The documentary “Japan’s Nightmare” opens on the streets of Tokyo’s Shinjuku district with a shot of people hurrying across a busy intersection, all with similar expressions on their faces. The film discusses the growing lack of independence of Japan’s youth, who are having a hard time making the transition from the warmth of their parents’ homes into a cold, isolating society, a sluggish economy, and a difficult job market. Many are now reluctant to leave home when they reach adulthood, and instead rely on their parents for room, board, and other material necessities. But this phenomenon isn’t unique to Japan; lost youth are a global phenomenon. What is going on?