Severe Mental Illness Among Adults with Atopic Eczema or Psoriasis: Population-Based Matched Cohort Studies within UK Primary Care

Elizabeth I Adesanya; Alasdair D Henderson; Julian Matthewman; Ketaki Bhate; Joseph F Hayes; Amy Mulick; Rohini Mathur; Catherine Smith; Helena Carreira; Sujit D Rathod; Sinéad M Langan; Kathryn E Mansfield

doi:10.2147/CLEP.S384605

Severe Mental Illness Among Adults with Atopic Eczema or Psoriasis: Population-Based Matched Cohort Studies within UK Primary Care

Clin Epidemiol. 2023 Mar 17:15:363-374. doi: 10.2147/CLEP.S384605. eCollection 2023.

Affiliations

¹ Department of Non-Communicable Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK.
² Division of Psychiatry, University College London, London, UK.
³ St John's Institute of Dermatology, Guys and St Thomas' Foundation Trust and King's College London, London, UK.
⁴ Department of Population Health, London School of Hygiene & Tropical Medicine, London, UK.

Abstract

Background: Existing research exploring associations between atopic eczema (AE) or psoriasis, and severe mental illness (SMI - ie, schizophrenia, bipolar disorder, other psychoses) is limited, with longitudinal evidence particularly scarce. Therefore, temporal directions of associations are unclear. We aimed to investigate associations between AE or psoriasis and incident SMI among adults.

Methods: We conducted matched cohort studies using primary care electronic health records (January 1997 to January 2020) from the UK Clinical Practice Research Datalink GOLD. We identified two cohorts: 1) adults (≥18 years) with and without AE and 2) adults with and without psoriasis. We matched (on age, sex, general practice) adults with AE or psoriasis with up to five adults without. We used Cox regression, stratified by matched set, to estimate hazard ratios (HRs) comparing incident SMI among adults with and without AE or psoriasis.

Results: We identified 1,023,232 adults with AE and 4,908,059 without, and 363,210 with psoriasis and 1,801,875 without. After adjusting for matching variables (age, sex, general practice) and potential confounders (deprivation, calendar period) both AE and psoriasis were associated with at least a 17% increased hazard of SMI (AE: HR=1.17,95% CI=1.12-1.22; psoriasis: HR=1.26,95% CI=1.18-1.35). After additionally adjusting for potential mediators (comorbidity burden, harmful alcohol use, smoking status, body mass index, and, in AE only, sleep problems and high-dose glucocorticoids), associations with SMI did not persist for AE (HR=0.98,95% CI=0.93-1.04), and were attenuated for psoriasis (HR=1.14,95% CI=1.05-1.23).

Conclusion: Our findings suggest adults with AE or psoriasis are at increased risk of SMI compared to matched comparators. After adjusting for potential mediators, associations with SMI did not persist for AE, and were attenuated for psoriasis, suggesting that the increased risk may be explained by mediating factors (eg, sleep problems). Our research highlights the importance of monitoring mental health in adults with AE or psoriasis.

Keywords: dermatology; epidemiology; psychology.

Grants and funding

EA was funded by a British Skin Foundation (BSF) PhD studentship (Reference: 024/S/18). SML was supported by a Wellcome Trust Senior Research Fellowship in Clinical Science (205039/Z/16/Z). JFH is supported by a UK Research and Innovation (UKRI) grant (Reference: MR/V023373/1), the University College London Hospitals NIHR Biomedical Research Centre and the NIHR North Thames Applied Research Collaboration. This study is funded by the NIHR Research for Patient Benefit programme (Reference: PB-PG-0418-20025). The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care. SML was also supported by Health Data Research UK (Grant number: LOND1), which is funded by the UK Medical Research Council, Engineering and Physical Sciences Research Council, Economic and Social Research Council, Department of Health and Social Care (England), Chief Scientist Office of the Scottish Government Health and Social Care Directorates, Health and Social Care Research and Development Division (Welsh Government), Public Health Agency (Northern Ireland), British Heart Foundation and Wellcome Trust. CS and SML are investigators on the European Union Horizon 2020-funded BIOMAP Consortium (http://www.biomap-imi.eu/). Funders had no role in the study design, collection, analysis, and interpretation of data; in the writing of the report; and in the decision, submit the article for publication. This research was funded in whole or in part by the Wellcome Trust [205039/Z/16/Z]. For the purpose of Open Access, the author has applied a CC BY public copyright licence to any Author Accepted Manuscript (AAM) version arising from this submission.