A current perspective of suicide and attempted suicide.

Suicide, the eighth leading cause of death in the United States, accounts for more than 30 000 deaths per year. The total number of suicides has changed little over time. For example, 27 596 U.S. suicides occurred in 1981, and 30 575 occurred in 1998. Between 1981 and 1998, the age-adjusted suicide rate decreased by 9.3%from 11.49 suicides per 100 000 persons to 10.42 suicides per 100 000 persons (www.cdc.gov/ncipc/wisqars). The suicide rate in men (18.7 suicides per 100 000 men in 1998) is more than four times that in women (4.4 suicides per 100 000 women in 1998). In females, suicide rates remain relatively constant beginning in the midteens. In males, suicide rates are stable from the late teenage years until the late 70s, when the rate increases substantially (to 41 suicides per 100 000 persons annually in men 75 to 84 years of age). White men have a twofold higher risk for suicide compared with African-American men (20.2 vs. 10.9 suicides, respectively, each year per 100 000 men). The risk in white women is double that of women in U.S. nonwhite ethnic/racial minority groups (4.9 vs. 2.4 per 100 000 women each year). In countries other than the United States, the most recently reported rates of suicide vary widely, ranging from less than 1 in 100 000 persons per year in Syria, Egypt, and Lebanon to more than 40 in 100 000 persons per year in many former Soviet republics (www.who.int/whosis). Over the past century, Hungary had the world's highest reported rate of suicide; the reason is unknown. Of note, the reported rates of suicide in first-generation immigrants to Australia tend to be more similar to rates in their native country than to rates in their country of current residence (1, 2); these figures indicate the influence of culture and ethnicity on suicide rates. Suicide is the third leading cause of death in persons 15 to 34 years of age. The U.S. suicide rate in all youths decreased by 18% from 1990 to 1998 (www.cdc.gov/ncipc/wisqars) despite a 3.6-fold increase from 1992 to 1995 in white men, a 4.7-fold increase in African-American men, and a 2.1-fold increase in African-American women. Worldwide, from 1950 to 1995 in persons of all ages, suicide rates increased by approximately 35% in men and only approximately 10% in women (www.who.int/whosis). The reasons for the differences in rates among age, sex, and ethnic groups and the change in rates since the 1950s are unknown. Suicide is generally a complication of a psychiatric disorder. More than 90% of suicide victims have a diagnosable psychiatric illness (3-7), and most persons who attempt suicide have a psychiatric disorder. The most common psychiatric conditions associated with suicide or serious suicide attempt are mood disorders (3-8). Investigators have proposed many models to explain or predict suicide (9). One such explanatory and predictive model is the stress-diathesis model (10). One stressor is almost invariably the onset or acute worsening of a psychiatric disorder, but other types of stressors, such as a psychosocial crisis, can also contribute. The diathesis for suicidal behavior includes a combination of factors, such as sex, religion, familial and genetic components, childhood experiences, psychosocial support system, availability of highly lethal suicide methods, and various other factors, including cholesterol level. In this review, I describe the neurobiological correlates of the stressors and the diathesis. Literature for this review came from searches of the MEDLINE database (1996 to the present) and from literature cited in review articles. The factors that determined inclusion in this review were superiority of research design (use of psychiatric controls, quality of psychometrics, diagnostic information on the study sample, and definition of suicidal behavior; prospective studies were favored), adequate representation of major points of view, and pivotal reviews of key subjects. What is Suicidal Behavior? Suicidal behavior refers to the most clear-cut and unambiguous act of completed suicide but also includes a heterogeneous spectrum of suicide attempts that range from highly lethal attempts (in which survival is the result of good fortune) to low-lethality attempts that occur in the context of a social crisis and contain a strong element of an appeal for help (11). Suicidal ideation without action is more common than suicidal behavior (11). In most countries, men have a higher reported rate of completed suicide, whereas women have a higher rate of attempted suicide (12). Men tend to use means that are more lethal, plan the suicide attempt more carefully, and avoid detection. In contrast, women tend to use less lethal means of suicide, which carry a higher chance of survival, and they more commonly express an appeal for help by conducting the attempt in a manner that favors discovery and rescue (13, 14). Thus, suicidal behavior has two dimensions (13). The first dimension is the degree of medical lethality or damage resulting from the suicide attempt. The second dimension relates to suicidal intent and measures the degree of preparation, the desire to die versus the desire to live, and the chances of discovery. Intent and lethality are correlated with each other and with biological abnormalities associated with suicide risk (13, 15, 16). The clinical profiles of suicide attempts and completions overlap (17). Suicide attempters who survive very lethal attempts, which are known as failed suicides, have the same clinical and psychosocial profile as suicide completers (11, 17). The study and prevention of failed suicides are probably most relevant to completed suicides. Somewhat related to suicide attempters are patients with serious medical illnesses who do not adhere to treatment regimensfor example, diabetic patients who do not take prescribed medications to control blood sugar levels or persons who engage in high-risk behaviors, such as sky diving or mountaineering. These groups warrant further study to determine whether they have psychopathology that overlaps with the psychopathology of suicide attempters. Intent and lethality are also related to the risk for future completed suicide (13). Subsequent suicide attempts may involve a greater degree of intent and lethality (18), and a previous suicide attempt is an important predictor of future suicide (19, 20) or suicide attempt (21). Careful inquiry about past suicide attempts is an essential part of risk assessment in psychiatric patients. Because more than two thirds of suicides occur with the first attempt, history of a suicide attempt is insufficient to predict most suicides; additional risk factors must be considered. Clinical Correlates of Suicidal Behavior Psychological autopsy studies involve review of all available medical records and interviews with family members and friends of the deceased. This method generates valid psychiatric diagnoses (22), and most studies have found that more than 90% of suicide victims had a psychiatric disorder at the time of suicide (3-6, 23). That percentage may be underestimated because accurate data depend on finding informants who knew the victim's state of mind in the weeks before death. Approximately 60% of all suicides occur in persons with a mood disorder (3, 4, 6, 7), and the rest occur in persons with various other psychiatric conditions, including schizophrenia; alcoholism (24); substance abuse (5, 25, 26); and personality disorders (27), such as borderline or antisocial personality disorder (23, 28-30). Lifetime mortality from suicide in discharged hospital populations is approximately 20% in persons with bipolar disorder (manic depression), 15% in persons with unipolar depression, 10% in persons with schizophrenia, 18% in persons with alcoholism, and 5% to 10% in persons with both borderline and antisocial personality disorders (29-33). These personality disorders are characterized by emotional liability, aggression, and impulsivity. The lifetime mortality due to suicide is lower in general psychiatric populations (34, 35). Although suicide is generally a complication of a psychiatric disorder, most persons with a psychiatric disorder never attempt suicide. Even the higher-risk groups, such as persons with unipolar or bipolar mood disorders, have a lifetime suicide attempt rate less than 50%. Thus, persons with these psychiatric disorders who die by suicide differ from those who never attempt suicide. To understand those differences, investigators have compared persons who have attempted suicide and those who have not by matching psychiatric diagnosis and comparable objective severity of illness (10). Suicide attempters differ in two important ways from nonattempters with the same psychiatric disorder. First, they experience more subjective depression and hopelessness and, in particular, have more severe suicidal ideation. They also perceive fewer reasons for living despite having the same objective severity of psychiatric illness and a similar number of adverse life events. One possible explanation for the greater sense of hopelessness and greater number of suicidal ideations is a predisposition for such feelings in the face of illness or other life stressor. The pressure of greater lifetime aggressivity and impulsivity suggests a second diathesis element in suicidal patients. These individuals not only are more aggressive toward others and their environment but are more impulsive in other ways that involve, for example, relationships or personal decisions about a job or purchases. A propensity for more severe suicidal ideation and a greater likelihood of acting on powerful feelings combine to place some patients at greater risk for suicide attempts than others. For clinicians, important indicators of such a diathesis are a history of a suicide attempt, which indicates the presence of a diathesis for suicidal behavior, and a family history of suicidal behavior. Suicidal behavior is known to be transmitted within families,