The use of visual analog scales in mood disorders: a critical review.

Patient-rated visual analog scales are a useful tool in the measurement of mood. The historical development of such scales and their design are reviewed. The simplicity of these scales promotes high compliance and, in addition, they have been shown to be both reliable and valid. While clinician-rated measurements of mood are an accepted standard, self-report of symptoms provides complementary and important information about the course and variability of illness from the patient's perspective.