The medical utility of very few species of Passiflora has been scientifically studied. In initial trials for treatment of generalized anxiety disorder, Maypop extract performed as well as oxazepam but with less short-term side effects. It was recommended to follow up with long-term studies.
More Info: http://en.wikipedia.org/wiki/Passion_flower
More Info: http://en.wikipedia.org/wiki/Passion_flower