Premature mortality in adults using New Zealand psychiatric services

People with experience of mental illness, in particular those accessing mental health services, have increased mortality compared to the general population, but no studies have examined the situation in New Zealand. This study uses a complete national dataset to estimate mortality rates from natural and external causes for adults using psychiatric services compared to the general New Zealand population.

Routinely collected data on adults aged 18-64 using secondary mental health services between January 2002 and December 2010 were linked to death registrations over the same period. Indirect standardisation was used to estimate the mortality ratio (SMR) for those with any contact with mental health services over this period compared to the New Zealand population.

Both men and women using mental health services in New Zealand have more than twice the mortality rate of the total population [combined SMR 2.14 (95% CI 2.09-2.19)], with an increased risk of death from cancer and cardiovascular disease [SMRs=1.31(1.24-1.37), and 1.69 (1.60-1.79) respectively], and external causes (suicide and accidents) [SMR 3.11 (3.00-3.23)]. People with a diagnosis of a psychotic disorder had three times the overall death rate of the population.

This study confirms that those using mental health services in New Zealand are dying prematurely from both natural and external causes, and provides evidence which supports calls for coordinated action on this issue.