The proposed clinical trial will be run by psychiatry researcher, Professor of Molecular Psychiatry Dr. Philip Asherson at King's College, London, UK. Professor Asherson conducted a small clinical trial of THC and CBD 1:1 in a small sample group, showing
similar effect sizes as for Ritalin in inattentive symptoms and better than Ritalin for hyperactive symptoms. Professor Asherson intends to replicate those results in a larger sample size that could generate statistical significance and establish efficacy.
You can read about that pilot study at https://www.europsy-journal.com/article/S0924-9338(17)30036-6/fulltext. Professor Aherson's bio is at https://kclpure.kcl.ac.uk/portal/philip.asherson.html