Twelve-Month Use of Mental Health Services in the United States:  Results From the National Comorbidity Survey Replication FREE

Recent reports from the surgeon general¹ and the President’s New Freedom Commission on Mental Health² stress the importance of improving mental health treatment in the United States. Accurate general population data on current mental health treatments are needed for policy planning in this area. The Epidemiologic Catchment Area Study provided the first such data in the 1980s, finding that only 19% of respondents with recent DSM-III³ mental disorders received any treatment in the 12 months before interview.⁴ A decade later, the National Comorbidity Survey (NCS) found that 25% of respondents with 12-month DSM-III-R⁵ disorders received treatment in the 12 months before the interview.⁶

In the decade since the baseline NCS, important changes have occurred in the US mental health services delivery system. Advances in treatments have expanded the spectra of eligible patients and providers who feel comfortable delivering these treatments.^7- 9 Pharmacological treatments have been widely promoted through direct-to-consumer advertising.¹⁰ Complementary and alternative medicine (CAM) therapies have experienced widespread acceptance.^11- 13 Community programs promoting awareness, screening, and help seeking for mental disorders have been launched.^14- 15 Delivery of mental health services in primary care, managed care, and behavioral “carve-out” systems has expanded dramatically.^16- 19 Evidence-based guidelines, disease management programs, and report cards have been developed to improve the quality of care.^20- 29 New policies have been introduced to reduce barriers to service use, including parity legislation and initiatives for vulnerable elderly populations and those with a serious mental illness.^30- 32

The rapidity of these changes has rendered earlier information on mental health treatment obsolete. Up-to-date data are needed to assess the impact of recent changes in mental health delivery systems and to guide mental health care (HC) policy initiatives. The National Ambulatory Medical Care Survey⁷ and the Healthcare for Communities Community Tracking Survey³³ suggest that use of certain HC treatments for mental disorders may be increasing, although the 2002 National Survey on Drug Use and Health found that most adults with serious disorders still receive none.³⁴

The present report provides basic descriptive data from the recently completed NCS Replication (NCS-R).³⁵ We first examine the proportions of respondents with 12-month disorders who obtain any treatment in the 12 months before interview, by disorder and service sector. Because the intensity and quality of treatment have often been poor in earlier studies,^36- 38 we also examine median numbers of visits and proportions receiving minimally adequate treatment concordant with evidence-based guidelines. Finally, we examine sociodemographic correlates of treatment and treatment adequacy.

The NCS-R is a nationally representative household survey of respondents 18 years and older in the coterminous United States.^39- 40 Face-to-face interviews were carried out with 9282 respondents between February 5, 2001, and April 7, 2003. Part 1 included a core diagnostic assessment administered to all respondents. Part 2 assessed risk factors, correlates, service use, and additional disorders, and was administered to all part 1 respondents with lifetime disorders plus a probability subsample of other respondents. The overall response rate was 70.9%. The NCS-R recruitment, consent, and field procedures were approved by the Human Subjects Committees of Harvard Medical School and the University of Michigan, Ann Arbor.

DSM-IV diagnoses were made using the World Health Organization’s World Mental Health (WMH) Survey Initiative version of the Composite International Diagnostic Interview (CIDI),⁴¹ a fully structured lay-administered diagnostic interview that generates International Classification of Diseases, 10th Revision (ICD-10),⁴² and DSM-IV⁴³ diagnoses. Twelve-month DSM-IV disorders considered herein include mood (bipolar I and II disorders, major depressive disorder, and dysthymia), anxiety (panic disorder, agoraphobia without panic, specific phobia, social phobia, generalized anxiety disorder, obsessive-compulsive disorder, posttraumatic stress disorder, and separation anxiety disorder), impulse control (intermittent explosive disorder), and substance (alcohol and other drug abuse and dependence) disorders. All diagnoses are considered with organic exclusions and diagnostic hierarchy rules, with the exception of the substance disorders, for which abuse is defined with or without dependence. Blind clinical reappraisals using the Structured Clinical Interview for DSM-IV^39,44 showed generally good concordance between WMH CIDI lifetime diagnoses and the Structured Clinical Interview for DSM-IV for anxiety, mood, and substance disorders. The WMH CIDI lifetime diagnoses of impulse control disorders have not been validated, and evaluation of WMH CIDI 12-month diagnoses is ongoing.

All part 2 respondents were asked whether they ever received treatment for “problems with your emotions or nerves or your use of alcohol or drugs.” A list of types of treatment providers was presented in a respondent booklet to provide a visual recall aid. The list of professionals included was as follows: a psychiatrist, a general practitioner or family physician, any other physician (eg, cardiologist, gynecologist, or urologist), a social worker, a counselor, any other mental health professional (eg, a psychotherapist or a mental health nurse), a religious or spiritual advisor (eg, a minister, priest, or rabbi), or any other healer (eg, a chiropractor, herbalist, or spiritualist). Separate assessments were made for different types of professionals, support groups, self-help groups, mental health crisis hotlines (assumed to be visits with nonpsychiatrist mental health specialists), CAM therapies, and use of other treatment settings, including admissions to hospitals and other facilities (each day of admission was assumed to include a visit with a psychiatrist). Follow-up questions asked about age at first and most recent contacts and number and duration of visits in the past 12 months.

Reports of 12-month service use were classified into the following categories: psychiatrist, nonpsychiatrist mental health specialist (psychologist or other nonpsychiatrist mental health professional in any setting, social worker or counselor in a mental health specialty [MHS] setting, or use of a mental health hotline), general medical (GM) provider (primary care physician, other general physician, nurse, or any other health care professional not previously mentioned), human services (HS) professional (religious or spiritual advisor or social worker or counselor in any setting other than a specialty mental health setting), and CAM professional (any other type of healer, such as a chiropractor, participation in an Internet support group, or participation in a self-help group). Psychiatrist and nonpsychiatrist specialist categories were combined into a broader MHS category; MHS was also combined with GM into an even broader HC category. Human services and CAM were also combined into a non-HC category.

Minimally adequate treatment was defined based on available evidence-based guidelines^24- 29 as receiving either pharmacotherapy (≥2 months of an appropriate medication for the focal disorder plus >4 visits to any type of physician) or psychotherapy (≥8 visits with any HC or HS professional lasting an average of ≥30 minutes). The decision to require 4 or more physician visits for pharmacotherapy was based on the fact that 4 or more visits for medication evaluation, initiation, and monitoring are generally recommended during the acute and continuation phases of treatment in available guidelines.^20- 25 Appropriate medications for disorders included antidepressants for depressive disorders, mood stabilizers or antipsychotic agents for bipolar disorders, antidepressants or anxiolytic agents for anxiety disorders, antagonists or agonists (disulfiram, naltrexone, or methadone hydrochloride) for alcohol and other substance disorders, and any psychiatric drug for impulse control disorders.⁹ At least 8 sessions were required for minimally adequate psychotherapy based on the fact that clinical trials demonstrating effectiveness have generally included 8 psychotherapy visits or more.^20- 25 For alcohol and other substance disorders, self-help visits of any duration were counted as psychotherapy visits. Treatment adequacy was defined separately for each 12-month disorder (ie, a respondent with comorbid disorders could be classified as receiving minimally adequate treatment for one disorder but not for another).

Respondents who began treatments shortly before the NCS-R interview may not have had time to fulfill requirements, even though they were in the early stages of adequate treatment. Furthermore, brief treatments have been developed for certain disorders.^45- 46 We, therefore, created a broader definition of minimally adequate treatment for sensitivity analyses that consisted of receiving 2 or more visits to an appropriate treatment sector (1 visit for a presumptive examination/diagnosis and ≥1 visit for treatment) or being in ongoing treatment at interview.

Sociodemographic variables included cohort (defined by age at interview and categorized as 18-29, 30-44, 45-59, and ≥60 years), sex, race-ethnicity (non-Hispanic white, non-Hispanic black, Hispanic, and other), completed years of education (0-11, 12, 13-15, and ≥16), marital status (married-cohabitating, previously married, and never married), family income in relation to the federal poverty line⁴⁷ (categorized as low [≤1.5 times the poverty line], low average [>1.5-3 times the poverty line], high average [>3-6 times the poverty line], and high [≥6 times the poverty line]), urbanicity defined according to 2000 census definitions⁴⁸ (large and smaller metropolitan areas; central cities, suburbs, and adjacent areas; and rural areas), and health insurance coverage (including private, public, or military sources).

The NCS-R data were weighted to adjust for differences in probabilities of selection, differential nonresponse, residual differences between the sample and the US population, and oversampling in the part 2 sample.³⁹ Basic patterns of service use were examined by computing proportions in treatment, mean and median numbers of visits among those in treatment, and probabilities of treatments meeting the criteria for minimal adequacy. Logistic regression⁴⁹ analysis was used to study sociodemographic predictors of receiving any 12-month treatment in the total sample, treatment in particular sectors among those receiving any treatment, and treatment meeting the criteria for minimal adequacy. Standard errors were estimated using the Taylor series method as implemented in a computer software program (SUDAAN).⁵⁰ Multivariate significance tests in the logistic regression analyses were made using Wald χ² tests based on coefficient variance–covariance matrices that were adjusted for design effects using the Taylor series method. Statistical significance was evaluated using 2-sided design-based tests and the .05 level of significance.

Of the respondents, 17.9% used services in the prior year, including 41.1% of those with 12-month DSM-IV disorders and 10.1% of those without them (Table 1) (Kessler et al⁵¹ describe the prevalence of 12-month disorders in the NCS-R). The proportion of cases in treatment ranged from a high for dysthymia to a low for intermittent explosive disorder. Most treatments occurred in the HC sectors (15.3% of respondents, representing 85.5% of those in treatment) and, within the HC sectors, the GM sector (9.3% of respondents, representing 52.0% of those in treatment).

The median number of 12-month visits (Table 2) among those receiving any treatment was 2.9, and was significantly higher among those with disorders than among those without disorders (z = 5.8, P<.001). Because respondents with no disorder make up most of the population (74.6%), they account for nearly one third of all visits (33.2%) and visits to specific sectors. Within-sector medians ranged from a high for CAM to a low for GM.

The mean numbers of visits (data not shown, but available from the authors) are consistently much higher than the median. For example, the median among patients receiving any treatment was 2.9, compared with the mean of 14.7. Mean visits were significantly higher among patients with a disorder (16.9) than among those without a disorder (11.6) (z = 3.1, P = .001). Within-sector means were highest for CAM (29.8) and nonpsychiatrist specialty (16.1), lower for psychiatrist (7.5) and HS (7.1), and lowest for GM (2.6). Based on these data, the proportion of all visits made in specific sectors was highest for nonpsychiatrist specialty (38.0%) and CAM (31.3%), lower for psychiatrist (12.6%), and lowest for GM (9.1%) and HS (9.0%).

The greater magnitude of means than medians implies that comparatively few patients receive a disproportionately high share of all visits (Table 3). For example, although nearly 60% of patients seen by psychiatrists made fewer than 5 visits in the year, they accounted for only one sixth of all visits to psychiatrists. Those making 50 or more visits to psychiatrists in the year, while representing only 1.6% of all patients seen by psychiatrists, accounted for 20.2% of all psychiatrist visits. One way to compare these distributions across sectors is to calculate the proportion of patients at the upper end of the service use distribution who account for 50% of all visits to the sector. This percentage is between 6.4% (HS) and 23.6% (GM) of patients across sectors.

Of the treated patients with disorders, only 32.7% were classified as receiving at least minimally adequate treatment (Table 4). Probabilities of treatment being at least minimally adequate were highest in the MHS sectors and lowest in the GM sector.

In sensitivity analyses (data not shown, but available from the authors) using the broader definition of minimally adequate treatment (ie, receiving ≥2 visits to an appropriate sector or being in ongoing treatment at the time of interview), the percentage of patients receiving treatment that was at least minimally adequate increased to 47.8%. Probabilities were highest in the psychiatrist (53.3%) and nonpsychiatrist specialty (51.1%) sectors, and lower in the HS (46.9%) and GM (33.2%) sectors.

After controlling for the presence of all individual 12-month mental disorders, the odds of receiving any 12-month mental health treatment is significantly related to being younger than 60 years, female, non-Hispanic white, and previously married; not having a low average family income; and not living in a rural area (Table 5). Among those who received any treatment, treatment in one of the HC sectors is significantly related to not being in the age range of 18 to 29 years, not being non-Hispanic black, living in rural areas, and having health insurance. Among those who received HC treatment, MHS treatment is significantly related to being younger than 60 years, male, college educated, not married, and not living in a rural area.

None of the sociodemographic variables we considered was significantly related to treatment adequacy among people who received treatment after controlling for the presence of all individual 12-month mental disorders (Table 6). We did not find significant sociodemographic correlates of treatment adequacy in the GM sector. Correlates of adequate MHS treatment include a high level of education and living in a rural area. Finally, the adequacy of non-HC treatment seems to be highest among patients aged 18 to 29 years, males, and those married.

These results should be interpreted with the following 5 limitations in mind. First, the NCS-R excludes people who are homeless or institutionalized. Because these people make up only a small proportion of the population, these results apply to most of the population. Another frame exclusion is that the WMH CIDI did not assess all DSM-IV disorders. Therefore, some respondents in treatment classified as not having a disorder may actually have met the criteria for a DSM-IV disorder not assessed.

Second, systematic survey nonresponse (ie, people with mental disorders having a higher survey refusal rate than those without disorders) or systematic nonreporting (ie, recall failure, conscious nonreporting, or error in the diagnostic evaluation) could lead to bias in the estimates of unmet need for treatment. Given what we know about the associations between true prevalence and these errors,^{39- 40,52- 55} it is likely that unmet need for treatment has been underestimated.

Third, without corroborating data on service use, we cannot study the validity of self-reported treatment use in the NCS-R. Recent studies^56- 57 of the Ontario Health Survey suggest that self-reports of mental health service use overestimate administrative treatment records, especially concerning the number of visits and among respondents with more distressing disorders. Unlike the Ontario Health Survey, the NCS-R did attempt to minimize such inaccuracies by using commitment probes (ie, questions designed to measure a subject’s commitment to the survey) and excluding the few respondents (<1%) who failed to endorse that they would think carefully and answer honestly. Nevertheless, potentially biased recall of mental health service use remains a limitation. To the extent that it occurred, our results are likely to underestimate unmet need for treatment, especially among those with more serious disorders.

Fourth, our definitions of minimally adequate treatment may differ from others in use and, to our knowledge, their relationships with important clinical outcomes have not been studied. In addition, respondents diagnosed as having a disorder shortly before interview may not have had enough time to meet our main definition. Brief treatments have also been described for certain phobias⁴⁵ and alcohol disorders.⁴⁶ However, our sensitivity analyses using broader definitions (ie, ≥2 visits to an appropriate sector or being in ongoing treatment at the time of interview) accounted for these possibilities and still found that half of treated cases are cared for inadequately.

Fifth, no effort was made to determine the need for treatment based on the severity of disorders. It is possible that respondents with untreated or inadequately treated disorders are disproportionately made up of mild or self-limiting cases. An evaluation of the relationship between disorder severity and treatment adequacy is an important next step in the analysis of the NCS-R data, but goes beyond the scope of this initial report.

With these limitations in mind, the results reported herein document serious problems in the treatment of people with mental disorders in the United States. Increasing use of some modalities, most notably pharmacotherapies and physician-administered psychotherapies,^7,36,58- 59 has generated hope that mental disorders are being treated much more effectively than in the past. Our results suggest that such optimism is premature. Mental health service use remains disturbingly low, with most patients not receiving any care in the prior year. Among the minority who receive services, not all are treated in a HC sector. Even those who successfully access the HC sector often fail to get sufficient visits for clinical assessments, delivery of treatments, and appropriate ongoing monitoring.^29,58,60 Furthermore, only one third of treatments meet minimal standards of adequacy based on evidence-based treatment guidelines,^20- 25 confirming results of earlier studies.^36- 38,61

The frequent use of treatments with uncertain benefit is striking. This is especially worrisome for CAM treatments, which account for 31.3% of all mental health visits despite a paucity of data supporting their efficacy.^{11- 13,62- 65} A challenge for the providers of conventional services is to determine why CAM has such great appeal and whether legitimate aspects related to this appeal (eg, a greater orientation to patient-centered care) can be adopted by conventional mental HC providers to increase the attractiveness of evidence-based treatments.

Conversely, many services are being consumed by respondents without apparent disorders. Although respondents without disorders are less likely to receive treatment or as many visits once in treatment as those with disorders, they make up such a majority of the population that they account for nearly one third of all visits. Some services are undoubtedly being used appropriately to treat active mental disorders not assessed in the NCS-R, to treat subthreshold symptoms, as secondary prevention of lifetime disorders, or even as primary prevention of disorders.⁶⁶ However, given the profound unmet need for mental health services among people with well-defined mental disorders, the potential diversion of so many treatment resources to individuals without mental disorders is concerning.⁶⁷

The highly skewed distribution of visits, in which a few patients account for most visits, implies that more people with disorders could be effectively treated with existing levels of resources through better allocation. It is less clear, though, how to develop a principled basis for deciding what the optimal allocation of treatment resources should be or how the organization and financing of services would have to be modified to achieve it. Some features of managed care, such as prior authorization and utilization review, could presumably be applied to unnecessary use but not underuse—in fact, application of such features may have an unintended consequence of worsening unmet needs for treatments. Furthermore, it is not clear how any optimal allocation plan that is developed would be implemented in the decentralized US HC system, as this remains a formidable task even in centralized HC systems.⁶⁸

The proportion of NCS-R respondents who reported 12-month mental health service use (17.9%) is higher than the value found a decade earlier in the baseline NCS (13.3%)⁶ and the value found a decade before that in the Epidemiologic Catchment Area Study (12.3%).⁶⁹ By far, the greatest part of this expansion occurred in the GM sector. General physicians often act as gatekeepers responsible for initiating mental health treatments themselves and for deciding whom to triage for specialty care.^70- 71 Increasing awareness of mental disorders on the part of primary care physicians, coupled with an increase in consumer demand stimulated by direct-to-consumer advertising, has probably also played a role in this growth.^72- 75 However, the fact that only a few patients treated in the GM sector receive minimally adequate care makes these trends concerning. Reasons for the low rate of treatment adequacy are unclear, but presumably involve provider factors (eg, competing demands, inadequate reimbursements for treating mental disorders, and less training and experience in treating mental disorders) and patient factors (eg, worse compliance with treatments than in MHS sectors).^{18- 19,76- 77}

Service use also varied across disorders. The greater treatment for panic disorder than specific phobia or for substance dependence than substance abuse presumably reflects the influence of greater distress and impairment on help seeking.^78- 82 The generally lower treatment rates for externalizing disorders (eg, substance disorders and intermittent explosive disorder) may reflect diminished perceived needs for treatment on the part of patients and tendencies for patients and providers to view these problems as social or criminal rather than medical.^83- 84 In the case of impulse control disorders, an additional issue is that effective treatments are just emerging.^85- 86

The NCS-R results concerning sociodemographic predictors of mental health service use are generally consistent with prior research in showing that vulnerable groups often have elevated risks of undertreatment. The lower overall rate of treatment among older people may be due to the greater perceived stigma of mental disorders among people in this age range.⁸¹ The fact that among those receiving HC older respondents are less likely to obtain it in specialty settings may likewise reflect the unacceptability of mental health treatments to elderly persons.^87- 88

The lower rate of treatment among men is consistent with most previous research^6,69 and is potentially explained by greater perceived stigma and women’s greater abilities to translate nonspecific feelings of distress into conscious recognition of having a mental health problem.^89- 90 The fact that male patients are more likely than female patients to use MHS care may be due to primary care physicians’ greater willingness to treat women, while referring men to specialists.^91- 92 Whatever the cause, it results in male patients having a considerably higher probability of receiving adequate treatment than female patients.

The lower overall rate of treatment among racial and ethnic minorities is generally consistent with prior research.⁹³ On the other hand, among people who received treatment, there were no significant associations between race-ethnicity and treatment adequacy. These patterns, at least superficially, point to the importance of barriers on the part of potential patients to accessing HC rather than inadequacies in the quality of care once patients enroll in treatment. Recent studies in minority communities⁹⁴ document that experiences and expectations of mistreatment due to prejudice may still be key factors in discouraging early access to HC for mental disorders.

Despite the absence of race-ethnicity differences in treatment adequacy among patients, low education and low income were associated with increased odds of not receiving any treatment (income), not receiving specialty care among HC patients (education), and receiving less adequate specialty treatment than other patients in the MHS sectors (education). Because racial-ethnic minorities have lower aggregate education and income than nonminorities, these effects lead to gross increases in unmet need for treatment among minorities, even though the effects may be mediated by low socioeconomic status.

Similar to the original NCS, we found that having insurance was associated with using HC sectors among people receiving any treatment.^37,95 These are worrisome findings for the uninsured, given the lack of demonstrated effectiveness for most non-HC treatments.^62- 64 Surprisingly, insurance was not related to receiving anytreatment or adequacy among people receiving treatment. The effects of low income most likely reflect the formidable influences of financial barriers; because insurance was controlled, these results imply that simply having insurance may not be sufficient to overcome these effects.⁹⁶ Interestingly, those with the lowest incomes were associated with more treatment than those with low-average incomes, perhaps because the near poor do not qualify for often more generous entitlements for the indigent. Given our adjustment for income, the positive association between education and MHS care may be because of more than education being a proxy for greater financial resources to pay for specialty services; instead, it may reflect an importance placed on knowledge and cognitive processes in many psychotherapeutic modalities.⁹⁶

Greater use of mental health services among those previously married may indicate the power of relationship loss or strife as a motivator for seeking treatment.⁸¹ The finding that the unmarried who seek HC are more likely to obtain it in specialty settings may reflect that counseling is often a preferred modality for those with relational difficulties. Finally, lower treatment in rural areas probably reflects the scarcity of treatment resources, especially in the MHS sector; however, the limited MHS care that does exist is superior.⁹⁷

Three broad types of intervention are suggested by the results. First, outreach efforts are needed to increase access to and initiation of treatments. Interventions of this type could include renewed community awareness and screening programs, new means for financing mental health services, and expansion of treatment resources for underserved areas.^{14- 15,30- 32,97} Second, interventions are needed to improve the quality of care delivered to patients with mental disorders. Several disease management programs that enhance treatment adequacy and adherence have already been proved successful and cost-effective.^{26- 28,98- 99} Performance standards, such as those in the Substance Abuse and Mental Health Services Administration’s Center for Mental Health Services Consumer-Oriented Mental Health Report Card⁶⁰ and those of the National Committee for Quality Assurance,²⁹ could further optimize quality and monitor future interventions’ impacts. Third, initiatives are needed to increase the uptake of successful programs and treatment models. Widespread failure to disseminate proved interventions may, in fact, explain why large unmet needs persist in the United States, despite earlier efforts to address this problem. Substantial barriers to the uptake of effective interventions exist, including competing clinical demands and distorted incentives for effectively treating mental disorders faced by providers, particularly in primary care.^{18- 19,76- 77,100} Purchasers may also hesitate to take up proved interventions because they lack metrics to help understand what their return on investment will be.¹⁰¹ Ongoing initiatives seeking to overcome these barriers include the Robert Wood Johnson Depression in Primary Care Program⁷⁷ and the National Institute of Mental Health–sponsored Work Outcomes Research and Cost-effectiveness Study.¹⁰¹

Correspondence: Philip S. Wang, MD, DrPH, Department of Health Care Policy, Harvard Medical School, 180 Longwood Ave, Boston, MA 02115 (wang@hcp.med.harvard.edu).

Submitted for Publication: June 9, 2004; final revision received October 7, 2004; accepted November 9, 2004.

Group Members: Collaborating investigators of the NCS-R include Ronald C. Kessler, PhD, Harvard Medical School (principal investigator); Kathleen Merikangas, National Institute of Mental Health, Rockville, Md (coprincipal investigator); Doreen Koretz, PhD, Harvard University, Cambridge; James Anthony, PhD, MSc, Michigan State University, East Lansing; William Eaton, PhD, The Johns Hopkins University, Baltimore, Md; Meyer Glantz, PhD, National Institute on Drug Abuse, Bethesda, Md; Jane McLeod, PhD, Indiana University, Bloomington; Mark Olfson, MD, MPH, New York State Psychiatric Institute, College of Physicians and Surgeons of Columbia University, New York; Harold A. Pincus, MD, University of Pittsburgh, Pittsburgh, Pa; Greg Simon, MD, and Michael Von Korff, ScD, Group Health Cooperative; Philip S. Wang, MD, DrPH, Harvard Medical School; Kenneth B. Wells, MD, MPH, University of California, Los Angeles; Elaine Wethington, PhD, Cornell University, Ithaca, NY; and Hans-Ulrich Wittchen, PhD, Institute of Psychology, Technical University Dresden, Dresden, and Max Planck Institute of Psychiatry, Munich, Germany.

Funding/Support: The NCS-R is supported by grant U01-MH60220 from the National Institute of Mental Health; the National Institute on Drug Abuse; the Substance Abuse and Mental Health Services Administration, Rockville; grant 044708 from The Robert Wood Johnson Foundation, Princeton, NJ; and the John W. Alden Trust, Boston.

Disclaimer: The views and opinions expressed herein are those of the authors and should not be construed to represent the views of any of the sponsoring organizations, agencies, or the US government.

Additional Information: A complete list of NCS publications and the full text of all NCS-R instruments can be found at http://www.hcp.med.harvard.edu/ncs. Send correspondence to ncs@hcp.med.harvard.edu. The NCS-R is carried out in conjunction with the WMH Survey Initiative. These activities were supported by the John D. and Catherine T. MacArthur Foundation, Chicago, Ill; Pfizer Foundation, Cambridge; US Public Health Service (R13-MH066849, R01-MH069864, and R01-DA016558), Washington, DC; Fogarty International Center (FIRCA R01-TW006481), Bethesda; Pan American Health Organization, Washington, DC; Eli Lilly and Company, Indianapolis, Ind; Ortho-McNeil Pharmaceutical, Inc, Raritan, NJ; GlaxoSmithKline, Triangle Park, NC; and Bristol-Myers Squibb, New York. A complete list of WMH publications and instruments can be found at http://www.hcp.med.harvard.edu/wmh.

Acknowledgment: We thank Jerry Garcia, Sara Belopavlovich, Eric Bourke, and Todd Strauss for their assistance with manuscript preparation; and the staff of the WMH Data Collection and Data Analysis Coordination Centers for their assistance with instrumentation, fieldwork, and consultation on data analysis.