“Generalized anxiety disorder (GAD) is one of the most common mental disorders; however, there is no brief clinical measure for assessing GAD. The objective of this study was to develop a brief self-report scale to identify probable cases of GAD and evaluate its reliability and validity.”
With these words, in 2006, the GAD-7 measure entered the world.
Before the-full scale rollout of the IAPT programme from about 2008/9 onwards, using the GAD-7 measure felt like a bit of a minority sport in the UK. The CORE measures (particularly the CORE-OM) were in far more common use, and pretty much the measure of choice within counselling in primary care services.
All that changed when the GAD-7, together with its sister measure for depression, the PHQ-9, were favoured as the default measures for reporting within the IAPT Minimum Dataset (MDS). Since then, though I don’t know the numbers, I think would be fair to say that GAD-7 and PHQ-9 are now the measures most commonly used in psychological therapy in the UK.
7 item screening measure of symptoms of anxiety in previous two weeks
4-point Likert scale
Response options: Not at all; Several days; More than half the days and Nearly every day, scored 0, 1, 2, and 3, respectively
Scoring range 0 – 21
Clinical cut-off: 8 (UK: IAPT)
Reliable change index (RCI): 4 (UK: IAPT)
What is it?
The Generalized Anxiety Disorder (GAD-7) questionnaire is a seven-item, self-report anxiety measure designed to identify probable cases of GAD and assess the severity of anxiety symptoms. It was developed over 2004 – 5 and tested in a network of 15 primary care sites located in 12 states in the US. [i]
The seven items were distilled from an initial pool of 13 items. Nine of these reflected the full range of symptom criteria for GAD from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). A further four items were included on the basis of a review of existing anxiety scales. After a period of rigorous testing of their relative properties, the 13 items were further refined down to the final seven.
What does it measure?
GAD-7 measures symptoms of anxiety and the extent to which the respondent has experienced them during the previous two weeks. The first three items relate to the two core criteria of the DSM-IV definition of GAD (see below). Response options are “Not at all,” “Several days,” “More than half the days,” and “Nearly every day.” These options are scored as 0, 1, 2, and 3, respectively.
Scoring the measure
The scoring range of each GAD-7 item is between 0 and 3, with 3 being the highest level of severity.
The client is guided to consider each statement and how often they have experienced feeling this way over the past fortnight. They are asked to then tick the box which corresponds most closely to their experience, using the categories at the top of each column from Not at all to Nearly every day.
A total score for the measure can be obtained by adding the totals for each column at the foot of each and adding these together in the Total Score T space shown above. This will give a figure of somewhere between 0 – 21.
What do the numbers mean?
Increasing scores represent higher levels of symptom severity. In terms of severity the following bands are commonly used:
0-5: Mild anxiety
6-10: Moderate anxiety
11-15: Moderately severe anxiety
15-21: Severe anxiety
According to the paper by Spitzer et al [i] a score of 10 or greater on the GAD-7 represents a reasonable cut point for identifying cases of GAD. Interestingly, however, in the UK, the IAPT programme guidance sets 8 and above as the cut-off for ‘clinical caseness’, and the reliable change index (RCI) at 4 points. This is the degree of change required for it to be classed as reliable i.e. change greater than might occur due to chance or measurement error.
Copyright, cost and where to obtain the measure
Copyright of the GAD-7 is held by Pfizer Inc. The measure is free to use and may be downloaded, along with the PHQ-9 and other instruments, at the PHQ website here
Instructions for both the Patient Health Questionnaire (PHQ) and GAD-7 measures can also be found on the PHQ website here
[i] Spitzer, R. L., Kroenke, K., Williams, J. B., & Löwe, B. (2006). A brief measure for assessing generalized anxiety disorder: the GAD-7. Archives of Internal Medicine, 166 (10), 1092-1097. Read the full article here https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/410326
Löwe, B., Decker, O., Muller, S., Brahler, E., Schellburg,D., Herzog, W. & Herzberg, PY. (2008). Validation and standardisation of the GAD-7 https://www.ncbi.nlm.nih.gov/pubmed/18388841
How to choose a therapy outcome measure
Introducing measures into working with clients
Made to measure: CORE
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