Elsevier

General Hospital Psychiatry

Volume 39, March–April 2016, Pages 24-31
General Hospital Psychiatry

Screening for anxiety disorders with the GAD-7 and GAD-2: a systematic review and diagnostic metaanalysis

https://doi.org/10.1016/j.genhosppsych.2015.11.005Get rights and content

Abstract

Objective

To systematically review the accuracy of the GAD-7 and GAD-2 questionnaires for identifying anxiety disorders.

Methods

A systematic review of the literature was conducted to identify studies that validated the GAD-7 or GAD-2 against a recognized gold standard diagnosis. Pooled estimates of diagnostic test accuracy were produced using random-effects bivariate metaanalysis. Heterogeneity was explored using the I2 statistic.

Results

A total of 12 samples were identified involving 5223 participants; 11 samples provided data on the accuracy of the GAD-7 for identifying generalized anxiety disorder (GAD). Pooled sensitivity and specificity values appeared acceptable at a cutoff point of 8 [sensitivity: 0.83 (95% CI 0.71–0.91), specificity: 0.84 (95% CI 0.70–0.92)] although cutoff scores 7–10 also had similar pooled estimates of sensitivity/specificity. Six samples provided data on the accuracy of the GAD-2 for identifying GAD. Pooled sensitivity and specificity values appeared acceptable at a cutoff of 3 [sensitivity: 0.76 (95% CI 0.55–0.89), specificity: 0.81 (95% CI 0.60–0.92)]. Four studies looked at the accuracy of the questionnaires for identifying any anxiety disorder.

Conclusions

The GAD-7 had acceptable properties for identifying GAD at cutoff scores 7–10. The GAD-2 had acceptable properties for identifying GAD at a cutoff score of 3. Further validation studies are needed.

Introduction

Anxiety disorders are common and debilitating conditions. A total of 14–29% of people will experience an anxiety disorder during their lifetime and there is evidence that they reduce quality of life, impact upon occupational functioning and are associated with increased morbidity [1], [2], [3], [4].

Most people with anxiety disorders will be seen in primary care [5]. Despite this, observational studies indicate that anxiety disorders are underdiagnosed and undertreated in this setting [6], [7]. Recently, it has been suggested that care might be improved if clinicians used standardized questionnaires in order to identify patients with anxiety disorders who have not previously been recognized [8]. Often a distinction is drawn between screening (offering a test to an entire population at risk) and case finding (offering a test to those at highest risk of having the condition). Those in favor of identifying anxiety disorders in this way argue that it would improve diagnosis and treatment rates and lead to improved outcomes for patients [9]. Advocates also argue that there may be a benefit to the wider economy via the reduction of unnecessary healthcare costs associated with undiagnosed mental health problems and an increase in productivity [3], [10]. However, there is considerable uncertainty about the value of screening for mental health problems [11], [12] and the lack of evidence for screening and case finding for anxiety disorders has been noted [13].

Critics of screening suggest that too little attention has been paid to the harms of screening to those who are incorrectly diagnosed as having a mental health problem (false positives) [14], [15]. Harms include the stigma of being diagnosed with a mental health problem and unnecessary (and costly) interventions such as drug or psychological treatment. These patients may not only be subjected to the harms of unnecessary treatment but may also divert scarce healthcare resources away from those with genuine mental health problems [14], [15]. Underresourced mental health services are another concern to those opposing screening for mental health problems. Critics argue that mental health services are already stretched and it is therefore unethical to screen for mental health problems when adequate treatment and follow-up would be unavailable for the majority of patients identified [14], [15].

Much of the argument surrounding screening for mental health problems has focused upon depression. Few randomized controlled trials have examined the efficacy of screening for anxiety disorders. Before the effectiveness of screening for anxiety disorders can be fully evaluated, an accurate screening tool with an agreed cutoff score must be identified [16]. One potential candidate for this is the GAD-7 questionnaire [17]. Herr et al. [18] conducted a systematic review of screening tools and concluded that the GAD-7 had the best performance characteristics for identifying generalized anxiety disorder (GAD) in comparison to other measures. This conclusion was based upon the results of the original validation study by the authors of the questionnaire [17]. The GAD-7 was originally validated in a primary care sample and a cutoff score of 10 (which the authors considered optimal) had a sensitivity value of 0.89 and a specificity value of 0.82 for identifying GAD. The authors of the questionnaire also found acceptable sensitivity and specificity values when the questionnaire was used as a general screen to identify other anxiety disorders (Panic Disorder, Social Anxiety and PTSD) (GAD-7, score ≥ 8: sensitivity: 0.77, specificity: 0.82). The short-form version of the GAD-7 questionnaire, the GAD-2, may also be used as a screen for anxiety [19]. Given the time constraints of consultations, it is of value to look at the accuracy of this measure in addition to the GAD-7. When validated in the same primary care sample, the authors of the questionnaire considered a cutoff score of 3 as optimal, which produced a sensitivity value of 0.86 and a specificity value of 0.83 for identifying GAD [19]. The GAD-2 had a sensitivity of 0.65 and a specificity of 0.88 when used as a more general screen for anxiety disorders.

In the UK, NICE recommended the use of the GAD-2 as a tool to help assess anxiety disorders [13]. This recommendation was based on the results of the original validation papers by the authors of the questionnaire [17], [19]. In addition, recent guidance in America recommended case finding for anxiety using the GAD-7 in cancer patients [20], [21]. While the results of the original validation study for these measures are promising, it is important to compile information on diagnostic accuracy from other validation studies. We conducted a systematic review and diagnostic metaanalysis of studies that used the GAD-7 or GAD-2 questionnaires as screening or case-finding tools for identifying GAD or any other anxiety disorder. Collating diagnostic test accuracy information from all studies will help to establish if these tools should be recommended for the purpose of screening or case finding.

Section snippets

Methods

A systematic review of the literature was performed. A protocol for the study was published in the PROSPERO international register for systematic reviews (registration number CRD42014006494). We followed Centre for Reviews and Dissemination guidance [22] in the conduct of the review and PRISMA guidance [23] in the reporting of the review.

Results

A total of 2344 citations were screened for eligibility once duplicates had been removed. Full text was obtained for 24 citations of which 10 were excluded (see Fig. 1). Reasons for exclusion were as follows: three studies did not compare the GAD-7/GAD-2 to a suitable ‘gold standard’ clinical interview [31], [32], [33]; two studies did not use the GAD-7 or GAD-2 in their analysis [34], [35]; two studies were commentaries and did not conduct original research [36], [37]; one study (comprising

Discussion

National clinical guidance in the UK and US recommends the use of the GAD-7 and GAD-2 questionnaires for case finding [13], [20]. This paper sought to summarize the diagnostic test accuracy of these measures to determine if their use as screening or case-finding tools should be advocated. A systematic review and synthesis of studies looking at the accuracy of the GAD-7 and GAD-2 questionnaires for identifying GAD and other anxiety disorders was undertaken. A total of 14 citations (12 samples)

Conclusions

If the GAD-7 is to be used for identifying GAD, clinicians may wish to consider using a lower cutoff score of 8 or 9 in order to optimize sensitivity. A cutoff score of 3 appears to provide the highest sensitivity/specificity balance for the GAD-2 identifying GAD. If the GAD-7 is to be used for identifying any anxiety disorder, a cutoff score of 8 looks to provide reasonable sensitivity and specificity. However, due to the small number of studies found, this requires further investigation.

Financial support

None, this project was undertaken by the first author as part of a postgraduate master’s degree.

Acknowledgements

The authors thank the Department of Health Sciences at the University of York for funding the master’s degree through which this project was undertaken by the first author.

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  • Cited by (0)

    Conflicts Of Interest: None.

    1

    Present address: Leeds Institute of Health Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom.

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