Investigating the factors contributing to suicidal behaviour in older New Zealanders

Abstract

Background Globally, suicide rates increase with age between the ages of 60 and 90 years. In New Zealand, men aged ≥85 years had the highest suicide rates among all age groups between 2008 and 2017. This thesis systematically investigates the factors associated with suicidal behaviours along the suicidality continuum (death wish, suicide attempt and completed suicide) in older New Zealanders. Methods Four key studies were performed: 1. A cross-sectional study on the predictors of death wishes in older people assessed for home support and long-term aged residential care. 2. A retrospective cohort study on the characteristics of older people presenting with selfharm to emergency departments. 3. A study using coroner records investigating the characteristics of older people who died by suicide. 4. A mixed-method study using coroner records exploring the characteristics of older people with and without terminal cancer who died by suicide. Results 1. Depression, loneliness and poor self-reported health had the greatest association with death wishes in this sample. 2. Perceived physical illness was the most common stressor associated with self-harm in this sample. Older people who had a positive blood alcohol reading were more likely to repeat self-harm/suicide within 12 months. 3. The older the person, the less likely they were to have contact with psychiatric services in the month prior to suicide. However, most older people had had contact with their general practitioner within one month of suicide. 4. Older people with terminal cancer who died by suicide were less likely to have had a diagnosis of depression than those without terminal cancer. Of the terminal cancer cases, 82.6% had a motivational basis that would be understandable to uninvolved observers and resemble rational suicide. Conclusions This thesis has identified depression, physical illness and alcohol as important contributors of late-life suicidal behaviour. Primary care could be the setting for screening depression and suicide risks, particularly for those who are suffering from physical illness. Older people with terminal illness and poor quality of life may choose to end their life to alleviate their suffering, but future studies are needed to clarify the role of depression in these cases.