Internet-delivered Cognitive-Behavioral Therapy for Generalized Anxiety Disorder: Its Effectiveness in Nationwide Routine Care (Preprint)

BACKGROUND Internet-delivered, therapist-supported Cognitive Behavioral Therapy (iCBT) is efficacious for Generalized Anxiety Disorder (GAD), but few studies have as yet reported its effectiveness in routine care. OBJECTIVE To examine whether a new 12-session iCBT program for GAD is effective in nationwide routine care. METHODS The program was free-of-charge for patients and its completion time was unrestricted. A specialized iCBT clinic delivered iCBT to 1,099 physician-referred patients. We measured symptoms with online questionnaires. The primary measure of anxiety was the GAD-7; secondary measures were, for pathological worry, the Penn State Worry Questionnaire (PSWQ) and, for anxiety and impairment, the Overall Anxiety Severity and Impairment Scale (OASIS). RESULTS Patients completed a mean 7.8 (65.1%) of 12 sessions, and 44.1% of patients completed all sessions. Effect size in the whole sample for GAD-7 was large (d=0.96; 95%CI: 0.87-1.05). For completers, effect sizes were very large, d=1.34 (95%CI: 1.25-1.53) for GAD-7, d=1.14 (95%CI:1.00-1.27) for PSWQ, and 1.23 (95%CI:1.09-1.37) for OASIS. Patients who dropped out also benefited from the treatment. Greater symptomatic relief (GAD-7) was associated with more completed sessions, older age, and being referred from private or occupational care. Of 894 patients with baseline GAD-7 score ≥10, those achieving a reliable recovery amounted to 421 (47.1%). CONCLUSIONS This nationwide, free-of-charge, therapist-supported HUS-iCBT for GAD was effective in routine care, but further research must establish comparative effectiveness and optimize the design of iCBT for GAD for different patient groups and individual patients. CLINICALTRIAL Nationwide internet-delivered computer-assisted cognitive-behavioral therapy (iCBT) for psychiatric disorders. https://www.isrctn.com/ISRCTN55123131