Designing and Validating a Dual-Layer HCI Framework for OCD Mobile Training: Cognitive System Architecture and User-Centered UI with Emotional Ease

Abstract

Obsessive-Compulsive Disorder (OCD) is a chronic psychological condition affecting approximately 1.2% of adults in the United States and 1%–2% of individuals worldwide. The urgency for scalable, self- guided interventions has increased in the aftermath of the COVID-19 pandemic, especially for individuals with mild OCD-like symptoms who lack access to formal clinical care. This dissertation presents the design, implementation, and validation of HOOM, a mobile-based OCD training system grounded in cognitive behavioral therapy principles (CBT) and informed by a dual-level application of human-computer interaction principles (HCI). The system integrates (1) system-level usability engineering, such as sequential module progression and real-time task logic, with (2) UI-level emotional design strategies, including nature-inspired visuals, gamified badge feedback, and affective interface cues. These complementary HCI strategies aim to support both functional usability and emotional user comfort and engagement. To evaluate this dual-layer design, the dissertation employs a threefold validation strategy: system-level software testing confirmed efficiency, effectiveness,clarity, and accuracy of interaction logic; user-based UX testing—including surveys and open-ended feedback—validated emotional comfort, task satisfaction, and ease of use; and heuristic expert evaluation, based on Nielsen’s design principles (e.g., #4 Consistency and #8 Aesthetic & Minimalist Design), assessed whether the UI design aligned with established aesthetic and usability standards. Results demonstrate that well-established HCI principles, when applied at both system and emotional levels, can yield measurable improvements in usability and user experience. Overall, this work offers a validated, experience-centered design approach for mobile mental health interventions and provides transferable insights for future cognitive support systems in digital therapeutics.