Shionogi will pay a one time fee and share costs with Shire upon approval for Japan, one of the world's most rapidly growing ADHD markets, the company said on Friday.
ADHD is among the most common child mental disorders, affecting around 3 to 5 percent of children globally. The prevalence of ADHD in Japan is almost 8 percent.
Children with ADHD are excessively restless, impulsive and easily distracted, and often have trouble at home and in school. There is no cure, but the symptoms can be kept in check by a combination of behavioral therapy and medication.
Earlier this month, U.S. researchers said stimulants used to treat ADHD do not increase the risk of heart attacks, strokes or sudden death.
Shares in Shire were down 0.64 percent at 2,021 pence on Friday.
(Reporting by Adveith Nair; editing by Rhys Jones)