A novel approach for evaluating and comparing multiple antipsychotic polypharmacy in adults across specialist intellectual disability services in England and Wales: A retrospective feasibility cohort study

Authors

• Samuel J. Tromans, Adult Learning Disability Service, Leicestershire Partnership NHS Trust, UK
• Helen Neilens, University of Plymouth
• Crispin Musicha, Peninsula Medical School
• Victoria Allgar, Peninsula Medical School
• Emily Stanyard, Medical Statistics Group, University of Plymouth, Plymouth, UK
• Richard Laugharne, Peninsula Medical School
• Paula McGowan, Peninsula Medical School
• Angela Hassiotis, University College London
• Sarah Lennard, Peninsula Medical School
• Lance V. Watkins, University of Plymouth
• Bhathika Perera, University College London
• Kiran Purandare, Central and Northwest London NHS Foundation Trust, UK
• Ashok Roy, Coventry and Warwickshire Partnership Trust, Birmingham, UK
• Indermeet Sawhney, Hertfordshire Partnership University NHS Foundation Trust Hatfield, UK
• Sujeet Jaydeokar, Cheshire and Wirral Partnership NHS Foundation Trust, Chester, UK
• Ryan Ashford, Medical Statistics Group, University of Plymouth, Plymouth, UK
• Chris Rollinson, Peninsula Medical School
• Hanna Abraham, Medical Statistics Group, University of Plymouth, Plymouth, UK
• Nusra Khodabux, Adult Learning Disability Service, Leicestershire Partnership NHS Trust, UK
• Ogheneochuko Akusu, Adult Learning Disability Service, Leicestershire Partnership NHS Trust, UK
• Samuel Paisley, North East London NHS Foundation Trust
• Georgios Mousailidis, Hertfordshire Partnership University NHS Foundation Trust Hatfield, UK
• Meera Naran, De Montfort University, Leicester, UK
• Rohit Shankar, Peninsula Medical School

ORCID

• Crispin Musicha: 0000-0003-0482-3218
• Victoria Allgar: 0000-0002-5228-2623
• Sarah Lennard: 0000-0001-9033-6752
• Lance V. Watkins: 0000-0002-0447-5906
• Chris Rollinson: 0000-0002-9378-251X
• Rohit Shankar: 0000-0002-1183-6933

Abstract

Background:In England and Wales, significant numbers of people with intellectual disability (PwID) are prescribed antipsychotics for a range of licensed and non-licensed indications, particularly behaviours that challenge. There is no system to compare antipsychotic prescribing practices across specialist adult intellectual disability (ID) services.Aim:This study aimed to determine whether converting antipsychotics and their doses to equivalent chlorpromazine units enables comparison of licensed (psychosis, etc.) and non-licensed (behaviours that challenge) prescribing between different services.Method:A feasibility retrospective cohort study using convenience sampling captured anonymized data of PwID on ⩾2 antipsychotics across eight specialist England and Wales adult ID services. The doses prescribed across 2017–2023 were converted to chlorpromazine-equivalent values, and antipsychotic dose burden across services was compared. Patients’ characteristics and antipsychotic dosing are summarized descriptively. A mixed-effects regression model determines changes in chlorpromazine unit values across time. Subgroup analysis explores trends. Stata: Release 17 (StataCorp, 2021) and R (R Core Team, 2025) were used.Results:Of the 424 reviewed records, a higher proportion were male (ranging from 58% to 71% across census years) and white individuals (73%–85%). Autism (42%–58%), psychotic illness (61%–71%), and behaviours that challenge (77%–87%) were the most common comorbidities. Chlorpromazine units could be captured for 98% (n = 416). PwID with psychosis, behaviours that challenge, depression, or attention-deficit/hyperactivity disorder were prescribed significantly higher chlorpromazine-equivalent doses. Over 25% were prescribed more than 1000 mg/day chlorpromazine equivalent, which exceeds the British National Formulary-recommended maximum dose.Conclusions:Our study suggests that converting antipsychotic doses to chlorpromazine units is a simple and effective way to understand and compare prescribing burden for PwID. It also facilitates measuring prescribing and implementing best practice.

DOI Link

10.1177/02698811261478609

Publication Date

2026-08-31

Publication Title

Journal of Psychopharmacology

ISSN

0269-8811

Deposit Date

2026-08-31

Funding

The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Baily Thomas Charitable Fund

Additional Links

https://journals.sagepub.com/doi/10.1177/02698811261478609

Keywords

learning disability, neurodevelopmental psychiatry, antipsychotic, behaviours that challenge, chlorpromazine equivalent, conversion tool

Creative Commons License

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License

Recommended Citation

Tromans, S., Neilens, H., Musicha, C., Allgar, V., Stanyard, E., Laugharne, R., McGowan, P., Hassiotis, A., Lennard, S., Watkins, L., Perera, B., Purandare, K., Roy, A., Sawhney, I., Jaydeokar, S., Ashford, R., Rollinson, C., Abraham, H., Khodabux, N., Akusu, O., Paisley, S., Mousailidis, G., Naran, M., & Shankar, R. (2026) 'A novel approach for evaluating and comparing multiple antipsychotic polypharmacy in adults across specialist intellectual disability services in England and Wales: A retrospective feasibility cohort study', Journal of Psychopharmacology, . Available at: 10.1177/02698811261478609