This study demonstrates that rates of "behavioral deviance" (conduct disturbance in school) and psychiatric disorder in ten-year-old children were twice as high in an inner London area as on the Isle of Wight. This was consistent for inner London as a whole and was true of both boys and girls. There was also a higher over-all rate of psychiatric disorder for girls and boys in the London area, with a high rate of situation-specific psychiatric disorder shown only in the home.