A Japanese journalist in Cuba sees decaying buildings and undernourished citizens and wonders, "Why aren't these people depressed? Why, on the contrary, do they seem positively happy?"

She asks around: "What's the secret?" To which one wag replies, "There's no order-in pizza here; we can't become hikikomori."

So hikikomori is known even in distant Cuba. It's as Japanese as anime and manga. It refers to a pathological withdrawal from all social activities into the solitary security of one's own room, often for years, sometimes for life. It's alarmingly widespread in Japan — 700,000 hard-core cases and an additional 1.5 million considered borderline, government figures for 2010 show. Many live on ordered-in food, hence the joke. To indulge in misery you need wealth, infrastructure. Cubans have neither. They can't afford to be depressed.