Culturally Adapted Guided Internet-Based Cognitive Behavioral Therapy for Hong Kong People With Depressive Symptoms: Randomized Controlled Trial
Authors: Pan Jia-Yan , Rafi Jonas 
Published: February 2025

Background
A significant number of individuals with depression in Hong Kong remain undiagnosed and untreated through traditional face-to-face psychotherapy. Internet-based cognitive behavioral therapy (iCBT) has emerged as a tool to improve access to mental health services. However, iCBT remains underdeveloped in Chinese communities, particularly in Hong Kong.

Objective
This study aims to (1) develop and evaluate the effectiveness of a culturally and linguistically appropriate guided iCBT program for Hong Kong Chinese with depressive symptoms, and (2) explore their treatment adherence.

Methods
An 11-week guided iCBT program, “Confront and Navigate Depression Online” (CANDO), consisting of 8 online modules, was developed and implemented for Hong Kong residents. The program was accessible via either an online platform (web-based iCBT) or a smartphone app (app-based iCBT). A 3-arm randomized controlled trial was conducted, with participants recruited through open recruitment and referrals from 2 local non-governmental organizations. A total of 402 eligible participants with mild to moderate depressive symptoms were randomly allocated into 3 groups: (1) web-based iCBT (n=139); (2) app-based iCBT (n=131); and (3) waitlist control (WLC) group (n=132), who transitioned to the web-based iCBT group after waiting for 11 weeks. Therapist support was provided by a clinical psychologist through 3 counseling sessions and weekly assignment feedback. The primary outcomes were the Beck Depression Inventory-II (BDI-II) and the 9-item Patient Health Questionnaire (PHQ-9), while the secondary outcome measures included the 12-item General Health Questionnaire (GHQ-12), the Chinese Automatic Thoughts Questionnaire (CATQ), and the Chinese Affect Scale (CAS). These scales were administered at preintervention, postintervention, and at 3-month and 6-month follow-up assessments. Data analysis was conducted using linear mixed effects modeling, adhering to the intent-to-treat principle.

Results
Participants in both the web- and app-based iCBT groups reported significant improvements compared with the WLC group on all primary (P<.001) and secondary measures (P<.001 and P=.009) at posttreatment. Large between-group effect sizes were observed in the reduction of depressive symptoms, with Cohen's d value of 1.07 (95% CI 0.81-1.34) for the web-based group and 1.15 (95% CI 0.88-1.43) for the app-based group on the BDI-II. Additionally, the web- and app-based groups showed effect sizes of 0.78 (95% CI 0.52-1.04) and 0.95 (95% CI 0.63-1.27) on PHQ-9, respectively. Medium to large effect sizes were observed for secondary outcomes at posttreatment. These positive effects were maintained at both the 3- and 6-month follow-ups, with medium to large within-group effect sizes. The adherence rate in the 2 iCBT groups was 154 out of 270 (57.0%) for completing all 8 online modules and 152 out of 270 (56.3%) for attending all 4 counseling sessions (including an intake interview). The recovery rate, as measured by the BDI-II at posttreatment, was 35 out of 90 (39%) for the web-based group and 36 out of 91 (40%) for the app-based group, compared with 3 out of 112 (3%) in the WLC group.

Conclusions
Culturally and linguistically adapted iCBT is an effective and feasible treatment for Hong Kong Chinese with mild to moderate depressive symptoms, demonstrating a satisfactory recovery rate and treatment adherence. ICBT offers an accessible and viable alternative to face-to-face interventions in Hong Kong. The Hong Kong government should allocate more resources and support the use of iCBT as a tool to treat people with depressive symptoms.

Trial Registration
ClinicalTrials.gov (NCT04388800); https://clinicaltrials.gov/study/NCT04388800