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Revised Prevalence Estimates of Mental Disorders in the United States
Using a Clinical Significance Criterion to Reconcile 2 Surveys' Estimates
William E. Narrow, MD, MPH;
Donald S. Rae, MA;
Lee N. Robins, PhD;
Darrel A. Regier, MD, MPH
Arch Gen Psychiatry. 2002;59:115-123.
ABSTRACT
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Background Current US mental disorder prevalence estimates have limited usefulness
for service planning and are often discrepant. Data on clinical significance
from the National Institute of Mental Health Epidemiologic Catchment Area
Program (ECA) and the National Comorbidity Survey (NCS) were used to produce
revised estimates, for more accurate projections of treatment need and further
explication of rate discrepancies.
Methods To ascertain the prevalence of clinically significant mental disorders
in each survey, responses to questions on life interference from, telling
a professional about, or using medication for symptoms were applied to cases
meeting symptom criteria in the ECA (n = 20 861) and NCS (n = 8098).
A revised national prevalence estimate was made by selecting the lower estimate
of the 2 surveys for each diagnostic category, accounting for comorbidity,
and combining categories.
Results Using data on clinical significance lowered the past-year prevalence
rates of "any disorder" among 18- to 54-year-olds by 17% in the ECA and 32%
in the NCS. For adults older than 18 years, the revised estimate for any disorder
was 18.5%. Using the clinical significance criterion reduced disparities between
estimates in the 2 surveys. Validity of the criterion was supported by associations
with disabilities and suicidal behavior.
Conclusions Establishing the clinical significance of disorders in the community
is crucial for estimating treatment need. More work should be done in defining
and operationalizing clinical significance, and characterizing the utility
of clinically significant symptoms in determining treatment need even when
some criteria of the disorder are not met. Discrepancies in ECA and NCS results
are largely due to methodologic differences.
INTRODUCTION
AMONG THE issues facing the field of psychiatric epidemiology are 2
challenges for future research. The first relates to limitations in currently
available surveys as tools for mental health service planning. Two large community
surveys, the National Institute of Mental Health Epidemiologic Catchment Area
Program (ECA) and the National Comorbidity Survey (NCS), have been the main
sources for estimates of treatment need in the United States.1-3
These surveys showed overall 1-year mental and addictive disorder prevalence
rates approaching 30% and lifetime rates approaching 50%. If these prevalence
rates are taken as a proxy for mental health treatment need, the mental health
system would have to expand enormously to meet this need, with attendant increases
in workforce deployment and overall costs. Alternatively, the clinical significance
of these community-based rates, and therefore their suitability as a proxy
for treatment need, has been questioned.4-5
The high disorder rates in the ECA and NCS were accompanied by low service
use rates, with less than one third of persons with an active mental disorder
using mental health services in a 1-year period.6-7
The extent to which the untreated cases represent unmet need for treatment
as opposed to absence of need for treatment because of mild or transient symptoms
is not clear.8-11
A closer examination of the clinical significance of community prevalence
rates is warranted.
The second challenge is methodologic, having to do with explaining the
differences in the prevalence rates of individual disorders between the ECA
and the NCS. Reconciling these differences is important for policy and planning
purposes, in that more consistent results will lead to less confusion among
the end users of the data and more confidence in the reliability of the methods
and the diagnoses themselves. Recent work4
showed that the differences could be partially reconciled by accounting for
changes in diagnostic criteria between DSM-III and DSM-III-R (particularly for the anxiety disorders), and
the different age ranges in the 2 surveys. Several factors could not be controlled
for, including different sampling frames, the use of a "commitment question"
in the NCS, and stem question placement and other differences (eg, a more
complete assessment of phobias) in the NCS diagnostic interview. Another factor
that has been raised but not empirically examined is whether the cases identified
by these different survey methods differ in the clinical significance of their
symptoms. That is, do higher rates indicate an improved sensitivity of the
methods and instrumentation to identify clinically significant cases, or an
oversensitivity, in that the excess cases meet symptom criteria but are not
clinically significant?
The concept of clinical significance of mental disorders plays a role
in both of these issues. Clinical significance has been a part of the DSM definition of mental disorder starting with DSM-III.12 Currently, DSM-IV13 defines a mental disorder as
a clinically significant behavioral or psychological syndrome
or pattern that occurs in an individual and that is associated with present
distress (e.g., a painful symptom) or disability (i.e., impairment in one
or more important areas of functioning) or with a significantly increased
risk of suffering death, pain, disability, or an important loss of freedom.13(pxxi)
The concept was further highlighted in DSM-IV
by its inclusion in the diagnostic criteria for many disorders, in the context
of distress or impairment in social, occupational, or other important areas
of functioning.13(p7) For example, criterion
E of generalized anxiety disorder states: "The anxiety, worry, or physical
symptoms cause clinically significant distress or impairment in social, occupational,
or other important areas of functioning."13(p436)
Despite the prominence of clinical significance in diagnostic criteria,
there is currently no consensus as to how it should be defined or operationalized.
In large epidemiologic surveys, direct clinical judgment is rarely used because
of the high cost of clinical time and the large number of subjects, so proxy
measures are used.14 The developers of the
Diagnostic Interview Schedule (DIS) used in the ECA, and the related University
of Michigan version of the Composite International Diagnostic Interview (UM-CIDI)
used in the NCS, placed structured questions in the interviews to address
the clinical significance of symptoms and syndromes.15-17
With these questions, clinical significance was assumed if the respondent's
symptoms led him or her to mention them to a doctor or other professional,
or if the symptoms interfered with his or her everyday life, or if the respondent
took medication for the symptoms. Thus, clinical significance was related,
if imperfectly, to concepts of symptom prominence or severity (and possibly
the resulting distress), impairment in functioning, and treatment (including
self-treatment) with medication.
The question arises, then, as to whether these questions, if applied
to the existing prevalence estimates, will produce more realistic rates for
policy and service planning, and to what extent differences in clinical significance
affect prevalence differences between the ECA and the NCS. This article presents
revised prevalence estimates of clinically significant mental disorders, with
evidence of their validity, as an initial attempt to address these questions.
METHODS
EPIDEMIOLOGIC SURVEYS
The National Institute of Mental Health ECA has been described at length
in previous publications.1-2,18
It was conducted from 1980 to 1985 in 5 sites, which provided 18 571
household and 2290 institutional residents 18 years and older. Two face-to-face
interviews were done 12 months apart (wave 1 and wave 2). A telephone interview
(face-to-face in New Haven, Conn) of the household respondents was conducted
6 months after wave 1. Questions on use of health services were asked at each
interview. Diagnostic data were obtained at waves 1 and 2 only. The data were
weighted to account for unequal probabilities of selection for each person
sampled and for nonresponse. The data were also weighted on the basis of the
age, sex, and race or ethnicity distribution of the 1990 US Census. The DSM-III psychiatric diagnoses were assessed with the DIS.
The NCS3 was a cross-sectional survey
of a nationally representative household sample of 8098 adolescents and adults
aged 15 to 54 years, conducted from 1990 to 1992. Data were weighted to account
for nonresponse and unequal probabilities of selection, and to adjust the
data to national population distributions on the basis of the 1989 US National
Health Interview Survey. The UM-CIDI was used to obtain DSM-III-R diagnoses. Although generalized anxiety disorder and posttraumatic
stress disorder were assessed only in the NCS, obsessive-compulsive disorder,
anorexia nervosa, somatization disorder, and cognitive impairment were assessed
only in the ECA.
CLINICAL SIGNIFICANCE QUESTIONS
In the ECA DIS, the clinical significance questions were as follows:
Did you tell a doctor about (symptom[s])? Did you tell any other professional
about (symptom[s])? Did you take medicine for (symptom[s]) more than once?
Did (symptom[s]) interfere with your life or activities a lot? The NCS included
the following clinical significance questions: Did you ever tell a doctor
other than a psychiatrist about (symptom[s])? Did you ever see a mental health
specialist about your (symptom[s])? Did you ever see any other professional
about (symptom[s])? Did you ever take medication more than once because of
(symptom[s])? How much did your (symptom[s]) ever interfere with your life
or activities—a lot, some, a little, or not at all?
Although the questions assessing clinical significance were similar
in the 2 studies, they were applied differently. In the DIS, for anxiety disorders,
dysthymia, schizophrenia, somatization disorder, anorexia nervosa, and antisocial
personality disorder, the clinical significance of a symptom was determined
by using a decision tree of clinical significance questions posed to the respondent.
When the respondent acknowledged talking to a physician or other professional,
or taking medicine, or that the symptom interfered with his or her life a
lot, then the symptom was treated as clinically significant. For these disorders,
the diagnostic algorithms were constructed so that only clinically significant
symptoms were considered. For ECA diagnoses of major depression, mania, and
drug use disorders, and for virtually all of the NCS diagnoses, individual
symptoms were not assessed for clinical significance. Rather, at the end of
each diagnostic module, clinical significance questions were posed to those
respondents who had sufficient symptoms for a potential diagnosis. The results
of these questions could then be applied, independently of the diagnostic
algorithm, to the persons who met symptom criteria for a disorder.
SERVICE USE
Service use during a 1-year period for mental health or substance use
problems was assessed. For the ECA, treatment data came from the initial interview,
or from the 6-month and 12-month follow-up interviews, depending on when the
respondent's mental disorder was detected.6
For the NCS, a retrospective report of treatment during the year before the
interview was used. Ambulatory settings were categorized into specialty mental
and addictive or general medical sectors. Combined, these 2 sectors are referred
to as the health systems sector.6
CRITERION VALIDITY
To provide a test of the validity of the clinically significant mental
disorders, several variables indicative of clinical severity and disability
were chosen. From both surveys, lifetime history of suicidal ideation and
suicide attempts, and whether the respondent was in full-time work or school,
were used. From the NCS only, an item was used that inquired whether in the
past month the respondent had been unable to work or had had to cut back on
work or usual activities for 2 or more days. From the ECA only, receipt of
disability compensation was used.
DETERMINING RATES OF CLINICALLY SIGNIFICANT MENTAL DISORDERS IN THE
ECA AND NCS
To maximize comparability, comparisons between the ECA and NCS were
limited to the population aged 18 to 54 years. As in previous analyses, we
focused on 1-year prevalence and used the single wave of data from the NCS
and 2 waves of data from the ECA to maximize case ascertainment.4
Prevalence rates of clinically significant disorders were determined by identifying
the percentage of the population that met all criteria for diagnosis, including
clinical significance. The ECA disorders with symptom-level assessment of
clinical significance did not need revisions. To determine rates of clinically
significant disorders when questions were asked for the syndrome as a whole,
rather than symptom by symptom, we considered a positive response to any of
the questions (for the NCS life interference question, "a lot") to indicate
a clinically significant syndrome. Standard errors were calculated by Taylor
series linearization19 and 95% confidence intervals
were constructed. Table 1 summarizes
the revisions to the diagnostic variables that were necessary for limiting
cases to those with clinical significance.
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Table 1. Overview of Methods to Produce Rates of Clinically Significant
Disorders*
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Because no diagnostic algorithm was available for bipolar II disorder
in the NCS, it was constructed de novo. We also created a past-year prevalence
rate for the ECA's diagnosis of dysthymia. This rate is likely to be an overestimate,
since persons with lifetime histories of both major depression and dysthymia
were asked in the ECA to date only their most recent depressive "spell," whether
it was due to dysthymia or major depression.
To approximate nontransient conditions of cognitive impairment in the
ECA, such as dementia and mental retardation, respondents were selected who
met criteria for "definite" or "possible" severe cognitive impairment at both
waves of interviews. Assuming that proxy interviews were due to cognitive
impairment in the respondent, persons with definite or possible severe cognitive
impairment at wave 1 and a proxy interview at wave 2 were also chosen.
For DSM-III alcohol abuse, impairment in functioning
was a required criterion. The DIS assessed this through questions about school
or job problems, arrests, family objections to drinking, and other social
problems. The standard clinical significance questions were not asked. For
alcohol dependence, DSM-III criterion A required
either pathological use or impairment in functioning. To estimate a clinically
significant rate of alcohol dependence in the ECA, impairment in functioning
was required whether or not there was a pattern of pathological use.
In the NCS, previously published rates of substance use disorders were
based on "broad" definitions of disorder. For the clinically significant rates
of substance abuse and dependence, the "narrow" definitions of disorder were
used. The narrow abuse definition required meeting abuse criteria within the
past year and having no history of substance dependence. The narrow dependence
definition required ever having had a substance dependence disorder, having
had symptoms in the past 12 months, and having had 3 or more substance-related
problems during the past year. Clinical significance questions were asked
in the NCS for both alcohol and other drug use disorders. For these analyses,
questions were also taken from the UM-CIDI that most closely corresponded
to the alcohol-related impairment questions in the DIS. If any one of the
clinical significance or other impairment questions was answered positively
for the narrowly defined substance use disorders, then the clinical significance
criterion was met.
REVISING PREVALENCE RATES ON THE BASIS OF DATA FROM BOTH SURVEYS
To obtain revised prevalence rates for ages 18 to 54 years, we followed
a conservative procedure previously used in an independent scientific analysis
comparing the ECA and NCS.20 For the supraordinate
categories of any anxiety disorder, any mood disorder, and any substance use
disorder, and for individual miscellaneous disorders, we selected the lower
prevalence estimate of the 2 surveys. For disorders covered in only 1 survey,
we used that estimate. To obtain the overall prevalences for "any mental disorder"
with and without substance use disorders, we combined the chosen estimates
after removing overlaps to account for comorbidity.
To obtain revised prevalence rates for persons 55 years or older, a
group not interviewed in the NCS, rates in the ECA were accepted if ECA rates
for ages 18 to 54 years were lower than NCS rates for that age group. If the
NCS had the lower rate, the NCS rate that would have been obtained for the
older age group was estimated by multiplying the NCS rate for the younger
group by the ratio between estimates for younger and older subjects in the
ECA. Finally, to obtain prevalence rates for all adults older than 18 years,
the revised estimates for the older and younger age groups were weighted by
the resident population census figures for 1990 and combined.
Differences in service use and validity indicators between respondents
who met both diagnostic and clinical significance criteria and those who met
diagnostic criteria without clinical significance were determined for each
supraordinate diagnostic category. Because dysthymia had symptom-level clinical
significance questions in the ECA, the "diagnosis only" group could not be
calculated for total mood disorders. Instead, comparisons for unipolar major
depression were made.
RESULTS
EFFECT OF THE CLINICAL SIGNIFICANCE CRITERION ON PREVALENCE RATES
In both the ECA and the NCS, prevalence rates were reduced when the
available clinical significance questions were applied. For the NCS, these
reductions were generally in the 30% to 40% range (Table 2). The largest change in NCS prevalence was 50% for social
phobia (7.4% without the clinical significance questions and 3.7% with the
questions), and the smallest change was 18% for generalized anxiety disorder
(3.4% without the clinical significance questions and 2.8% with the questions).
Overall prevalence rates for NCS "any mental disorder" and "any disorder including
substance use disorders" were reduced by about one third when the clinical
significance questions were applied.
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Table 2. One-Year Prevalence Rates From the NCS Study*
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Changes to the ECA prevalence rates (Table 3) were less striking than in the NCS, because for relatively
few disorders in the ECA was symptom information collected independent of
the clinical significance questions. For example, there was no change in the
prevalence of anxiety disorders from previously published rates because only
clinically significant symptoms were included in the diagnostic algorithms.
In contrast, the prevalence of ECA unipolar major depression, for which clinical
significance was asked at the syndrome level, was reduced by 23% when clinical
significance questions were used, compared with a 39% decrease in the NCS.
Severe cognitive impairment and drug use disorders among 18- to 54-year-olds
in the ECA showed large decreases in prevalence when clinical significance
data were applied. Table 3 also
shows that the previous usage of a lifetime estimate of dysthymia without
the clinical significance criterion grossly inflated the previously published
1-year estimates for any mood disorder in the ECA. The large reduction in
dysthymia prevalence contributed to a 44% reduction in the rate of any mood
disorder with clinical significance compared with previously published rates.
Overall, the ECA prevalence rates for any disorder and any disorder including
substance use disorders were reduced by about 17% in the 18- to 54-year age
range.
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Table 3. One-Year Prevalence Rates From the ECA Study*
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In the group aged 55 years and older in the ECA, rates for mental disorders
were generally lower than in the 18- to 54-year-old group, particularly for
substance use disorders, panic disorder, and antisocial personality disorder.
As expected, rates were higher for severe cognitive impairment in this age
group. Overall, 15.2% of persons older than 54 years had a clinically significant
mental disorder, and 17.3% had either a mental or substance use disorder.
When age groups were combined in the ECA, 17.2% of the adult population had
a mental disorder, and 22.5% had a mental or substance use disorder.
EFFECT OF THE CLINICAL SIGNIFICANCE CRITERION ON ECA-NCS DISCREPANCIES
Comparisons between the 2 surveys are not straightforward because of
their different methods for assessing clinical significance. However, the
95% confidence intervals in Table 2
and Table 3 show that, after the
clinical significance criterion is applied, the NCS rates are usually the
same or lower than the comparable ECA rates. The exceptions to this are social
phobia, which had a significant change in criteria between DSM-III and DSM-III-R and was assessed in
a different manner in the NCS, and bipolar disorder. Notably, differences
in major depression rates are not statistically significant after the clinical
significance criterion is applied, although the ECA point estimates remain
lower than those of the NCS.
REVISED PREVALENCE ESTIMATES USING DATA FROM BOTH SURVEYS
Table 4 shows the revised
estimates of clinically significant mental disorders. With the use of the
conservative method of accepting the figure from the survey with the lower
prevalence estimate when both surveys covered the disorder, the NCS was chosen
for the supraordinate anxiety and substance use disorders categories, and
the ECA was chosen for mood disorders. When only 1 survey covered the disorder,
its estimate was used, so generalized anxiety disorder and posttraumatic stress
disorder were taken from the NCS; obsessive-compulsive disorder, antisocial
personality disorder, anorexia nervosa, somatization disorder, and severe
cognitive impairment were taken from the ECA. For schizophrenia–nonaffective
psychosis, we used the ECA estimate because the NCS's unique clinical reassessment
method was applied to no other disorder in either survey. After accounting
for comorbidity and combining the chosen estimates, the overall revised 1-year
prevalence rate for 18- to 54-year-olds was 16.5% for any mental disorder
not including substance use disorders and 20.9% for any mental or substance
use disorder (Table 4). For all
persons older than 18 years, the overall prevalence of any mental or substance
use disorder was 18.5%, reflecting the lower prevalence of disorders in persons
older than 54 years.
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Table 4. Revised One-Year Prevalence Rates, Aged 18 Years and Older*
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SERVICE USE FOR MENTAL HEALTH OR SUBSTANCE USE REASONS
The percentage of persons with a clinically significant mental or addictive
disorder who used services in the health systems sector was remarkably similar
for the ECA and the NCS (Table 5). With the clinical significance criterion in place, the ECA showed slightly
higher overall rates of use in the general medical sector and lower rates
of use in the specialty mental and addictive sector compared with the NCS.
The major disparity in overall use between the 2 surveys was among persons
with mood disorders because of differences in general medical use. Compared
with previous analyses of the 2 surveys that did not use the clinical significance
questions,6-7 service use rates
increased more for the NCS disorders than for the ECA disorders when clinical
significance was required. As expected given the nature of the clinical significance
questions, reported ambulatory service use was significantly lower for those
who met symptom criteria without meeting the clinical significance criterion
than for those who met the clinical significance criterion.
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Table 5. One-Year Disorders With and Without Clinical Significance:
Percentage of Persons Receiving Ambulatory Treatment in the Past Year for
Mental Health or Substance Use Reasons, Aged 18 to 54 Years*
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INDICATORS OF VALIDITY
The usefulness of the clinical significance indicators was evaluated
by their association with suicidal ideas and behavior and indicators of disability
(Table 6). Higher levels of suicidal
ideation and attempts were associated with clinically significant disorders
in both surveys for anxiety disorders and unipolar major depression, but not
for substance use disorders. Indicators of disability (ie, receiving disability
compensation and problems with work in the past month) showed similar trends
for anxiety disorders and substance use disorders in the NCS.
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Table 6. One-Year Disorders With and Without Clinical Significance:
Percentage of Persons With Specified Validity Indicators, Aged 18 to 54 Years*
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Comorbidity between clinically significant and non–clinically
significant disorders may have obscured differences in the validity comparisons.
For example, further analyses showed that half the persons in the NCS whose
substance use disorder did not meet the clinical significance criterion had
another disorder that was clinically significant. In both surveys about one
third of those with a disorder that did not meet the clinical significance
criterion had a comorbid disorder that did.
COMMENT
The prevalence rates of mental and substance use disorders were substantially
reduced by using data generated from the ECA and NCS clinical significance
questions. These revised rates represented a group of persons with higher
levels of disability and suicidal ideation than in previous estimates, which
we consider preliminary evidence of the validity of the data. We also found
a high degree of comorbidity between clinically significant and non–clinically
significant syndromes. Discrepancies in the rates of mood disorders between
the ECA and the NCS, a source of scientific controversy in the past, were
brought significantly closer together with use of the clinical significance
data.
These analyses raise several methodologic issues. Although we found
significant differences between those who met and did not meet clinical significance
criteria as operationalized by the developers of the DIS and the CIDI, assessment
methods need further study. For example, is it preferable to assess clinical
significance at the symptom level, as with the ECA anxiety disorders, or at
the syndrome level, as with the ECA and NCS mood disorders? Furthermore, it
is not yet clear whether survey questions assessing clinical significance
should be uniform across disorders, as in the ECA and NCS, or tailored to
distinctive clinical characteristics and impairments of individual disorders.
For example, the degree and quality of life interference experienced by persons
with drug dependence will likely differ on aggregate from the life interference
experienced by persons with social phobia. Such differences are not picked
up by the current clinical significance questions. The usefulness of global
assessments of functioning and their relationships to disorder-level assessments
also need further clarification.21
The ongoing experience of comparing and reconciling the 2 surveys points
out the importance of having explicit criteria for all aspects of mental disorders,
including clinical significance, functional impairment, and subjective distress.
This methodologic work also points out the complexity of community surveys
of mental disorders and the large effects that seemingly small modifications
can have on their results. It is not until these changes are understood that
we can have a good idea whether rate differences are real or methodologic
artifacts. It now appears that many of the differences in ECA and NCS rates
are due to differences in methods.
The policy implications of epidemiologic survey results continue to
resonate as mental health systems, both public and private, struggle to compete
for shrinking health care dollars. Even relatively modest changes in the prevalence
rate of mental disorders will have an impact on the planning of service systems.
For example, in this study the change in overall prevalence of mental disorders
from 29.6% in the ECA and 30.2% in the NCS, to 20.9% with the use of our conservative
point estimates represents a decrease of about 13.3 million and 13.9 million
Americans, respectively. For all adults older than 18 years, the revised estimate
of 18.5% represents a decrease of about 19.2 million people from the ECA estimate
of 28.0%. The good news is that these lower numbers are likely to represent
a group more needful of services. Unfortunately, even when disorders are restricted
to those with clinical significance, their numbers are still overwhelming
for planning purposes. There are several unremediable sources of imprecision
in our current data, which, if remedied, might have produced further reductions
in prevalence rates. These include the lifetime time frame of the DIS and
UM-CIDI, which does not allow for assessment of the presence of each symptom
in the past year. Similarly, the clinical significance questions were asked
only on a lifetime basis. Incorporating more specific dating of this information
would probably reduce the prevalence rates, although at the expense of increased
respondent burden. The imperfect specificity of the diagnostic instruments
likely also contributes to overestimates of true prevalence rates. Finally,
the clinical significance question about life and activity interference was
different in the 2 surveys. The ECA used a dichotomous response option (yes
[a lot] or no [not a lot]) and the NCS used a scaled response ("a lot," "some,"
"a little," or "not at all"). Persons who answered yes to the ECA question
may have answered "some" if the NCS question had been used, and therefore
would not have met the clinical significance criterion as we defined it.
As psychiatric epidemiology moves into its next generation, a major
goal will therefore be to establish more precise and clinically relevant prevalence
estimates than did the ECA and the NCS, the seminal surveys of this generation.
Several challenges lie ahead. First, the field has progressed to a point where
large, expensive "catch-all" surveys will be replaced by surveys targeted
to specific goals. Unmet treatment need is sure to be one goal; causal and
protective factors are sure to be another, but the ideal design for one goal
is not the same as that for the other. Second, efforts to improve the validity
of the DIS and CIDI disorders should continue. Third, advances in the operationalization
of disability constructs and their translation into survey instruments should
be incorporated into research plans. Future population-based surveys should
include full assessments of functioning and link level of functioning to the
course of mental disorders over time. The development and psychometric testing
of the second World Health Organization Disability Assessment Schedule for
administration by lay interviewers holds promise in this regard.22-23
Further work also needs to be done in defining treatment need, beyond
current diagnostic notions. Persons with subsyndromal psychiatric symptoms
can have significant disability and therefore may require treatment.24-26 These subsyndromal
cases represent persons who may never meet disorder criteria, who may be in
the prodromal phase of a full-blown mental disorder, or who, because of treatment
or spontaneous remission, no longer meet full criteria for a disorder.27 Longitudinal descriptive and experimental studies
would help clarify this heterogeneous group's characteristics and need for
mental health services. Very little is known about the clinical significance
and treatment needs for disorders that are not currently included in epidemiologic
surveys, such as most personality disorders, adjustment disorders, and impulse
control disorders. In addition, estimates of treatment refusal by those with
clinically significant disorders would be helpful to complete the picture
of unmet need. Finally, the lack of any definitive epidemiologic study of
the mental health needs of children in the United States has been a hindrance.
Estimates of treatment need in this group vary widely, and all are based on
limited samples.28 The developmental consequences
of childhood-onset disorders, including their persistence into adulthood,
are necessary to form a clinically and developmentally sensitive epidemiology
of mental disorders.
AUTHOR INFORMATION
Accepted for publication June 26, 2001.
This study was supported with funds from the American Psychiatric Foundation,
Washington, DC, and the van Ameringen Foundation, New York, NY.
Earlier versions of this article were prepared while the first author
(W.E.N.) was with the National Institute of Mental Health, Bethesda, Md, and
were presented at the Annual Meeting of the American Psychiatric Association,
Washington, DC, May 19, 1999, and the Biennial Symposium of the World Psychiatric
Association Section on Epidemiology and Public Health, Turku, Finland, August
3, 1999.
We thank Ronald C. Kessler, PhD, Maritza Rubio-Stipec, ScD, and the
peer reviewers of the ARCHIVES for their helpful comments and assistance on
previous versions of this article.
Corresponding author and reprints: William E. Narrow, MD, MPH, American
Psychiatric Institute for Research and Education, 1400 K St NW, Washington,
DC 20005 (e-mail: wnarrow{at}psych.org).
From the American Psychiatric Institute for Research and Education,
Washington, DC (Drs Narrow and Regier and Mr Rae); and Department of Psychiatry,
Washington University School of Medicine, St Louis, Mo (Dr Robins).
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