The prevalence of late-life mental disorders in New Zealand and Austrlia is still unknown. Austalian and New Zealand researchers have engaged with the challenge of estimating population rates of mental disorders over the last 20 years. One outcome of this work has been the provision of estimates of how these rates may differ between age-group cohorts.
Snowdon, J., Almeida, O. P., & O'Connor, D. W. (2016). Dubious findings concerning the prevalence of late-life depression. Australian & New Zealand Journal of Psychiatry, 50(3), 284-285. https://doi.org/10.1177/0004867415583701