Cause-specific mortality among patients with psychosis: disentangling the effects of age and illness duration.

Background: There is a large mortality gap between patients with a nonaffective psychotic disorder and those in the general population, is associated with both natural and nonnatural death causes.

Objective: This study aims to assess whether mortality risks vary for different causes of death according to the duration since diagnosis and age in a large sample of patients with nonaffective psychotic disorder.

Methods: Data of patients with nonaffective psychotic disorder (n = 12,580) from 3 Dutch psychiatric registers were linked to the cause of death register of Statistics Netherlands and compared with personally matched controls (n = 124,143) from the population register. Death rates were analyzed by duration since the date of the registered diagnosis of the (matched) patient and their age using a Poisson model.

Results: Among patients, the rates of all-cause death decreased with longer illness duration. This was explained by lower suicide rates. For example, among those between 40 and 60 years of age, the rate ratios (RR) of suicide during 2-5 and > 5 years were 0.52 and 0.46 (p = 0.002), respectively, when compared with the early years after diagnosis. Compared with controls, patients experienced higher rates of natural death causes during all stages and in all age categories, rate ratios 2.35-5.04; p < 0.001-0.025. There was no increase in these rate ratios with increasing duration or increasing age for patients when compared with controls.

Conclusions: The high risk of natural death causes among patients with nonaffective psychotic disorder is already present at a comparatively young age. This suggests caution in blaming antipsychotics or the accumulating effects of adverse lifestyle factors for premature death. It is better to proactively monitor and treat somatic problems from the earliest disease stages onward.