Background SignificanceMajor depression is the number one cause of disability worldwide. 1 The lifetime prevalence of major depression in the United States is 16.6%, but is as high as 19.8% for those in more recent birth cohorts. 2 Depression, known as a "life course" disorder, usually has its first onset in mid-adolescence, and recurs every five to seven years in 80% of individuals.3 Most people with major depression do not obtain treatment4; of those who do obtain evidencebased treatments, approximately one-third do not improve.5 -6 Depression is associated with substantial impairment both during and after the episode. Many who suffer from depression © 2010 Elsevier Inc. All rights reserved.Corresponding Author: Benjamin Van Voorhees, MD, MPH, Section of General Internal Medicine, Department of Medicine, The University of Chicago, 5841 South Maryland Blvd, Chicago, IL 60637, bvanvoor@medicine.bsd.uchicago.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.Disclosures: Benjamin W. Van Voorhees has served as a consultant to Prevail Health Solutions, Inc, Mevident Inc, San Francisco and Social Kinetics, Palo Alto, CA, and the Hong Kong University to develop Internet-based interventions. In order to facilitate dissemination, the University of Chicago recently agreed to grant a no-cost license to Mevident Incorporated (3/5/2010) to develop a school-based version. Neither Dr. Van Voorhees nor the university will receive any royalties or equity. Dr. Van Voorhees has agreed to assist the company in adapting the intervention at the rate of $1,000/day for 5.5 days. The CATCH-IT Internet site and all materials remain open for public use and made freely available to healthcare providers at http://catchit-public.bsd.uchicago.edu/. NIH Public Access Value of Technology-Based Approaches in Preventing DepressionThe Institute of Medicine (IOM) has published two major reports on the prevention of mental, emotional, and behavioral disorders18 -19 and has called for the development and rigorous evaluation of new technology based on new prevention strategies. Technologybased delivery offers considerable benefits including easy access (time and space), patient autonomy, and "non-consumable" services that are autonomous from traditional (face-toface) interventions.13 , 20 In the IOM model ( Figure 1, interventions are deployed to prevent the onset of illness in individuals who do not already meet diagnostic criteria for these disorders. Such interventions can be universal (applied to the entire population), selected (applied to those with a risk factor for disorder), and indicated (applied ...