Retirement of one of the PIs and participation in another multi center study, within which the same patient inclusion criteria were used.

Panic disorder with agoraphobia is a prevalent and one of the most handicapping anxiety disorders. Although the efficacy of psychological treatment for panic disorder with agoraphobia has been the subject of a great deal of research, studies comparing cognitive-behavioral therapy and exposure in vivo have regularly been underpowered to detect small to moderate differences. Therefore, the primary purpose of the present study is to investigate if the combination of cognitive techniques with exposure in vivo is superior to the effects of exposure alone for patients with moderate to severe agoraphobia.

Anxiety disorders are the most common group of mental illnesses, with lifetime prevalence estimates ranging between 10-30% (Kessler et al 2007). They are an economic burden on society and the sixth largest cause of disability globally (Baxter et al 2014; Fineberg et al 2013). Suffering from an anxiety disorder is distressing, with affected individuals reporting adverse effects on quality of life comparable to sufferers of major depressive disorder, and in excess of the population norm (Mendlowicz and Stein 2000). Panic disorder with agoraphobia is especially prevalent and one of the most handicapping anxiety disorders.

Although the efficacy of psychological treatment for panic disorder with agoraphobia has been the subject of a great deal of research (Sanchez-Meca, Rosa-Alcazar, Marin-Martinez & Gomez-Conesa, 2010), studies comparing cognitive-behavioral therapy and exposure in vivo have regularly been underpowered to detect small to moderate differences.

Therefore, the primary purpose of the present study is to investigate if the combination of cognitive techniques with exposure in vivo is superior to the effects of exposure alone for patients with moderate to severe agoraphobia. Participants suffering from panic disorder, agoraphobia receive exposure-based treatment with elements of cognitive restructuring (CBT-group) or without such elements (Exposure-only group) delivered according to treatment manuals and in individual sessions with a maximum of 30 sessions á 50 minutes. Both treatments cover psychoeducation on the nature of anxiety and panic, interoceptive and intensified situational exposure exercises. In the CBT group identification and correction of maladaptive thoughts about anxiety and its consequences is furthermore part of the treatment package.

Inclusion Criteria:

• Diagnosis of panic disorder with agoraphobia by trained clinician using a structured interview
• The anxiety disorder is considered to be the patient's main current problem
• Age between 18 and 65 years
• The patient has agreed to participate in the study

Exclusion Criteria:

- Diagnosis of bipolar disorder, psychotic disorder, alcohol/substance abuse or dependency (within past 3 months), prominent risk of self-harm, organic mental disorder; concurrent psychotherapeutic or psychopharmacological treatment

Data will be available upon request.

Available upon request from August 2021

Researchers in the field of anxiety disorders, meta-analysis, contact: tobias Teismann