RESUMEN
OBJECTIVE: To compare the efficacy of massed vs. spaced group cognitive behavioural therapy (CBT) for patients with panic disorder with or without agoraphobia (PD). METHOD: Thirty-nine PD patients were randomly assigned to massed group CBT (daily 4-h sessions in week 1, two 2-h sessions in week 2 and one 2-h session in week 3) or traditional spaced weekly group CBT (13 consecutive, weekly 2-h sessions). The content and number of hours in the two treatment schedules were identical. Outcome was assessed after treatment, and at 3, 6 and 18 months of follow-up. RESULTS: Both treatment groups achieved significant improvement on all measures with large pre- to post-treatment and pre-treatment to follow-up effect sizes. No between-group differences were registered. Adherence and patient satisfaction did not differ between groups. CONCLUSION: The massed, 3-week group CBT schedule proved to be effective and feasible for PD patients with outcomes comparable with that of standard, spaced group CBT.