The epidemiology of major depressive disorder: results from the National Comorbidity Survey Replication (NCS-R).
BACKGROUND
Uncertainties exist about prevalence and correlates of major depressive disorder (MDD).


OBJECTIVE
To present nationally representative data on prevalence and correlates of MDD by Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria, and on study patterns and correlates of treatment and treatment adequacy from the recently completed National Comorbidity Survey Replication (NCS-R).


METHODS
Face-to-face household survey conducted from February 2001 to December 2002.


METHODS
The 48 contiguous United States.


METHODS
Household residents ages 18 years or older (N = 9090) who responded to the NCS-R survey.


METHODS
Prevalence and correlates of MDD using the World Health Organization's (WHO) Composite International Diagnostic Interview (CIDI), 12-month severity with the Quick Inventory of Depressive Symptomatology Self-Report (QIDS-SR), the Sheehan Disability Scale (SDS), and the WHO disability assessment scale (WHO-DAS). Clinical reinterviews used the Structured Clinical Interview for DSM-IV.


RESULTS
The prevalence of CIDI MDD for lifetime was 16.2% (95% confidence interval [CI], 15.1-17.3) (32.6-35.1 million US adults) and for 12-month was 6.6% (95% CI, 5.9-7.3) (13.1-14.2 million US adults). Virtually all CIDI 12-month cases were independently classified as clinically significant using the QIDS-SR, with 10.4% mild, 38.6% moderate, 38.0% severe, and 12.9% very severe. Mean episode duration was 16 weeks (95% CI, 15.1-17.3). Role impairment as measured by SDS was substantial as indicated by 59.3% of 12-month cases with severe or very severe role impairment. Most lifetime (72.1%) and 12-month (78.5%) cases had comorbid CIDI/DSM-IV disorders, with MDD only rarely primary. Although 51.6% (95% CI, 46.1-57.2) of 12-month cases received health care treatment for MDD, treatment was adequate in only 41.9% (95% CI, 35.9-47.9) of these cases, resulting in 21.7% (95% CI, 18.1-25.2) of 12-month MDD being adequately treated. Sociodemographic correlates of treatment were far less numerous than those of prevalence.


CONCLUSIONS
Major depressive disorder is a common disorder, widely distributed in the population, and usually associated with substantial symptom severity and role impairment. While the recent increase in treatment is encouraging, inadequate treatment is a serious concern. Emphasis on screening and expansion of treatment needs to be accompanied by a parallel emphasis on treatment quality improvement.
Kessler
Ronald C
RC
Department of Health Care Policy, Harvard Medical School, Boston, MA 02115, USA. NCS@hcp.med.harvard.edu
Berglund
Patricia
P
Demler
Olga
O
Jin
Robert
R
Koretz
Doreen
D
Merikangas
Kathleen R
KR
Rush
A John
AJ
Walters
Ellen E
EE
Wang
Philip S
PS
D000328:Adult; D015897:Comorbidity; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology*; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D007406:Interview, Psychological; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D015995:Prevalence; D012044:Regression Analysis; D012647:Self-Assessment; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology