The results of a recent NIMH-supported study provide the strongest evidence to date that depression increases the risk of having a future heart attack. Analysis of data from a large-scale survey revealed that individuals with a history of major depression were more than four times as likely to suffer a heart attack over a 12-13 year follow-up period, compared to people without such a history. Even people with a history of two or more weeks of mild depression were more than twice as likely to have a heart attack, compared to those who had had no such episodes. Although associations were found between certain psychotropic medications and heart attack risk, the researchers determined that the associations were simply a reflection of the primary relationship between depression and heart trouble. The question of whether treatment for depression reduces the excess risk of heart attack in depressed patients must be addressed with further research.

NIMH is planning to present a major conference with other NIH Institutes on depression and co-occurring illnesses. The outcomes of this conference will guide NIMH investigation of depression both as a contributing factor to other medical illnesses and as a result of these illnesses.

Women and Depression

Nearly twice as many women (12 percent) as men (7 percent) are affected by a depressive illness each year. At some point during their lives, as many as 20 percent of women have at least one episode of depression that should be treated. Although conventional wisdom holds that depression is most closely associated with menopause, in fact, the childbearing years are marked by the highest rates of depression, followed by the years prior to menopause.

NIMH researchers are investigating the causes and treatment of depressive disorders in women. One area of research focuses on life stress and depression. Data from a recent NIMH-supported study suggests that stressful life experiences may play a larger role in provoking recurrent episodes of depression in women than in men.

The influence of hormones on depression in women has been an active area of NIMH research. One recent study was the first to demonstrate that the troublesome depressive mood swings and physical symptoms of premenstrual syndrome (PMS), a disorder affecting three to seven percent of menstruating women, result from an abnormal response to normal hormone changes during the menstrual cycle. Among women with normal menstrual cycles, those with a history of PMS experienced relief from mood and physical symptoms when their sex hormones, estrogen and progesterone, were temporarily "turned off" by administering a drug that suppresses the function of the ovaries. PMS symptoms developed within a week or two after the hormones were re-introduced. In contrast, women without a history of PMS reported no effects of the hormonal manipulation. The study showed that female sex hormones do not cause PMS - rather, they trigger PMS symptoms in women with a preexisting vulnerability to the disorder. The researchers currently are attempting to determine what makes some women but not others susceptible to PMS. Possibilities include genetic differences in hormone sensitivity at the cellular level, differences in history of other mood disorders, and individual differences in serotonin function.

NIMH researchers also are currently investigating the mechanisms that contribute to depression after childbirth (postpartum depression), another serious disorder where abrupt hormonal shifts in the context of intense psychosocial stress disable some women with an apparent underlying vulnerability. In addition, an ongoing NIMH clinical trial is evaluating the use of antidepressant medication following delivery to prevent postpartum depression in women with a history of this disorder after a previous childbirth.

Child and Adolescent Depression

Large-scale research studies have reported that up to 2.5 percent of children and up to 8.3 percent of adolescents in the United States suffer from depression. In addition, research has discovered that depression onset is occurring earlier in individuals born in more recent decades. There is evidence that depression emerging early in life often persists, recurs, and continues into adulthood, and that early onset depression may predict more severe illness in adult life. Diagnosing and treating children and adolescents with depression is critical to prevent impairment in academic, social, emotional, and behavioral functioning and to allow children to live up to their full potential.

Research on the diagnosis and treatment of mental disorders in children and adolescents, however, has lagged behind that in adults. Diagnosing depression in these age groups is often difficult because early symptoms can be hard to detect or may be attributed to other causes. In addition, treating depression in children and adolescents remains a challenge, because few studies have established the safety and efficacy of treatments for depression in youth. Children and adolescents are going through rapid, age-related changes in their physiological states, and there remains much to be learned about brain development during the early years of life before treatments for depression in young people will be as successful as they are in older people. NIMH is pursuing brain-imaging research in children and adolescents to gather information about normal brain development and what goes wrong in mental illness.

Depression in children and adolescents is associated with an increased risk of suicidal behaviors. Over the last several decades, the suicide rate in young people has increased dramatically. In 1996, the most recent year for which statistics are available, suicide was the third leading cause of death in 15-24 year olds and the fourth leading cause among 10-14 year olds. NIMH researchers are developing and testing various interventions to prevent suicide in children and adolescents. However, early diagnosis and treatment of depression and other mental disorders, and accurate evaluation of suicidal thinking, possibly hold the greatest suicide prevention value.