The
Nature and Impact of Mood Disorders
Breaking Ground, Breaking
Through: The Strategic Plan for Mood Disorders Research of the National
Institute of Mental Health addresses two types of mood
disorder—major depression and bipolar disorder, also known as
manic-depressive illness. The term depression, of course, refers not
only to an illness, but also to moods and behaviors that occur in the
normal course of life. Unlike the normal shifts in mood that most people
experience, however, the symptoms of
depression are
more extreme and frequently incapacitating.
These symptoms include a
persistent sad mood; loss of interest or pleasure in activities that
were once enjoyed; significant change in appetite or body weight;
difficulty sleeping or oversleeping; physical slowing or agitation; loss
of energy; feelings of worthlessness or inappropriate guilt; difficulty
thinking or concentrating; and recurrent thoughts of death or suicide. A
diagnosis of depression is made if an individual has five or more of
these symptoms every day during a 2-week period. In
bipolar disorder,
episodes of depression alternate with episodes of mania, a condition
marked by periods of abnormally and persistently elevated mood or
irritability accompanied by at least three of the following symptoms:
overly inflated self-esteem; decreased need for sleep; increased
talkativeness; racing thoughts; distractibility; increased goal-directed
activity or physical agitation; and excessive involvement with
pleasurable activities that have a high potential for risky
consequences.
By
far the more common of the two, major depression affects approximately
19 million American adults at any given time and an estimated 6 percent
of children ages 9 to 17. For reasons that are not clearly understood,
depression occurs twice as often among women as men. Five to 14 percent
of women will have an episode of depression at some point in their lives
in contrast to 2 to 4 percent of men. Bipolar disorder affects some 2.3
million American adults, or approximately 1 percent of the population,
and distributes roughly equally between men and women. Although firm
data are lacking on the extent to which bipolar disorder affects
children and adolescents, clinical experience suggests that some
proportion of children and adolescents who have major depression
eventually will be found to have bipolar disorder; this likelihood
increases if the depressed young person has a family member with bipolar
disorder.
Today, the intense and disabling
symptoms of depression and bipolar disorder often can be relieved
through treatment involving combinations of medications and
psychotherapy. Yet even with appropriate treatment, both depression and
bipolar disorder tend to be episodic and recurrent; that is, after a
person has been depressed once and recovers, he or she is likely to have
in the future one or more episodes of depression, and/or mania in the
case of bipolar disorder. Single episodes are the exception. This
pattern of illness implies high, and sustained, personal, family, and
societal costs—costs that can and will be reduced substantially through
an accelerated program of research and discovery.