Overall Critical View
The three studies reviewed—Matsumoto et al. (2024), and Du et al. (2021 ) Hedman-Lagerlöf et al. (2023), have illustrated the advantage of using multiple methodological approaches to understand Cognitive Behavioural Therapy (CBT), they have also highlighted the inherent trade-offs between them.
The randomised controlled trial (RCT) by Matsumoto et al. (2024) represents the gold standard for establishing causal relationships. Through random assignment, the study could confidently attribute symptom reductions in social anxiety to the unguided internet-based CBT program, rather than to extraneous factors. This was a major strength, especially when dealing with psychological interventions where placebo effects, expectancy, and self-selection often complicate findings. However, the trial’s limitations were also notable. Follow-up was brief, so researchers lacked an opportunity to evaluate the survival of improvements, and only targeted the cohort of adolescents with subthreshold social anxiety disorder and young adults. In this way, it can only be said to have a limited external validity, that is, its doubtful about whether it could have been applied to any clinical population, as well as health systems outside Japan.
Another relatively novel concept that was introduced in the qualitative study of Du et al. (2021) was the patient perspective. By thematically analysing interviews, the study showed barriers more frequently neglected in quantitative research, including dissatisfaction with limited human support and the difficulty of accessing technology in NHS Scotland. These findings were useful and supplementary to trial data, as they indicated implementation factors, such as referral pathway and user experience, which accounted for the success of CBT interventions in real-life scenarios. This, of course, was the limitation of such insights, as since they were context-specific, they couldn’t be generalised.
Conversely, the systematic review and meta-analysis provided by Hedman-Lagerlof et al. (2023) summarised the results of 31 RCTs and thereby presented scope and statistical accuracy. The quality of the pooled evidence was sufficient confirmation that therapist-guided ICBT was relatively identical in terms of its effectiveness to conventional face-to-face CBT. This had significant policy implications and indicates that to curb shortages of resources in mental health services, digital delivery can help without compromising results. However, meta-analysis served as a vulnerability of its studies. The interpretation was complicated due to the high heterogeneity of target conditions, delivery format, and outcome measures. Furthermore , publication bias can spur reported efficacy, and it appears that, because controlled research settings were used, there was limited confidence in the applicability in everyday clinical practice.
Taken together, the three methodologies formed a complementary evidence base: the RCT offered internal validity, the meta-analysis provided breadth and synthesis, and the qualitative study contributed contextual depth. The combination demonstrated that while CBT was effective across formats, future research must bridge methodological divides to ensure findings are both causally robust and practically applicable.