ETIOLOGY AND RISK FACTORS

The exact cause of suicidal behavior is unknown, but it is clear that the etiology is multifactorial (Zalsman, 2019). Studies done to date have found that suicide is most often caused by a collection of risk factors and underlying vulnerabilities, as discussed below.

Biologic Factors

Biologic factors that contribute to suicide include a person’s genetic predisposition and personality traits, neurobiology, structural brain changes, immune system dysregulation, neuropsychology, and psychopathology.

NEUROBIOLOGY

Suicide is the result of a complex set of factors reflected in the neurobiology of the suicidal individual. Data indicate that mental disorders are present in over 90% of suicides in our society, and many of them are associated with biological changes. However, there are many other factors that correlate with suicidality that also have biological aspects, including predisposing personality traits, effects of acute and chronic stress, gender, and age (NAS, 2019).

Serotonin and Epinephrine

Reduced serotonergic neurotransmission has been a long-standing hypothesis in the etiology of suicide and mood disorders, and evidence suggests that serotonin mediates inhibition of impulsive action (Underwood et al., 2018: NAS, 2019).

Suicidal individuals also appear to have lower levels of norepinephrine, also called noradrenaline, in the part of the brain called the locus ceruleus. Norepinephrine participates in modulation of numerous behaviors (including stress response) and promotes formation of and strengthens memories, especially those created in stress situations. It has profound effects on a small set of behaviors, including those that are commonly disrupted in depression (Khroud & Saadabadj, 2019).

Hypothalamic-Pituitary-Adrenal Axis

The hypothalamic-pituitary-adrenal (HPA) axis is a system tying together the hypothalamus and the pituitary gland with the adrenal glands. It controls the body’s responses to actual, anticipated, or perceived harm. It also controls the ability to adapt to stressors over time. Dysregulation of the HPA axis in vulnerable people can lead them to develop severe depression, severe anxiety disorders, and suicidal behavior following traumatic events or chronic stress (Reiss & Dombeck, 2019a; NAS, 2019).

STRUCTURAL CHANGES IN THE BRAIN

From brain scans, researchers have found there are significant differences in the volume of gray matter between people who have attempted suicide and those who have not. Those who attempted suicide had less gray matter in regions related to emotional regulation, emotional response, and memory. They also had a decreased amount of white matter connecting brain areas that are involved in these functions. Structural changes within the frontostriatal pathway may result in an impaired control of behavior and emotion, leading to suicidal behavior (Balcioglu & Kose, 2018).

INFLAMMATION

Mounting evidence implicates dysregulation of the immune system in the pathophysiology of suicidality, suggesting that inflammation is involved in suicidal behavior. Where inflammation of the brain was noted, it was usually in the anterior cingulate cortex, which is involved with cognition and emotional responses. Signs of inflammation were also noted to a smaller degree in the insular cortex, which plays a role in regulating emotional function, and in the prefrontal cortex, implicated in cognitive processes related to behavior (Holmes et al., 2018; Brundin et al, 2017).

NEUROPSYCHOLOGICAL DEFICITS

Neuropsychological deficits can develop during the prenatal, perinatal, and postnatal periods of life. Prenatal causes may include genetic or chromosomal disorders, metabolic conditions, brain malformations, or maternal disease. Perinatal causes may involve events during labor and delivery leading to encephalopathy. Postnatal causes may include hypoxic ischemic injury, infections, traumatic brain injury, and severe and chronic social deprivation, among others (Schofield, 2018).

PSYCHOPATHOLOGY

Psychiatric diseases account for a large majority of suicides and suicide attempts—at least 10 times as high as in the general population. Psychological autopsies (collected from family relatives, friends, and healthcare providers) from the middle of the previous century and onward have revealed that most (at least 90%) of those who have died by suicide were experiencing a mental disorder, the relevant risk factors being depression, substance use disorders, and psychosis (Brådvik, 2018; Bachmann, 2018).

Anxiety disorders more than double the risk of suicide attempts, and a combination of depression and anxiety greatly increases the risk. Symptoms of psychosis (delusions, command auditory hallucinations, paranoia) may increase the risk regardless of the specific diagnosis (Schreiber & Culpepper, 2019).

One in four active duty members of the U.S. military exhibit symptoms of mental illness, which are mostly the manifestation of posttraumatic stress disorder (PTSD), depression, traumatic brain injury, and/or stress related to transition back to civilian life (Shirol & Current, 2019).

Psycho-Sociocultural Factors

Psycho-sociocultural factors refers to a person’s ability to consciously or unconsciously interact with the social and cultural environment. They involve past experiences; the environment in which a person lives; the relationships with and support from others; the cultural norms; and the cognitive abilities, intellect, personality, and other psychological factors that make someone respond to their environment in their own unique way.

DEVELOPMENTAL FACTORS

A body of research indicates that early-life events occurring before or around the time of birth or in the first years of life can play a role in influencing susceptibility to suicide.

While studies suggest that early-life factors may predispose to suicide, the mechanisms involved remain unknown. It is possible that they can produce changes in DNA methylation that subsequently influence an individual’s vulnerability to mental disorders and suicide (Björkenstam et al., 2017).

Epidemiology shows that major risk factors for attempted suicide or suicide are childhood adversities such as sexual and/or physical abuse, neglect, caregiver psychopathology, and family or community violence (Geoffroy et al., 2017).

SOCIAL FACTORS

Having a network of supportive family, friends, and colleagues is important to a person’s self-esteem. Those with close social relationships cope better with stress and have better overall psychological and physical health. Isolation, however, can lead to feelings of depression and alienation, both of which can lead to suicidal thoughts and behaviors (Reiss & Dombeck, 2019b).

SOCIOCULTURAL FACTORS

Sociocultural factors are customs, lifestyles, and values that characterize a society. They include aesthetics, language, law, politics, religion, social organization, marital status, technology, material cultures, values, and attitudes.

Cultural groups can be supportive, creating feelings of belonging and serving as a safety net when members need support while experiencing problems or stressors. Being a member of a tightly united group can serve as a suicide deterrent.

The “down side” of group membership may be that it requires stressful obligations and high levels of commitment, leading a member of the group to adapt to the norms rather than think for themself. Some groups can be repressive and oppressive, which may contribute to suicidal thoughts and feelings. Some groups may even demand a person sacrifice him- or herself for the greater good (Reiss & Dombeck, 2019b).

Marriage is considered a cultural universal. Suicide occurs more frequently in people who are not married than those who are, and the risk of suicide is nearly two times greater in the nonmarried than the married (Schreiber & Culpepper, 2019).

Occupation-related factors have an influence on suicidal behavior. Suicide may be greater in those who work in unskilled occupations. Among highly skilled workers, physicians have the highest suicide rate of any profession—more than twice that of the general population (Anderson, 2018).

Social norms dictate whether or not suicide is stigmatized. Many societies and religions, such as Christianity, ban suicide, considering it a taboo behavior or a sin. Others allow suicide (MPAC, 2019).

It has been found that the rise in suicide and suicide attempts by adolescents correlates with the rise in electronic communication and social media. Social media and internet use contribute to poorer sleep quality, which in turn contributes to depressive symptoms in this age group (Twenge et al., 2019; McCarthy, 2019).

Adverse Life Events

An extensive body of sociodemographic and psychological autopsy studies finds that almost all persons who died by suicide had experienced at least one stressful life event (usually more than one) within the year prior to death. Specific events that increase the risk of suicide include:

• Death of a family member
• Interpersonal conflicts (family or relationships with third parties)
• Separation/divorce
• Rejection
• Humiliation
• Physical illness
• Chronic physical pain
• Unemployment
• Problems at work
• Financial problems
• Serious injury or attack
• Sexual or physical abuse
• Rape
• Personal loss
• Domestic violence
• Problems with the law
• Change of residence/moving
  (Maniou et al., 2017)

Factors Leading to Suicide According to Age

Suicide crosses all age groups in the United States, and suicide rates globally follow a standard pattern of increasing with age, with rates highest in people ages 70 years and older (IHME, 2018).

CHILDREN

Suicidal ideation occurs in prepubertal children, but suicide attempts and suicide deaths are rare. The number of young children who kill themselves has always been small, but it has been steadily increasing over time. For the very young (ages 5 to 11), suicide occurs in the United States at a rate of one every five days. These numbers, however, may not fully reflect reality, as failed attempts are not reported and some suicide deaths may be seen as accidents (Sheftall et al., 2016).

Parents often do not take talk of suicide by young children seriously because they believe kids do not understand the concept. By ages 5 to 7, however, children begin to understand death, though many do not grasp its irreversibility until about age 11 (Mink, 2018). Younger children who die by suicide are more likely to be of above-average intelligence, possibly exposing them to the developmental level of stress experienced by older children (Kennebeck & Bonin, 2017).

In a recent study of children ages 5 to 11 who died by suicide, the majority were black males who died at home by hanging, strangulation, or suffocation. Children were found to more often have had relationship problems with family members or friends. Very few left a suicide note, but nearly one third were found to have discussed suicide intent to another person before death. The children were found to more often have attention-deficit disorder with or without hyperactivity and less often experienced depression or dysthymia compared to early adolescents (ages 12 to 14) (Sheftall et al., 2016).

ADOLESCENTS

Adolescents have a relatively higher rate of suicide attempts than adults, and the majority who attempt suicide have a significant mental health disorder, usually depression (AACAP, 2018).

As adolescents develop their capacity for abstract and complex thinking, they are more capable of contemplating life circumstances, envisioning a hopeless future, considering suicide as a possible solution, and planning and executing a suicide attempt (Kennebeck & Bonin, 2017).

In a study of adolescents who attempted suicide, the weakest influence was direct social pressures that promote suicide, and the three strongest motivators were:

• Extreme emotional or psychological pain
• Desire to escape from one’s own thoughts, feelings, or actions
• Belief that things cannot get better or that one’s situation cannot improve
  (Klonsky, 2019)

A systematic review of studies has found the high prevalence of adolescents consuming cannabis generates a large number of young people who are at risk for developing depression and suicidality (Gobbi et al., 2019).

YOUNG ADULTS

Among 18- to 34-year-olds, there has been a 25% increase in suicide deaths since 2007, which is a greater increase in suicide deaths than among other age groups, except for children and adolescents. This age group has a number of risk factors that increase vulnerability to suicide:

• Impulse control centers in the brain are not fully developed until the mid-to-late-20s.
• They take more risks with sexual and drug-use behaviors compared to older adults.
• They make up the highest percentage of the U.S. military.
• They face high costs of postsecondary education and mounting student debt.
• The housing market is largely out of their reach.
• They lack the protective factors other age groups typically have, such as a supportive physical and social environment and financial safety nets.
• They are the age group with the greatest nonmedical and prescription use of opioids.
• They are beginning and growing in their chosen career.
• They grew up with a succession of negative events, including the 9/11 terror attacks, the Iraq and Afghanistan Wars, and the Great Recession.
• The impact of the rise of social media impacts the sense of their future prospects.
  (TFAH, 2019; Anderson P., 2019)

MIDDLE-AGED ADULTS

Middle age (ages 35 to 64) is a time of maximum risk, with suicide rates increasing in both middle-aged men and women, although men are much more likely than women to die by suicide. Middle-aged men represent 19% of the U.S. population and account for 40% of suicide deaths (SPRC, 2019a).

The middle-age years are marked by heavy personal, social, and familial responsibilities and obligations, including growing and grown children and caring for aging parents. Issues such as unemployment, social disconnection, relationship breakdown, and job loss are sources of stress among this population (AFSP, 2019).

OLDER ADULTS

Suicide rates are high among adults ages 65 and older, and in particular among older men. Men ages 85 and older have the highest rate of any group in the country. Suicide attempts by older adults are more likely to result in death because:

• Older adults plan more carefully and use more deadly methods.
• Older adults are less likely to be discovered and rescued.
• Physical frailty of older adults means they are less likely to recover from an attempt.
  (SPRC, 2019b)

The main suicide risk factors for the older adult include:

• Grieving the death of a spouse (one of the most prevalent risk factors)
• Psychiatric and neurocognitive disorders
• Social isolation/exclusion
• Bereavement
• Transition in physical health
• Loss of independence
• Physical and psychological pain
• Cognitive impairment
  (Conejero et al., 2018a ; SPRC, 2019b)

Suicide Risk among Specific Populations

Although suicide affects all groups of the population, the risk and protective factors for suicide may differ. The following summarizes risk and protective factors among specific populations.

PERSONS WITH DEMENTIA

Recent study findings suggest that late-stage dementia could protect against suicidal ideation and suicide attempts. On the other hand, the risk of suicide is higher during the early phase of cognitive decline. The following factors may contribute to increasing the suicide rate in early dementia include:

• Awareness of cognitive decline and feelings of being a burden to significant others
• Anticipation of future loss of autonomy
• An increased prevalence of comorbid mood and adjustment disorders
• Presence of still good cognitive functions in the early stage that allow the person to plan and complete a suicidal act
• Deficits in executive functions, decision-making, and inhibition process
  (Conejero et al., 2018b)

ADULTS WITH LEARNING DISABILITIES

The prevalence of lifetime suicide attempts among those with a learning disability, such as dyslexia, is much higher than those without a learning disability. Adults with a learning disability had nearly double the odds of having ever attempted suicide, even after adjusting for childhood adversities, mental illness, addiction history, and sociodemographics (Fuller-Thomson et al., 2018).

CAREGIVERS

As the population in the United States ages, more people require care provided by family members in managing all aspects of daily living. The risk to the health and well-being of caregivers is well documented. They report high levels of stress and have higher rates of depression and anxiety as well as poorer physical health than noncaregivers. Caregivers are often affected by a wide range of stressors, including exposure to domestic violence, financial difficulties, or stressful life events. This may be more marked among those caring for someone with dementia. Research has found that one fourth of caregivers looking after family members with dementia contemplated suicide more than once in the prior year, and almost a third said they were likely to attempt suicide in the future (Joling et al., 2017; Rosato et al., 2019).

MILITARY SERVICE PERSONNEL

Suicide is the second leading cause of death among U.S. military personnel. A recent study asked a group of active-duty soldiers why they tried to kill themselves, and out of the 33 reasons they had to choose from, all of the soldiers included a desire to end intense emotional distress (MSRC, 2019).

Experiencing child abuse, being sexually victimized, and exhibiting suicidal behavior before enlistment are significant risk factors for service members and veterans, making them more vulnerable to suicidal behavior when coping with combat and multiple deployments.

Military personnel reporting child abuse as children have been found to be three to eight times more likely to report suicidal behavior. Sexual trauma of any type increases the risk for suicidal behavior. Men who have experienced sexual trauma are less likely to seek mental health care than females, as they may see it as a threat to their masculinity, a strong predictor of suicide attempts in military personnel. Service members who attempted suicide before joining the military are six times more likely to attempt suicide after joining the military (APA, 2019a).

A number of psychosocial factors are associated with suicide risk in the military, including relationship problems, administrative/legal issues, and workplace difficulties. Medical conditions that are associated with an increased risk for suicide among military personnel include traumatic brain injury, chronic pain, and sleep disorders (USUCDP, 2019).

Suicide among women in the military has increased at twice the rate of male service members. The primary reason is sexual trauma, particularly incidences of harassment and rape while stationed overseas. An estimated one in four military women are victims of sexual trauma. This number, however, is believed to be low due to the stigma and possible consequences associated with reporting. Sexual trauma combined with combat stress can result in a higher risk of dying by suicide (Gorn, 2019).

MILITARY VETERANS

There is strong evidence that among veterans who experienced combat trauma, the highest suicide risk has been observed in those who were wounded multiple times and/or were hospitalized as a result of being wounded.

Studies that looked specifically at combat-related PTSD found that the most significant predictor of both suicide attempts and the preoccupation with thoughts of suicide is combat-related guilt about acts committed during the times of war. Those with only some PTSD symptoms have been found to report hopelessness or suicidal ideation three times more often than those without PTSD (VA, 2019).

Suicide Protective Factors

Although there are many risk factors for suicide, there are also many factors that protect people from making an attempt or dying by suicide. These protective factors are both personal and environmental. One of the most important of these factors is restricted access to lethal means (SPRC, 2019c).