Excess mortality by natural causes of Italian schizophrenic patients

The risk of mortality over a 5- to 8-year period for a total 1-year prevalence cohort of schizophrenic patients extracted by means of the South-Verona Psychiatric Case Register (Italy) was assessed using three methods: (1) case control with both non-psychotic patients and the general population matched for sex and age; (2) indirect standardization using mortality tables; (3) a recently described method using survival tables. All methods yielded an excess mortality associated with schizophrenia, close to the two-fold increase described in other studies, while the survival tables method produced a higher standardized mortality ratio (SMR). The increased SMR did not appear solely attributable to suicide. Most deaths were attributable to natural causes. This is a departure from other recently reported mortality studies. The possible reasons are discussed.