Assessing anxious features in depressed outpatients

Abstract

Both the 17-item Hamilton Rating Scale for Depression (HRSD 17) and 30-item Inventory of Depressive Symptomatology - Clinician-rated (IDS-C 30) contain a subscale that assesses anxious symptoms. We used classical test theory and item response theory methods to assess and compare the psychometric properties of the two anxiety subscales (HRSD ANX and IDS-C ANX) in a large sample (N=3453) of outpatients with non-psychotic major depressive disorder in the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study. Approximately 48% of evaluable participants had at least one concurrent anxiety disorder by the self-report Psychiatric Diagnostic Screening Questionnaire (PDSQ). The HRSD ANX and IDS-C ANX were highly correlated (r=0.75) and both had moderate internal consistency given their limited number of items (HRSD ANX Cronbach's alpha=0.48; IDS-C ANX Cronbach's alpha=0.58). The optimal threshold for ascribing the presence/absence of anxious features was found at a total score of eight or nine for the HRSD ANX and seven or eight for the IDS-C ANX. It would seem beneficial to delete item 17 (loss of insight) from the HRSD ANX as it negatively correlated with the scale's total score. Both the HRSD ANX and IDS-C ANX subscales have acceptable psychometric properties and can be used to identify anxious features for clinical or research purposes. © 2011 John Wiley & Sons, Ltd.