At least 50 percent of suicides are a result of, or occur during, a primary mood disorder. Suicide has become the eighth leading cause of death in the general population and the third leading cause of death for individuals between the ages of fifteen and twenty-four. One suicide occurs every twenty minutes in the United States; there is a suicide every three minutes among women in China. Caucasian Americans are also more prone to commit suicide than African Americans. Rates of suicide attempts are higher among adolescents than the elderly, but rates of suicidal completion are higher among the elderly. This may be due either to higher fatality in the methods used by the elderly, or the decrease in physical resilience of elderly individuals. The lethality of the methods and varying immediacy and efficacy of medical treatment may also partially explain the higher rates of suicide completion in non-Western cultures. For every one completed suicide, there are ten attempted suicides. Finally, there are gender differences; women are three times more likely than men to attempt suicide, yet men are four times more likely to complete suicide. This seems to be reflective of the different methods used by the genders: Men are more likely to use more violent and immediately fatal methods such as guns, while women are more likely to use methods that allow for intervention and discovery, such as drug overdoses.

Studies have found that there are ten main elements that appear often in cases of suicide and thus have come to be considered the common elements leading to suicide. It has been found that the common purpose of suicide attempts is to try to find a solution to a problem; the common goal is the cessation of consciousness. The common stimulus is unbearable psychological pain, and the common stressor is frustrated psychological needs. The common emotion is hopelessness/helplessness, and the common cognitive state is ambivalence. The common perceptual state is constriction, or tunnel vision, and the common action is escape. Finally, the common interpersonal act is communication of intentions, and the common pattern is a consistency in life-long patterns of coping mechanisms. The DSM-IV does not offer a classification system for suicide, instead listing suicidal idealization as a symptom of mood disorders.

Emile Durkheim, a French sociologist, has proposed a classification system for suicide that concentrates on the social circumstances in which the individual lives. According to this system, there are four types of suicides: egoistic, anomic, altruistic, and fatalistic. Egoistic suicides, following a pattern of diminished integration, are individuals who have become detached from society and come to believe that their existence is meaningless. Most of the individuals in this group suffer from mental disorders or are recently divorced, and usually exhibit signs of depression and apathy. Individuals who compose the category of altruistic suicides, with a pattern of excessive integration, exist in a community wherein the social rules dictate that that person's life is sacrificial. Anomic suicides, with a pattern of diminished regulation, usually result from sudden disruptions in the social hierarchy or norms, such as economic or political crises, or disruptions in the individual's normal life. The typical feelings associated with this group of individuals are anger, disappointment, and exasperation. The final group of classification is that of fatalistic suicides, with a pattern of excessive regulation, which are very uncommon; fatalistic suicides occur among individuals who believe that the circumstances surrounding their lives have simply become unbearable.

Two problems with Durkheim's system are that many of the types seem to be highly comorbid, and that it is not clear why other members who exist within the same social group, subject to the same social pressures, do not commit suicide.