Epidemiology

Patients with suicidal or homicidal ideation are encountered frequently in the emergency department (ED). Approximately 0.4% of all ED visits in the United States involve suicidal patients, and suicide accounted for 34,598 deaths in 2007 (almost twice the number of deaths by homicide, 18,361), which makes it the 10th leading cause of death overall.¹ For Americans aged 15 to 24 years, suicide ranks as the third leading cause of death.² This age group also accounts for more ED visits for attempted suicide and self-injury than any other age group does. More than 1200 children and adolescents complete suicide annually in the United States,³ and it is estimated that 11 attempted suicides occur per suicide death.¹ More than 40% of individuals 16 years or older who completed suicide were evaluated in an ED in the year before their terminal act.³

Although the rate of attempted suicide was highest in female patients 15 to 19 years old, nearly five times as many males died by suicide in this age group. About six times as many males as females died by suicide in the 20- to 24-year age group, and older, non-Hispanic white men have a suicide rate than is staggeringly higher than the national average for the general population. Of patients with evidence of self-harm, poisoning was the cause of death in 13% of males and 40% of females, suffocation in 24% of males and 21% of females, and firearms in 56% of males and 30% of females.¹ Self-mutilation (by cutting or piercing) was observed in 20% of patients evaluated in the ED for a suicidal gesture. One third of suicidal patients were admitted for inpatient management, one third were transferred to an off-site facility, and one fifth were referred to outpatient psychiatric services.⁴

Intentionally harmful behavior also constitutes a growing problem in children, adolescents, and young adults. It has been estimated that the prevalence of mental illness among youth in Canada and the United States approaches 15% to 20%, with an anticipated 50% increase by 2020. Pediatric mental health complaints account for 1.6% of all annual ED visits in the United States and 1% of all annual ED visits in Canada.^2,5

Homicide ranks as the most common cause of death in black males 15 to 24 years of age and is the second leading cause of deaths for all youths in this age group. In 2005 alone, more than 5000 deaths by homicide occurred in this age group, and in 2006 this age group received medical care for more than 750,000 cases of nonfatal violent injury.⁶

A focused risk assessment is the primary objective for the emergency provider caring for a patient who is threatening harm to self or others. Risk assessments vary widely, depending on the circumstances of the patient, comorbid disease, mental status, and other social issues. The main challenge to effective risk assessment is the lack of a specific diagnostic test to stratify threat in suicidal or homicidal patients. No interventional test is currently available to determine who is at greatest risk for injury—data for risk stratification come from psychologic autopsy, which is the study of patient characteristics in completed suicides. Predictive data for outcomes of these patients after ED evaluation are lacking. This chapter focuses on the directed examination and evaluation of patients who pose threats of harm to self or others.

Pathophysiology

Numerous factors influence the likelihood of self-harm, including depression and other mental disorders, alcohol or substance abuse, separation or divorce, physical or sexual abuse, and significant medical conditions such as human immunodeficiency virus infection, cancer, and dialysis-dependent renal failure (see the “Red Flags” box). Previous suicide attempters also have more concurrent general medical conditions, alcohol or substance abuse, work hours missed, and current suicidal ideation than do nonattempters.⁷ More than 90% of people who die by suicide have a mental health disorder, a substance abuse disorder, or both.¹ Depression is a significant and common risk factor to address because one in three patients encountered in the ED have moderate to severe depression. In adult male ED patients, depression is more strongly associated with the likelihood of perpetrating violent behavior than excessive alcohol consumption is.⁸

Besides the presence of risk factors, poorly understood biologic factors probably influence self-harm. Serotonin levels have been studied in suicidal patients, and data suggest that lower levels of cerebral 5-hydroxyindoleacetic acid (a serotonin metabolite) are found in patients who attempt suicide.^9–11 Increasing serotonin levels through pharmacotherapy with drug classes such as tricyclic antidepressants or selective serotonin reuptake inhibitors is a common treatment of depression and suicidal ideation.

Presenting Signs and Symptoms

Patients may seek treatment in the ED after considering or attempting to harm themselves or others. These actions range from unsuccessful, yet serious gestures to the use of suicidal ideation for secondary gain. Clinical suspicion should always be high, and patients’ complaints must be taken seriously. Careful, open-ended, nonjudgmental questioning can help discern the level of risk by understanding the patient’s intent.

In addition, emergency physicians should be cognizant of interactions with adolescent patients and consider screening either formally or informally for suicidal ideation. A recent study evaluated the feasibility of screening nonpsychiatric patients for suicide risk and targeted patients between the ages of 10 and 21 years. In this study interval, 37 of 50 patients with psychiatric complaints screened positive for suicide risk. However, 27 of 106 patients evaluated for nonpsychiatric complaints also screened positive for suicide risk. Each of the patients underwent formal psychiatric consultation, and none of the patients with nonpsychiatric complaints warranted hospitalization but were provided with available outpatient psychiatric services. Interestingly, screening of nonpsychiatric patients did not increase the overall length of stay.³

Injured patients with a concerning mechanism (ingestion, single-person car accident, fall) should be screened for suicidal ideation and intent. If an attempt is uncovered, the provider should solicit the patient’s feelings about survival. It is important to understand why patients survived as a predictor of immediate or ongoing risk for harm. The following questions should be considered: