Context
The Primary Care Evaluation of Mental Disorders (PRIME-MD) was developed
as a screening instrument but its administration time has limited its clinical
usefulness.Objective
To determine if the self-administered PRIME-MD Patient Health Questionnaire
(PHQ) has validity and utility for diagnosing mental disorders in primary
care comparable to the original clinician-administered PRIME-MD.Design
Criterion standard study undertaken between May 1997 and November 1998.Setting
Eight primary care clinics in the United States.Participants
Of a total of 3000 adult patients (selected by site-specific methods
to avoid sampling bias) assessed by 62 primary care physicians (21 general
internal medicine, 41 family practice), 585 patients had an interview with
a mental health professional within 48 hours of completing the PHQ.Main Outcome Measures
Patient Health Questionnaire diagnoses compared with independent diagnoses
made by mental health professionals; functional status measures; disability
days; health care use; and treatment/referral decisions.Results
A total of 825 (28%) of the 3000 individuals and 170 (29%) of the 585
had a PHQ diagnosis. There was good agreement between PHQ diagnoses and those
of independent mental health professionals (for the diagnosis of any 1 or
more PHQ disorder, κ = 0.65; overall accuracy, 85%; sensitivity, 75%;
specificity, 90%), similar to the original PRIME-MD. Patients with PHQ diagnoses
had more functional impairment, disability days, and health care use than
did patients without PHQ diagnoses (for all group main effects, P<.001). The average time required of the physician to review the
PHQ was far less than to administer the original PRIME-MD (<3 minutes for
85% vs 16% of the cases). Although 80% of the physicians reported that routine
use of the PHQ would be useful, new management actions were initiated or planned
for only 117 (32%) of the 363 patients with 1 or more PHQ diagnoses not previously
recognized.Conclusion
Our study suggests that the PHQ has diagnostic validity comparable to
the original clinician-administered PRIME-MD, and is more efficient to use.
Figures in this Article
Mental disorders in primary care are common, disabling, costly, and
treatable.1- 5
However, they are frequently unrecognized and therefore not treated.2- 6
Although there have been many screening instruments developed,7- 8
PRIME-MD (Primary Care Evaluation of Mental Disorders)5
was the first instrument designed for use in primary care that actually diagnoses
specific disorders using diagnostic criteria from the Diagnostic
and Statistical Manual of Mental Disorders, Revised Third Edition9(DSM-III-R) and Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition10(DSM-IV).
PRIME-MD is a 2-stage system in which the patient first completes a
26-item self-administered questionnaire that screens for 5 of the most common
groups of disorders in primary care: depressive, anxiety, alcohol, somatoform,
and eating disorders. In the original study,5
the average amount of time spent by the physician to administer the clinician
evaluation guide to patients who scored positively on the patient questionnaire
was 8.4 minutes. However, this is still a considerable amount of time in the
primary care setting, where most visits are 15 minutes or less.11
Therefore, although PRIME-MD has been widely used in clinical research,12- 28
its use in clinical settings has apparently been limited. This article describes
the development, validation, and utility of a fully self-administered version
of the original PRIME-MD, called the PRIME-MD Patient Health Questionnaire
(henceforth referred to as the PHQ).
DESCRIPTION OF PRIME-MD PHQ
ABSTRACT
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DESCRIPTION OF PRIME-MD PHQ
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STUDY PURPOSE
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METHODS
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RESULTS
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COMMENT
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REFERENCES
The 2 components of the original PRIME-MD, the patient questionnaire
and the clinician evaluation guide, were combined into a single, 3-page questionnaire
that can be entirely self-administered by the patient (it can also be read
to the patient, if necessary). The clinician scans the completed questionnaire,
verifies positive responses, and applies diagnostic algorithms that are abbreviated
at the bottom of each page. In this study, the data from the questionnaire
were entered into a computer program that applied the diagnostic algorithms
(written in SPSS 8.0 for Windows [SPSS Inc, Chicago, Ill]). The computer program
does not include the diagnosis of somatoform disorder, because this diagnosis
requires a clinical judgment regarding the adequacy of a biological explanation
for physical symptoms that the patient has noted.
A fourth page has been added to the PHQ that includes questions about
menstruation, pregnancy and childbirth, and recent psychosocial stressors.
This report covers only data from the diagnostic portion (first 3 pages) of
the PHQ. Users of the PHQ have the choice of using the entire 4-page instrument,
just the 3-page diagnostic portion, a 2-page version (Brief PHQ) that covers
mood and panic disorders and the nondiagnostic information described above,
or only the first page of the 2-page version (covering only mood and panic
disorders) (Figure 1).
Figure 1. First Page of Primary Care Evaluation
of Mental Disorders Brief Patient Health QuestionnaireGrahic Jump Location+View Large |
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View in Article ContextCopyright held by Pfizer Inc, but may be photocopied ad libitum.
For office coding, see the end of the article.
The original PRIME-MD assessed 18 current mental disorders. By grouping
several specific mood, anxiety, and somatoform categories into larger rubrics,
the PHQ greatly simplifies the differential diagnosis by assessing only 8
disorders. Like the original PRIME-MD, these disorders are divided into threshold
disorders (corresponding to specific DSM-IV diagnoses,
such as major depressive disorder, panic disorder, other anxiety disorder,
and bulimia nervosa) and subthreshold disorders (in which the criteria for
disorders encompass fewer symptoms than are required for any specific DSM-IV diagnoses: other depressive disorder, probable alcohol
abuse or dependence, and somatoform and binge eating disorders).
One important modification was made in the response categories for depressive
and somatoform symptoms that, in the original PRIME-MD, were dichotomous (yes/no).
In the PHQ, response categories are expanded. Patients indicate for each of
the 9 depressive symptoms whether, during the previous 2 weeks, the symptom
has bothered them "not at all," "several days," "more than half the days,"
or "nearly every day." This change allows the PHQ to be not only a diagnostic
instrument but also to yield a measure of depression severity that can be
of aid in initial treatment decisions as well as in monitoring outcomes over
time. Patients indicate for each of the 13 physical symptoms whether, during
the previous month, they have been "not bothered," "bothered a little," or
"bothered a lot" by the symptom. Because physical symptoms are so common in
primary care, the original PRIME-MD dichotomous-response categories often
led patients to endorse physical symptoms that were not clinically significant.
An item was added to the end of the diagnostic portion of the PHQ asking
the patient if he or she had checked off any problems on the questionnaire:
"How difficult have these problems made it for you to do your work, take care
of things at home, or get along with other people?" As with the original PRIME-MD,
before making a final diagnosis, the clinician is expected to rule out physical
causes of depression, anxiety and physical symptoms, and, in the case of depression,
normal bereavement and history of a manic episode.
STUDY PURPOSE
ABSTRACT
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DESCRIPTION OF PRIME-MD PHQ
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STUDY PURPOSE
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METHODS
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RESULTS
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COMMENT
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REFERENCES
Our major purpose was to test the validity and utility of the PHQ in
a multisite sample of family practice and general internal medicine patients
by answering the following questions:
Are diagnoses made by the PHQ as accurate as diagnoses
made by the original PRIME-MD, using independent diagnoses made by mental
health professionals (MHPs) as the criterion standard?Are the frequencies of mental disorders found by
the PHQ comparable to those obtained in other primary care studies?Is the construct validity of the PHQ comparable
to the original PRIME-MD in terms of functional impairment and health care
use?Is the PHQ as effective as the original PRIME-MD
in increasing the recognition of mental disorders in primary care patients?How valuable do primary care physicians find the
diagnostic information in the PHQ?How comfortable are patients in answering the questions
on the PHQ, and how often do they believe that their answers will be helpful
to their physicians in understanding and treating their problems?