Social anxiety disorder (SAD) is a common, chronic and disabling mental disorder. Cognitive Behaviour Therapy (CBT) is a highly effective treatment of SAD and internet CBT (iCBT) offers a cost-effective and convenient alternative to face to face approaches, with high fidelity and demonstrated efficacy. The aim of the current paper was to evaluate the effectiveness of an iCBT programme for SAD (The This Way Up Clinic Shyness Programme) when delivered in routine practice through two different pathways. Patients in the prescription pathway (Study 1, N=368, 50% female, mean age=34) were ‘prescribed’ the Shyness Programme by a registered practitioner of the This Way Up Clinic who supervised their progress throughout the programme. Patients in the referral pathway (Study 2, N=192, 50% female, mean age=36) were referred to the This Way Up Clinic and supervised by a specialist CBT clinician at the clinic. Intention-to-treat marginal model analyses demonstrated significant reductions in primary outcomes of social anxiety symptoms (Mini-SPIN) and psychological distress (K10), corresponding to large effect sizes (Cohen's d =.82–1.09, 95% CIs .59–1.31) and secondary outcomes of impairment (WHODAS-II) and depressive symptoms (PHQ9), corresponding to small effect sizes (Cohen's d =.36–.46, 95% CIs .19–.68) for patients in both pathways. Results provide evidence of the effectiveness of iCBT for social anxiety disorder when delivered in routine practice. 
The effectiveness of internet cognitive behaviour therapy (iCBT) for social anxiety disorder across two routine practice pathways