Reliability and validity of a structured interview guide for the Hamilton Anxiety Rating Scale (SIGH-A)

The Hamilton Anxiety Rating Scale, a widely used clinical interview assessment tool, lacks instructions for administration and clear anchor points for the assignment of severity ratings. We developed a Structured Interview Guide for the Hamilton Anxiety Scale (SIGH-A) and report on a study comparing this version to the traditional form of this scale. Experienced interviewers from three Anxiety Disorders research sites conducted videotaped interviews using both traditional and structured instruments in 89 participants. A subset of the tapes was co-rated by all raters. Participants completed self-report symptom questionnaires. We observed high inter-rater and test-retest reliability using both formats. The structured format produced similar but consistently higher (+ 4.2) scores. Correlation with a self-report measure of overall anxiety was also high and virtually identical for the two versions. We conclude that in settings where extensive training is not practical, the structured scale is an acceptable alternative to the traditional Hamilton Anxiety instrument.