Three different methods of measuring depression were studied in ten severely depressed patients. Serial assessments were made using the Beck Depressive Inventory (self-rating scale), the Hamilton Rating Scale (physician-rated scale), and objective behavioral measures. The hypothesis was that these three methods would show a significant correlation; the study confirms this. The behavioral measures are an inexpensive method of assessing the depth of depression and seem to predict the posttreatment adaptation better than the Beck Depressive Inventory or the Hamilton Rating Scale. Behavioral measures should be useful in future research to assess the results of drug or somatic therapies.