Prevalence, Treatment, and Control of Depressive Symptoms in the United States: Results from the National Health and Nutrition Examination Survey (NHANES), 2005–2008

Ruth S. Shim, MD, MPH; Peter Baltrus, PhD; Jiali Ye, PhD; George Rust, MD, MPH


J Am Board Fam Med. 2011;24(1):33-38. 

In This Article

Abstract and Introduction


Background: Depression remains a major public health problem that is most often evaluated and treated in primary care settings. The objective of this study was to examine the prevalence, treatment, and control of depressive symptoms in a national data sample using a common primary care screening tool for depression.
Methods: We analyzed a sample of adults (n = 4836) from 2005 to 2008 National Health and Nutrition Examination Survey data. Depressive symptoms were assessed using the Patient Health Questionnaire (PHQ-9) to determine the overall prevalence, rates of treatment, and antidepressant control of mild, moderate, moderately severe, and severe depressive symptoms.
Results: Of the sample, 20.1% reported significant depressive symptoms (PHQ-9) score, ≥5), the majority of whom had mild depressive symptoms (PHQ-9) score, 5–9). Even among individuals with severe depressive symptoms, a large percentage (36.9%) received no treatment from a mental health professional or with antidepressant medication. Of those taking antidepressants, 26.4% reported mild depressive symptoms and 18.8% had moderate, moderately severe, or severe depressive symptoms.
Conclusions: Despite greater awareness and treatment of depression in primary care settings, the prevalence of depressive symptoms remains high, treatment levels remain low, and control of depressive symptoms are suboptimal. Primary care providers need to continue to focus their efforts on diagnosing and effectively treating this important disease.


Depression continues to be major cause of illness and disability throughout the world.[1–5] The World Health Organization identified depression as the fourth leading cause of total disease burden and the leading cause of disability worldwide.[6] In the United States, recent samples estimate a lifetime depression prevalence of 16.2% and a 12-month prevalence of 6.6%.[7]

In the past, depression was often underdiagnosed and untreated by physicians in primary care settings.[8] Studies of elderly patients in primary care settings suggest that complex patients with multiple comorbidities have a higher risk of depression, which is more closely associated with their overall burden of illness than with any one specific disease.[9] Although rates of treatment are increasing, many people still do not have adequate control of depressive symptoms.[7] A recent study of a large national sample found that few Americans diagnosed with depression receive guideline-concordant treatment, with racial/ethnic minority populations receiving even less treatment than non-Hispanic whites.[10] However, management and treatment of depression in primary care settings is an important issue; previous research has shown that individuals are more likely to seek mental health treatment in primary care settings rather than in specialty mental health clinics. This is particularly true of racial and ethnic minority populations.[11]

The National Health and Nutrition Examination Survey (NHANES) has been used to assess nationwide levels of treatment and control of other chronic diseases[12] but not depression. According to Cutler et al,[13] NHANES has become "the principal means to track progress in preventing, treating, and controlling hypertension, " guiding national initiatives such as the National High Blood Pressure Education program. In recent versions of the NHANES, use of the Patient Health Questionnaire (PHQ)-9 has allowed for greater accuracy in the diagnoses of mild, moderate, moderately severe, and severe depressive symptoms.[14] Gonzales et al[10] assessed treatment and control rates in a mutliethnic national sample using Collaborative Psychiatric Epidemiology Survey data, but the diagnostic instrument used, the 16-item Quick Inventory of Depressive Symptomology—Self Report is not as commonly used in primary care settings as the PHQ-9. To date, there has been no published study assessing prevalence, treatment, and control using the nationally recognized NHANES dataset and the PHQ-9 instrument, which is widely used to screen for depression and to guide ongoing treatment decisions in primary care and psychiatric settings. Therefore, we examined prevalence of depressive symptoms, rates of treatment, and overall levels of treatment response using the PHQ-9 data in 2005 to 2008 NHANES data.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.