The Hamilton Depression Rating Scale (HDRS) is the most widely used scale for patient selection and follow-up in research studies of treatments of depression. Despite extensive study of the reliability and validity of the total scale score, the psychometric characteristics of the individual items have not been well studied. In the only reliability study to report agreement on individual items using a test-retest interview method, most of the items had only fair or poor agreement. Because this is due in part to variability in the way the information is obtained to make the various rating distinctions, the Structured Interview Guide for the HDRS (SIGH-D) was developed to standardize the manner of administration of the scale. A test-retest reliability study conducted on a series of psychiatric inpatients demonstrated that the use of the SIGH-D results in a substantially improved level of agreement for most of the HDRS items.