Abstract
The findings the latest National Survey of Mental Health and Wellbeing (NSMHW) reported in the July 2009 edition of the journal present an interesting contrast to the official statistics for suicide in Australia. The latest survey suggests that the number of people in Australia with any form of mental illness was similar to the previous survey [1] and the proportion of people identified as having a mental illness who were receiving treatment was 34.9% in 2007, compared to 32.5% in 1997 [2]. Furthermore, the proportion of Australians reporting suicidal ideas or a suicide attempt had also barely changed, because the 1997 survey found a 12-month prevalence of suicidal ideation of 2.9% and that 0.3% of the population had attempted suicide [3], and in 2007 those figures were 2.3 and 0.4%, respectively [4]. However, in the 10 years between the surveys the number of deaths recorded as suicide declined dramatically. According to Australian Bureau of Statistics (ABS) there were 2,720 suicide deaths in 1997, a rate of 14.7 per 100,000, which fell to 1880 deaths in 2007, a rate of 8.9 per 100,000 [5–7].
We examined figures provided by the ABS for the methods used to commit suicide, using the International Classification of Diseases (ICD) 10 codes for the period 1997 – 2007. Suicide rates were calculated for hanging, strangulation and suffocation (X70); non-gas poisoning (X61, X66, X68 and X69); poisoning with gas (X67); use of firearm or explosive (X72 – X75); jumping from a height (X80); self-stabbing and cutting (X78); and drowning (X71) for each state and territory. A residual category of suicides by other methods was calculated by subtracting the figures for the sum of the seven main methods from the annual total for each state and territory.
ABS figures for the populations of males and females in June of each year in each state and territory were used to calculate annual non-age-adjusted suicide rates [8]. The sum of the suicides and populations in each year of each decade was used to calculate male and female suicide rates. Changes in rates of male (Figure 1) and female (Figure 2) suicide by method were plotted as a stacked area chart.
Suicide methods by males 1997–2007.
Suicide methods by females 1997–2007.
Although there has been some debate about the completeness of the ABS suicide figures and several publications discussing the reasons for an under-reporting of suicides, the error rate is unlikely to have changed significantly over the 10 years between the 1997 and 2007 surveys. Moreover, relatively few of the suicides using methods in which there was the greatest decline, such as self-shooting, would not have been counted as suicides. An examination of the changes in the methods used to commit suicide indicates a decline in suicide by methods in which the availability of lethal means has been restricted, for example, the reduced availability of firearms since the firearms ‘buy back’ scheme, [9,10] the introduction of catalytic converters in all new cars [11] and the decline in use of tricyclic antidepressants [12]. The ABS figures show only limited substitution to other readily available lethal means, such as hanging and jumping from a height.
This examination of changes in the methods used to commit suicide suggests that the best way to further reduce the rate of suicide is to further reduce the availability of lethal means, rather than by increasing the number of people with psychiatric disorders who are receiving treatment or by trying to guess who might commit suicide. These measures include further restrictions in the availability of firearms, increasing the regulation of medications that have been used in fatal overdoses, installing physical barriers at well-known jumping points [13], improved observation in psychiatric hospitals and lockups and any measure that reduces alcohol abuse [14]. A further period of economic prosperity of the kind enjoyed in the 10 years up to 2007 might also be accompanied by a further decline in the rates of suicide.