Attacking attention deficit hyperactivity disorder (ADHD) from two different angles, thanks to a new asset just brought aboard, should help Collegium Pharmaceutical Inc. protect its revenue stream in the pesky and widespread condition. Stoughton, Mass.-based Collegium disclosed its pact March 19 with Corium Therapeutics Holdings LLC for the former to buy the latter’s Azstarys (serdexmethylphenidate and dexmethylphenidate).