Journal of the New Zealand Medical Association, 06-June-2003, Vol 116 No 1175
Suicide in New Zealand II: a review of risk factors and prevention
This paper aims to provide a summary of suicide in New Zealand. The previous paper examined time trends and the epidemiology of suicide.1 The objectives of this paper are to: (a) provide a summary of the research evidence about risk and protective factors for suicide and attempted suicide in young people aged <25 years and adults aged ≥25; and (b) examine the implications of this knowledge for approaches to suicide prevention. The review is based upon New Zealand research, supplemented by evidence from the international literature.
To place this discussion in perspective it is useful to begin by reviewing rates of suicidal behaviours amongst both youth (age 15–24) and adults (≥25 years). During the last decade, two sets of factors have focused public and professional attention on youth suicide in New Zealand. First, rates of youth suicide increased dramatically in the mid-1980s, peaking in the mid-1990s. Second, this increase led to New Zealand having high youth suicide rates compared with other OECD countries. In turn, concerns about these matters have raised important issues about the risk factors that predispose young people to attempt to take their lives.
However, although current policy emphases in New Zealand have focused on youth suicide, the majority of those who die by suicide are adults aged ≥25: 75.6% of the 516 deaths by suicide in 1999 (www.nzhis.govt.nz). Almost half of all these adult suicides were males aged 25–44. This review also considers health and related issues associated with risks of suicide in adults.
A conceptual model of youth suicidal behaviour
To organise the review of risk and protective factors for suicidal behaviour into an orderly conceptual framework, Figure 1 provides a model of the development of youth suicidal behaviours. This model assumes that the factors that contribute to suicidal behaviour may be organised into six domains that are conceptually related: genetic and biologic factors; social and demographic background; childhood adversity; personality characteristics; life stresses; and mental health factors. The model further assumes that four sets of factors (genetic and biologic factors; social factors; family factors; personality characteristics) act as broad, ‘distal’ determinants of an individual’s vulnerability or resiliency to suicidal behaviour. Those most vulnerable tend to come from socially disadvantaged backgrounds; to have genetic and biologic predispositions to suicidal behaviours; to be exposed to childhood adversity and to have personality and cognitive difficulties. Those with most resiliency tend to show the opposite profile. These four sets of factors influence both an individual’s vulnerability and resiliency to mental illness and his/her level of life-event exposure. Mental illness and exposure to stress and adversity are the more proximal determinants of suicidal behaviour.
Since research evidence suggests that a broadly similar conceptual model applies to adult suicidal behaviour, in the interests of brevity this review will use the framework in Figure 1 to review the factors that contribute to risk of, and protection from, suicide, for youth and for adults aged ≥25, noting the similarities and differences in risk factors between the two groups. This model is based upon an empirically-derived, individual risk-factor approach. While alternative paradigms for suicidal behaviour (including, for example, social causation, psychoanalytic and philosophical models) have been proposed, there are difficulties in reconciling these theoretical frameworks with the existing evidence on risk factors for suicide.2 For this reason, this summary is based not upon a particular theory of suicide but upon a general conceptual model of the ways in which suicidal behaviour is influenced by various risk-factor domains.
Figure 1. Conceptual model of domains of factors for suicidal behaviours amongst young people (click here to view Figure 1)
Genetic and biologic factors
A family history of suicidal behaviour is a strong risk factor for suicide and suicide attempt for both youth and adults,3 suggesting that there are genetic factors that predispose individuals either to suicide per se or to the psychiatric disorders with which suicide is associated. Using twin designs, studies have suggested that up to 45% of the variance in suicidal behaviour may be genetic in origin.4 In a second line of research, researchers have attempted to identify biologic and genetic markers for suicidality, focusing particularly on those involving the serotonergic system.5 More work is required to clearly identify, and clarify, the role of a range of genetic and biologic factors in suicidality.
Social and demographic factors
Several New Zealand studies have examined linkages between suicide attempts and suicide in young people, and a series of measures of socioeconomic and educational disadvantage.6,7 Rates of suicidal behaviour were elevated amongst young people with poor educational qualifications and from families with low socioeconomic status. It is likely that the major route by which socioeconomic adversity leads to suicidal behaviour is as a result of linkages between socioeconomic factors and mental health and adjustment in adolescence.7
Similar trends have been found for adults and older adults.8,9 In addition, adults who die by suicide are more likely than the general population to have never married, to be divorced or widowed, and to live alone.10,11 Some of these findings may be explained by high rates of psychopathology in those with serious suicidal behaviour (see below).
Numerous studies suggest clear linkages between exposure to childhood adversity and risk of later suicidal behaviour amongst young people. These studies have found elevated rates of suicidal behaviours amongst young people who have experienced: parental separation or divorce; sexual, physical or emotional abuse and neglect; parental psychopathology; family discord and violence; impaired parent–child relationships; and experience of institutional or welfare care.12–14 In general, experiences of childhood adversities tend to act cumulatively, with those most at risk of suicidal behaviour being characterised by multiple childhood disadvantage.2,7,15
For adults, compared with youth, early childhood factors appear to be less influential in risks of suicidal behaviours. The likely reason for this is that, with the passage of time, the effects of adverse childhood experiences become overlaid by other life experiences, resulting in earlier experiences playing a decreasing role in the aetiology of adult suicide. Nevertheless, older adults (≥55 years) with serious suicidal behaviour tend to have histories of childhood adversity (including sexual abuse and poor paternal care), suggesting that early exposure to such adversity may confer enduring vulnerability for the development of mood disorders and suicidal behaviour.16
Risks of suicidal behaviour are increased amongst young people with particular personality characteristics,17,18 including high levels of neuroticism, hopelessness, impulsivity, risk taking, and low self-esteem. It is likely that personality is linked to suicidality by two major pathways. First, certain personality traits (neuroticism, for example) act as predisposing factors for mental disorders, notably depression and substance-use disorders. In turn, these disorders are associated with increased risk of suicidal behaviour (see below). Second, these personality traits may also influence the ways in which young people react to adverse life events.
Similar personality traits (hopelessness, neuroticism, anxiety, timidity, cognitive rigidity, impulsivity, aggression, and a strong sense of personal independence) have been shown to be associated with suicidal behaviours in adults and older adults.19 In addition, elevated rates of suicidal behaviour have been found amongst those with borderline personality disorder and antisocial personality disorder.16,20
Mental health factors
Whilst genetic and biologic factors, social factors, childhood adversity, and personality characteristics may act to determine individual susceptibility to suicidal behaviours, the major risk factors for suicidal behaviours are mental disorders. Four disorders have consistently been identified as making major contributions to youth suicidal behaviours: mood disorders (including depression, bipolar disorders); substance-use disorders (alcohol, cannabis and other drug abuse and dependence); conduct disorder, antisocial and offending behaviours; and anxiety disorders.21
A consequence of the linkages between mental disorder and suicidality is that many young people making suicide attempts or dying by suicide will have a history of contact with medical, welfare and related services for mental health problems. New Zealand research suggests that the majority (80%) of young people making serious suicide attempts have had contact, at some time in their lives, with such services for psychiatric problems, with 30% having a history of psychiatric hospital admission prior to making suicide attempts.22
Similarly, mental disorders prove to be the strongest predictors of suicidal behaviours in adults. These disorders include mood disorders, substance-use disorders, antisocial behaviours and non-affective psychosis, and there is a clear trend for risks of suicide attempt and suicide to increase with increasing comorbidity.16,23 Findings suggest that individuals with two or more disorders had odds of serious suicide attempt that were 90 times of those with no disorders.24
The contribution of psychiatric illness to suicide risk tends to increase with increasing age: mental disorder (particularly depression) plays a more dominant role in determining suicide risk in adults ≥45 years than in younger individuals.25
Given the strong role of mental disorders in adult suicide, individuals who die by suicide or make suicide attempts tend to have histories of mental illness, of previous suicide attempts, and of mental health care, including psychiatric hospital admission.23
Various forms of psychosocial stress or discrimination may act to precipitate suicidal behaviours.14 For youth, research has tended to focus on three areas:
In common with findings for youth, research suggests that exposure to recent adverse life experiences plays an influential role in precipitating suicidal behaviours in adults. For adults, the key life events that increase risk of suicidal behaviour are interpersonal losses and conflicts (including marital separation, serious family arguments, unemployment, change of residence, retirement), financial problems and job problems.9,25
Some of the life events that precede serious suicidal behaviour appear to be generated by an individual’s own behaviour.32 Furthermore, specific life events (separation, serious family arguments, financial problems and unemployment) often appear to arise from problems with alcohol.32 Research evidence also suggests age and gender differences in the association between life events and suicidal behaviour, with younger subjects likely to have more life events than older subjects, and males likely to experience more life events than females.32
In older adults, health impairments, somatic illnesses and declining physical capacity play a role in precipitating suicidal behaviour, with some evidence that physical health problems play an increasingly influential role with increasing age, particularly for males. In a study of subjects aged ≥65 who died by suicide, visual impairment, neurological disorders, and malignant disease were associated with increased risk of suicide.33
A further set of factors associated with suicidal behaviours in adults relates to various forms of social interaction. Those making serious suicide attempts are likely to be characterised by high rates of social isolation, feelings of loneliness, poor social support and lack of a close, confiding relationship.16,23
There is growing interest in the exploration of a range of protective factors that may mitigate risks of suicidal behaviour. This interest has been motivated by the observation that many people with exposure to risk factors do not develop suicidal tendencies. Only a minority of those with depression develop suicidal behaviour, for example.
Such observations suggest that there may be a range of protective factors that act to mitigate the effects of exposure to risk factors. Although there has been increasing interest in protective or resiliency factors for youth suicidal behaviour,34 there has been relatively little research in this area. Rather, many of the factors suggested as protective factors for suicidal behaviour have been speculative, or have been extrapolated from research in other fields.
Factors that have been suggested as providing protection or resiliency against the development of suicidal behaviours include: an adaptable temperament; good self-esteem; problem-solving skills; social support and social networks; a good emotional relationship with at least one person in the family; positive school experiences; and spiritual faith.34
In New Zealand, some of these issues have been addressed using data from a 21-year longitudinal study of a birth cohort of over 1000 young people.35 This analysis identified a series of factors that acted to exacerbate or mitigate risks of suicidal behaviour amongst young people with depression. These factors included: a family history of suicidal behaviour; childhood sexual abuse; neuroticism; novelty-seeking behaviour; self-esteem; and peer affiliations. Positive configurations of these factors (no family history of suicide; no childhood sexual abuse; low neuroticism; low novelty-seeking behaviour; high self-esteem; and absence of deviant peer affiliations) increased resiliency to suicide attempt, whereas negative configurations acted to increase vulnerability to suicidal behaviour.
In contrast to the current emphasis on protective factors in youth suicide, there has been relatively little research interest in the role of protective factors for suicide in adults. One exception has been research that suggests that having children acts as a protective factor for females and minimises risk of suicidal behaviour.36 A further set of protective factors is suggested by a recent study of adults ≥65 years, which found that having a hobby and actively participating in organisations decreased suicide risk.9 More generally, these findings perhaps suggest that social attachments and social obligations may form important protective factors against suicidal behaviour.
Issues for older adults
A population of particular interest are older adults, ≥65 years. Until the mid-1970s, international and New Zealand suicide rates were highest amongst older males and concerns centred on this group. When suicide rates amongst young males in New Zealand increased dramatically from the mid-1970s, the focus of interest moved from older people to youth. In many countries, however, there was no substantial increase in youth suicide rates at this time, and interest in the issue of suicide rates amongst older adults was maintained. Internationally, there has been a recent resurgence of interest in older-adult suicide, with recognition that the progressive ageing of populations in the industrialized world is likely to increase absolute numbers of suicides and suicide attempts among older adults. Further concerns about suicidal behaviour in older adults have been prompted by recent focus on the issues of assisted suicide, euthanasia, ‘right to die’ arguments, longer life expectancy for the elderly, and limitations on the availability of health resources.
Suicidal behaviour in older adults has a number of features that are not shared with younger age groups.37 Older adults make fewer non-fatal suicide attempts than younger people. Reasons for this may include their being physically more frail, and therefore less likely to survive suicide attempts; that they are more often living alone, and so less likely to be found in time to be helped after a suicide attempt; and that they use more lethal methods of suicide attempt, perhaps reflecting a stronger intent to die. Finally, although the risk factors for elderly suicide overlap with risk factors for other age groups, amongst older age groups mental health factors, predominantly depression, play a more significant role.16
Risk and protective factors for suicide in Maori
This review provides a perspective on risk and protective factors in suicide from population-based studies. The extent to which the findings from these studies apply to Maori is largely unknown. In particular, there have been suggestions that, while Maori may share risk factors with non-Maori, their unique cultural and historical background may present different risk factors and interpretations for suicidality than those for other New Zealand groups:38,39
‘There are additional risk factors which apply only to Maori and other indigenous youth. These are the risk factors relevant to cultural alienation, the impact of history through intergenerational modelling and behavioural transfer, and confusion over identity.’38
The extent to which this is so remains to be determined, but this issue is being investigated by projects funded by the Health Research Council focused on risk and protective factors for Maori youth suicide. Parallel research is being conducted for Pacific Island youth (www.hrc.govt.nz).
In contrast to youth suicide, where Maori have higher rates than non-Maori, rates of suicide for Maori adults ≥25 years are similar to, or lower than, non-Maori rates (www.nzhis.govt.nz). There has been relatively little research to examine the extent to which risk and protective factors for suicidal behaviour in Maori adults differ from, or are similar to, those for non-Maori. There is some limited suggestion that aetiological factors may differ with ethnic identification. For example, official statistics suggest that suicide amongst Maori aged ≥45 is virtually non-existent, suggesting culturally specific factors that protect this group against suicide. In 1999, amongst those aged ≥45, only one Maori person died by suicide, compared with 154 non-Maori. In addition, research in the 1980s suggested that approximately one quarter of all Maori male suicide deaths were accounted for by suicides in prisons.40 The extent to which this trend holds at the present time is not known.
Implications for prevention: youth
The research findings outlined above provide the foundations for developing prevention approaches to reduce suicidal behaviour. The evidence suggests that such policies should be organised around two major themes:
1. Youth mental health
While a range of social, personality, childhood and related factors make contributions to risks of suicidal behaviour, by far the largest contribution comes from mental health measures and, particularly, mood disorders, previous suicidal behaviour, and prior mental health problems.41 These findings imply that a major plank of any suicide prevention strategy must involve approaches that aim to improve the detection, treatment, management and prevention of these disorders in young people.
There are a number of approaches by which this general objective might be achieved:
(a) Population-based programmes The most general way is through population-based approaches that encourage positive mental health, improved public understanding of mental illness, and improved detection, treatment and management of mental disorders. For suicide prevention two approaches may be of particular use: initiatives focusing on the better recognition, treatment and management of depression in young people; and parallel programmes designed to address substance-use disorders. For example, population-based drug prevention programmes delivered in schools have been found to reduce both drug and polydrug use.42
(b) Clinical interventions Although population-based initiatives may reduce rates of mental disorders within the population, inevitably a fraction of the population will develop such disorders. This requires the availability of adequate psychiatric services to address the mental health needs of young people within tertiary, secondary and primary care.
(c) Support for at-risk youth A significant proportion of those dying by suicide have made a previous suicide attempt, suggesting that one approach to suicide prevention is through evidence-based, targeted programmes that attempt to address the psychiatric and other needs of young people following their contact with health services for suicide attempts. Research has identified a further population of at-risk young people – specifically, those with conduct disorder and antisocial behaviours – suggesting that another approach to suicide prevention is through the development of evidence-based prevention programmes targeted to young people in juvenile justice programmes and institutions. An example of support programmes for at-risk youth is provided by a programme targeting youth at risk for high-school dropout, of whom approximately 40% have been shown to be also at risk for suicidal behaviour.43 Those who participated in a classroom programme designed to provide support and increase skills were found to have decreased levels of suicide-risk behaviours, depression, hopelessness, anger and stress, and increased levels of social support, self-esteem and personal control.44
2. Early intervention
A second theme that pervades research into youth suicidal behaviour is that a small but conspicuous group of young people vulnerable to suicidal behaviours is characterised by childhood histories of social disadvantage and family dysfunction. These findings suggest that an important step in reducing the number of young people who are vulnerable to suicidal behaviours is through programmes that reduce the number of children exposed to unsatisfactory, disadvantaged or dysfunctional environments that lead to risk of later suicide attempt.
There are a number of strategies by which this target might be achieved:
(a) Population-based programmes Programmes designed to reduce social inequity and social discrimination may make an effective contribution to youth suicide prevention by providing an equitable social environment in which other, more-targeted approaches to suicide prevention would have their best chance of success. Another population-based approach is focused on the development of general mental health programmes, which aim to foster good mental health skills to promote resiliency and address the psychosocial needs of young people exposed to stress and adversity. There is increasing emphasis in youth suicide prevention efforts, for example in the USA, on school-based competency-promoting and stress-reducing programmes to reduce risks of mental disorders and behaviours with which suicidal behaviour is associated.45
(b) Support for at-risk families and children A further approach to youth suicide prevention lies with the provision of family support and early intervention programmes targeted to at-risk families and designed to ameliorate infant and early-childhood exposure to family disadvantage and dysfunction, and to optimise childhood and adolescent educational and life opportunities.
In addition, an important New Zealand research finding has been that young people in welfare care are at increased risk of suicidal behaviour compared with their peers who do not access welfare care.46 A further approach to suicide prevention may lie in developing targeted programmes to ensure young people in welfare care receive adequate, supportive care and protection, and appropriate mental health services.
A major population-based component of many national suicide prevention strategies focuses on restricting access to means of suicide. However, the ubiquitous availability of the most common methods of suicide in New Zealand (hanging, vehicle exhaust gas), suggest that there is limited scope for the restriction of access to means of suicide to play a substantial role in New Zealand suicide prevention, for youth or adults.
Most young people who die by suicide are not teenagers but young adults aged 20–24 years. However, the majority of those who make non-fatal suicide attempts are young (predominantly female) teenagers. This observation implies that youth suicide prevention programmes need to be inclusive and developed for the entire age range 15–24 years. To date, youth suicide programmes have tended to focus on school-based approaches. There is a dearth of prevention programmes appropriate for young males aged 19–24 who have left school.
The effective prevention of youth suicide will likely require a multi-sectoral approach that integrates both individual-level and population-level programmes to minimise the circumstances that encourage suicidal behaviours in young people. There is also a need to develop a public/private partnership to address youth suicide prevention, with this partnership coordinated across government agencies and integrated across public and private sectors. Such structures will require adequate government and community support and resources to ensure that reductions in youth suicide rates are pursued using empirically developed and well-evaluated programmes.
Implications for prevention: adults
The profile of risk and protective factors in adults is similar in many ways to that for youth. The major exception is that childhood and family experiences appear to play a lesser role in suicidal behaviours by older people and, conversely, mental health factors and recent life events emerge as being more influential. This is particularly evident for mood disorders, which play an increasingly significant role in the aetiology of suicide with increasing age. For example, in the Canterbury Suicide Project, amongst those aged 55 and older, individuals with a current mood disorder had odds of suicidal behaviour and attempt that were over 150 times higher than the odds for those without mood disorders.16 In contrast, amongst those aged 25 to 45 the odds ratio was 20.25 The major implication of these findings is that for adult, and particularly older adult, populations prevention strategies should focus very strongly on the detection, treatment and management of depression and the better recognition of the life event, social, family and related factors that may contribute to the development of depression in older adults.
An example of such approaches is provided by a structured education programme for general physicians on the island of Gotland that focused on the recognition and treatment of depression. Several outcome measures were assessed, including antidepressant and anxiolytic prescribing, referrals for psychiatric consultation, psychiatric inpatient treatment, sick leave for depression, and suicides. Positive results were found for the programme, although the findings were the subject of some debate. The suicide rate subsequently increased, coincident with the departure of almost half of the physicians trained in the programme.47,48
A further example of a community-level programme is provided by the US Air Force suicide prevention programme, which appears to have reduced suicide rates by focusing on improving knowledge and attitudes about suicide, increasing identification of at-risk individuals and improving access to help and treatment (http://www.e-publishing.af.mil/pubfiles/af/44/afpam44-160/afpam44-160.pdf). A similar approach could be adopted by workplace organisations and institutions with high rates of suicide.
Many adult and older-adult suicidal individuals appear to have generally poor social circumstances. The extent to which these circumstances arise from psychopathology (particularly depression) and personality traits, and the extent to which it might be possible to encourage social participation by at-risk individuals is an area in which further research is needed. A promising finding in this area, for example, is suggested by reduced suicide rates (at least for females) reported for an elderly population who were supported by regular telephone contact and needs assessment.49
The majority (75%) of those who die by suicide have contact with primary-care providers in the year prior to death, and one third have contact with mental health services.50 In the final month before death, 45% of suicide victims have contact with primary-care providers, with rates of contact higher amongst older, compared with younger, adults. These contacts suggest primary care providers are potentially well placed to detect and assist a substantial fraction of those with mood disorders and suicidal behaviours. However, there is also a need to improve public knowledge and attitudes about mental illness, depression and treatment, in order to encourage and support help-seeking behaviours amongst those adults, predominantly males, who do not presently go to primary care providers. For this group, there is also a need to develop alternative sources of community-based support.
The need for a national suicide prevention strategy for all ages
In recent years, the emphasis in New Zealand policy in suicide prevention has been almost exclusively in the area of youth suicide. This is reflected in the fact that New Zealand has a National Youth Suicide Prevention Strategy but no parallel strategy for adults. In addition, responsibility for youth suicide prevention programmes is vested in the Ministry of Youth Affairs. There are no parallel structures within the Ministry of Health for adults and older adults. New Zealand has (unusually) appointed an Associate Minister of Health with special responsibility for youth suicide prevention, yet there is no ministerial responsibility for suicide prevention in general.
This emphasis on youth suicide has been motivated by continued claims that New Zealand has ‘the highest rate of youth suicide in the world’. This claim is not correct and, furthermore, has obscured the fact that the majority of those dying by suicide in New Zealand are not youth but rather adults aged 25–45. These considerations suggest that there is an urgent need to develop a national suicide prevention policy that is applicable to all age groups, and accords all age groups equal levels of care and protection. The above review suggests that much of this policy can be borrowed and adapted from existing youth suicide prevention policies. However, policies for adults and older adults may need to place less emphasis on childhood, family and social factors, and greater emphasis on mental health factors and particularly on the role of depression.
New Zealand was notable in being amongst the first countries to develop a national youth suicide prevention strategy. However, in the area of adult and older adult suicide prevention New Zealand now lags behind other countries in that research, policy and political interest have virtually ignored the problem of suicide in adults. The result is that New Zealand is now unique in the world in having a youth suicide prevention policy but no parallel policy to address suicide prevention in adults. The United States, the United Kingdom, Australia, Canada, Finland, Sweden, Norway, and a number of other countries now have suicide prevention strategies for people of all ages. It does not seem acceptable for policy processes in New Zealand to have disenfranchised the majority of those dying by suicide in this way.
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: firstname.lastname@example.org
issue | Search journal |
Archived issues | Classifieds
| Hotline (free ads)
Subscribe | Contribute | Advertise | Contact Us | Copyright | Other Journals