Childhood suicide is described as a self-inflicted death occurring before the fifteenth birthday. It is the only psychiatric condition that is subject to documentation by age, gender, and method in all developed countries. At all ages, the rate in whites is greater than that in nonwhites. In the male population, completed suicides are more common than in the female population, although attempts are more common in the female population. The suicide mortality rate (completed suicide) in 10- to 14-year-olds in 2000 was 1.5 per 100,000; the mortality rate in the 15- to 19-year-old age group was 8.2 per 100,000. Some 4% of high school students have made a suicide attempt in the last year, and 8% have attempted suicide in their lifetime. Estimates hold that only one in eight suicide attempts comes to medical attention.

Apparently, suicide is related to maturation, and younger children may be protected, possibly because planning the event may require abstract reasoning, formulation of a plan, and the development of a poor self-concept. Children attempting suicide also must be able to understand the severity of the situation and understand the means to use to complete the act. The rarity of suicide before puberty also may be lower because two risk factors, depressive disorder and substance abuse, are not common among younger children. Suicide may not be reported fully because of possible stigma, and such underreporting leads to difficulty in interpreting accident statistics that may include suicide in children. For example, if a child deliberately runs into the street, he may do so with suicidal intent. Clarifying the specific means used for suicide is important.

Some have suggested that the increase in completed suicide in the United States for the 15- to 19-year-old group may be explained by the availability of firearms. The most common means for completed suicide is a firearm, followed in descending order of incidence by hanging or suffocation, self-poisoning, and the use of gas. In England, government control of gas in the home led to a significant reduction in suicide, and the control of availability of firearms often has been suggested to bring about a similar effect in the United States.

Suicide attempts occur three times more often in girls than in boys during the adolescent years. However, young men are five times more likely to die by suicide. Young men often use firearms, jump from heights, or inhale carbon monoxide, whereas young women more often use self-poisoning. Often, the word overdose is used in emergency room settings to describe such behavior, but the more appropriate designation is self-poisoning.

Cognitive maturation is a factor in successful suicide. Children who have higher intellectual ability and higher standards of living may be more prone to deal with failure by blaming themselves. Pressure to admit antisocial behavior after a disciplinary crisis and other interpersonal disagreements may be followed by suicide attempts in vulnerable adolescents. The occurrence of psychiatric illness in families, particularly depression in siblings or parents, is another important risk factor. The best predictor of a suicide attempt is a prior attempt; previous parasuicide has been noted to be as high as 40% in completed suicides. Suicide may occur in the context of psychiatric illness and may be the result of internal conflict. It varies in frequency and intensity with age and often is related to interpersonal difficulties with parents and teachers.

An important etiology of suicide in adolescents is affective disorder, major depression, or bipolar disorder. This condition may be primary, as a response to severe stress, or it may be secondary to another preexisting illness. It is the most significant diagnosis related to completed suicide, and increased risk occurs during the depressed phase or episode. When those with affective disorders are in remission from their depression, the risk of suicide is not increased statistically. The greatest risk occurs during the first year after the diagnosis of the depression.

Two other conditions are associated with completed suicide: drug abuse (particularly alcoholism) and schizophrenia. Suicide associated with schizophrenia is less common than that associated with an affective disorder. For a person with schizophrenia, the history of a previous attempt, the presence of an associated depressive syndrome, or self-destructive hallucinations increase the risk.

In contrast to completed suicide, attempted suicide is more common in individuals who have a hysterical personality style or antisocial personality traits. These personality traits, complicated by the use of drugs, increase the risk for an attempt. An additional risk factor is a family history of suicide. This may be related to the modeling that can occur from knowing that another family member has completed suicide. Family genetic studies provide evidence for familial transmission in suicide; this is confirmed in twin and adoption studies. At a molecular level, serotonin seems to be one of the key neurotransmitters implicated in suicidal behavior. Therefore, genes coding for proteins involved in serotonergic neurotransmission have been extensively studied in case-control association studies on suicide.

Information about the clinical picture of completed suicide is gathered by techniques termed the psychological autopsy, a method initially developed for use with adults but more recently applied to adolescents. Interviews are conducted with those who knew the individual who has committed suicide. The completed-suicide population has a dominance of depression as the primary diagnosis. Few individuals who complete suicide do not have psychiatric symptoms. Suicide assessment takes into account a history of behavioral change before the event: Suicide does not just happen. Before an attempt, the most common associated events are communication of suicidal thoughts, history of suicide attempts, and previous contact with a psychiatrist. Most individuals have communicated their intent to others on several occasions (generally by indicating that they wish to die and that others would be better off without them), by comments about methods of suicide, and by predicting that others would find a dead person. Often, these communications are not taken seriously by friends and family members, but taking them seriously is extremely important.