Culturally Adapted Guided Internet-Based Cognitive Behavioral Therapy for Hong Kong People With Depressive Symptoms: Randomized Controlled Trial

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 accessto mental health services. However, iCBT remains underdeveloped in Chinesecommunities, particularly in Hong Kong. Objective: This study aims to (1) develop and evaluatethe 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 smartphoneapp (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 outcomeswere 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 ChineseAffect 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 effectiveand feasibletreatmentfor Hong Kong Chinesewith 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