ArticleThe British journal of psychiatry : the journal of mental science2021
Clozapine treatment and risk of COVID-19 infection: retrospective cohort study.
Article in The British journal of psychiatry : the journal of mental science, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 61 papers, 7 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
61 citing papers in PubMed, 7 syntheses or guidelines pooled it, 93 citations in OpenAlex.
- Vaccination and clozapine use: a systematic review and an analysis of the VAERS database.European archives of psychiatry and clinical neuroscience · 2025Pooled it
- Clozapine Therapy and COVID-19: A Systematic Review of the Prevalence Rates, Health Outcomes, Hematological Markers, and Patient Perspectives.Schizophrenia bulletin · 2023Pooled it
- Psychotropic drug repurposing for COVID-19: A Systematic Review and Meta-Analysis.European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology · 2023Pooled it
- Ethnic disparities in clozapine prescription for service-users with schizophrenia-spectrum disorders: a systematic review.Psychological medicine · 2022Pooled it
- Association Between Mood Disorders and Risk of COVID-19 Infection, Hospitalization, and Death: A Systematic Review and Meta-analysis.JAMA psychiatry · 2021Pooled it
- The association of smoking status with SARS-CoV-2 infection, hospitalization and mortality from COVID-19: a living rapid evidence review with Bayesian meta-analyses (version 7).Addiction (Abingdon, England) · 2021Pooled it
- Toxicity of psychotropic drugs in patients with COVID-19: A systematic review.General hospital psychiatryPooled it
- Hospitalisation and mortality outcomes after second COVID-19 vaccination among Australians living with severe mental illness: Findings from a matched case-control study using national data linkage.The Australian and New Zealand journal of psychiatry · 2026Observational
- Factors associated with infection-related hospitalisations in severe mental illness: a retrospective cohort study.BMJ mental health · 2026Article
- A study on the effect of COVID-19 infection on the serum concentration of antipsychotic drugs.BMC psychiatry · 2025Article
- COVID-19 disease outcomes in patients receiving clozapine versus other antipsychotics: a national study in Qatar.Frontiers in psychiatry · 2025Article
- Sodium Valproate Use in Japanese Patients with Schizophrenia and Coronavirus Disease Is Associated with an Increased Risk of Pneumonia.Journal of clinical medicine · 2023Article
- COVID-19 pandemic in the intensive care unit: Psychological implications and interventions, a systematic review.World journal of psychiatry · 2023Article
- Links between COVID-19 and Parkinson's disease/Alzheimer's disease: reciprocal impacts, medical care strategies and underlying mechanisms.Translational neurodegeneration · 2023Review
- Dementia and psychotropic medications are associated with significantly higher mortality in geriatric patients hospitalized with COVID-19: data from the StockholmGeroCovid project.Alzheimer's research & therapy · 2023Observational
- COVID-19 Vaccines and the Virus: Impact on Drug Metabolism and Pharmacokinetics.Drug metabolism and disposition: the biological fate of chemicals · 2023Review
- Infections associated with clozapine: a pharmacovigilance study using VigiBaseFrontiers in pharmacology · 2023Article
- The Impacts of Clozapine Use on the Risk and Outcomes of COVID-19 Disease in Patients with Schizophrenia.Noro psikiyatri arsivi · 2023Article
- Modifiable contributing factors to COVID-19: A comprehensive review.Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association · 2023Review
- Clozapine and COVID-19 Vaccination: Effects on blood levels and leukocytes. An observational cohort study.Acta psychiatrica Scandinavica · 2022Observational
1 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
5 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundClozapine, an antipsychotic with unique efficacy in treatment-resistant psychosis, is associated with increased susceptibility to infection, including pneumonia.
aimsTo investigate associations between clozapine treatment and increased risk of COVID-19 infection in patients with schizophrenia-spectrum disorders who are receiving antipsychotic medications in a geographically defined population in London, UK.
methodUsing information from South London and Maudsley NHS Foundation Trust (SLAM) clinical records, via the Clinical Record Interactive Search system, we identified 6309 individuals who had an ICD-10 diagnosis of schizophrenia-spectrum disorders and were taking antipsychotics at the time of the COVID-19 pandemic onset in the UK. People who were on clozapine treatment were compared with those on any other antipsychotic treatment for risk of contracting COVID-19 between 1 March and 18 May 2020. We tested associations between clozapine treatment and COVID-19 infection, adjusting for gender, age, ethnicity, body mass index (BMI), smoking status and SLAM service use.
resultsOf 6309 participants, 102 tested positive for COVID-19. Individuals who were on clozapine had increased risk of COVID-19 infection compared with those who were on other antipsychotic medication (unadjusted hazard ratio HR = 2.62, 95% CI 1.73-3.96), which was attenuated after adjusting for potential confounders, including clinical contact (adjusted HR = 1.76, 95% CI 1.14-2.72).
conclusionsThese findings provide support for the hypothesis that clozapine treatment is associated with an increased risk of COVID-19 infection. Further research will be needed in other samples to confirm this association. Potential clinical implications are discussed.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.