The usefulness of the Zung Self-Rating Depression Scale as a screening instrument to uncover masked depression, and the benefits of early identification and treatment with alprazolam, were evaluated in a general medical practice population. There was a 95% scale acceptance by patients and a 12% overall prevalence of depression based on SDS results. Patients who scored in the depressed range on the SDS were, on a randomized basis, either identified immediately to their physicians and treated with alprazolam (N = 21) or identified after 4 weeks (natural history controls, N = 20). Treatment resulted in improvement in 66% of the identified group versus a 35% spontaneous improvement in the control group (p less than .05).