Older adults with schizophrenia and dementia: Analysis of a national dataset

Individuals with schizophrenia develop dementia in late life at higher rates than the general population. This is arguably explained by high rates of chronic medical conditions and exposure to antipsychotic medications. This risk has implications for public health. We aimed to test this in a large New Zealand database.

Participants in this study were New Zealanders aged 65 years or older who had an interRAI assessment completed during the study period (July 2013-June 2020). This cohort study analysed data from 168,780 individuals. The majority were European (87%), and mostly assessment was for home care (86%).

There were 2103 individuals with schizophrenia, 1.25% of the total sample, mean age of 75 years (±1.9) and 61% female. A minority of individuals with schizophrenia, 23%, also had a dementia diagnosis. At 82 years of age (±1.7) and 60% female, 25% of individuals without schizophrenia had a dementia diagnosis; the difference from rate of dementia in individuals with schizophrenia was not statistically significant.

These findings suggest that further study is needed about the processes that lead to dementia diagnoses in older individuals with schizophrenia.