BACKGROUND: The Bergen 4-Day Treatment (B4DT) is a concentrated cognitive behaviour therapy (CBT) approach that has shown promise in treating panic disorder (PD). However, the effectiveness of the B4DT, particularly regarding long-term outcomes in rural clinical settings, remains underexplored. METHODS: A total of 58 patients were included using a naturalistic open-label trial design. Patients were assessed at 12-month follow-up. Measures included the Panic Disorder Severity Scale (PDSS), the Patient Health Questionnaire-9 (PHQ-9), and the Generalized Anxiety Disorder-7 scale (GAD-7). RESULTS: The study revealed significant and lasting reductions in PD symptoms, with a high rate of remission maintained at 12-month follow-up (82.8%). Regarding the secondary outcomes, significant improvements in symptoms of depression and generalized anxiety were also shown. CONCLUSIONS: The B4DT represents a promising treatment approach for PD, demonstrating stable long-term outcomes in rural settings. This finding supports the potential of concentrated CBT formats in achieving sustained symptom improvement in patients with PD, warranting further investigation and broader implementation. TRIAL REGISTRATION: The study was reviewed by the Regional Committee for Medical Research Ethics Northern Norway, REK North (REK Nord2021/273145).