A secondary analysis was performed to examine the potential impact of pre-existing problems. We refer to these as onset models as our interest is in the effect of lifetime self harm among those not currently exhibiting symptoms of each outcome measure. For example, an observed association between self harm and later alcohol problems at age 18 years might be due, in whole or in part, to increased alcohol use at baseline. Consequently, for each outcome in turn, we flagged those who had shown evidence of pre-existing problems and examined the associations between self harm and the outcome among the problem-free participants. The indicators of pre-existing problems were specific to each outcome and utilised any available data collected during the period from age 11 to 16 years. More information is provided in the footnote to table 3.
