Assessment of Anxiety in Clinical Trials with Depressed Patients Using the Hamilton Depression Rating Scale

Background The Hamilton Depression Rating Scale (HAMD 17 ) is an outcome measure widely used in major depressive disorder (MDD) clinical trials. The objective of this analysis was to assess the validity of the anxiety/somatisation factor of the HAMD 17 as a measure of anxiety in patients with MDD. Methods We pooled data from 1466 outpatients with MDD from four 8-week controlled studies of duloxetine. We performed a factor analysis of the HAMD 17 to investigate the anxiety/somatisation factor. Results The HAMD 17 factor analysis yielded 6 factors, but did not yield the pre-specified anxiety/somatisation factor. This latter factor showed weak correlation with the Hamilton Anxiety Scale total and subscale scores at baseline (0.46), but higher correlation coefficients over the trials up to 0.81. We identified another anxiety factor that included the hypochondriasis item in this sample. Conclusion Findings from this large sample suggest that the factor structure of the HAMD 17 is unstable in MDD and that the anxiety/somatisation subscale should not be routinely used for anxiety assessment in depressed patients.