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User:Rkang101/PHQ-9

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Development and History

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The Primary Care Evaluation of Mental Disorders (PRIME-MD) was developed in the 1990s by a group of researchers at Columbia University as a tool to screen for mental health problems in individuals seeking medical care. Its development was supported by a grant from the pharmaceutical company Pfizer. The original PRIME-MD evaluated symptoms of depression, anxiety, somatoform disorders, alcohol use, and eating disorders (12 disorders in total). The length of the original assessment limited its feasibility; consequently, a shorter version, consisting of 11 multi-part questions - the Patient Health Questionnaire (PHQ.[1]) was developed and validated. In addition to the PHQ, a nine-item version to assess symptoms of depression (PHQ-9[2]), a seven-item version to assess symptoms of anxiety (GAD-7), and a 15-item version to detect somatic symptoms (PHQ-15[1]) have been validated.

Although the PHQ is intended as a comprehensive screening tool and assesses for five symptom clusters (depressive, anxiety, somatoform, alcohol, and eating disorders), the shorter scales (PHQ-9, GAD-7, PHQ-15) can also be given together in order to evaluate multiple symptom domains. Though less commonly used, there are also brief versions of the PHQ-9 and GAD-7 that may be useful as screening tools in some settings. There is also a PHQ-SADS (somatic, anxiety, depressive symptoms) screener designed to be used in primary care settings. In recent years, the PHQ-9 has been validated for use in adolescents[1], but a version for adolescents (PHQ-A[1]) was also developed and validated.

Importantly, the PHQ and PHQ-9 have been used in a broad range of populations, including medical populations, epidemiological, geriatric, and adolescent, as screens for depression[1][3][4][5] [6].Although these tests were originally designed as self-report inventories they can also be administered by trained health care practitioners[7]. The PHQ, PHQ-9, and GAD-7 have been translated into more than 20 languages; these translated versions are available on the PHQ website (www.phqscreeners.com). Additionally, the measures have been validated in a number of different populations internationally [8][9][10].

Use of the PHQ-15 has been limited primarily to research due to the relatively small number of clinicians who specialize in somatoform disorders. Additionally, several large pharmaceutical companies use the PHQ-15 in their drug trials in the US, Australia, Germany, in the elderly population, and in veterans and active soldiers .

Versions

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All versions of the PHQ are free to use, and most versions are available in multiple languages through the parent website: http://www.phqscreeners.com[11]

PRIME-MD

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This is the original version of the measure, which has been largely phased out in favor of the new, shorter versions described below.

PHQ

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The PHQ includes modules covering depression, anxiety, alcohol use, eating disorders, and somataform disorders. Modules are scored separately to arrive at provisional DSM-IV diagnoses (important to note that this tool is intended as a screening measure and provisional diagnoses should be confirmed by a licensed clinician). The English language version of the PHQ is available here.

PHQ-9

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The PHQ-9 is a nine-item scale designed to assess symptoms of depression. Each item is scored on a 0-to-3 point scale (“not at all” to “nearly every day”). Scoring rules may vary by population; one rubric suggests that scores of 5, 10, 25, and 20 correspond to mild, moderate, moderately severe, and severe depression [2]. The English language version of the PHQ-9 is available here.

GAD-7

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The GAD-7 is a seven-item scale designed to assess symptoms of anxiety. Each item is scored on a 0-to-3 point scale (“not at all” to “nearly every day”). Cut points of 5, 10, and 15 correspond to mild, moderate, and severe anxiety [12]. The English language version of the GAD-7 is available here.

PHQ-15

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The PHQ-15 is a fifteen-item scale to assess the severity of somatic symptoms and the presence of somatoform disorders [1]. The development of the PHQ-15, a subset of the PHQ, is intended to help with the assessment of somatoform disorders[13][1]. Previous assessments of somatoform disorders required more symptoms for a diagnosis of somatoform disorder, meaning that approximately 10-20% of patients with this disorder were being accurately diagnosed [1]. Furthermore, assessments not only needed to capture more reliable and valid data by focusing on current rather than past symptoms, but also needed to update the “medically unexplained” requirement for these symptoms [1]. It is scored on a 0 (“not at all”) to 2 (“bothered a lot”) scale. Total scores range from 0 to 30, with cutpoints of 5, 10 and 15 corresponding to mild, moderate and severe somatic symptom severity, respectively [14][1]. The English language version of the PHQ-15 is available here

GAD-2

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The GAD-2 is a two-item (first two items of the GAD-7) scale to screen for anxiety [15].

PHQ-2

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The PHQ-2 is a two-item (first two items of the PHQ-9) scale to screen for depression [16].

PHQ-4

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The PHQ-4 is the combination of the PHQ-2 and the GAD-2; it is intended to screen for depression and anxiety [17]. The English language version of the PHQ-4 is available here.

PHQ-8

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The PHQ-8 is an eight-item scale developed specifically to screen for depression in American epidemiological populations [18].

PHQ-A

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The PHQ-A is a four module self report to evaluate depression, anxiety, substance use and eating disorders in adolescent primary care patients [19].

PHQ-SADS

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The PHQ-SADS is the combined PHQ-9, GAD-7 and PHQ-15 and is used to screen for depression, anxiety, and somatic symptoms at once [1]. The English language version of the PHQ-SADS is available here.

Limitations

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All versions of the PHQ described here are self reports and, consequently, are subject to inherent biases, including social desirability [20] and poor retrospective recall [21]. The influence of these biases can mitigated by following up with a structured or semi-structured interview, the gold standard for diagnostic assessment [22]. The time period assessed by each scale could also be a limitation; the PHQ-9 asks about the last four weeks, whereas the GAD-7 focuses on the past two weeks, and the PHQ asks about various time periods from the last two weeks to the last six months. Depending on the time period in question, this may or may not require a revision (i.e., if you are interested in depression over the last six months, you might alter the instructions), which could impact the validity of the measure. The scoring thresholds recommended are influenced by the samples in which they were validated and correspond with different levels of sensitivity and specificity [23], which may or may not match well with the intended use of the scale.

Research

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See Tables 1 and 2.

Table 1. Norms and reliability statistics* for the primary versions of the PHQ.

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Reliability refers to whether the scores are reproducible.

Measure Criterion Rating (adequate, good, excellent, too good*) Explanation
PHQ Norms Excellent Multiple convenience and random samples, as well as research studies in both clinical and nonclinical sample [24][25].
Internal consistency (Cronbach’s alpha, split half, etc.) Good Cronbach’s alpha reported at .88 for measuring depression [24].
Inter-rater reliability Good Kappas range from .64-.81 for depression [26]. Kappa for anxiety is .83 [26].
Test-retest reliability (stability) Not published No published studies formally checking test-retest reliability.
Repeatability Not published No published studies formally checking repeatability.
PHQ-9 Norms Excellent Multiple convenience and random samples, as well as research studies in both clinical and nonclinical samples [27][28].
Internal consistency (Cronbach’s alpha, split half, etc.) Good Cronbach’s alphas range from .83 to .89 [2][29].
Inter-rater reliability Good One study of Nigerian university students reported kappas between .83 and .92 [10].
Test-retest reliability (stability) Adequate Correlation between administrations done within 48 hours was .84 [2].
Repeatability Not published No published studies formally checking repeatability.
GAD-7 Norms Excellent Multiple convenience and random samples, as well as research studies in both clinical and nonclinical samples [1].
Internal consistency (Cronbach’s alpha, split half, etc.) Good Cronbach’s alpha reported at .92 [1].
Inter-rater reliability Good The interviewer vs. self-rated correlation ranges from .83 and .84 [1].
Test-retest reliability (stability) Good Reported as .83 [1].
Repeatability Not published No published studies formally checking repeatability.
PHQ-15 Norms Excellent Two large studies with convenience and random samples used. One research studies (N=906)  in clinical sample and one research study (N=6000)  in nonclinical sample [1].
Internal consistency (Cronbach’s alpha, split half, etc.) Excellent Cronbach’s alpha reported at .80 [1].
Inter-rater reliability Not published No published studies formally checking repeatability.
Test-retest reliability (stability Good Kappa = .60 when administration was done within 2 weeks of first test [13][1].
Repeatability Not published No published studies formally checking repeatability.

*For ratings benchmarks related to norms and reliability, see https://en.wikiversity.org/wiki/Evidence_based_assessment/Reliability

Table 2. Validity and utility statistics* for the primary versions of the PHQ.

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Validity describes the evidence that an assessment tool measures what it was supposed to measure. There are many different ways of checking validity. For screening measures, diagnostic accuracy and discriminative validity are probably the most useful ways of looking at validity.

Measure Criterion Rating (adequate, good, excellent, too good*) Explanation with references
PHQ Content validity Good Covers DSM-IV criteria for major depressive disorder, panic disorder, other anxiety disorder, bulimia nervosa, other depressive disorder, probable alcohol abuse or dependence, and somatoform and binge eating disorders [30].
Construct validity (e.g., predictive, concurrent, convergent, and discriminant validity) Adequate Construct validity has not been fully established, and more substantial evidence of convergent and discriminant validity would be helpful [31]. Validity is consistent with PRIME-MD [30].
Discriminative validity Excellent AUCs range from .89 to .92 for detecting depression [24][32].
Validity generalization Not published No published studies formally checking validity generalization.
Treatment sensitivity Not published No published studies formally checking treatment sensitivity.
Clinical utility Good The PHQ is free and can be completed independently by the patient; it assesses a wide array of mental health concerns [30].
PHQ-9 Content validity Excellent Covers the DSM-IV criteria for major depressive disorder [2].
Construct validity (e.g., predictive, concurrent, convergent, and discriminant validity) Good Higher PHQ-9 scores were correlated with greater self-reported disability days, clinic visits, health-care utilization, as well as difficulties in activities and relationships [2].
Discriminative validity Too excellent An average sensitivity of .77 and specificity of .94 (corresponding to an AUC .94) in primary care settings suggests good discriminative validity in populations that are generally not depressed, but it may not perform as well in clinical populations [28].
Validity generalization Variable A meta-analysis of 27 samples suggested that performance of the PHQ-9 is highly heterogeneous; pooled sensitivity is low and specificity is high [27].
Treatment sensitivity Good In a treatment study using three medical outpatient cohorts, the PHQ-9 has been shown to be sensitive to change over time [33].
Clinical utility Good The PHQ-9 is brief, free to use, and easy to score. It has good specificity, but the poor sensitivity could lead to false negatives [27], which is a problem for a screening tool. It is likely to perform best in samples where the prevalence of depressive disorders is high [28]. To improve clinical utility, meta-analyses suggest increasing cut score to 10 or higher to improve sensitivity [27][28].
GAD-7 Content validity Good Covers seven of the core symptoms for generalized anxiety disorder [12].
Construct validity (e.g., predictive, concurrent, convergent, and discriminant validity) Good Scores correlate with the Beck Anxiety Inventory (r= .72) and the anxiety subscale of the SCL-90 (r=.74) [1].
Discriminative validity Too excellent AUC for detecting generalized anxiety disorder was .91, for panic disorder AUC= .85 for panic disorder, AUC=.83 for social anxiety disorder, and AUC=.83 for PTSD [1].
Validity generalization Good Validity has been established across multiple populations [34][35].
Treatment sensitivity Good The GAD-7 showed good sensitivity to treatment effects in two RCTs [36].
Clinical utility Excellent The GAD-7 is brief, free to use, and easy to score [12]. It is sensitive to change following treatment [37]. There is some evidence that elderly people may require some help to complete the scale accurately [34].
PHQ-15 Content validity Good Scores correspond well to DSM-IV somatoform diagnoses from the SCID [13][14].
Construct validity (e.g., predictive, concurrent, convergent, and discriminant validity) Adequate PHQ-15 scores correlated with medically unexplained symptom counts (r=.52) measured via an independent psychiatric review [14][1].
Discriminative validity Excellent Sensitivity was 78% and specificity was 71% for a DSM-IV diagnosis of somatoform disorder, with a corresponding AUC of .76 [13].
Validity generalization Adequate Although the PHQ-15 is currently being used in major studies in several European countries and Australia, there is evidence that it does not perform as well in Hispanic populations [1][38].
Treatment sensitivity TBD Meta-analysis states that the treatment sensitivity for the PHQ-15 has not been researched much, but there is some support that the PHQ-15 is sensitive to treatment [1].
Clinical utility Good The PHQ-15 is easy to use, free, and has a high discriminant and convergent validity, it has also been validated in many different clinical populations [1].

*For ratings benchmarks related to validity, see https://en.wikiversity.org/wiki/Evidence_based_assessment/Validity

See also

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References

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  1. ^ a b c d e f g h i j k l m n o p q r s t u v w x Kroenke, Kurt; Spitzer, Robert L.; Williams, Janet B. W.; Löwe, Bernd (2010-07-01). "The Patient Health Questionnaire Somatic, Anxiety, and Depressive Symptom Scales: a systematic review". General Hospital Psychiatry. 32 (4): 345–359. doi:10.1016/j.genhosppsych.2010.03.006. ISSN 1873-7714. PMID 20633738.
  2. ^ a b c d e f Kroenke, Kurt; Spitzer, Robert L; Williams, Janet B W (2017-02-15). "The PHQ-9". Journal of General Internal Medicine. 16 (9): 606–613. doi:10.1046/j.1525-1497.2001.016009606.x. ISSN 0884-8734. PMC 1495268. PMID 11556941.
  3. ^ Li, Chunyu; Friedman, Bruce; Conwell, Yeates; Fiscella, Kevin (2007-04-01). "Validity of the Patient Health Questionnaire 2 (PHQ-2) in Identifying Major Depression in Older People". Journal of the American Geriatrics Society. 55 (4): 596–602. doi:10.1111/j.1532-5415.2007.01103.x. ISSN 1532-5415.
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  33. ^ Löwe, Bernd; Kroenke, Kurt; Herzog, Wolfgang; Gräfe, Kerstin (2004-07-01). "Measuring depression outcome with a brief self-report instrument: sensitivity to change of the Patient Health Questionnaire (PHQ-9)". Journal of Affective Disorders. 81 (1): 61–66. doi:10.1016/S0165-0327(03)00198-8. ISSN 0165-0327. PMID 15183601.
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  38. ^ Interian, Alejandro; Allen, Lesley A.; Gara, Michael A.; Escobar, Javier I.; Díaz-Martínez, Angélica M. "Somatic Complaints in Primary Care: Further Examining the Validity of the Patient Health Questionnaire (PHQ-15)". Psychosomatics. 47 (5): 392–398. doi:10.1176/appi.psy.47.5.392.


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