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| Journal of the New Zealand Medical Association,
06-June-2003, Vol 116 No 1175
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Suicide in New Zealand I: time trends and
epidemiology
Annette Beautrais
In recent years there has been increasing public and
professional interest in the issue of suicide in New
Zealand.1,2 This interest has largely been
motivated by concerns about New Zealand’s high rates of youth suicide in
comparison with international statistics. Despite this public interest, there
have been relatively few attempts to provide accessible summary data on what is,
and what is not, known about suicide in New Zealand. This is the first of two
articles that attempt to address, in summary form, a series of key issues
relating to suicidal behaviour.
This article examines the basic epidemiology of suicidal
behaviours in New Zealand including: (a) time trends; (b) gender differences;
(c) age differences; and (d) differences in terms of ethnicity. A second article
will examine risk factors for suicidal behaviour and approaches to suicide
prevention for young people (age <25), and for adults (age
≥25).3
Time trends in suicide, 1950–1999Figure 1 presents overall trends in
suicide rates from 1950 to 1999 derived from data provided by the New Zealand
Health Information Service (NZHIS). The data represent all those deaths for
which there are coroners’ verdicts of suicide.
Suicide rates for males have shown a relatively steady
increase during the 50-year period. The male rate of suicide in 1999 was 18.9
deaths per 100 000, compared with 13.3 deaths per 100 000 in 1950. In contrast,
the rate for females has remained relatively static: 4.6 deaths per 100 000 in
1950, and 6.4 deaths per 100 000 in 1999.
The increase in rates of male suicide is largely, but not
wholly, explained by a rapid increase in rates of youth (15–24 years)
suicide that occurred after 1970. This can be seen from Figure 2, which shows
time trends in youth suicide for the 50-year period from 1950–1999. Rates
of male youth suicide began to increase in the 1970s and then showed an abrupt
increase over the period from the mid-1980s to the mid-1990s. However, in the
last five years (1995–1999), the male youth suicide rate in New Zealand
has declined.
In addition, during the last 15 years there has been a
steady increase in the rate of female youth suicide. In 1985, females accounted
for 20% of youth suicides (age 15–24). In 1999, 31% of youth suicides were
female.
Figure 1. Suicide rates, total population by gender,
1950–1999 (annual age-standardized rates)
  Figure 2. Youth (15-24 years) suicide rates by gender,
1950–1999, (age-standardized rates)
Age differences in suicide ratesThe comparisons in Figures 1 and 2
do not provide a comprehensive description of age differences in suicidal
behaviours. Figure 3 shows age-specific rates of suicide for males and females
presented in five-year intervals, for 1999. The following conclusions may be
drawn from this graph:
Figure 3. Suicide rates by age and gender, New Zealand,
1999
 To place the results in Figure 3 in context, Figure 4 shows
the percentages of total deaths that are attributable to suicide for each age
and gender group. This Figure thus permits assessment of the extent to which
suicide contributes to mortality within a given age group. It shows that, for
both genders, the percentage of deaths attributable to suicide tends to increase
up to ages 20–24, and then declines with increasing age. After age 60,
suicide accounts for an inconsequential proportion of all deaths.
Figure 4. Percentage of total mortality accounted for
by suicide, by age and gender, 1999
 Ethnicity and suicideAs a result of changes in the ways
in which the ethnicity of those dying by suicide has been recorded it is not
possible to examine ethnic differences in suicide rates prior to
1995.1,4 Before this time, the ethnicity of
suicide was based upon an assessment of the individual’s extent of Maori
descent. Recognition of the limitations of this method of measurement led to a
revision of data collection methods. Since 1995, ethnicity has been defined on
the basis of the family’s report of the individual’s ethnic
self-identification. This change in definitions led to a clear discontinuity in
time-series data, and an under-enumeration of Maori suicide prior to
1995.
Figure 5a compares Maori and non-Maori suicide rates, for
all ages, during the period 1996–1999. It shows that, for both males and
females, from 1996 through to 1998, Maori had higher rates of suicide than
non-Maori. However, the most recent data (1999) show no difference between Maori
and non-Maori suicide rates, for both males and females.
The results in Figure 5a may be elaborated by examining
trends in youth (15–24 years) suicide data. These are shown in Figure 5b.
The trends in Figure 5b differ from those for the total population. For both
young males and females, Maori have had higher rates of suicide than non-Maori
each year from 1996 to 1999. The most recent data (1999) suggest that young
Maori males and females are approximately one and a half times more likely to
die by suicide than non-Maori young people.
Figure 5a. Maori and
non-Maori suicide rates, total population by gender,
1996–1999
 Figure 5b. Maori and non-Maori suicide rates,
15–24 years by gender, 1995–1999
 Trends in methods of suicideThe methods by which people die by
suicide are of considerable policy relevance to the extent that one approach to
suicide prevention is through restriction of access to particular methods. For
example, it has been suggested that in the United States restriction of access
to firearms could result in substantial reductions in suicide
rates.5,6
In New Zealand, the commonly used methods of suicide vary
with gender. For males, the most frequently used methods are hanging, vehicle
exhaust gas, and firearms.7 Figure 6a shows
time trends in these major methods of suicide for males of all ages for the
period 1980–1999. It is evident that over the last two decades there have
been substantial increases in the use of both hanging and vehicle exhaust gas,
and a recent decline in the use of firearms. Currently, firearms account for
only 11% of all male suicide deaths.
 In females, the most commonly used methods of suicide are
hanging, vehicle exhaust gas and
self-poisoning.7 Figure 6b shows time trends in
rates of suicide for these common methods, for females of all ages, from 1980 to
1999. There have been major changes in female methods of suicide. In 1980 the
leading method was self-poisoning. Over the years the use of this method has
declined (with self-poisoning accounting for 8% of female suicide deaths in
1999), and there have been increases in the use of hanging and vehicle exhaust
gas. The use of hanging increased five-fold from 1980 to 1999, with hanging
accounting for the majority (almost 85%) of all female suicide deaths in
1999.
Figure 6b. Trends in major methods of female suicide,
1980–1999 (percentage of total suicides)
 Both Figures 6a and 6b show clear increases in suicide by
hanging for both males and females.
These increases are largely accounted for by an increasing use of hanging
amongst young people aged 15–24. Figures 7a and 7b show time trends in the
major methods of youth suicide for males and females. These figures show that,
for both genders, hanging has become increasingly common, currently (1999)
accounting for 65% of male, and 75% of female, youth suicides.
Figure 7a. Trends in major methods of male youth
suicide, 1980–1999 (percentage of total suicides)
 Figure 7b. Trends in major methods of female youth
suicide, 1980–1999 (percentage of total suicides)
 DiscussionOver the last fifty years there have
been clear changes in rates of suicide, with increased rates evident for both
genders and amongst younger age groups. The net result of these trends is that
suicide makes a significant contribution to mortality in New Zealand and,
particularly, to mortality amongst those under 35 years.
The reasons for the rapid increase in male youth suicide
rates in the mid-1980s and the more recent increase in female youth suicide
rates are not known. It has been suggested that these increases reflected the
effects of economic restructuring on the life opportunities of young people,
particularly males.8 However, this explanation
is not consistent with the fact that, at an individual level, associations
between economic factors and youth suicide rates tend to be relatively
modest.9–12
In an examination of time trends in suicidal behaviour for
the European Union, Rutter and Smith concluded that explanations for the rapid
increase in youth suicide might usefully be sought in the following
areas:
‘increased rates of
depression; the increase in the use of alcohol and psychoactive drugs; the
possible role of antisocial behaviour; the influence of suicidal models, either
within the family and intimate circle, or in the mass media; the possible
increase in family conflict and decline in parental support associated with
changes in family structures; the possible effect of an extended period of
social dependency during adolescence; and the likely role of changing
circumstances in society as a
whole.’13
It is likely that these same circumstances have played a
role in the increase in youth suicide observed in New Zealand.
Public and policy attention in New Zealand has tended to
focus upon youth suicide with tacit assumption that such suicide is
predominantly teenage suicide. This misperception has led to a public view that
youth suicide prevention programmes need to be school based to reach those young
people most at risk of suicide. However, young people at school constitute only
a minority of the population involved in youth suicide. Recent (1999) data
suggest that only approximately 15% of youth suicides occurred amongst young
people who were at school, with the majority (two thirds) of youth deaths
occurring amongst young people aged 19 to 24 years. This suggests the need for
policy emphases to shift away from adolescent populations and to pay greater
attention to the needs of young adults in the age range of
20–29.
The period of highest risk for suicide for both males and
females appears to be from age 20 to 45 years. The needs of this population have
not been well served by current policies, which have tended to focus on youth
suicide with an emphasis upon suicide amongst school-aged young people. For
example, whilst policy guidelines have been developed for addressing the issue
of youth suicide, there has been no corresponding investment into addressing the
more prevalent problem of suicide in adults aged 20–45.
In common with other trends in mortality in New
Zealand,14,15 Maori youth emerge as being at
higher risk for suicide than non-Maori youth. Estimates suggest that rates of
Maori youth suicide are approximately one and a half times higher than those of
non-Maori. The reasons for the higher rate of suicide amongst young Maori are
not clearly understood but it has been suggested that these may be due to social
and cultural inequalities that make Maori particularly vulnerable to suicidal
behaviours.16
A feature that pervades suicide data is the higher rates of
suicide by males. This difference extends across age (Figures 1–4 above)
and ethnicity (Figure 5), and has often led to the assertion that ‘suicide
is a male problem’. This claim is potentially misleading. In fact, when
the spectrum of suicidal behaviours in the population is examined, females
emerge as being more prone to suicidal behaviour than males. For example,
findings from the Christchurch Health and Development Study have suggested that
females report suicidal thoughts at 1.3 times the rate of males and make suicide
attempts at almost twice the rate of males.17
These trends are also evidenced in hospitalisation statistics. In 1999/2000, for
example, 63% of all admissions to hospital in NZ for suicide attempts were
females (www.nzhis.govt.nz).
The association between suicidal behaviour and gender is
thus paradoxical. Although females show higher rates of suicidal ideation and
suicide attempt, males more frequently die by suicide. The key to this gender
paradox probably lies largely, if not wholly, with gender differences in choice
of method for suicide attempt. As may be seen from Figures 6 and 7,
traditionally there have been marked differences in male and female method
choices, with females more often choosing self-poisoning and males more often
choosing the more lethal methods of hanging and vehicle exhaust gas.
The extent to which gender differences in suicidal
behaviours could be explained by gender-related differences in method choice has
been examined in a recent paper comparing suicide attempts by young males and
females.18 This analysis suggested that nearly
all of the gender differences in rates of youth suicide arose from
gender-related differences in method choice. The paper concluded:
‘The fact that males were
more likely than females to die by suicide was completely explained by the use
of more immediately lethal methods of suicide attempt by males. While the
majority of males who died by suicide used hanging, vehicle exhaust gas,
firearms, and jumping, the majority of serious suicide attempts by females were
by self-poisoning, a method which, while it may have high toxicity, tends to
have low lethality and a relatively slow rate of action.’
These findings have potentially important implications given
the increasing use by females of highly lethal methods such as hanging and
vehicle exhaust gas (Figure 7b). Indeed, it would appear that the recent
increase in female youth suicide is largely, if not wholly, due to the
increasing use of hanging as a method of suicide by young females.
The clear majority of suicides, in people of all ages, occur
by hanging. The dominance of hanging, and the ubiquitous availability of the
materials and opportunities for hanging, suggest that there is extremely limited
potential to reduce suicide by restricting access to means of suicide. The clear
policy implication of this observation is that suicide prevention in New Zealand
needs to focus on a range of approaches designed to address the known risk
factors for suicidal behaviour.3
Author information:
Annette L Beautrais, Principal Investigator, Canterbury Suicide Project,
Christchurch School of Medicine and Health Sciences, Christchurch
Correspondence: Dr A
L Beautrais, Canterbury Suicide Project, Christchurch School of Medicine and
Health Sciences, P O Box 4345, Christchurch. Fax: (03) 372 0405; email: suicide@chmeds.ac.nz
References:
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