Psychiatrist Rika Kayama is an outspoken doctor specializing in mental illness, a best-selling writer and a popular social commentator.
Her latest book, "Shigamitsukanai Ikikata" ("A Way of Life in Which You Don't Cling to Anything"), has sold 422,000 copies since it was published in July.
In the book, Kayama, based on her clinical experience and research, suggests 10 rules by which stressed people can live happy lives. The rules recommend people not cling to money, love or children — and not pursue dreams through employment.