Change in the life expectancy gap among people with mental illness: a 14-year population-based cohort study in Australia.

BACKGROUND

People with psychiatric disorders die substantially earlier than the general population, with life expectancy gaps of 10-20 years reported internationally. Prior Australian data indicated this gap was widening, whereas evidence from other countries has been mixed. We aimed to determine whether the life expectancy gap in people with hospitalised psychiatric disorders versus the general population is changing in Queensland, Australia, and to identify which causes of death drive excess mortality.

METHODS

We conducted a retrospective population-based cohort study using linked Queensland hospital admissions and death registry data. Adults (≥18 years) with a principal psychiatric diagnosis across seven diagnostic categories were included, excluding dementia. Life expectancy was estimated using life-table methods and compared to Queensland norms. We calculated standardised mortality ratios (SMRs) across four time-periods and quantified the absolute and proportional contribution of specific causes to excess mortality using excess mortality rates per 100,000 person-years and attributable fractions.

FINDINGS: The analytic cohort comprised 255,448 individuals contributing 2,204,719 person-years. The life expectancy gap narrowed significantly for both sexes (p < 0·001): from 13·4 to 9·4 years in females and 16·7 to 12·1 years in males. All-cause SMRs declined from 2·35 (95% CI 2·23-2·47) to 1·73 (1·67-1·79) in females and 3·12 (2·98-3·25) to 2·10 (2·04-2·16) in males. The gap did not narrow significantly in either sex among people with schizophrenia or other psychoses, in females with affective psychoses, or in females with neurotic or alcohol and substance use disorders. Although intentional self-harm was the largest single contributor to proportional excess mortality in males, the combined excess mortality rate from physical health causes was substantially greater than from self-harm (440·0 and 441·9 versus 163·7 and 83·5 per 100,000 person-years in males and females respectively).

INTERPRETATION: The life expectancy gap between people with psychiatric disorders and the general population in Queensland has narrowed over 14 years, although the absolute gap remains considerable, and people with schizophrenia and related psychotic disorders have not shared equally in these gains. Physical illness is the principal driver of excess mortality, therefore prioritising physical health care for people with mental illness is essential to closing the gap, especially in psychotic disorders.

FUNDING: None.