I have yet to do data collecting research specifically on THT and EZDS. However, THT is a mindfulness exercise which is a form of cognitive behavior therapy. There is already research data out there on mindfulness, so you can find some here.
Mindfulness Training Improves Working Memory Capacity and GRE Performance While Reducing Mind Wandering
Randomized Controlled Trial of Mindfulness Meditation for Generalized Anxiety Disorder: Effects on Anxiety and Stress Reactivity
Mindfulness-based interventions in schools—a systematic review and meta-analysis
Students and Teachers Benefit from Mindfulness-Based Stress Reduction in a School-Embedded Pilot Study
Mindfulness Matters: Can Living in the Moment Improve Your Health?