Quick rating of depressed mood in patients with anxiety disorders.

Background: Regular assessment of mood is often important for treatment but traditional measures can be time-consuming. A quick'litmus test' is needed.
Aims: To test the reliability and validity of a single-item scale for mood.
Method: Mood was measured repeatedly in 812 patients (258 in-patients, 554 out-patient) being treated in an anxiety disorders unit. Patients had self- and clinician ratings of a single-item depression scale and also rated the 21-item Beck Depression Inventory (BDI-21). Their single-item scores were compared with BDI-21 scores and with outcome measures.
Results: The single-item depression scores correlated 0.71 to 0.78 with the BDI-21 scores. Clinically useful cut-off points were identified. Depression scores at discharge, but not pre-treatment, correlated significantly with improvement in the main problem.
Conclusions: The quick single-item depression scale, whether rated by patient or by clinician, is a reasonable rough guide to mood in anxiety disorders and saves time for the patient and the clinician compared to longer measures.