EVIDENCE-BASED ANSWER
The GAD-7 has the best evidence and utility in the primary care setting for generalized anxiety disorder (strength of recommendation [SOR]: A), while the proprietary Quick PsychoDiagnostics Panel (QPD) has the best operating characteristics for panic disorder (SOR: B).
Clinical commentary
These time-savers can narrow the options
Jon O. Neher, MD
Valley Family Medicine, Renton, Wash
The family physician’s office is awash with psychosocial problems—sometimes intertwined with physical illness, sometimes just noted as a smoldering comorbidity. Clearly, when you strongly suspect a patient’s chief complaint is due to anxiety or panic, a focused interview that adheres to Diagnostic and Statistical Manual of Mental Disorders, 4th ed (DSM-IV) is the gold standard for making the diagnosis. However, validated questionnaires are helpful time savers in a busy practice and they assure a certain baseline level of thoroughness. They are also helpful in narrowing the diagnostic options when the presenting complaint is vague and multiple diagnoses are being entertained.
Evidence summary
All diagnoses of generalized anxiety disorder and panic disorder are clinical; they require the clinician’s judgment of objective findings. This Clinical Inquiry assesses the accuracy of case finding for these disorders, using screening tools, against the reference standard of a structured interview established by the criteria of the DSM-IV.
The TABLE compares the tools discussed here. Sensitivity, specificity, and likelihood ratios are calculated according to the authors’ designated cut points for the tools’ scores.
None of the authors recommend using these tools alone to make a diagnosis; clinicians must combine these instruments with an office interview to establish their diagnosis.
TABLE
How the anxiety and panic disorder screening tools stack up
| DISEASE | TOOL | Sn (%) | Sp (%) | LR+ | LR– | SAMPLE SIZE |
|---|---|---|---|---|---|---|
| Generalized anxiety disorder | GAD-71 | 89 | 82 | 4.9 | 0.13 | 965 |
| ASQ-152 | 93 | 96 | 23.3 | 0.07 | 250 | |
| QPD3 | 79 | 90 | 7.9 | 0.23 | 203 | |
| Panic disorder | QPD3 | 71 | 97 | 23.7 | 0.30 | 203 |
| MHI-54 | 100 | 65 | 2.9 | 0 | 246 | |
| PDSR5 | 89 | 100 | ∞ | 0.11 | 139 | |
| Sn, sensitivity; Sp, specificity; LR+, positive likelihood ratio; LR–, negative likelihood ratio. | ||||||
GAD-7 tool is brief and in the public domain
For diagnosing generalized anxiety disorder, the GAD-7 has the best evidence for its utility. It was studied in a large, primary care–based sample size, is brief, and is in the public domain. It has a positive likelihood ratio of 4.9 (ie, the odds that a person has generalized anxiety disorder are 4.9 times higher if the GAD-7 is positive).1
The Anxiety Screening Questionnaire (ASQ-15) also has good likelihood ratios, but the sample population was small, selected, and over half of the subjects were from a psychiatric practice.2 The QPD has similar likelihood ratios to the GAD-7, but it requires purchase of proprietary software, and the supporting evidence is based on a small, selected, and compensated study group.3
Likelihood ratios are good for QPD and panic disorder
Panic disorder research yielded 3 screening tools: QPD, the Mental Health Index 5 (MHI-5), and the Panic Disorder Self-Report (PDSR).
- The QPD reports an excellent positive likelihood ratio and good negative likelihood ratio for panic disorder. As mentioned above, these results are limited by the quality of its sample size and the expense.3
- The MHI-5 screens for panic disorder with a single item taken from a larger questionnaire for panic disorder and depression. It has 100% sensitivity but a poor positive likelihood ratio. The sample size was very small—only 9 persons with panic disorder were tested.4
- The PDSR shows 100% specificity at the recommended cut-off point and a good negative likelihood ratio. Its weaknesses are a small study size, the homogeneity of the study population, who were self-selected, as well as the lengthiness of the questionnaire.5
Recommendations from others
A clinical practice guideline from the National Institute for Health and Clinical Excellence (UK) recommends a screening tool and structured interview or clinician consultation to establish a DSM-IV diagnosis for anxiety disorders. It reviews several ratings scales without grading utility or accuracy.6
The American Psychiatric Association has one guideline specifically addressing panic disorder, with a short paragraph describing the use of the DSM-IV via a structured interview to establish the diagnosis.7