BEHAVIOR THERAPY 32, 751–764, 2001 005-7894/01/0751–0764$1.00/0 Copyright 2001 by Association for Advancement of Behavior Therapy All rights for reproduction in any form reserved. 751 Treatment of Panic Disorder Via the Internet: A Randomized Trial of a Self-Help Program Per Carlbring Bengt E. Westling Uppsala University Peter Ljungstrand Interactive Institute, University of Gothenburg Lisa Ekselius Uppsala University Hospital Gerhard Andersson Uppsala University and Uppsala University Hospital This controlled study evaluated an Internet-delivered self-help program plus mini- mal therapist contact via e-mail for people suffering from panic disorder. Out of the 500 individuals screened using the self-administered diagnostic instrument Compos- ite International Diagnostic Interview in shortened form (World Health Organiza- tion, 1999), 41 fulfilled the inclusion criteria. These participants were randomized to either treatment via the Internet or to a waiting-list control. The main components of the treatment were psychoeducation, breathing retraining, cognitive restructuring, interoceptive exposure, in vivo exposure, and relapse prevention. From pre- to post- test self-help, participants improved significantly more on almost all dimensions. The results from this experiment generally provide evidence for the continued use and de- velopment of self-help programs for panic disorder distributed via the Internet. As evidenced by several trials, cognitive-behavioral therapy (CBT) is a highly effective treatment for panic disorder (Barlow, Gorman, Shear, & Woods, 2000), This study was sponsored by grants from the Swedish Foundation for Health Care Sciences and Allergy Research, the Boëthius Foundation, the Swedish Council for Research in the Humanities and Social Sciences, and the Swedish Medical Research Council. We thank Elke Zuercher-White for kind permission to use parts of her book in this treatment study. Address correspondence to Gerhard Andersson, Ph.D., Department of Psychology, Uppsala University, Box 1225, SE-751 42 Uppsala, Sweden; e-mail: gerhard.andersson@psyk.uu.se