BACKGROUND: Individuals with schizophrenia (SCZ) suffer from higher morbidity and mortality than the general population. Some of this is due to concurrent somatic disease.

AIMS: To identify and compare the somatic comorbidities antemortem (AM) and postmortem (PM) in autopsied decedents with SCZ and with no mental illness (NMI), using the Charlson Comorbidity Index (CCI).

MATERIALS: A total of 106 autopsied decedents with SCZ and 156 decedents with NMI were included. AM diagnoses were sampled from Danish national health registers. PM diagnoses were included from forensic autopsies. Negative binomial regression models were used to test associations between age, sex, SCZ diagnosis, manner of death and the CCI score both AM and PM.

RESULTS: The CCI score increased significantly from AM to PM for both decedents with SCZ and NMI (SCZ, AM 0.669 vs PM 1.208, p = 0.008) (NMI, AM 0.519 vs PM 1.218, p = 0.000). Regression analysis showed that age was significantly associated with the CCI score both AM and PM (AM, OR 1.044 [1.029-1.060] p ≤ 0.001) (PM, OR 1.028 [1.015-1.041], p ≤ 0.001). A diagnosis of SCZ was correlated with the CCI score AM but not PM (AM, OR 1.880 [1.207-2.928], p = 0.005) (PM, OR 1.170 [0.828-1.654], p = 0.374).

CONCLUSION: The autopsies revealed undiagnosed diseases in both decedents with SCZ and NMI. The diseases were primarily of cardiovascular, pulmonary and gastrointestinal origin and may have contributed to premature mortality. Age was the only covariate significantly associated with the CCI score both AM and PM; the SCZ diagnosis was positively correlated to the CCI score before death.