Risk Factors

Although major depression may begin at any age, onset is generally in the 20s or 30s. Symptoms typically develop over days to weeks and, if untreated, may last from six months to two years, after which most patients return to normal functioning. However, in about 25% of affected patients, the depression becomes chronic and low-grade.



Risk factors for depression include prior episodes, a family history of depression, female sex, recent childbirth, stressful life events, older age, and substance abuse (Table 1). One major depressive episode is associated with up to a 50% risk of a subsequent episode, two episodes with a 50% to 90% risk, and three or more episodes with a greater than 90% risk of recurrence. First-degree relatives of patients with bipolar disorder have a 12% risk of recurrent major depression. There also appears to be an increased risk for patients with family histories of other forms of severe depression. The association is less clear with mild depression.

Risk Factors for Depression:

Family history of depression
Female sex
Older age
Prior episodes of depression
Recent childbirth
Stressful events
Substance abuse

Women are twice as likely as men to have depression. Whether this is due to societal pressures, physiologic differences, or a combination of the two is unknown. Vulnerability is especially high during the postpartum period,with nonpsychotic depression occurring in as many as 15% of women within six months of giving birth and true postpartum psychosis affecting 0.05% to 0.2% of new mothers within a few days of delivery. Significant psychosocial stressors such as the loss of a parent, child, spouse, or job or the termination of an important relationship may trigger onset of major depression. Older patients often present with atypical signs and symptoms of depression (e.g., anorexia, insomnia, anhedonia, impaired concentration) that are falsely assumed to be secondary to age or an underlying medical condition. Physicians should be particularly alert to the possibility of recurring or new-onset major depression in patients recently transferred to nursing homes, as a number of studies have shown the prevalence in that setting to be as high as 20%. However, new-onset depression in an older patient is fairly unusual and should signal a search for an underlying metabolic or medication-related cause.




Comments

PlainJane, United States

This was a very helpful article in doing an assignment for Abnormal Psychology at Colorado Technical University in my RN to BSN program. Thank you.