Decades before it was given a name, Michelangelo Antonioni recognized the malady we now call attention deficit disorder. In his great 1960s films, "L'Avventura," "La Notte," "Eclipse" and "Red Desert," but especially in "L'Avventura," his masterpiece, it wasn't diagnosed as a chemical imbalance, but as a communicable social disease. Stephen Holden reports.