EXECUTIVE SUMMARY
Background
The Scottish Development Centre for Mental Health, in partnership with the University of Edinburgh (Research Unit in Health, Behaviour and Change and General Practice Section) and the University of Stirling (Department of Applied Social Science and Department of Nursing and Midwifery), were commissioned by the then Scottish Executive to undertake a review of the literature on risk and protective factors for suicide and suicidal behaviour.
The review had two overarching aims: first, to describe and assess current knowledge regarding the societal and cultural factors associated with increased incidence of suicide (risk factors), and to delineate the population subgroups that are at increased risk of suicidal behaviour; and second, to describe and assess current knowledge regarding factors that promote resilience and healthy survival against suicidal behaviour amongst people who are exposed to known suicidal risk conditions (protective factors).
Methods
The review was undertaken in four stages: first, the search for high quality systematic reviews relating to both risk and protective factors; second, the search for primary studies relating to protective factors; third, consultation with an expert panel to identify other evidence (e.g. in unpublished reports or the 'grey' literature) relating to protective factors; and, fourth, mapping the evidence on both risk and protective factors to identify the best quality and most recent studies for inclusion. At Stages 1 and 2 attention was paid to the recognition of areas characterised by an absence of evidence. Reviews/primary studies had to be published in the English language between January 1996 and February 2007.
Reviews/primary studies which focused on experimental studies of interventions, assisted suicide/euthanasia, suicidal thoughts and ideation (when not linked with suicidal behaviour) and self-destructive behaviours (such as pathological gambling or dangerous driving) were excluded. References were mapped into categories, informed by checklists of known risk and protective factors at individual, psychosocial and societal levels. Gaps in the evidence were identified and detailed. Data was extracted into a database specifically tailored to the requirements of the review. A robust quality assessment strategy, drawing on checklists relevant to the range of studies included in the review, was employed. An assessment of the transferability of findings to the Scottish context was made for each included review/study. The results were analysed and synthesised around the categories illustrated by the mapping tools for risk and protective factors, risk groups and levels of determinant. Particular attention was paid to drawing out data on marginalised groups.
Results
Results of the review are presented in two main sections. The first presents evidence from systematic reviews of risk factors, while the second contains both review-level and primary study evidence related to protective factors against suicidal behaviour. In total, there were 23 systematic reviews of risk factors, one systematic review of protective factors, and 44 primary studies relating to protective factors.
Risk factors
Mental illness
Across all age groups, genders and in a wide range of geographical locations, several diagnoses of mental illness, including affective disorders, schizophrenia, personality disorders and childhood disorders, and a history of psychiatric treatment in general have been established as risk factors for completed suicide. In schizophrenia and borderline personality disorder suicide risk appears to be elevated around the time of first diagnosis. For bipolar disorder and schizophrenia the elevated risk of suicide is further exacerbated by other risk factors, such as a history of suicide attempts, other psychiatric diagnoses, drug or alcohol misuse, anxiety, recent bereavement, severity of symptoms and hopelessness.
Attempted suicide
Those who self-harm have a much greater risk of dying by suicide compared with those who do not engage in this behaviour.
Substance misuse
Substance misuse increases the risk of suicide attempt and death by suicide. The risk associated with opioid use disorders and mixed intravenous drug use is greater than that for alcohol misuse. The risk of suicide from alcohol misuse is greater among women than among men.
Epilepsy
There is increased suicide risk associated with epilepsy. This risk varies across different types of epilepsy and in relation to the degree of severity of the effects of the illness. Persons who have temporal lobe epilepsy or who have had temporal lobectomies or surgical resections have an even greater risk of suicide.
Personality traits
There may be increased suicide risk associated with particular individual/personality factors. The evidence is particularly heterogeneous in this section both within and between reviews. Nevertheless, it can be stated with reasonable confidence that suicide risk is higher in: a wide range of personality traits including hopelessness, neuroticism, extroversion, impulsivity, aggression, anger, irritability, hostility, anxiety, attention deficit hyperactivity disorder ( ADHD) and eating disorders such as anorexia nervosa and bulimia; and low problem-solving skills.
Genetic predisposition
Two reviews explored the evidence for genetic links to suicidal behaviour. There was no association between an intron 7 polymorphism of the TPH gene or for the 5- HT2A gene and suicidal behaviour.
Menstrual cycle, pregnancy and abortion
The risk of suicide attempt may increase in phases of the menstrual cycle which have lower oestrogen levels and in women who suffer from pre-menstrual syndrome. Pregnancy was also identified as a period during which women may experience elevated risk of suicidal behaviour. Furthermore, there is limited evidence that suicide rates are higher in women who have abortions compared to those who carry the baby to full term. However, careful analysis and replication of these findings is required and any confounding factors such as abuse rates or mental illness should be examined.
Unemployment
Unemployment is linked to elevated risk of suicide. Occupational social class and suicide and deliberate self-harm ( DSH) are inversely linked: the lower the social class, the higher the risk of suicidal behaviour. Despite this, the highest proportional mortality rates for suicide are found in medical doctors and farmers, with female doctors having a higher risk of suicide than male doctors, reasons for this are not clearly established. Employment in the police force was not found to be a risk factor for suicidal behaviour.
Poverty
Poverty and deprivation are linked to suicide risk at an ecological (area) level. Areas with greater levels of socio-economic disadvantage (lower SES) have higher suicide rates.
Protective factors
Coping skills
Problem-solving skills may be protective against suicidal behaviour among those who have attempted suicide. There is conflicting evidence on the interplay between the suicide risk factor of hopeless and problem-solving-based coping skills. One study shows that problem-solving coping may mediate against hopelessness among adults who have attempted suicide while another demonstrates that hopelessness can mediate against the protective effect of problem-solving-based coping.
A number of coping skills requiring an element of self agency appear to be protective against suicidal behaviour particularly among adolescents, including self-control and self-efficacy, instrumentality , social adjustment skills, positive future thinking and sublimation. Being in control of emotions, thoughts and behaviour can mediate against suicide risk associated with sexual abuse among adolescents.
Reasons for living
High levels of reasons for living, future orientation and optimism protect against suicide attempt among those with depression. Hopefulness is protective against suicide among African-American women exposed to poverty and domestic violence. There is some evidence that those who have previously attempted suicide can develop positive coping strategies to protect themselves against future suicidal behaviour. Resilience factors are better predictors of suicidal behaviour than the amount of exposure to stressful life events.
Physical activity and health
There is some evidence that an attitude towards sport as a healthy activity and participation in sporting activity is protective against suicidal behaviour among adolescents. A perception of positive health may be protective against suicide among females who have experienced sexual abuse.
Family connectedness
Good relationships with parents mitigate against suicide risk, especially in adolescents and including those who have been sexually abused. Positive family relationships also provide a protective effect for adolescents including those with learning disabilities. Further evidence suggests that positive maternal coping strategies can have a protective effect on female adolescents. Having children living at home is protective against suicide for women; however, another study indicates that this protective effect may not exist among women who are HIV-positive.
Marriage is a protective factor against suicide (although more so for white females than black females in the USA). There is also evidence that marriage has a protective buffering effect against socio-economic inequalities related to suicide, particularly for men. It is important to consider other confounding variables including the finding that married men were less likely than non-married men to have problems with drugs, sex, gambling and having used or currently using psychiatric medicine.
Supportive schools
Supportive school environments, including access to healthcare professionals, are important protective factors among adolescents including those who have experienced sexual abuse, those with learning disabilities and those who identify as lesbian, gay, bisexual or transgendered.
Social support
Social support in general is protective against suicide among a range of population groups, including black Americans and women who have experienced domestic abuse.
Religious participation
There is a wide range of evidence to suggest that religious participation may be a protective factor against suicidal behaviour. However, the protective effect of religious participation can vary according to the level of secularisation within a country or community and social and cultural integration. Moral sanctions against suicide promoted by members of a religious community may have wider protective effect on the non-religious members of a community where the religious members are in the majority. Religious observance does not confer equal protection on individuals. Other factors, such as the observance of traditional cultural rituals, may have a stronger protective effect. The manner in which individuals relate to their God (in terms of religious coping style or private versus public expressions of religiosity) may further highlight different levels of protective factors within a single religious community.
Employment
There is some evidence that employment, especially full-time, has a protective effect against suicide. However, employment was not found to be protective among women who were HIV-positive.
Exposure to suicidal behaviour
One study found that exposure to accounts of suicidal behaviour in the media and, to a lesser extent, exposure to the suicidal behaviour of friends or acquaintances may be protective against nearly lethal suicide attempts. However, it is important to note that there is also a body of evidence of the suicide risks associated with media reporting.
Social values
Traditional social values may have a protective effect against suicidal behaviour among adolescent girls, while individualistic values may have a protective effect among adolescent boys.
Health treatment
Access to treatment by a health professional may be protective against repeat suicide attempts.
Gaps in the evidence available to this review
Key gaps in the review-level evidence for risk are:
- Children, especially looked after children
- Older people
- Being affected by aftermath of suicidal behaviour or completed suicide
- Prison/incarceration of young offenders
- Bereavement
- Rural/isolated communities
- Urban deprivation
- Homelessness
- HIV/ AIDS
- Being LGBT
- Isolation and loneliness
- Aggression/violence
- Non-help seeking
- Those who have been physically and sexually abused
- Media exposure to suicide
- Disability
Primary study level evidence is available for these gaps. Gaps identified in the evidence for protective factors were:
- Self help and help seeking
- Neighbourhood quality
- Social capital
- Older people
Conclusions
The interplay between a number of risk and protective factors at individual and psychosocial levels that may impact in different ways on different individuals and communities at different times, must be taken into consideration when attempting to understand which factors promote resiliency and vulnerability to suicide and suicidal behaviour. Suicide is complex, risk can change with circumstance, what is a risk or protective factors for one person may not be the same for another in similar circumstances.
The evidence in this review reinforces the current approach to suicide prevention policy in Scotland and suggests that those involved in suicide prevention policy should consider identifying strategies that:
- tackle societal and structural risk determinants that result in social injustices that lead to social and health inequalities which the evidence links to inequalities in suicide risk
- enhance individual and psychosocial protective factors in the general population (and those who are more vulnerable) that prevent them from becoming future members of suicide risk groups where possible e.g. mentally ill, prisoners, unemployed, in poverty
- focus on developing family and community connectedness
- challenge and identify ways to remove cultural values and beliefs that unfairly expose certain groups to elevated suicidal risk such as those who are sexually abused, LGBT, prisoners, older people from society and institutions
- target interventions to particular suicide risk groups taking into account the highly distinct and individual risk and protective combinations to which people are exposed to
- seek to identify mechanisms that reduce the exposure of individuals and communities to multiple risk factors
- seek to identify mechanisms that increase the exposure of individuals and communities to multiple protective factors
- Ensure the continuation of the current national and local initiatives to work with the media, in particular the press, to enhance the protective aspects of responsible reporting of suicide
- support research that can increase knowledge and understanding of the complex interplay between risk and protective factors at individual, psychosocial and societal levels amongst different individuals and population groups across the life span
The importance of multi-strategies to strengthen protective factors, such as increasing problem-solving capabilities in individuals whilst promoting the development of supportive family and school environments is emphasized.
Future research on the determinants of suicide and suicidal behaviour should:
- address marginalised groups by building in greater ethnic and cultural diversity in samples
- explore resilience and protective factors within the context of the interaction of protective factors, adversity and risk factors rather than assume that protective factors can be identified as simply the inverse of risk
- attempt to understand the links between individual, psychosocial and societal risk and protective factors by using multi-level modelling to combine these variables in studies
- explore the individual, psychosocial and societal-level causal mechanisms behind the protective effects of spirituality
- address differences and commonalities between exposure to risk and protective factors between males and females as the determinants literature provides little evidence on why there should be different rates of suicide for males than females
- develop qualitative study designs that can provide further indepth and individualised insights into the complexities of modelling the interplay between risk and protective factors for suicide and suicidal behaviour across the life course