January 1, 2011Open Access

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

Q: What is the clinical evidence from this study?

Study design: Cross-Sectional. Population: Depressive symptoms (n=10283). Intervention: Antidepressant medication and/or mental health professional counseling vs. No treatment. Primary outcome: Prevalence of depressive symptoms (PHQ-9 score ≥5) (95% CI 20.1-23.3).

Key Result

In a nationally representative sample of US adults, 21.6% reported significant depressive symptoms, and 36.9% of individuals with severe depressive symptoms received no treatment.

Study Design

Type

Cross-Sectional (n=10,283)

PICO

Population

Depressive symptoms (n=10,283)

Intervention / Comparator

Antidepressant medication and/or mental health professional counseling vs No treatment

Primary Outcome

Prevalence of depressive symptoms (PHQ-9 score ≥5) (20.1-23.3)

Limitations

Lack of clinical specificity that might be obtained from direct review of clinical records
PHQ-9 threshold of 5 may be overly sensitive but not specific
Potential underreporting of treatment due to recall errors or stigma
Individuals reporting antidepressant use may be taking it for conditions other than depressive symptoms
No repeated measures or longitudinal tracking to assess the impact of treatment
Individuals with bipolar depression may be prescribed mood stabilizers rather than antidepressants, leading to a slight underestimate of treatment rates

Abstract

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.

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