Table 1.

Characteristics of the four groups.

	Group
	NoCCD/noAA/D (N ¼ 112)	CCD-alone (N ¼ 42)	AA/D-alone (N ¼ 168)	CCD þ AA/D (N ¼ 182)
Mean age (SD)	21.2 (2.2)	21.7 (3.1)	22.0 (2.9)	22.6 (3.2)
Mean Shipley IQ (SD)	108.5 (8.2)	104.5 (10.3)	105.3 (7.7)	102.4 (12.2)
Mean age of onset of alcohol abuse/dependency (SD)	-*	-*	17.6 (2.4)	15.9 (2.6)
Mean antisocial problem behaviour count (SD)	3.20 (2.87)	16.24 (6.97)	11.42 (6.45)	21.08 (7.21)
Mean alcohol abuse problem count (SD)	2.99 (3.5)	15.71 (14.76)	34.07 (17.87)	42.18 (17.16)
Mean conduct disorder problem count (SD)	4.22 (3.47)	17.52 (5.70)	12.14 (5.43)	20.21 (4.69)
Marijuana abuse problem count (SD)	0.42 (2.54)	9.33 (10.14)	10.24 (11.51)	17.15 (11.74)
Drug abuse problem count (SD)	0.03 (0.28)	16.88 (27.83)	13.76 (26.18)	25.80 (31.11)

Notes: NoCCD/noAA/D ¼ a history of neither conduct disorder nor alcohol abuse or dependence; CCD-alone ¼ a history of childhood conduct disorder, AA/D-alone ¼ a history of alcohol abuse or dependence without a history of conduct disorder; CCD þ AA/D ¼ a history of childhood conduct disorder with a history of alcohol abuse or dependence.

^*Alcohol abuse/dependency was an exclusion criterion for these groups