Shares of ACADIA Pharmaceuticals (ACAD -1.98%) shot through the roof today, up 30% as of this filming. In the video below, Fool health-care analyst David Williamson discusses news of some great phase 3 trial results for the company's drug Pimavanserin, which treats psychosis in patients with Parkinson's disease. David tells investors how good the results were, and what advantages this drug candidate could have over its competition if it reaches FDA approval.