Introduction
obsessive-compulsive, Obsessive-compulsive disorder, depressive, OCD, chronic mental illness, disability
Obsessive-compulsive disorder (OCD) is a common and chronic mental illness with a high rate of disability [Internet-based cognitive behavioral therapy (ICBT) makes online treatment available to patients. ICBT is divided into therapist-guided ICBT and self-guided ICBT. ICBT has the advantages of convenience and time saving, which can solve the problem of uneven distribution of medical resources and make up for the limitations of conventional CBT. The results of meta-analyses have shown that therapist-guided ICBT is as effective as face-to-face CBT (ffCBT) for various mental health conditions [ICBT for OCD has been generally proven to be effective. A randomized controlled trial (RCT) in 2013 showed that ICBT and the iCBT program in book format (bCBT) were more effective than the waiting treatment group (waitlist) in improving the obsessive-compulsive and depressive symptoms of patients with OCD [At present, although the number of international studies on the treatment of OCD with ICBT is gradually increasing, most RCTs conducted only set a waitlist or traditional medicine group to compare with ICBT and do not use ffCBT as the control group. In most cases, these waitlist controls are not restricted to take part in any psychotherapy or physiotherapy other than ffCBT, which introduces irrelevant variables. In addition, many current studies on ICBT for OCD are affected by comorbidities and heterogeneous medications. The latest ICBT research on OCD mainly focuses on children and adolescents, and there is a lack of research on adults. Up to now, there is no research on ICBT for OCD and its health economics analysis of OCD in China. Given these deficiencies, the efficacy and costs of ICBT for OCD in China deserve further research. Considering feasibility and cost-effectiveness, cognitive behavioral group therapy (CBGT) was set as the ffCBT active control group in this study. In a meta-analysis of CBT for OCD, individual CBT showed small and nonsignificant effect sizes (0.17) compared to CBGT and showed a noninferior efficacy of CBGT to individual CBT [The study conducted an RCT to compare the feasibility, safety, efficacy, and cost-effectiveness of ICBT, CBGT, and TAU in patients with OCD. TAU involved the administration of psychotropic medications as usual. Both ICBT and CBGT were combined with medical treatment, and patients in the ICBT or the CBGT group also took psychotropic medications as usual. The study used therapist-guided ICBT because a meta-analysis showed that therapist-guided ICBT has better effects than self-guided ICBT [The study aimed to investigate the efficacy and cost-effectiveness of ICBT related to CBGT and TAU for adults with OCD in China. The study was a noninferiority trial and hypothesized that the efficacy of therapist-guided ICBT is no less than that of face-to-face CBGT and medical treatment for OCD. In addition, ICBT was expected to be more cost-effective due to lower costs of treatment.