Hair cortisol concentrations in decedents with severe mental illness – An autopsy-based cohort study

•Severe mental illness is associated with a reduction in life expectancy of up to 20 years.•Some of this excess mortality may be due to chronic physiological hypercortisolemia.•Hair cortisol concentrations may be a useful biomarker for measuring average levels of cortisol over longer time.•We found no association between psychiatric diagnosis and hair cortisol levels.•Hair cortisol was elevated in patients with a history of a prescription for either SSRI and/or benzodiazepine drugs.