Performance of the GAD-7 in adults with dissociative seizures 2022 Goldstein, Stone, Chalder, Carson et al

Highlights

• We validated the GAD-7 anxiety scale in adults with dissociative seizures (DS).
• We found high internal consistency for the GAD-7 in adults with DS.
• Factor Analysis indicated one main factor and measurement invariance for the GAD-7.
• GAD-7 has weak diagnostic utility for generalised anxiety disorder in adults with DS.
• Clinical correlations with the GAD-7 support a fear-avoidance treatment model for DS.

Abstract

Purpose
Little is known about the accuracy of the GAD-7, a self-report anxiety measure, in detecting generalised anxiety disorder (GAD) in people with dissociative seizures (DS). We evaluated the reliability, validity and uniformity of the GAD-7 using a diagnosis of GAD on the Mini-International Neuropsychiatric Interview as a reference.

Methods
We assessed 368 adults with DS at the pre-randomisation phase of the CODES trial. Factor analysis for categorical data assessed GAD-7 uniformity. Diagnostic accuracy was assessed by estimating the area under the curve (AUC). We evaluated discriminant validity, reviewed data on convergent validity and calculated internal consistency. We explored correlations between GAD-7 scores and monthly DS frequency, frequency of severe seizures and measures of behavioural and emotional avoidance.

Results
Internal consistency of the GAD-7 was high (α = 0.92). Factor analysis elicited one main factor and general measurement invariance. Diagnostic accuracy was fair (AUC = 0.72) but the best balance of sensitivity and specificity occurred at a cut-off of ≥12 and still had a specificity rate of only 68%. Discriminant and convergent validity were good. GAD-7 scores correlated positively with DS frequency, severe seizure frequency, behavioural and emotional avoidance (all p < 0.001).

Conclusion
Findings regarding internal consistency and factor structure parallel previous psychometric evaluations of the GAD-7. Correlations between GAD-7 scores and DS occurrence/severity and avoidance are evidence of the concept validity of GAD-7 and provide further support for a fear-avoidance treatment model for DS. However, the utility of the GAD-7 as a diagnostic instrument for generalised anxiety disorder is limited in patients with DS.

Open access, https://www.seizure-journal.com/article/S1059-1311(22)00270-9/fulltext