This randomized controlled trial investigated a tailored ICBT for young Brazilians

ICBT was effective in reducing anxiety and depressive symptoms

Large effect sizes were found for depression, stress, and insomnia symptoms

Moderate effect sizes were found for anxiety and improvements in quality of life

Anxiety and depressive disorders are highly prevalent in Brazil, with higher vulnerability among young adults. Despite the high prevalence, Brazil faces significant challenges in its mental health care system, with only a minority receiving treatment. Tailored internet-delivered cognitive behavioral therapy (ICBT) offers a promising strategy to address this treatment versus demand gap. This study examines the efficacy of individually tailored ICBT intervention with on-demand support for reducing anxiety and depressive symptoms in young adults.

This two-arm randomized controlled trial involved Brazilian young adults (aged 18–24 years) who were randomly assigned to either a treatment group (n = 46) or a waitlist control group (n = 46). The 8-week treatment included individually tailored ICBT with therapist support on-demand via chat, conducted on an online platform. Primary outcomes were symptoms of anxiety and depression. Secondary measures included stress, insomnia, smartphone and social media use, perfectionism, and quality of life. A six-month follow-up was conducted.

Multiple regression analysis indicated that the treatment group, in comparison to the control group, showed significant reductions in anxiety, depression, stress, and insomnia, as well as improvements in quality of life, with moderate to large effects sizes.

ICBT is a viable intervention for young Brazilians experiencing common mental health symptoms. Further research is needed to explore implementation and impact on other populations.

Internet-based cognitive-behavioral therapy

Anxiety

Depression

Young adults

Randomized controlled trial

© 2025 The Authors. Published by Elsevier B.V.