Investigating the Mental-Physical Health Interface Using National Register-based Data

While existing research has convincingly demonstrated that many mental and physical health conditions do oftentimes co-occur together, the causality between distinct pairs of mental and physical health conditions as well as the outcomes resulting from the co-occurrence of these, remain incompletely described and understood. In the present thesis, I have set out to answer a set of questions connected to both the aetiology and consequences of co-occurring mental and physical health conditions, particularly using national register-based health data. Concerning the aetiology, I present novel evidence that the extensive psychiatric morbidity in childhood-onset type 1 diabetes is unlikely to be fully explicable by common underlying biological mechanisms, but at least part of the associations between rheumatoid arthritis and depression, schizophrenia, and Alzheimer’s disease might be a consequence of such mechanisms and/or disease related factors such as medication effects. Concerning the consequences of co-occurring mental and physical health conditions, I have demonstrated higher risks of mortality and larger losses of life-years in both people with substance use disorders and severe mental illnesses following the onset of a wide range of physical health conditions compared with counterparts who only had the respective physical health condition. In people with severe mental illness, I have showed that this excess mortality exceeds what could be attributed to having more physical comorbidity in this patient group. Further related to consequences of co-occurring mental and physical health conditions, I have showed that the elevated risk of post-SARS-CoV-2 infection mortality in people with substance use and psychotic disorders, demonstrated in a number of previous studies, persisted even after control for clinically-recorded physical illness, including at the later phases of the pandemic. Taken together, the findings of this thesis align with the notion that the old-fashioned silos between mental and physical healthcare are not reflective of empirical reality and are leading to unnecessary losses of human lives. Identifying ways of providing holistic care for mental and physical health conditions that is feasible, acceptable, affordable, effective, and, crucially, sustainable, thus constitutes probably one of the greatest challenges for medicine.

Name dc:type.qualificationname

Doctor of Philosophy (PhD)

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

University of Cambridge

Year dc:date.issued

2024

Author dc:creator

• Formánek, Tomáš

Advisor dc:contributor.advisor

• Jones, Peter

• Causal inference
• Evidence triangulation
• Life-years lost
• Mental disorders
• Mortality
• Observational data
• Somatic comorbidity

Licence

• https://www.repository.cam.ac.uk/bitstreams/4838a64a-acbe-4c75-ba7b-e78d82fbeb11/download
• https://creativecommons.org/licenses/by/4.0/

Language dc:language

eng

DOI dc:identifier.doi

https://doi.org/10.17863/CAM.117409

OAI identifier oai:identifier

oai:www.repository.cam.ac.uk:1810/382758