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Australian suicide trends 1964-1997: youth and beyond?

Christopher H Cantor and Kerryn Neulinger
Med J Aust 1999; 171 (3): 137-141.
Published online: 2 August 1999
Research

Australian suicide trends 1964-1997: youth and beyond?

Christopher H Cantor, Kerryn Neulinger and Diego De Leo

MJA 1999; 171: 137-141

Abstract - Introduction - Methods - Results - Discussion - Acknowledgements - References - Authors' details
- - More articles on Psychiatry


Abstract Objective: To examine Australian suicide rates across all ages, and compare Australian rates with those of other Western nations.
Design: Australian Bureau of Statistics data were used to examine Australian suicide trends, 1964-1997, by age and sex. For comparison, suicide rates of 22 other Western nations, 1990-1994, were obtained from the World Health Organization.
Results: Australian suicide rates for males 15-24 years and 25-34 years rose from 1964-1997. Comparable rates for females showed no significant change. Suicide rates for several of the older age and sex groups declined over this period. Comparison with suicide rates of other Western nations showed that, while Australian youth suicide rates are relatively high, this is not the case for older age groups. Australian suicide rates are higher than those in the European nations of origin of our major migrant groups, but similar to those of other Western nations also recently colonised by Europeans (Canada, the United States and New Zealand).
Conclusions: Priorities for suicide prevention in Australia are correctly concentrated on youth, but the targeted age range should be extended to include men aged 25-34 years. A comprehensive policy should also not neglect the needs of other age groups. Further epidemiological study of national and international data may suggest new approaches to suicide prevention.


Introduction It is well known that there is a high suicide rate in Australian males aged 15-24 years, and previous and present governments have instituted committees to address youth suicide rates.1 There have been only sporadic reports of suicide rates in other age groups,2 including suggestions of high rates in elderly people.2,3

We present suicide rates and trends across all ages, placing them in context by comparing them with rates from other Western nations. The national focus on youth suicide to the relative exclusion of older age groups is examined in the light of these data.


Methods

Australian suicide

and population data for 1964-1997 were obtained from the Australian Bureau of Statistics (ABS) and annual suicide rates (per 100 000 estimated mean resident population) were calculated (see Appendix). These were plotted by 10-year age groups and sex over time. Change over time was examined by comparing the suicide rate in 1964-1966 (rates were averaged to smooth out random fluctuations within one-year periods) with the suicide rate in 1995-1997; 95% confidence intervals were calculated for these two time periods to assess the significance of change. Variations in suicide rate trends over this 34-year period were assessed by calculating the series autocorrelation suicide rates and the values of Pearson's correlation coefficient.

Years of potential life lost (YPLL) were calculated for 10-year age and sex groups for the most recent year (1997). The formula used was adapted from that used by the Australian Bureau of Statistics4 in order to incorporate age groups (Box 1). The Australian population at 30 June 1991 was chosen as the standard population, as suggested by the Australian Bureau of Statistics.

International data were obtained from the World Health Organization (WHO)5-8 and Lester and Yang.9 Mean suicide rates were calculated for 23 Western countries (including Australia), averaged over 1990-1994, for 10-year age and sex groups. These 10-year age and sex rates were then ranked to compare Australia with other nations.


Results Figures 1-8 show suicide rates over time for sex and 10-year age groups, as well as all ages combined.

Males

  • Suicide rates overall and for those aged 15-24 and 25-34 years increased significantly over time (1964-1966 to 1995-1997).

  • The rise in suicide rates from 1973-1997 for men aged 25-34 years was of similar magnitude to the rise for those aged 15-24 years (Figures 2 and 3).

  • Suicide rates in the older age groups (35 to 75 years and over) declined (for men aged 35-44 years and 75 years and over these declines were not statistically significant).

  • Significant autocorrelations (P < 0.01) were found in each age group and for all ages combined.

    Females

  • Suicide rates overall and for each age group from 25 to 75 years and over declined significantly (1964-1966 to 1995-1997).

  • There was no change in suicide rates for females aged 15-24 years.

  • Significant autocorrelations
  • (P < 0.01) were found for all ages combined and for most age groups (the exceptions were those aged 15-24 years and 75 and over).

    Years of potential life lost by suicide in 1997 are shown in Box 2.

    Boxes 3a and 3b list the mean suicide rates (per 100 000 population) by age group and sex for 23 Western nations, including Australia.


    Discussion The priority accorded to youth suicide prevention by successive Australian governments is supported by our data. In the last three decades, when overall suicide rates were falling, the suicide rate of males 15-24 years more than doubled. Suggestions of a plateauing of this rate since 1989 are not supported by the latest figures for 1997, although it is premature to draw conclusions either way. (It should also be noted that at the time of submission of this article there were significant concerns about the validity of the 1997 suicide rate figures. For example, major rises in rates in New South Wales and Victoria were absent from Queensland -- the next most populous State -- suggesting the possibility of interstate data collection influences.)

    From a policy perspective, the most important finding is that suicide rate increases since 1973 for men aged 25-34 years have paralleled those of 15-24 year olds, with even less evidence of a recent plateau. Despite having shorter life expectancies, the toll in potential years of life lost (in 1997) was greatest for 25-34 year olds. These years are also the peak years for early parenthood, making the likelihood of there being bereaved offspring greater than in the younger group. These findings suggest that priority initiatives for youth suicide prevention should be extended to those aged 15-34 years, if not further (the high level of potential years of life lost continues to 44 years). The Federal Government's recently announced National Suicide Prevention Policy provides for ages beyond youth, by recognising that rising rates are not confined to the age group 15-24 years and that high suicide rates in the elderly should not be overlooked.

    It is unclear whether or to what extent the suicide phenomenon in boys and young men might be a cohort effect -- a "damaged" generation. The later commencement of the rise in suicide rate in men aged 25-34 years and the, as yet, absence in this age group of the possible 1990s plateau could be seen as consistent with this.

    Rates in females aged 15-24 years showed no convincing rise. It has previously been noted that suicide rates in females aged 15-19 years rose modestly between 1960 and 1989, while rates for those aged 20-24 years showed no overall change over this period.10 However, much of the rise in females aged 15-19 years was in the early 1960s, predating the rise in rates of 15-19-year-old males, but coinciding with a general, transient rise in suicide rates in females of all ages. Perhaps the most important observation regarding young females in the present study is that their suicide rates remained relatively static at a time when rates for most other female age groups declined.

    Suicide rates in children under 15 years of age have not significantly altered over time, although the small numbers involved do not lend confidence to rate estimates. The recording of suicide in children under the age of 10 years is affected by the different criteria used by the Australian Bureau of Statistics for determining suicide: it is considered that children have a limited ability to form an intent to suicide. Hence, more explicit evidence of suicidal intent is required,11 usually a coroner having stated explicitly that suicide was the cause of death. As most State and Territory Coroners' Acts discourage if not prohibit such findings (for all ages), such explicit statements are unlikely.11

    Beyond 35 years in women, and 45 years in men, and up to 75 years and over for both sexes, Australian suicide trends are striking. In both sexes there have been major declines, and for much of the period these declining male and female rates have been parallel, quite unlike the trends for 15-24 year olds. It is unclear whether these declining rates have as yet plateaued. Even if this were not the case, it is inevitable that these declining rates will shortly level out and increase again (from the trends over the complete period a number of these age rates would reach zero in the early decades of the next century). In the early 1960s, suicide rates, particularly in women and in older age groups, rose in association with an epidemic of barbiturate poisoning, subsequently to fall in the late 1960s, reaching rates in the early 1970s similar to those before this epidemic.12,13 The causal factors determining the subsequent decline in rates of those between 35 and 74 years are yet to be determined. It is possible that such determination might yield valuable clues as to the causes and possible methods of preventing suicide in young people.

    International comparisons should be interpreted conservatively, as variations in data collection systems will account for some of the variations. With these reservations in mind, among 23 Western nations, Australian suicide rates for 15-24 year olds ranked fourth for males and eighth for females (Boxes 3a and 3b). Australian rates for both sexes between the ages of 35 and 74 years, as well as declining, compared favourably internationally (ranking in the middle of or below those of other Western nations).

    Although Australian suicide rates for those over 75 years were not declining, they nevertheless again compared favourably from an international perspective. Whereas the Australian suicide rate for 15-24-year-old males was over half that of the highest-placed nation (Finland), the corresponding ratio for males 75 years and over was about one-sixth. For females, these comparisons were even more marked. Nevertheless, a comprehensive policy should not overlook the needs of men over 75 years, especially as, in Australia, suicide rates in this age group surpass those of all other age groups.

    The Western nations with lower suicide rates include those that provided most of the early immigrants to Australia: Greece, Italy (except in the elderly), the United Kingdom and Ireland. The highest suicide rates were in mainland Western Europe (especially Hungary) and Scandinavia (especially Finland). Some of these nations, for example Denmark, have profiles radically different from that of Australia, with lower youth suicide rates but much higher rates in those over 35 years of age.

    Canada and, to a lesser extent, the United States and New Zealand are the nations with suicide rate profiles most similar to Australia's. All four of these nations have common characteristics of European migration, a comparatively short history (apart from their indigenous populations), geographical isolation, climatic extremes and more.10 They serve as potentially valuable nations to study shared characteristics that may affect suicide rates.

    Studies have yet to provide explanations for these similarities and differences which have often been overlooked, largely as a consequence of the worldwide lack of epidemiological mental health data. While differences in prevalence of psychiatric disorders are potentially relevant, the magnitude of the different international rates suggests other factors may operate. Hungary and Finland share common cultural origins and high suicide rates. It has been suggested that Finland's high suicide rates in young men may relate to cultural expectations that men should be tough and resilient14 -- a suggestion that might be equally relevant in Australia, New Zealand, the United States and Canada. It is possible that a better understanding of cultural influences and how to positively modify them might be relevant to suicide prevention.



    Acknowledgements
    The study was funded by Griffith University and Queensland Health through their co-funding of the Australian Institute for Suicide Research and Prevention. We thank the Australian Bureau of Statistics for providing information on suicide and population numbers.


    References
    1. Commonwealth Department of Health and Family Services. Youth suicide in Australia: a background monograph. 2nd edition. Canberra: AGPS, 1997.
    2. Snowdon J. Suicide rates and methods in different age groups: Australian data and perceptions. Int J Geriat Psychiatry 1997; 12: 253-258.
    3. Hassan R, Carr J. Changing patterns of suicide in Australia. Aust N Z J Psychiatry 1989; 23: 226-234.
    4. Australian Bureau of Statistics. Causes of death, Australia, 1996: 73. (Catalogue No. 3303.0.)
    5. World Health Organization. World Health Statistics Annual 1992. Geneva: WHO, 1993.
    6. World Health Organization. World Health Statistics Annual 1993. Geneva: WHO, 1994.
    7. World Health Organization. World Health Statistics Annual 1994. Geneva: WHO, 1995.
    8. World Health Organization. World Health Statistics Annual 1995. Geneva: WHO, 1996.
    9. Lester D, Yang B. Suicide and homicide in the twentieth century: Changes over time. Commack, NY: Nova Science, 1998: 165-204.
    10. Cantor CH, Leenaars AA, Lester D, et al. Suicide trends in eight predominantly English-speaking countries 1960-1989. Soc Psychiatry Psychiatr Epidemiol 1996; 31: 364-373.
    11. Cantor CH, Neulinger K, Roth J, Spinks D. The epidemiology of suicide and attempted suicide among young Australians: a report to the National Health and Medical Research Council: Australian Institute for Suicide Research and Prevention. In press.
    12. Oliver G, Hetzel BS. An analysis of recent trends in suicide rates in Australia. Int J Epidemiol 1973; 2: 91-101.
    13. Whitlock FA. Suicide in Brisbane, 1956-1973: The drug-death epidemic. Med J Aust 1975; 1: 737-743.
    14. Retterstol N. Suicide in the Nordic countries. Psychopathology 1992; 25: 254-265.

    (Received 14 Jan, accepted 7 Jun, 1999)


    Authors' details Australian Institute for Suicide Research and Prevention, Griffith University, Nathan, QLD.
    Christopher H Cantor, FRANZCP, MRCPsych, Senior Research Psychiatrist;
    Kerryn Neulinger, BBehSc, GradDipPsych, Research Assistant;
    Diego De Leo, MD, PhD, Director.

    Reprints will not be available from the authors.
    Correspondence: Dr C H Cantor, Australian Institute for Suicide Research and Prevention, Griffith University, Nathan, QLD 4111.
    Email: C.CantorATmailbox.gu.edu.au






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    3a: Mean male suicide rates (per 100000 population) for 23 Western countries by 10-year age groups, 1990-1994


    15-24 yearsFinland 41.4
    New Zealand 39.0
    Switzerland 25.8
    Australia 25.7
    Canada 25.2
    Norway 24.9
    Austria 24.3
    USA 21.9
    Hungary 20.1
    Scotland 19.0
    Ireland 18.3
    N Ireland 17.6
    Belgium 15.7
    France 15.3
    Germany 14.0
    Sweden 13.4
    Denmark 13.0
    Engl/Wales 11.1
    Netherlands 9.3
    Spain 7.0
    Italy 6.1
    Portugal 5.8
    Greece 4.0
    25-34 yearsFinland 60.7
    Hungary 54.4
    Switzerland 32.7
    New Zealand 32.0
    France 32.0
    Belgium 30.5
    Austria 30.3
    Australia 29.0
    Canada 29.0
    Ireland 27.1
    Denmark 26.4
    Norway 26.1
    Scotland 26.1
    USA 24.6
    Sweden 23.9
    N Ireland 22.4
    Germany 21.3
    Engl/Wales 16.3
    Netherlands 15.9
    Portugal 13.2
    Spain 10.6
    Italy 10.3
    Greece 5.6

    35-44 yearsHungary 82.0
    Finland 67.8
    France 40.1
    Denmark 38.1
    Austria 37.2
    Belgium 35.6
    Switzerland 33.0
    Sweden 29.3
    Canada 27.3
    Norway 26.9
    Scotland 26.2
    Germany 26.0
    Australia 25.2
    New Zealand 23.9
    USA 23.5
    Ireland 22.9
    Netherlands 17.7
    Engl/Wales 17.4
    N Ireland 15.5
    Portugal 11.8
    Italy 10.6
    Spain 9.4
    Greece 5.9
    45-54 yearsHungary 95.1
    Finland 64.1
    Denmark 47.5
    Austria 41.5
    France 40.1
    Switzerland 39.8
    Belgium 36.2
    Sweden 31.9
    Germany 31.1
    Norway 28.8
    Canada 25.6
    Scotland 24.2
    Australia 24.2
    New Zealand 24.2
    USA 23.1
    Ireland 19.6
    Netherlands 16.7
    Engl/Wales 16.2
    N Ireland 15.1
    Portugal 14.6
    Italy 12.6
    Spain 11.9
    Greece 6.7

    55-64 yearsHungary 84.6
    Finland 57.3
    Austria 46.7
    Denmark 42.6
    Switzerland 41.9
    belgium 38.9
    France 38.1
    Germany 32.2
    Sweden 30.7
    Norway 28.8
    Ireland 25.9
    USA 25.0
    Canada 24.2
    New Zealand 23.2
    Australia 22.9
    Portugal 21.5
    Netherlands 18.6
    Scotland 18.1
    N Ireland 17.4
    Spain 17.4
    Italy 17.1
    Engl/Wales 12.8
    Greece 7.8
    65-74 yearsHungary 92.5
    Austria 61.1
    Belgium 50.4
    Switzerland 47.4
    France 47.1
    Denmark 46.4
    Finland 45.9
    Germany 35.9
    Sweden 33.7
    USA 30.9
    Norway 30.7
    Portugal 30.1
    Australia 24.4
    Spain 23.2
    Italy 22.9
    Canada 22.1
    New Zealand 21.2
    Netherlands 19.7
    Ireland 18.3
    Scotland 14.3
    N Ireland 12.8
    Engl/Wales 11.9
    Greece 10.1

    75+ yearsHungary 183.0
    Austria 118.0
    France 103.0
    Belgium 98.6
    Switzerland 89.8
    Germany 86.1
    Denmark 74.9
    Finland 71.9
    Portugal 59.1
    USA 55.4
    Sweden 51.9
    Spain 47.8
    Italy 44.3
    Netherlands 35.4
    Australia 32.8
    Norway 31.8
    New Zealand 29.8
    Canada 28.9
    Engl/Wales 17.1
    Scotland 16.0
    Greece 15.8
    Ireland 13.8
    N Ireland 13.3
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    Appendix: Identifying suicide deaths in Australia11

    Coding deaths as suicide relies on an interaction between the Australian Bureau of Statistics (ABS) and State and Territory coroners and government medical officers. The six States and two Territories of Australia each have different Coroners' Acts. Most States and Territories discourage coroners from making formal pronouncements about suicide. Western Australia and New South Wales are the only States that routinely use suicide verdicts. ABS receives information from coroners that is generally sufficient for coding in most cases.

    Deaths that were in reality suicides, but were not deemed as such by coroners or the ABS, will most likely be coded as undetermined deaths or accidents, and involve similar causes as suicide deaths (eg, poisoning). There has been a rise in both undetermined and accidental deaths in recent years. However, the impact of these uncertainties is unlikely to be sufficient to greatly alter our overall study findings.

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    3b: Mean female suicide rates (per 100000 population) for 23 Western countries by 10-year age groups, 1990-1994


    15-24 yearsFinland 7.5
    Austria 6.2
    Hungary 6.2
    New Zealand 6.2
    Sweden 5.9
    Switzerland 5.8
    Norway 5.5
    Australia 5.1
    Belgium 5.1
    Canada 4.9
    France 4.5
    USA 3.8
    Netherlands 3.7
    Scotland 3.7
    Germany 3.5
    Denmark 3.3
    Ireland 2.5
    N Ireland 2.4
    Portugal 2.2
    Engl/Wales 2.1
    Italy 1.8
    Spain 1.7
    Greece 0.7
    25-34 yearsFinland 12.0
    Belgium 11.8
    Hungary 11.6
    Sweden 10.1
    Switzerland 9.0
    France 9.0
    Scotland 8.3
    Austria 8.0
    Denmark 7.7
    New Zealand 7.3
    Netherlands 7.2
    Norway 7.1
    Ireland 6.7
    Australia 6.6
    Canada 6.4
    Germany 5.7
    Germany 5.7
    N Ireland 3.9
    Portugal 3.5
    Engl/Wales 3.5
    Italy 2.9
    Spain 2.6
    Greece 1.4

    35-44 yearsHungary 20.3
    Finland 17.4
    Denmark 15.7
    Belgium 14.5
    Switzerland 13.5
    France 13.0
    Austria 12.1
    Sweden 11.8
    Norway 9.8
    Netherlands 9.6
    Canada 8.1
    Germany 7.7
    New Zealand 6.9
    Scotland 6.8
    N Ireland 6.8
    Australia 6.6
    USA 6.6
    Ireland 4.8
    Engl/Wales 3.9
    Italy 3.9
    Portugal 3.8
    Spain 3.0
    Greece 1.3
    45-54 yearsHungary 26.5
    Denmark 25.5
    Finland 20.4
    Belgium 18.2
    Austria 17.1
    Switzerland 16.7
    France 16.5
    Sweden 15.0
    Germany 12.1
    Norway 11.5
    Netherlands 9.5
    N Ireland 9.4
    New Zealand 8.9
    Canada 8.1
    USA 7.3
    Scotland 7.2
    Australia 7.0
    Ireland 6.8
    Portugal 5.0
    Italy 4.9
    Engl/Wales 4.7
    Spain 3.9
    Greece 2.3

    55-64 yearsDenmark 28.5
    Hungary 28.0
    Belgium 17.9
    France 17.6
    Finland 17.5
    Austria 17.4
    Switzerland 17.0
    Sweden 15.4
    Germany 12.9
    Norway 12.0
    Netherlands 10.9
    New Zealand 7.7
    Ireland 7.7
    Australia 6.9
    USA 6.8
    Italy 6.8
    Scotland 6.7
    Canada 6.4
    Portugal 6.2
    Spain 6.0
    N Ireland 4.8
    Engl/Wales 4.7
    Greece 2.4
    65-74 yearsHungary 37.6
    Denmark 31.5
    Belgium 23.5
    Switzerland 19.8
    Austria 18.5
    France 17.9
    Germany 16.7
    Sweden 13.5
    Finland 13.3
    Norway 12.4
    Netherlands 10.4
    Spain 8.8
    Portugal 8.1
    Italy 8.0
    New Zealand 6.6
    Australia 6.6
    Ireland 6.4
    Scotland 6.4
    USA 6.2
    Canada 6.1
    Engl/Wales 5.2
    N Ireland 3.9
    Greece 2.8

    75+ yearsHungary 67.3
    Denmark 30.2
    Austria 28.5
    Germany 26.4
    France 25.3
    Belgium 24.2
    Switzerland 23.0
    Sweden 14.2
    Portugal 12.2
    Netherlands 12.1
    Spain 11.9
    Finland 9.6
    Italy 9.3
    Norway 9.2
    Australia 8.0
    Scotland 6.0
    USA 6.0
    Engl/Wales 5.9
    Canada 4.7
    New Zealand 4.3
    Greece 3.4
    Ireland 3.0
    N Ireland 2.5
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    Received 15 November 2018, accepted 15 November 2018

    • Christopher H Cantor
    • Kerryn Neulinger


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