Photo of Hugh Claridge at the 2023 Doctoral College Conference 'Making the invisible visible'

Hugh Claridge

Postgraduate Research Student


My research project


Research projects


John Martin Corkery, Wan-Chu Hung, Hugh Claridge, Christine Goodair, Caroline S Copeland, Fabrizio Schifano (2021)Recreational ketamine-related deaths notified to the National Programme on Substance Abuse Deaths, England, 1997–2019, In: Journal of Psychopharmacology35(11)pp. 1324-1348

Background: Ketamine is a phencyclidine derivative with dissociative anaesthetic properties. Increasing numbers of individuals in England take ketamine recreationally. Information on deaths arising from such use in England is presented. Methods: Cases were extracted on 31 January 2020 from the National Programme on Substance Abuse Deaths database, based on text searches of the cause of death, coroner’s verdict and positive toxicology results for the terms ‘ketamine’ or ‘norketamine’. Findings: During 1997–2005, there were

Hugh Claridge, Claire A. Price, Rofique Ali, Elizabeth A. Cooke, Simon De Lusignan, Adam Harvey-Sullivan, Catherine Hodges, Natalia Khalaf, Dean O'Callaghan, Ali Stunt, Spencer A Thomas, Joanna Thomson, Agnieszka Lemanska (2024)Determining the feasibility of calculating pancreatic cancer risk scores for people with new-onset diabetes in primary care (DEFEND PRIME): study protocol, In: BMJ Open14(1)e079863

Introduction Worldwide, pancreatic cancer has a poor prognosis. Early diagnosis may improve survival by enabling curative treatment. Statistical and machine learning diagnostic prediction models using risk factors such as patient demographics and blood tests are being developed for clinical use to improve early diagnosis. One example is the Enriching New-onset Diabetes for Pancreatic Cancer (ENDPAC) model, which employs patients’ age, blood glucose and weight changes to provide pancreatic cancer risk scores. These values are routinely collected in primary care in the UK. Primary care’s central role in cancer diagnosis makes it an ideal setting to implement ENDPAC but it has yet to be used in clinical settings. This study aims to determine the feasibility of applying ENDPAC to data held by UK primary care practices. Methods and analysis This will be a multicentre observational study with a cohort design, determining the feasibility of applying ENDPAC in UK primary care. We will develop software to search, extract and process anonymised data from 20 primary care providers’ electronic patient record management systems on participants aged 50+ years, with a glycated haemoglobin (HbA1c) test result of ≥48 mmol/mol (6.5%) and no previous abnormal HbA1c results. Software to calculate ENDPAC scores will be developed, and descriptive statistics used to summarise the cohort’s demographics and assess data quality. Findings will inform the development of a future UK clinical trial to test ENDPAC’s effectiveness for the early detection of pancreatic cancer. Ethics and dissemination This project has been reviewed by the University of Surrey University Ethics Committee and received a favourable ethical opinion (FHMS 22-23151 EGA). Study findings will be presented at scientific meetings and published in international peer-reviewed journals. Participating primary care practices, clinical leads and policy makers will be provided with summaries of the findings.

John M. Corkery, Barbara Loi, Hugh Claridge, Christine Goodair, Fabrizio Schifano (2018)Deaths in the Lesbian, Gay, Bisexual and Transgender United Kingdom Communities Associated with GHB and Precursors, In: Current Drug Metabolism19(13)pp. 1086-1099

Background: Misuse of gammahydroxybutrate (GHB) and its prodrugs gammabutyrolactone (GBL) and 1,4 butanediol (1,4-BD) has increased greatly since the early 1990s, particularly amongst lesbian, gay, bisexual and transgender (LGBT) individuals in recreational and sexual settings, e.g. ‘chemsex’. Objective and Method: This paper presents an overview of GHB pharmacotoxicology and provides analyses of cases in the LGBT population associated with the use of these substances extracted from the UK’s National Programme on Substance Abuse Deaths database, to which notification is voluntary. Results: From 1995 to September 2013, 21 GHB/GBL-associated fatalities were reported. None involved 1,4-BD. Typical victims were: Male (100%); White (67%), young (mean age 34 years); employed (90%); with a drug misuse history (81%). Most deaths were accidental (67%) or related to recreational drug use (19%), the remaining (potential) suicides. The majority of fatalities (83%) occurred in private residences, typically following recreational use; others occurred in specific ‘gay’-oriented locales including clubs and saunas. Three London boroughs accounted for 62% of all notified deaths, reflecting the concentration of both resident and visiting ‘gay’ individuals. However, this may be an artefact of the voluntary nature of the data submission procedure in particular areas. GHB/GBL alone was implicated in 10% of fatalities. The following substances were implicated either alone or in combination in the remaining cases (percentages may add to more than 100%): cocaine (38%); alcohol (33%); amphetamines (29%); ecstasy (29%); diazepam (24%); ketamine (24%); mephedrone (24%). Post-mortem blood levels: mean 660 (range 22 - 2335; S.D. 726) mg/L. Conclusion: Significant caution is needed when ingesting GHB/GBL, particularly with alcohol, benzodiazepines, stimulants, and ketamine. Risk of death is increased due to their CNS-depressant properties. Of these, ‘chemsex’ drugs such as cocaine, mephedrone and ketamine are of note. More awareness is needed in the ‘gay’ community about risks associated with the consumption of such substances.

Hugh Claridge, Joachim Tan, Maria Loane, Ester Garne, Ingeborg Barisic, Clara Cavero-Carbonell, Carlos Dias, Miriam Gatt, Susan Jordan, Babak Khoshnood, Sonja Kiuru-Kuhlefelt, Kari Klungsoyr, Olatz Mokoroa Carollo, Vera Nelen, Amanda J. Neville, Anna Pierini, Hanitra Randrianaivo, Anke Rissmann, David Tucker, Wladimir Wertelecki, Hermien de Walle, Joan K. Morris (2024)Ethics and legal requirements for data linkage in 14 European countries for children with congenital anomalies, In: BMJ Open13e071687 BMJ

Introduction Linking healthcare data sets can create valuable resources for research, particularly when investigating rare exposures or outcomes. However, across Europe, the permissions processes required to access data can be complex. This paper documents the processes required by the EUROlinkCAT study investigators to research the health and survival of children with congenital anomalies in Europe. Methods Eighteen congenital anomaly registries in 14 countries provided information on all the permissions required to perform surveillance of congenital anomalies and to link their data on live births with available vital statistics and healthcare databases for research. Small number restrictions imposed by data providers were also documented. Results The permissions requirements varied substantially, with certain registries able to conduct congenital anomaly surveillance as part of national or regional healthcare provision, while others were required to obtain ethics approvals or informed consent. Data linkage and analysis for research purposes added additional layers of complexity for registries, with some required to obtain several permissions, including ethics approvals to link the data. Restrictions relating to small numbers often resulted in a registry’s data on specific congenital anomalies being unusable. Conclusion The permissions required to obtain and link data on children with congenital anomalies varied greatly across Europe. The variation and complexity present a significant obstacle to the use of such data, especially in large data linkage projects. Furthermore, small number restrictions severely limited the research that could be performed for children with specific rare congenital anomalies.

Barbara Loi, John Martin Corkery, Hugh Claridge, Christine Goodair, Stefania Chiappini, Carla Gimeno Clemente, Fabrizio Schifano (2015)Deaths of individuals aged 16–24 years in the UK after using mephedrone, In: Human Psychopharmacology: Clinical and Experimental30(4)pp. 225-232

Objective Mephedrone is a stimulant drug chemically related to amphetamine, with effects similar to those of amphetamine and cocaine. This study aims to analyse fatalities following ingestion of mephedrone in the UK amongst 16- to 24-year-olds in 2009–2013, providing an update on data presented at the 2nd International Conference on Novel Psychoactive Substances. Methods A literature search was undertaken to identify published information on pharmacology, toxicity and fatalities associated with mephedrone. Fatalities involving mephedrone were extracted from the National Programme on Substance Abuse Deaths database, which receives information on drug-related deaths from coroners in the UK and Islands and other data suppliers. Selection criteria are as follows: deceased aged 16–24 years at time of death and mephedrone directly implicated in the cause of death and/or mentioned in the coroner's verdict. Results Thirty cases met the study criteria, and when known, all were of White ethnicity, most (85%) had a history of drug use and 73% were male. Two-thirds (63%) were accidental poisonings. Mephedrone was used with other substances in most cases (87%); other substances were implicated in 60% of deaths. Conclusions Mephedrone use can have potentially fatal consequences, especially in combination with other substances. Deaths from its use in the 16–24 years' age group continue to occur in the UK, despite it being a controlled drug. Health professionals and potential consumers should be alert to this risk. Copyright © 2015 John Wiley & Sons, Ltd.

Pruntha Yoganathan, Hugh Claridge, Lucy Chester, Amir Englund, Nicola J. Kalk, Caroline S. Copeland (2022)Synthetic Cannabinoid-Related Deaths in England, 2012–2019, In: Cannabis and Cannabinoid Research7(4)pp. 516-525

Aim: To identify drug-related death trends associated with synthetic cannabinoid receptor agonists (SCRAs) reported to the National Programme on Substance Abuse Deaths (NPSAD) from England. Design: Case reports from NPSAD (England) where a SCRA was detected in post-mortem tissue(s) and/or implicated in the death were extracted, analyzed, and compared against non-SCRA-related deaths that occurred over the same time period (2012–2019). Findings: One hundred sixty-five death SCRA-related reports were extracted, with 18 different SCRAs detected. Following the first death in 2012, a subsequent sharp increase in reporting is evident. Acute SCRA use was the underlying cause of death in the majority of cases (75.8%) with cardiorespiratory complications the most frequently cited underlying physiological cause (13.4%). SCRA users were predominantly found dead (68.6%), with a large proportion of those witnessed becoming unresponsive described as suddenly collapsing (81.6%). Psychoactive polydrug use was detected in 90.3% of cases, with alcohol the most commonly co-detected (50.3%), followed by opioids (42.2%), benzodiazepines/Z-drugs (32.1%), stimulants (32.1%, [28.5% cocaine]), and cannabis (24.8%). Compared to all non-SCRA-related NPSAD deaths occurring over the same time period, SCRA-related decedents were more predominantly male (90.3% vs. 72.0%; p

Christine Mary Goodair, John Corkery, Hugh Claridge (2014)Legal highs: a problem of definitions?, In: The Lancet383(9930)
Hugh Claridge, Michael Ussher (2019)Does financial support for medical students from low income families make a difference? A qualitative evaluation, In: BMC Medical Education19(1)153 BioMedCentral

The 2015–2020 strategic plan from the Office for Fair Access calls on institutions to provide contemporary assessments of the impact of their financial support for disadvantaged students on retention, progression, success, wellbeing and participation, throughout the student lifecycle. In response to this call, this article describes the first evaluation the authors are aware of, of a financial support scheme for students from lower income backgrounds attending a medical school.

Adrian A Deen, Hugh Claridge, Richard D Treble, Hilary J Hamnett, Caroline S Copeland (2021)Deaths from novel psychoactive substances in England, Wales and Northern Ireland: Evaluating the impact of the UK psychoactive substances act 2016, In: Journal of Psychopharmacology35(11)pp. 1315-1323

Background: ‘Legal highs’ began appearing in the UK in the mid-2000s. Whilst many of these substances were controlled under the 1971 Misuse of Drugs Act, novel compounds and new variants of controlled compounds were continuously being introduced to the recreational drug market. The Psychoactive Substances Act (PSA) was therefore implemented in 2016 as a blanket ban on all novel psychoactive substances (NPS). Aim: To evaluate the impact of the PSA on deaths following NPS use in England, Wales and Northern Ireland. Methods: Cases reported to the National Programme on Substance Abuse Deaths where death had occurred 3 years pre- or post-implementation of the PSA were extracted. Cases with NPS detected at post-mortem were analysed and compared against cases non-NPS cases. Results: 293 deaths with NPS detected were identified; 91 occurring before the PSA and 202 afterwards, indicating an 222.0% post-PSA increase. Contrastingly, non-NPS drug-related death case reporting increased by only 8.0%. Synthetic cannabinoid, anxiolytic/sedative and stimulant NPS were detected in the largest proportions of deaths pre-PSA; post-PSA stimulant NPS detections reduced whilst synthetic cannabinoid and anxiolytic/sedative detections increased. Post-PSA, average decedent age increased significantly (mean age pre-PSA 34.4 ± 10.8 vs post-PSA 38.3 ± 9.4), and they were significantly more likely to have been living in deprived areas (pre-PSA 50.0% vs post-PSA 65.9%). Conclusions: Reporting of deaths following NPS use has risen despite introduction of the PSA. Whilst deaths amongst younger individuals and those living in more affluent areas has reduced, additional approaches to prohibition are needed to curb their persistence in deprived demographics.

John M. Corkery, Barbara Loi, Hugh Claridge, Christine Goodair, Ornella Corazza, Simon Elliott, Fabrizio Schifano (2015)Gamma hydroxybutyrate (GHB), gamma butyrolactone (GBL) and 1,4-butanediol (1,4-BD; BDO): A literature review with a focus on UK fatalities related to non-medical use, In: Neuroscience & Biobehavioral Reviews53pp. 52-78 Elsevier

Misuse of gamma hydroxybutrate (GHB) and gamma butyrolactone (GBL) has increased greatly since the early 1990s, being implicated in a rising number of deaths. This paper reviews knowledge on GHB and derivatives, and explores the largest series of deaths associated with their non-medical use. Descriptive analyses of cases associated with GHB/GBL and 1,4-butanediol (1,4-BD) use extracted from the UK's National Programme on Substance Abuse Deaths database. From 1995 to September 2013, 159 GHB/GBL-associated fatalities were reported. Typical victims: White (92%); young (mean age 32 years); male (82%); with a drug misuse history (70%). Most deaths (79%) were accidental or related to drug use, the remainder (potential) suicides. GHB/GBL alone was implicated in 37%; alcohol 14%; other drugs 28%; other drugs and alcohol 15%. Its endogenous nature and rapid elimination limit toxicological detection. Post-mortem blood levels: mean 482 (range 0–6500; SD 758)mg/L. Results suggest significant caution is needed when ingesting GHB/GBL, particularly with alcohol, benzodiazepines, opiates, stimulants, and ketamine. More awareness is needed about risks associated with consumption.

Hugh Claridge, Khadija Stone, Michael Ussher (2018)The ethnicity attainment gap among medical and biomedical science students: a qualitative study, In: BMC Medical Education18(1) BioMedCentral

Black, Asian and Minority Ethnic (BAME) medical students and professionals frequently underachieve when compared with their White counterparts not only in the United Kingdom, but across the globe. There is no consensus for the definitive causes of this attainment gap, but suggestions contributing towards it include: increased feelings of isolation as a member of a minority culture or religion; a poorer higher education (HE) experience compared with White counterparts; and stereotype threat, whereby students underperform in exams from the stresses of fearing confirming to a negative-stereotype.

Hugh Claridge, Bryn D. Williams, Caroline S. Copeland (2020)A deadly trend in fentanyl fatalities (England, 1998–2017), In: British Journal of Clinical Pharmacology86(3)pp. 437-444 Wiley

Aim To identify trends in drug-related deaths associated with fentanyl and its derivatives, including novel variants, in England, 1998–2017. Methods Case reports from the National Programme on Substance Abuse Deaths (NPSAD) where a pharmaceutical fentanyl or non-pharmaceutical fentanyl derivative (NPFD) was found at post-mortem and/or implicated in the death were extracted for analysis. Results NPSAD has received case reports detailing 298 deaths in England from 1998–2017 where a fentanyl was found at post-mortem and/or implicated in the death. Hospital administered fentanyl is “very safe”, whereas pharmaceutical fentanyls in the community, procured either legitimately via prescription or illegitimately, carry high risk of unintentional death. Deaths involving NPFDs, which possess extreme potencies in comparison to morphine, have drastically risen over the past three years, and correlate with an increasing number of available compounds. Males, and those with existing opioid abuse disorders, are particularly susceptible to death related to NPFD intake. Conclusions The increasing availability of both pharmaceutical fentanyls and NPFDs represents a serious risk to public health. Unintentional misuse of these compounds in England is contributing to the exponential increase in fentanyl-associated deaths that is being observed at the global scale.

Stefania Chiappini, Hugh Claridge, John M. Corkery, Christine Goodair, Barbara Loi, Fabrizio Schifano (2015)Methoxetamine-related deaths in the UK: an overview, In: Human Psychopharmacology: Clinical and Experimental30(4)pp. 244-248

Objective The goal of this study is to provide an update on the data given on methoxetamine (MXE)-related fatalities that occurred in 2011–2013, presented at the Second International Conference on Novel Psychoactive Substances. Methods Fatalities involving MXE were extracted from the database of the National Programme on Substance Abuse Deaths, which receives information on drug-related deaths from Coroners in the UK and Islands (Isle of Man, Jersey, Guernsey) and other data suppliers. Results Eight cases, received by 3 September 2013, in which MXE was found at post-mortem and/or directly implicated in the death and/or mentioned in the Coroner's verdict are described. The median age at death was 27 years, with the majority of White ethnicity (6/8) and male (7/8). MXE was used together with other substances in 7/8 cases. MXE was found at post-mortem in all cases, directly implicated in the deaths of four and likely to have had an influence in two. Conclusions More research needs to be conducted into its health effects and toxicity potential. Health care professionals should be made aware of the potential health harms of MXE, in order to develop early intervention measures and minimise the number of MXE-related poisonings and fatalities. Copyright © 2015 John Wiley & Sons, Ltd.

John M Corkery, Peter Streete, Hugh Claridge, Christine Goodair, Duccio Papanti, Laura Orsolini, Fabrizio Schifano, Kanav Sikka, Sophie Körber, Amy Hendricks (2019)Characteristics of deaths associated with kratom use, In: Journal of Psychopharmacology33(9)pp. 1102-1123

Background: Kratom (Mitragyna speciosa Korth) use has increased in Western countries, with a rising number of associated deaths. There is growing debate about the involvement of kratom in these events. Aims: This study details the characteristics of such fatalities and provides a ‘state-of-the-art’ review. Methods: UK cases were identified from mortality registers by searching with the terms ‘kratom’, ‘mitragynine’, etc. Databases and online media were searched using these terms and ‘death’, ‘fatal*’, ‘overdose’, ‘poisoning’, etc. to identify additional cases; details were obtained from relevant officials. Case characteristics were extracted into an Excel spreadsheet, and analysed employing descriptive statistics and thematic analysis. Results: Typical case characteristics (n = 156): male (80%), mean age 32.3 years, White (100%), drug abuse history (95%); reasons for use included self-medication, recreation, relaxation, bodybuilding, and avoiding positive drug tests. Mitragynine alone was identified/implicated in 23% of cases. Poly substance use was common (87%), typically controlled/recreational drugs, therapeutic drugs, and alcohol. Death cause(s) included toxic effects of kratom ± other substances; underlying health issues. Conclusions: These findings add substantially to the knowledge base on kratom-associated deaths; these need systematic, accurate recording. Kratom’s safety profile remains only partially understood; toxic and fatal levels require quantification.

John M Corkery, Hugh Claridge, Christine Goodair, Fabrizio Schifano (2017)An exploratory study of information sources and key findings on UK cocaine-related deaths, In: Journal of Psychopharmacology31(8)pp. 996-1014

Cocaine-related deaths have increased since the early 1990s in Europe, including the UK. Being multi-factorial, they are difficult to define, detect and record. The European Monitoring Centre for Drugs and Drug Addiction commissioned research to: describe trends reported to Special Mortality Registries and General Mortality Registers; provide demographic and drug-use characteristic information of cases; and establish how deaths are identified and classified. A questionnaire was developed and piloted amongst all European Monitoring Centre for Drugs and Drug Addiction Focal Point experts/Special Mortality Registries: 19 (63%) responded; nine countries provided aggregated data. UK General Mortality Registers use cause of death and toxicology to identify cocaine-related deaths. Categorisation is based on International Classification of Diseases codes. Special Mortality Registries use toxicology, autopsy, evidence and cause of death. The cocaine metabolites commonly screened for are: benzoylecgonine, ecgonine methyl ester, cocaethylene and ecgonine. The 2000s saw a generally accelerating upward trend in cases, followed by a decline in 2009. The UK recorded 2700–2900 deaths during 1998–2012. UK Special Mortality Registry data (2005–2009) indicate: 25–44 year-olds account for 74% of deaths; mean age=34 (range 15–81) years; 84% male. Cocaine overdoses account for two-thirds of cases; cocaine alone being mentioned/implicated in 23% in the UK. Opioids are involved in most (58%) cocaine overdose cases.

Joan K. Morris, Ester Garne, Maria Loane, Ingeborg Barisic, James Densem, Anna Latos-Bieleńska, Amanda Neville, Anna Pierini, Judith Rankin, Anke Rissmann, Hermien de Walle, Joachim Tan, Joanne Emma Given, Hugh Claridge (2022)EUROlinkCAT protocol for a European population-based data linkage study investigating the survival, morbidity and education of children with congenital anomalies, In: BMJ Open11e047859

Introduction Congenital anomalies (CAs) are a major cause of infant mortality, childhood morbidity and long-term disability. Over 130 000 children born in Europe every year will have a CA. This paper describes the EUROlinkCAT study, which is investigating the health and educational outcomes of children with CAs for the first 10 years of their lives. Methods and analysis EUROCAT is a European network of population-based registries for the epidemiological surveillance of CAs. EUROlinkCAT is using the EUROCAT infrastructure to support 22 EUROCAT registries in 14 countries to link their data on births with CAs to mortality, hospital discharge, prescription and educational databases. Once linked, each registry transforms their case data into a common data model (CDM) format and they are then supplied with common STATA syntax scripts to analyse their data. The resulting aggregate tables and analysis results are submitted to a central results repository (CRR) and meta-analyses are performed to summarise the results across all registries. The CRR currently contains data on 155 594 children with a CA followed up to age 10 from a population of 6 million births from 1995 to 2014. Ethics The CA registries have the required ethics permissions for routine surveillance and transmission of anonymised data to the EUROCAT central database. Each registry is responsible for applying for and obtaining additional ethics and other permissions required for their participation in EUROlinkCAT. Dissemination The CDM and associated documentation, including linkage and standardisation procedures, will be available post-EUROlinkCAT thus facilitating future local, national and European-level analyses to improve healthcare. Recommendations to improve the accuracy of routinely collected data will be made.Findings will provide evidence to inform parents, health professionals, public health authorities and national treatment guidelines to optimise diagnosis, prevention and treatment for these children with a view to reducing health inequalities in Europe.

John M. Corkery, Christine Goodair, Hugh Claridge (2018)Synthetic Cathinones and Related Fatalities in the United Kingdom, In: Handbook of Novel Psychoactive Substances Routledge

In Chapter 11, “Synthetic Cathinones and Related Fatalities in the United Kingdom”, John M. Corkery, Christine Goodair, and Hugh Claridge present a comprehensive overview of synthetic cathinones, including use, morbidity, and mortality, while providing a comparison with other stimulants when possible. Authors also share unprecedented data on related fatalities in the United Kingdom over an extensive time scale.