Epidemiology of Depressive Disorders

Depressive disorders (i.e., major depression, dysthymia, bipolar disorder) are among the most common and disabling medical conditions throughout the world.  For example, about 9.5% of the US adult population will suffer from a form of depression during any given year which is approximately 18.8 million people.  In addition, 16-18% of women and 10% of men (3-4 million) will experience some form of depression.  The lifetime risk for depression is approximately 15-20% regardless of gender.

When one episode of depression is experienced, there is a 50% likelihood of recurrent episodes.  When a second episode of depression occurs, there is an 80-90% likelihood of recurrent episodes and 75% of depressive disorders are recurrent.

It is estimated 20% of depressed individuals will attempt suicide and 6% will be successful.  75% of those committing suicide have a depressive disorder.  The rate of successful suicide is four times greater in men.  Elderly persons have the highest suicide rate of any age group, largely accounted for by older white males with rates rising to 67.6 suicides per 100,000 in those 85 and older, more that 5.5 times the overall national rate of 12 per 100,000 (National Center for Health Statistics, 1992).  Suicide in the elderly is most likely to be a result of depression; in patients 75 years of age and older, 60-75% of suicides have diagnosable depression (Conwell, 1996).  Hopelessness is strongly linked to the presence of suicidal ideation and tends to persist in those with a past history of suicide attempts (Szanto et al.,1997).

About 10% of people with depression also will experience episodes of mania.  Bipolar depressive episodes usually last longer, have a greater likelihood of psychotic features, and convey a greater risk of suicide.  Bipolar disorder may be misdiagnosed as depression resulting in inappropriate treatment that may worsen the disease progression and outcome.

Depression coexists with a number of other medical and psychiatric conditions and numerous medications can cause depressive symptoms.[/vc_column_text][/vc_column][/vc_row]