Internet-based treatment for panic disorder: A three-arm randomized controlled trial comparing guided (via real-time video sessions) with unguided self-help treatment and a waitlist control. PAXPD study results.

A growing body of evidence suggests that Internet-based cognitive behavioral treatments (ICBT) are effective to treat anxiety disorders. However, the effect of therapist guidance in ICBT is still under debate and guided ICBT offered in a real-time audio-video communication format has not yet been systematically investigated. This three-arm RCT compared the efficacy of guided with unguided ICBT (12 weeks intervention) and a waitlist (WL). A total of 111 individuals meeting the diagnostic criteria for panic disorder (PD) were randomly assigned to one of three conditions. Primary outcomes were the severity of self-report panic symptoms and diagnostic status. Secondary outcomes were symptoms of depression, functional impairment, catastrophic cognitions, fear of sensations and body vigilance. At post-treatment, both active conditions showed superior outcomes regarding PD and associated symptoms (guided ICBT vs. WL: d = 1.04-1.36; unguided ICBT vs. WL: d = 0.70-1.06). At post-treatment, the two active conditions did not differ significantly in self-reported symptom reduction (d = 0.21-0.54, all ps > 0.05), but the guided treatment was superior to the unguided treatment in terms of diagnostic status (χ2 (1) = 13.15, p < 0.01). Treatment gains were maintained at successive follow-ups and the guided treatment became superior to the unguided treatment at 6 months follow-up (d = 0.72-1.05, all ps < 0.05).