Self Harm in New Zealand: Perspectives on Hospital Presentations and National Trends Across the Lifespan

Background: According to the World Health Organization, every year, roughly 800,000 people die due to suicide, which is one person every 40 seconds. It has also been shown that many more attempt suicide. Suicide is the third leading cause of death globally among 15–29 years olds (WHO, 2019). Self-harm (SH) is one of the most important risk factors for suicide and hence a better understanding of SH and a focus on adequate resources for individuals who engage in SH are of great importance to achieve the goal of reducing suicide. This study has evaluated the clinical demographics of the individuals who presented to the hospital from urban and rural areas in and around Invercargill, New Zealand. It also studied the SH in children and young adolescents who presented to the hospital. This study has also evaluated five year national trends in SH in individuals below 15 years of age and whether there was clustering of SH in Invercargill, and to see if socioeconomic deprivation was a variable contributing to SH. Methods: This study was a retrospective file audit between 1st January 2011 and 31st December 2012 conducted at the Southland Hospital, Invercargill, New Zealand. The comparison of rates of SH from urban and rural population in Southland and the SH in children and adolescents was carried out from this data. We also obtained a New Zealand national data set from 2008-2012 for all individuals below the age of 15 years who presented to the hospital with SH along with the diagnostic details, demographic details and deprivation scores. Age specific rates of SH were calculated using 2013 census data. Factors associated with repeated SH were evaluated using an exploratory generalised linear model. The residential addresses of the anonymised data was collected. Land parcels for Invercargill were obtained from the Land Information New Zealand online database. The residential parcels were selected and then assessed by area, with the smallest 5% and largest 5% of parcels removed. By doing this, schools, recreational areas and other parcels that were filling spaces but were not accessible as polygons for residences were excluded. Using Google Maps to visually assess and remove parcels that were shops or industrial areas further reduced the study area. By doing this, a total of 16,516 residential parcels were generated and it was used as possible residential addresses. It was then evaluated to see whether clustering of SH was present and if socioeconomic derivation was a variable contributing to SH. Findings: SH was more frequently seen in people from urban areas, in females, and in single, less educated and those who were unemployed in the urban participants. Urban Māori were more likely to attend hospital with SH compared to Māori from the rural areas. SH was noted in children between the ages of 9-15 years in the study and there was a preponderance of SH in females and in young individual with a family history of SH/suicide, history of childhood abuse, parental breakup and difficult relationships/arguments (parents, boyfriends and girlfriends). Psychiatric comorbidity, previous history of SH school/academic problems school bullying, recent alcohol, cannabis and synthetic cannabis use were other factors associated with SH in children and young adolescents. In the multi year national trends of SH, it was noted that SH was rare before the age of 11 years and case numbers increased exponentially. Overdose was the most common method of SH in youth of New Zealand and an association of SH with deprivation scores was observed. A higher incidence of psychiatric diagnosis was noted in the individuals with multiple episodes of SH. Hanging and strangulation as means of SH was more common among Māori compared to non Māori. An overall 113% increase was noted in SH cases over five years. The study also found a clustering up to ~500m, suggesting a social contagion. Deprivation index was noted to be contributing to clustering of SH. Funding: This research received no specific funding