Psychiatric hospitalisation and suicide among the very old in Denmark: population-based register study

BACKGROUND: Very old people have higher suicide rates than the younger elderly population. Psychiatric disorders are known to have a strong association with suicide among elderly people.

AIMS: To analyse the analyse the suicide risk associated with psychiatric hospitalisation among the very old (> or =80 years) compared with the middle-aged (50-64 years) and old (65-79 years) populations.

METHOD: Individual-level data on the entire Danish population aged 50 years or over were analysed for the period 1994-1998. Relative suicide risks were calculated using event-history analysis.

RESULTS: Among 1978 527 persons, 2323 died by suicide. Although the very old group exhibited a four-fold to five-fold increase in risk of suicide for those previously hospitalised, we noted an inverse interaction effect: the increase is distinctly smaller compared with that in the middle-aged and old groups.

CONCLUSIONS: The association between suicide and psychiatric hospitalisation is much weaker for the very old than for the old. Psychiatric disorders among very old people may be interacting with other disorders, may be underdiagnosed or treated in other healthcare settings.