The Prevalence and Impact of Depression

Alan J. Gelenberg, MD

Healthcare Technology Systems, Inc, Madison, Wisconsin

Prevalence and Recurrence of Depression

Depression is a common and often chronic illness, and understanding the prevalence and recurrent nature of depression is paramount in being able to recognize and treat this disorder in patients. According to the DSM-IV-TR,1 the lifetime risk for developing major depression is up to 25% in women and up to 12% in men, and the point prevalence of depression in the community is 5% to 9% in women and 2% to 3% in men. Similarly, the NCS-R2 found a 17% total lifetime prevalence of major depression, with about 20% of women and 13% of men developing the disorder at some point. Further, approximately 9% of women and 5% of men had depression during a 1-year period.2

On depressive episode recurrence, the STAR*D study3 reported that 25% of patients with depression have a chronic course of illness, and 75% of patients have recurrent episodes. According to Mueller et al,4 85% of patients who recovered from an index episode of depression experienced at least 1 recurrence during a 15-year follow-up period. Female gender, never marrying, longer duration of a depressive episode, and additional prior episodes were predictors of recurrence.4 Each episode of depression dramatically increases patients' likelihood of having a recurrence as follows: 1 episode = a 60% chance of a second, 2 episodes = a 70% chance of a third, and 3 episodes = a 90% chance of a fourth.1

A prospective study5 found that the probability that patients will remain well after recovering from an index episode dramatically decreased over a 5-year period
(AV 1AV 1). A significant difference in recurrence was established for patients who received tricyclic antidepressants and/or mood stabilizers compared with those who did not (P < .001) and those who had a history of fewer than 3 episodes compared with those who had 3 or more previous episodes (P < .05).5 Additionally, patients with unresolved or subthreshold symptoms after resolution of the index depressive episode had more than twice the risk of relapse and experienced a recurrence more than 3 times faster than asymptomatic patients.6 The recent REVAMP study7 found that 66% of patients with chronic depression had never received an adequate trial of antidepressant therapy, emphasizing the gap between the prevalence and treatment of this disorder. Thus, depression is a chronic disorder that needs to be adequately treated and monitored over time to ensure that patients achieve and maintain remission of all symptoms.

Impact of Depression

Because of the prevalence and chronicity of depression, its impact is felt globally. In 2004, WHO research8 found that depression was the leading cause of years lost due to disability for both men and women worldwide, of disease burden in not only low- to middle-income countries but also high-income countries, and of disease burden for women aged 15 to 44 years worldwide. Additionally, depression was the third leading cause of moderate and severe disability worldwide and of burden of disease worldwide, affecting up to 98.7 million people of all ages.8

Although the rate of current depression remained almost static from 1990 to 2000 in the United States, and the rate of treated depression increased substantially from almost 28% of those with depression to almost 44%, the economic burden of depression continued to rise.9 The overall cost of depression in the United States was $83.1 billion in 2000, a 7% increase from 1990 (using inflation-adjusted dollars). This economic burden consisted largely of work-related costs, with direct costs and suicide accounting for the rest of the expenditures (AV 2AV 2).9


Even though the number of suicides remained stable during the 10-year period,9 these rates also impact costs concerning mortality and hospitalization rates as well as lost productivity in the work place. Suicide was the 11th leading cause of death in the United States in 2004, accounting for 1.4% of total deaths.10 A meta-analysis11 reported that, for patients with affective disorders, the general mortality rate for suicide was 9% for outpatients and 20% for inpatients.

Depression can also influence the morbidity and mortality associated with other disorders, including cardiovascular disease and diabetes, and may impact autoimmune diseases and cancer.12 Overall, patients with depression have generally poor self-care12 and are 3 times more likely to be noncompliant with medical treatment recommendations, including medication regimens, diet and exercise programs, and smoking cessation, compared with nondepressed patients (95% CI = 1.96 to 4.89).13 Clearly, depression affects every aspect of patients' lives, from quality of life to treatment adherence to economic impact.

For Clinical Use

Depression is a common illness that is often recurrent in nature. Yet, many patients remain undertreated. The disorder seriously impacts patients' well-being as well as the economy, and, to reduce this burden, clinicians need to be as steadfast as ever to combat these negative consequences and help patients lead a symptom-free life. To achieve this, clinicians should:

  • Be aware of the highly recurrent nature of depression
  • Use an adequate dose and duration when treating patients
  • Provide long-term treatment to encourage remission of all symptoms
  • Continually monitor patients over time to help maintain recovery
  • Recognize that patients with depression are at risk for suicidality and treatment noncompliance


DSM-IV-TR = Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision
NCS-R = National Comorbidity Survey Replication
REVAMP = Research Evaluating the Value of Augmentation of Medication by Psychotherapy
STAR*D = Sequenced Treatment Alternatives to Relieve Depression
WHO = World Health Organization

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  1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision. Washington, DC: American Psychiatric Association; 2000.
  2. Kessler RC, Berglund P, Demler O, et al. Lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the National Comorbidity Survey Replication. Arch Gen Psychiatry. 2005;62(6):593–602.
  3. Rush AJ, Kilner J, Fava M, et al. Clinically relevant findings from STAR*D. Psychiatr Ann. 2008;38(3):188–193.
  4. Mueller TI, Leon AC, Keller MB, et al. Recurrence after recovery from major depressive disorder during 15 years of observational follow-up. Am J Psychiatry. 1999;156(7):1000–1006.
  5. Maj M, Veltro F, Pirozzi R, et al. Pattern of recurrence of illness after recovery from an episode of major depression: a prospective study. Am J Psychiatry. 1992;149(6):795–800.
  6. Judd LL, Paulus MJ, Schettler PJ, et al. Does incomplete recovery from first lifetime major depressive episode herald a chronic course of illness? Am J Psychiatry. 2000;157(9):1501–1504.
  7. Kocsis JH, Gelenberg AJ, Rothbaum B, et al. Chronic forms of major depression are still undertreated in the 21st century: systematic assessment of 801 patients presenting for treatment. J Affect Disord. 2008;110(1–2):55–61.
  8. World Health Organization. The Global Burden of Disease: 2004 Update. Geneva, Switzerland: WHO Press; 2008.
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  11. Bostwick JM, Pankratz VS. Affective disorders and suicide risk: a reexamination. Am J Psychiatry. 2000;157(12):1925–1932.
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  13. DiMatteo MR, Lepper HS, Croghan TW. Depression is a risk factor for noncompliance with medical treatment: meta-analysis of the effects of anxiety and depression on patient adherence. Arch Intern Med. 2000;160(14):2101–2107.