A randomized controlled trial of an Internet-based self-help skill strengthening (ISSS) intervention for secondary school teachers: a transdiagnostic intervention for common mental health problems

Mental health is crucial for educators, as it impacts their ability to effectively teach and engage with students. This two-arm parallel group randomized controlled trial (RCT) aims to investigate the efficacy of a transdiagnostic and low-intensity Internet-based self-help skill strengthening (ISSS) selective intervention based on problem-solving therapy (PST) for secondary school teachers with common mental health problems. Participants included secondary school teachers with probable depression/anxiety in Hong Kong. Participants were evenly randomized into the intervention and control groups based on computer-generated random number and block randomization (size of six). The primary outcomes were depressive symptoms and anxiety symptoms. Secondary outcomes included perceived stress, self-efficacy, work performance, and psychological well-being. We also tested problem solving and time management as potential mediators. There were 179 participants who finished the project (ISSS versus control = 94 versus 85). Linear mixed model showed significant main effect in time, F [2] = 11.29, p<.001, group, F [1] = 7.93, p=.007, and time by group interaction (F(2, 510.04) = 4.41, p=.013) on depressive symptoms, showing that intervention group had a greater improvement on level of depressive symptoms than control group over time. Similar results were found for anxiety symptoms, with significant main effect in time, F [2] = 13.81, p<.001, group, F [1] = 4.77, p=.032, and time by group interaction, F(2, 508.04) = 3.33, p=.037. Time management significantly and fully mediated the effects of groups on depressive symptoms at 6-month follow-up. It suggests that ISSS based on PST may be an effective transdiagnostic intervention to reduce depression and anxiety among secondary school teachers in Hong Kong. The identified underlying mechanisms can help to improve and maintain the efficacy of online PST. The RCT protocol was pre-registered at the ClinicalTrials.gov registry (NCT04564014) on September 22, 2020 prior to data collection.