HMM: Gender gap in teenage depression is twice as large in London as in Tokyo, study finds.. “By the age of 16, the difference in depressive symptoms between boys and girls in London was around twice as large as in Tokyo. The average level of depressive symptoms in teenage boys in Tokyo declined between the ages of 11 and 16, whereas for boys in London it increased slightly over time, following a similar trajectory to that of teenage girls in Tokyo.” Well, Tokyo doesn’t have English-language media.