Time trends in life expectancy of people with severe mental illness in Scotland, 2000-2019: population-based study

People with severe mental illness (SMI) have a higher risk of premature mortality than the general population.

To investigate whether the life expectancy gap for people with SMI is widening, by determining time trends in excess life-years lost.

This population-based study included people with SMI (schizophrenia, bipolar disorder and major depression) alive on 1 January 2000. We ascertained SMI from psychiatric hospital admission records (1981-2019), and deaths via linkage to the national death register (2000-2019). We used the Life Years Lost (LYL) method to estimate LYL by SMI and sex, compared LYL to the Scottish population and assessed trends over 18 3-year rolling periods.

We included 28 797 people with schizophrenia, 16 657 with bipolar disorder and 72 504 with major depression. Between 2000 and 2019, life expectancy increased in the Scottish population but the gap widened for people with schizophrenia. For 2000-2002, men and women with schizophrenia lost an excess 9.4 (95% CI 8.5-10.3) and 8.2 (95% CI 7.4-9.0) life-years, respectively, compared with the general population. In 2017-2019, this increased to 11.8 (95% CI 10.9-12.7) and 11.1 (95% CI 10.0-12.1). The life expectancy gap was lower for bipolar disorder and depression and unchanged over time.

The life expectancy gap in people with SMI persisted or widened from 2000 to 2019. Addressing this entrenched disparity requires equitable social, economic and health policies, healthcare re-structure and improved resourcing, and investment in interventions for primary and secondary prevention of SMI and associated comorbidities.