Those with schizophrenia died on average 11 years earlier than those without in 2019, compared with a difference of nine years in 2000.
Researchers also found no improvement in the life expectancy gap between those with major depression or bipolar disorder and the general population over the same time period.
Most of the premature deaths were due to natural causes, reflecting the poorer physical health of those with a severe mental illness, experts say.
Persistent gap
Researchers from the University of Edinburgh used two decades of data – from 2000 to 2019 – to examine gaps in life expectancy over time for 118,000 people with schizophrenia, bipolar disorder or major depression in Scotland.
Despite people generally living longer in 2019 than in 2000, there is a persistent gap in life expectancy between those with and without a mental health condition.
Between 2000 and 2002, men and women with schizophrenia lost an excess 9.4 and 8.2 life years respectively, compared with the general population. Between 2017 to 2019, this had increased to 11.8 and 11.1 years.
The life expectancy gap for those with major depression or bipolar disorder remained relatively steady across the same 20-year period. Based on most recent years, the life expectancy of those with either condition is around seven years shorter than those without a severe mental illness.
Contributing factors
The shorter life span of those with a severe mental illness is influenced by several factors, including a higher risk of multiple physical health issues, low socioeconomic status and higher rates of smoking.
Taking a combined approach to managing both mental and physical health could help to improve care and outcomes, experts say.
The study did not include data for the period 2020-2024, covering the pandemic, but scientists warn that reports of higher Covid-19 mortality in people with a severe mental illness suggest the life expectancy gap may have widened further in recent years.