Suicidal Behaviour Brian Draper

RISK FACTORS FOR SUICIDAL BEHAVIOUR

Risk factors in late life are similar to younger age groups and include demographic characteristics, psychopathology, personality traits, traumatic life events, physical ill health and disability, previous suicidal behaviour, genetic factors and access to lethal means². However, over the age range, factors have different levels of influence, with one psychological autopsy study finding major depression was more likely in suicides aged over 55 years while substance abuse was more likely in suicides aged 21 -54 years⁷. Risk factors that are more overtly important in suicidal behaviour in younger people may still convey vulnerability in late life. In a life cycle approach to understanding the development of risk for late life suicidal behaviour, it is important to recognize that some pathways begin early in life. It is often the interaction of distal risk factors with proximal factors that provides the lethal mix.

Demographic Factors

Across the life span, males have approximately a four times higher risk of suicide than females and with advancing age the male to female ratio increases¹. Females are at higher risk of non-fatal suicidal behaviour, with rates about 1.5 times higher than males, but the rates tend to converge with advancing age⁶ . There is some evidence that suicidal behaviour is more common in those who are divorced or widowed^2,4.

There is heterogeneity of suicide rates between countries and ethnicity appears to be a factor, with different suicide rates of ethnic groups within multicultural societies². For example, in Australia suicide rates of older migrants are closely related to suicide rates in their country of origin⁸. Other cross-national research has found elderly suicide rates to be associated with population growth, the elderly dependency ratio and the proportion of elderly in the population⁹. There is also regional variation within countries, with higher rates reported in rural areas of some countries such as Australia¹⁰. In the United States, cross-state variation is related to macro-social indicators of social integration and aspects of state-level policies¹¹. Low socioeconomic status has been found as a risk factor worldwide¹.

Early Life Factors

Genetic factors contribute to suicide risk by mediating transmission of impulsive aggression or neuroticism and neurocognitive deficits¹². While there has been little research in late life, one study has suggested that an interaction between genetic factors and the physiological effects of ageing might have an important role in violent suicides¹³. Genetic factors also work indirectly by increasing the risk of mood disorders and substance abuse¹².

Childhood adversity, which includes abuse and parental neglect through death, separation and inadequate care, is a well-established risk factor for suicidal behaviour, depression and substance abuse in younger adults¹²‘¹⁴. There is increasing evidence that childhood adversity influences late life suicidal behaviour and mental disorders too. Higher rates of childhood adversity were found in older persons who attempted suicide compared with controls¹⁵; childhood physical and sexual abuse was significantly more frequently reported by older persons with a history of suicidal behaviour, mood disorders and alcohol abuse in a large general practice survey¹⁶; and the risk of attempted suicide and suicide is higher in older Holocaust survivors¹.

Childhood adversity and genetic factors also affect personality development. A number of personality traits have been linked to suicidal behaviour in late life, including inflexibility, anxious, obsessional and ‘low openness to experience’ (individuals that are comfortable with the familiar and have a constricted range of interests) traits¹‘¹⁷. In essence these traits describe an older individual who has difficulty coping with the challenges related to ageing, including failing health, loss of confidants and demanding life events.

Adulthood Factors

It would seem self-evident that the lifestyle followed by an individual as an adult, including their interpersonal relationships and employment, will have some bearing on their health and well-being in late life. For example, involuntary job loss near retirement age has been found to lead to enduring depressive symptoms in individuals with low finances¹⁸.

The links to late life suicidal behaviour are indirect and largely mediated through the impact mid-life lifestyle factors have upon the development of late life risk factors such as physical health and depression. There is increasing evidence that mid-life vascular risk factors such as hypertension, smoking, diabetes and metabolic syndrome, which are associated with lifestyle factors such as diet and exercise, may lead to late life depression, cognitive impairment, and cerebrovascular and cardiovascular disorders^19,20. Further, a case- control of suicides over age 50 years found that cerebrovascular risk factor scores were significantly higher in suicide cases²¹.

Late Life Factors Psychopathology

Up to 97% of older persons with serious suicidal behaviour have a mental disorder^1,4,5,22. A review of controlled psychological autopsy studies found that the presence of any Axis I disorder was associated with an elevated risk of suicide in older persons with significant odds ratios ranging from 27.4 to 113.1²². Depression is the major independent risk factor across cultures and although the type of depression varies, major depression is the strongest predictor of suicidal behaviour in late life, accounting for about 50% of cases^1,4,5,7,22. Although many cases are recurrent episodes, first-episode major depression is prominent too^1,4,22. Other types of depression including dysthymia, minor depression and subsyndromal depression are also important and may have a particular role in older persons with co-morbid chronic physical ill health and disability^1,4. In the context of recovery from a depressive episode, unremitting hopelessness can increase suicide risk²³.

Other mental disorders are less commonly found in late life suicidal behaviour, though co-morbid disorders are common^1,4,5,22. Late- life psychoses, including schizophrenia and bipolar disorder, account for less than 10% of attempted and completed suicides^1,4,5,22. The role of anxiety disorders is unclear, with some studies finding an increased risk though it seems usually in the context of mixed anxiety/depressive states^1,22. Alcohol abuse, though less frequently implicated in old age compared to younger suicides, remains a significant factor especially with co-morbid depression^1,4,5. Personality disorders are less common in suicidal behaviour in late life compared with younger cohorts, being present in 2.5-7% of older suicide attempters^1,5.

Until recently, dementia has not been regarded as a risk factor for suicide. A nationwide longitudinal study from Denmark using register data reported that hospital-diagnosed dementia was associated with an elevated risk of suicide particularly in those aged 50-69 years, where the relative risk was 8.5 in men and 10.8 in women. The risk was higher in the first three months after diagnosis, particularly in men. Controlling for mood disorders reduced but did not eliminate the increased risk. The risk was higher in Alzheimer’s disease than in vascular dementia²⁴. In some, frontal lobe impairments may lead to impulsive, poorly planned attempts. It is unclear whether insight into the dementing process is a factor that increases the risk of suicidality^1,4.

Previous suicidal behaviour

Compared with younger age groups, a history of suicidal behaviour is less frequent in older persons with suicidal behaviour but follow-up studies of older suicide attempters have found high rates of repetition^1,25. In the WHO/EURO multicentre study of suicidal behaviour, 13% of older people admitted to hospital after a suicide attempt died by suicide within 12 months and 11% made further attempts²⁵. Survivors of suicidal behaviour in old age remain a high risk group and require close monitoring. Observational studies suggest that older suicide attempters are likely to receive specialist mental health management, particularly if they have a diagnosed mood disorder, but treatment studies are lacking⁵.

Physical health and disability

While physical ill health is a contributory factor in most cases of late life suicidal behaviour, its precise role is unclear¹. Some studies have found an independent effect of physical illness that is increased when there are multiple illnesses, while others have found little evidence of a physical illness effect^1,26. There is a lack of consistency regarding specific illnesses that might increase suicide risk, but chronic pain, breathlessness and functional impairment are frequently reported features^1,26. These may result in dependence on carers, loss of dignity and the fear of institutionalization that may contribute to demoralization, depression and suicidality. A threshold phenomenon may exist whereby the physically ill may become suicidal with milder degrees of depression⁴, or, put another way, physical illnesses may amplify suicide risk in those with premorbid vulnerability²⁷. Depression, pain and insomnia have the capacity to temporarily affect judgement by subtly distorting the patient’s perceptions in a manner that may convince family, friends and doctor of the ‘rationality’ of suicide, especially in those with terminal illness, which is present in about 5-10% of older persons with suicidal behaviour. Yet the wish to die usually resolves once these symptoms are treated. Psychological reactions occur, with some people feeling overwhelmed by the knowledge of a serious illness and others convincing themselves that they have cancer, often ignoring reassurances by their doctor²⁸. Some physical illnesses, including cancers, thyroid disorders and cerebrovascular disease, can cause severe depression and these might not be detected until after a suicide attempt⁴.

Psychosocial factors

In general, disruption of social ties increases suicide risk in old age independent of the presence of mental disorders²². As in other age groups, family discord is perhaps the most powerful psychosocial factor¹‘²²‘²⁷. In many cases the problems are chronic and there is some evidence that males are more vulnerable¹. It is likely that chronic family discord interacts with physical health issues in situations that include those who are disabled and feel a burden on others, and in caregivers who become severely stressed in caring for a disabled partner, where there is an increased risk of murder/suicide¹. A range of other life events, particularly those involving loss, including recent bereavement, and financial problems have been implicated in late life suicidal behaviour^1,4,5,27.

Living alone has consistently been identified as a factor and this is often regarded as a proxy for loneliness, social isolation and inadequate social support^1,4,5,22. Accommodation issues, including fear of nursing home placement and dissatisfaction with living arrangements, are also reported^1,4. It is unclear whether the suicide rate in nursing homes is different to the general population but the main risk factors of depression and physical disability are the same¹ . Indirect self-destructive behaviour, including refusal to eat, drink or take medications, is common in nursing home residents and while most cases appear to be associated with severe dementia rather than depression with suicidal intent⁶, there are likely to be some suicidal individuals.

Biological factors

As with the previously mentioned genetic factors, two other biological factors associated with suicide have not been well studied in late life. Serotonergic neurotransmitter abnormalities have been found to be associated with suicidal behaviour across the age range with low levels of 5-hydroxyindoleactic acid in cerebrospinal fluid²⁹. Non-suppression of the dexamethasone suppression test, which is a measure of the hypothalamic-pituitary axis activity in mood disorders, is also predictive of suicide²⁹.

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