Table S2.

Effect of Childhood Conduct Problems on Cumulative Poor Functioning, Using Different Symptoms Thresholds^a to Identify a Childhood History of Conduct Problems as Well as a Continuous Measure of Conduct Disorder Symptoms^b

	Measurement of Childhood History of Conduct Problems
	3+ Symptoms	4+ Symptoms	5+ Symptoms	Continuous Measure
	IRR (95% CI)	IRR (95% CI)	IRR (95% CI)	IRR (95% CI)
Does a childhood history of conduct problems predict cumulative poor functioning at age 18 years?
Effect of conduct problems (adjusted for sex)	1.65 (1.49, 1.82)	1.75 (1.58, 1.95)	1.96 (1.75, 2.18)	1.20 (1.17, 1.23)
Is the effect accounted for by young adult psychopathology?
Effect of conduct problems (adjusted for sex and young-adult psychopathology)	1.49 (1.37, 1.63)	1.50 (1.37, 1.65)	1.61 (1.45, 1.79)	1.15 (1.12, 1.17)
Is the effect accounted for by well-established risk factors?
Effect of conduct problems (adjusted for sex, young-adult psychopathology and well-established risk factors)	1.32 (1.21, 1.45)	1.31 (1.19, 1.45)	1.40 (1.26, 1.56)	1.11 (1.08, 1.14)
Is the effect accounted for by unmeasured familial risk factors?
Effect of conduct problems within twin pairs (adjusted for young-adult psychopathology)	1.23 (1.08, 1.41)	1.25 (1.07, 1.45)	1.30 (1.10, 1.54)	1.08 (1.01, 1.14)

Note: IRR = Incidence-rate ratio.

^aChildren were categorized as having a childhood history of conduct problems if they displayed equal to or more than the threshold number of conduct disorder symptoms at 1 or more assessment time points during childhood. Results reported in the main article using a threshold of 5+ symptoms are shown in boldface type.

^bThe continuous measure was computed by averaging conduct disorder symptoms across all assessment time points in childhood, for children with valid data at all 3 time points (n = 2,116).