

The total number of deaths testing positive for controlled substances, for each calendar year and quarter, are provided in table 1.

A number of drugs were detected for the first time when screening was expanded or testing was outsourced to other laboratories. Table 2 provides information on the initial screening period new or emerging substances, from which limited testing data was available, and also when testing is considered to have become routine across Scotland.

Note that these drugs may have been present before this time but were not being tested for, as they have only recently emerged in drug markets. These data will develop further as new or emerging drugs are added to routine toxicology screening by the SPA FS and NHS Grampian.

Detailed interpretation of the levels of drugs found present, drug interactions, co-morbidities, or other factors relating to death, are outside the scope of this analysis. This analysis does not imply that specific drugs were implicated in deaths nor that deaths were classified as ‘drug-related’, and it does not include consideration of wider causes of death.

It should be noted that increases observed in specific substances within this report may be due to differences in toxicology test approaches (e.g. detection of concentration levels of a particular drug) between outsourced laboratories and previous screening. This may result in increases in substance detection. Further data will be required and monitored to determine the impact of any differences in toxicology screening across laboratories.

Additionally, it is important to note that small numbers of detections for specific substances may result in large percentage differences between quarters. Where it is felt that data should be interpreted with caution due to small numbers, the number of detections has also been provided for context.

As some of the data received from other laboratory testing sites did not include date of death, other date variables have been used as a proxy to improve data completeness and enable the inclusion of these deaths within this report. Two separate date variables have been used to approximate date of death information, where this information was unavailable:

1. Date of the case being received or sent to other labs for toxicology testing.
2. Date of toxicology test being completed.

Similarly, as date of death was unavailable for those tests conducted by the Department of Clinical Biochemistry at NHS Grampian, the date when the case was received from the Crown Office and Procurator Fiscal Service has been used instead.

These dates listed above have been used in the analysis as they are considered to provide a close approximation to the month and year of death. It is anticipated that missing information on date of death will be improved over time, as further information becomes available.

Drug seizures in Scottish prisons

The Scottish Prisons Non-Judicial Drug Monitoring Project is a collaboration between the Scottish Prison Service and the Leverhulme Research Centre for Forensic Science at the University of Dundee (external website). The project tests drug seizures made across the Scottish prison estate in order to understand the changing characteristics of synthetic drugs, including synthetic cannabinoids, often referred to as 'spice'.

Analysis of the drug seizures in Scottish prisons from August 2023 to April 2024 is ongoing and not all data can be included in this report. We anticipate the updated data will be available for the next release in October 2024.

Since the last quarterly report, we have received data for a limited number of samples for the latest period (1 November 2023 to 30 April 2024):

• 23 samples were tested and contained an illegal substance.
• Synthetic cannabinoids were the most prevalent drug type. They were detected in 11 samples, with seven samples containing two cannabinoids.
• MDMB-4en-PINACA was the most common synthetic cannabinoid (9 detections), followed by MDMB-INACA (6).
• In the latest period, one sample contained a benzodiazepine (bromazolam). Please note that due to the limited number of samples received for testing since August 2023, these detections do not fully represent all benzodiazepine seizures within this reporting period.
• The most common sample type was powder (16 samples).

Complete data to July 2023 are available in a previous quarterly report.