We examined mental health and substance use outcomes at age 18 years, educational, and occupational outcomes at age 16 and 19 years, and self harm at age 21 years among 4799 participants who completed a detailed self report questionnaire on self harm at age 16 years: mean age 16 years and 8 months (SD 3 months). The postal questionnaire was sent to 9383 participants, of whom 4855 (51.7%) returned it and 4810 completed the self harm items. Data on lifetime suicidal intent accompanying self harm was missing for 11 respondents (figure). Characteristics of the subsample that responded to the self harm questionnaire have been described in detail elsewhere.2 Those who returned the questionnaire were more likely than those who did not to be female and white and to have lower parity (assessed during pregnancy), a mother with higher education (assessed during pregnancy), a higher household income, and a higher parental social class (assessed during pregnancy), and less likely to have experienced over-crowding (assessed during pregnancy) (see supplementary tables 1a and b).
