Adrian R. Allen, Jill M. Newby, Anna Mackenzie, Jessica Smith, Matthew Boulton, Siobhan A. Loughnan, Gavin Andrews

Internet cognitive-behavioural therapy (iCBT) for panic disorder of up to 10 lessons is well established. The utility of briefer programmes is unknown. To determine the efficacy and effectiveness of a five-lesson iCBT programme for panic disorder. Study 1 (efficacy): Randomised controlled trial comparing active iCBT (n=27) and waiting list control participants (n=36) on measures of panic severity and comorbid symptoms. Study 2 (effectiveness): 330 primary care patients completed the iCBT programme under the supervision of primary care practitioners. iCBT was significantly more effective than waiting list control in reducing panic (g=0.97, 95% CI 0.34 to 1.61), distress (g=0.92, 95% CI 0.28 to 1.55), disability (g=0.81, 95% CI 0.19 to 1.44) and depression (g=0.79, 95% CI 0.17 to 1.41), and gains were maintained at 3 months post-treatment (iCBT group). iCBT remained effective in primary care, but lower completion rates were found (56.1% in study 2 v. 63% in study 1). Adherence appeared to be related to therapist contact. The five-lesson Panic Program has utility for treating panic disorder, which translates to primary care. Adherence may be enhanced with therapist contact. None. © The Royal College of Psychiatrists 2016. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) licence.