Objective To determine time-trends in life expectancy (LE) of people with a severe mental illness (SMI) compared with the general population.

Design Observational population-based study.

Setting Scotland, 2000-2019. Linked psychiatric hospital admission and death records.

Participants Adults with a psychiatric hospital admission record for schizophrenia (28,797), bipolar disorder (16,657) or major depression (72,504) compared with the Scottish population (4.3 million adults in 2011).

Main outcome measures Trends over time in life years lost for people with schizophrenia, bipolar disorder or major depression compared with the Scottish population, for all deaths, and natural and unnatural deaths, stratified by sex.

Results Among people with SMI, one third died during the study period. Between 2000 and 2019, LE increased in the general Scottish population and the LE gap widened for people with schizophrenia. For 2000-2002, men and women with schizophrenia lost an excess 9.4 (95% CI 8.5 to 10.3) and 8.2 (7.4 to 9.0) life years, respectively, compared to the general population. In 2017-2019, this excess life years lost increased to 11.8 (10.9 to 12.7) and 11.1 (10.0 to 12.1) for men and women, respectively. There was no evidence of a change over time in the LE gap of 5 to 8 years for people with bipolar disorder or major depression. Changes in LE for natural and unnatural causes of death varied by individual SMI and sex.

Conclusions The LE gap in people with an SMI persisted or widened in Scotland from 2000-2019. These entrenched disparities reflect intersecting inequalities requiring coordinated solutions at multiple levels to improve LE in this and other marginalised and socially excluded groups.

What is already known on this topic

People with a severe mental illness (SMI) such as schizophrenia, bipolar disorder or major depression have a lower life expectancy (LE) than people without these conditions

This gap is largely due to natural causes, particularly cardiovascular disease

LE has increased for the general population but it is unclear whether the gaps in life expectancy for people with SMI have changed over time within the UK

What this study adds

The LE gap widened in people with schizophrenia and persisted for those with bipolar disorder and major depression in Scotland between 2000 and 2019

These findings reflect entrenched disparities in the LE of people with SMI

Multi-level and synergistic solutions are needed to address these disparities

All authors have completed the Unified Competing Interest form (available on request from the corresponding author) and declare: support from a Wellcome–TrustUniversity of Edinburgh Institutional Strategic Support Fund grant for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

This study was funded by a Wellcome Trust–University of Edinburgh Institutional Strategic Support Fund grant awarded to CJ. The funder had no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the article for publication.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Permission to conduct this study with pseudonymised, non-consented data was obtained from the Public Benefit and Privacy Panel of National Health Service National Services Scotland, reference number 1516-0626.

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

kelly.fleetwooded.ac.uk, r.alotaibisms.ed.ac.uk, sveunovonordisk.dk, d.smithed.ac.uk, sarah.wilded.ac.uk, caroline.jacksoned.ac.uk

Researchers can request access to the Scottish records used in this analysis by contacting the electronic Data Research and Innovation Service (eDRIS). Details of the available datasets and the application process are available from https://publichealthscotland.scot/services/data-research-and-innovation-services/electronic-data-research-and-innovation-service-edris. R scripts for the analyses presented in the paper are available at: https://github.com/kjfleetwood/le_smi_scot.

https://github.com/kjfleetwood/le_smi_scot